technical workshop on holistic responses to the need for resilient
TRANSCRIPT
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WORKSHOP REPORT
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LIST OF PARTICIPANTS
Name Agency/Organization
Abinales, Adam Association of Structural Engineers of the Philippines (ASEP)
Ambrosio, Ma. Nelia Housing Technology Design Office – National Housing Authority (HTDO-NHA)
Bañares, Eliezer Vicente Habitat for Humanity Philippines – CDO
Bautista, Edgar Freedom to Build (FTB)
Benavidez, Cecil Hilti Foundation
Cailing, Kathrin Department of Public Works and Highways (DPWH) – Bureau of HousingDesign
Calimlim, Elsa Juliana Social Housing Finance Corporation (SHFC)
Cinco, Thelma Philippine Atmospheric Geophysical and Astronomical ServicesAdministration (PAGASA)
Columna, Virgilio ASEP
Gabitan, Rey United Architects of the Philippines (UAP)
Germar, Fernando University of the Philippines Diliman - Building Research Service
Gilles, Stephanie UAP
Ison, Ronaldo ASEP
Jacobe, Ethel SHFC
Lanting, Janine Monica Hilti Foundation
Libutaque, Villa Mae Technical Assistance Movement for People and the Environment, Inc(TAMPEI)
Lo, Dexter Engineering Resource Center – Xavier University (ERC-XU)
Manzano, Liza Socorro Mines and Geosciences Bureau (MGB) – Central Office
Miranda, Jose UAP-Alabang ChapterUAP Emergency Architects
Narag, Ishmael Seismological Observation and Earthquake Prediction Division –Philippine Institute of Volcanology and Seismology (SOEPD-PHIVOLCS)
Peralta, Meredel HTDO-NHA
Penarubia, Henremagne SOEPD-PHIVOLCS
Quebral, Ramon AMH (Philippines), Inc.
Regala, Ma. Benita HTDO - NHA
Salzer, Corinna Hilti Foundation
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Schegg, Regula Hilti Foundation
Tamayo, Miriam ASEP
Tan, Charlie FTB
Tomas, Celso Jr. Technical Services Department – SHFC
Tutor, Florencio DPWH – Bureau of Research and Standards
Ubongen, Warren UN Habitat
Velasco, Jan
Villaraza, Carlos ASEP
Walt, Bruno Hilti Foundation
Zambrano, Albert Mapua Institute of Technology
Miclat, Sylvia Environmental Science for Social Change (ESSC)
Soriaga, Rowena ESSC
Annawi, Dallay ESSC
De Jesus, Mariel ESSC
Labrador, Joseph ESSC
Legal, Iris ESSC
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TABLE OF CONTENTS
I. ABOUT THE TECHNICAL WORKSHOP .............................................................................................5
A. THE CENTRALITY OF HOUSING IN PEOPLE’S LIVES AND THE NEED FOR MULTI-STAKEHOLDERS’ COLLABORATION ....................................................................................................5
B. SUPPORTING UNIFIED SOLUTIONS TO LOW-COST HOUSING: CONTRIBUTIONS OF THEASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES ....................................................5
C. UNPACKING “TECHNICAL WORKSHOP ON HOLISTIC SOLUTIONS TO THE NEED FORRESILIENT LOW-COST HOUSING”.......................................................................................................6
D. RATIONALE OF THE WORKSHOP ................................................................................................6
II. POLICIES AND PRACTICES RELATED TO LOW-COST HOUSING SITE SELECTION-SITE PLANNING,HOUSE DESIGN AND CONSTRUCTION THAT NEED REVIEW AND BETTER IMPLEMENTATION ............7
A. SOME LESSONS LEARNED...........................................................................................................7
B. POLICIES AND PRACTICES NEEDING REVIEW AND CHANGE .....................................................9
C. SOME STRATEGIES TO ADDRESS CRITICAL GAPS AND STAKEHOLDERS INVOLVED ...............13
D. EMERGING COLLABORATIVE ACTIONS ....................................................................................15
II. HAZARD SCENARIOS.....................................................................................................................16
A. SEVERE RISK MODELING ..........................................................................................................16
B. THE GEOHAZARD ASSESSMENT AND MAPPING PROGRAM OF THE MINES ANDGEOSCIENCES BUREAU .....................................................................................................................19
C. EARTHQUAKE HAZARDS AND SCENARIOS ..............................................................................23
III. EXPERIENCES IN HOUSING CONSTRUCTION, HOUSING SITE SELECTION, PLANNING ANDDEVELOPMENT .....................................................................................................................................26
A. TACKLING THE NEED FOR RESILIENT LOW-COST HOUSING HOLISTICALLY: INSIGHTS INTO APILOT PROJECT..................................................................................................................................26
B. PERFORMANCE ASSESSMENT OF RESIDENTIAL STRUCTURES ................................................29
C. REBUILDING POST-TROPICAL STORM SENDONG: CAGAYAN DE ORO EXPERIENCE ..............31
D. THE EXPERIENCE OF XAVIER ECOVILLE ....................................................................................33
E. THE EXPERIENCE OF DE LA COSTA HOUSING V: A PROJECT BY FREEDOM TO BUILD, INC ....35
F. INTEGRATING THE LANDSCAPE IN HOUSING SITE SELECTION AND SITE PLANNING .............38
IV. HOUSING-RELATED POLICIES ...................................................................................................41
A. STANDARDS FOR HOUSING DESIGN AND CONSTRUCTION ....................................................41
B. DENR ADMINISTRATIVE ORDER 2000-28 – REQUIRING THE CONDUCT OF ENGINEERING,GEOLOGIC AND GEOZAHARD ASSESSMENT (EGGA) FOR HOUSING PROJECTS AS AN ADDITIONALREQUIREMENT FOR THE ENVIRONMENTAL COMPLIANCE CERTIFICATE .......................................46
C. THE VALLEY FAULT SYSTEM AND SEISMIC GAPS: WHY THE STRUCTURAL CODE OF THEPHILIPPINES SHOULD BE REVISED....................................................................................................50
D. DRAFT HOUSING CODE.............................................................................................................52
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I. ABOUT THE TECHNICAL WORKSHOP
On 2 – 3 April 2014, Environmental Science for Social Change (ESSC) and the Association of StructuralEngineers of the Philippines (ASEP), with the support of Hilti Foundation and the United NationsEconomic and Social Commission for Asia and the Pacific (UNESCAP), facilitated a technical workshopon holistic responses to address the need for resilient low-cost housing.
This workshop brought together technical professionals involved in different aspects of low-costhousing development:
- Government regulatory bodies that implement housing-related policies and programs, andtechnical agencies that observe, analyze and monitor natural hazards (including trends andpossible hazard scenarios);
- Implementers of low-cost housing projects, including those from private sector foundationsand professional associations; and,
- Research and academic institutions working on disaster risk reduction and housing standards.
The technical workshop is part of a dialogue series to encourage exchanges between differentstakeholders and disciplines on how low-cost housing initiatives can be made more holistic, safe andresilient. Specifically, the activity aimed to take stock of housing policy and implementation gapsconsidering different hazard scenarios, and lay down a process for developing a “unified approach”for addressing the most critical gaps. The outcome of this workshop and the series of follow updiscussions and activities are going to feed into the draft national (Residential) Housing Code and aplanned national-level multi-stakeholder and multi-disciplinary gathering to be held in the last quarterof this year.
A. THE CENTRALITY OF HOUSING IN PEOPLE’S LIVES AND THE NEED FOR MULTI-STAKEHOLDERS’ COLLABORATIONBruno Walt, Hilti Foundation
Hilti Foundation expressed pleasure at the gathering of stakeholders involved in affordable housing,which is one of the programs that Hilti Foundation is engaged in. Owning a house for a family is a keyfactor as it can serve as a base to run a small company and generate income and wealth for a family.Related to housing is access to clean drinking water and sanitary facilities, which are recognized bythe United Nations as basic human rights. By collaborating, stakeholders from different fields can pooltogether and share their capacities, expertise and experiences as well as resources to find responsesto the problems related to low-cost housing. The problems are numerous and have many dimensionsthat no organization can solve them on its own.
B. SUPPORTING UNIFIED SOLUTIONS TO LOW-COST HOUSING: CONTRIBUTIONS OF THEASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINESVirgilio Columna, Association of Structural Engineers of the Philippines
ASEP has been doing its part in nation building, particularly in the advocacy for better structuralstandards, through the preparation of the National Structural Code of the Philippines (NSCP). TheNSCP is a referral code of the National Building Code (NBC). Through the years, ASEP has beendiligently upgrading the NSCP: it is now on its 6th edition and ASEP is preparing the 7th edition. ASEPalso prepared and submitted a final draft of Volume 2 (Bridge Code), and is coming up with Volume 3(Housing Code). The drafting of the Housing Code has been started, and inputs from this forum aregoing to be integrated in the code.
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Unified solutions for a commonly envisioned resilient housing structure can be developed through thecollaboration of people from different professions and areas of expertise. The solutions are not onlyabout the specifications and construction, but also include the assessment of the location andcollection of pertinent data needed to design resilient structures to be built in different parts of thecountry. Addressing the perennial disaster-related problems requires pooling of resources, talents,time and hearts. There are a lot of organizations (private and government) that are preparing plansand different shelters approaches, hence, the need for a holistic approach.
C. UNPACKING “TECHNICAL WORKSHOP ON HOLISTIC SOLUTIONS TO THE NEED FORRESILIENT LOW-COST HOUSING”Sylvia Miclat, Environmental Science for Social Change
Zeroing in on the theme of the technical workshop, the workshop is technical in that it is a gatheringof engineers, architects and hazard specialists. Ultimately, it is social as it is about people.
The objective is to look at holistic responses – solutions that are integrated, coherent andcomprehensive – in which engineering solutions is one of the responses. Many solutions are beingproposed by different groups, and these need to be put together.
As part of a unified approach, the solution must not simply be going back to where people werebefore. Resilience is not just bouncing back, but moving forward with better designs, structuralstrength and safer locations to increase people’s safety.
Low-cost housing is where the greatest needs are, with vast number of people in the margins exposedto high risks. Many of these families want to stretch savings to acquire a piece of land, or are givenpoor lands to take on. LGUs have to review their land use plans, to integrate the landscape, climatechange impacts and livelihoods in low-cost housing responses.
D. RATIONALE OF THE WORKSHOPCarlos Villaraza, Association of Structural Engineers of the Philippines
Each of the participants was chosen based on his/her area of expertise, and participation in theworkshop was encouraged based on one’s personal/professional capacity, not necessarily as anofficial representative of his/her agency or organization.
There is a need to have a unified effort, sharing of expertise of each one to come up with a resilientdesign. There are questions about climate change, but it is not the workshop’s agenda to debatewhether or not the stronger typhoons that the country has been experiencing are a result of climatechange. Rather, the workshop aims to discuss what is needed to make the houses safe from extremeevents, and extreme events must have scientific basis.
The workshop is a preliminary activity leading to a national dialogue to be held in the last quarter of2014. The next steps building up to a broader stakeholders’ dialogue depend on the outcome of thetechnical workshop. Participation during the national dialogue will be broadened to otherstakeholders in low-cost housing development, such as government agencies in the housing sector,private developers, community associations and homeowners associations. With the support ofUNESCAP, the knowledge and lessons to be shared during the workshop and national dialogues canbe shared with other Asian countries exposed to similar hazards.
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II. POLICIES AND PRACTICES RELATED TO LOW-COST HOUSING SITE SELECTION-SITE PLANNING, HOUSE DESIGN AND CONSTRUCTION THAT NEED REVIEWAND BETTER IMPLEMENTATION
The following summarizes points raised during breakout group workshop sessions to answer thefollowing questions:
- What have we learned about structural resilience of residential low-cost housing and supportinfrastructure (materials, design standards, execution) to mixed hazards of typhoon winds,flash flooding, landslides, storm surges and earthquakes?
- Considering different hazard scenarios, what are the gaps in:o low-cost housing site selection, planning and development practices?o housing design and construction standards?
- What housing-relatedpolicies standards,requirements andprotocols need improve-ment/changing or betterenforcement consideringthe evidence base fordifferent hazard scenariosand impacts?
- Who can help promotethe use of these proposedcriteria and protocols inhousing programs, andhow?
A. SOME LESSONS LEARNED
1. Some policies and regulatory standards in low-cost housing were instituted after majordisasters. Rather than being reactive to destructive events, there is a need to shift to a pro-active mindset to ensure safe low-cost housing and prevent loss of lives and properties.
o Administrative Order No 28, series of 2008 – which required the conduct of anengineering, geologic and geohazard assessment (EGGA) as an additional requirementfor housing projects in the application of the Environmental Compliance Certificate(ECC) – was issued in response to the Cherry Hills Subdivision landslide tragedy.
o Following the flooding of some relocation in Rodriguez, Rizal during the habagatrainfall in 2012, the Chair of the Housing and Urban Development CoordinatingCouncil (HUDCC) reminded the housing agencies to review the government’srelocation sites and to strictly implement the geohazard assessment by the Mines andGeosciences Bureau in subsequent relocation sites.
o The widespread destruction of houses and buildings wrought by the strong winds ofTyphoon Yolanda calls for better standards in housing design.
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2. Site selection, site planning and building design must be informed by a comprehensiveidentification and assessment of all hazards that may affect a site.
o In assessing the susceptibility of a site to flooding, it is important to consider past floodevents as reference points but there is also a need to consider projections of whatmay happen in the future. With climate change, projection of extreme events and increase in the
intensity and frequency of typhoons must inform housing plans in terms ofsite selection and site planning and housing construction.
o Earthquakes, major landslide and flood events are changing the landscape and, thus,there is a need to review and update hazard maps and the assessments made of thesusceptibility of potential and existing housing sites.
o Social Housing Finance Corp (SHFC) is increasingly becoming aware of the importanceof selecting safe sites for low-cost housing. SHFC provides financing (CommunityMortgage Program) for onsite HOAs to be able to acquire the land they are occupyingand for offsite HOAs to acquire a piece of land, undertake site development andconstruct their houses within SHFC’s loan ceilings. One of the CMP sites in Iligan Citywas wiped out during TS Sendong.
o The housing units in social housing are not “critical” structures, but structural integrityof the housing units is a critical consideration in low-cost housing development.
3. Increasing frequency and intensity of hazards requires review of existing housing-relatedcodes and policies, structural requirements for houses, monitoring standards andrequirements for materials to be more responsive to these extreme events
o Policies, such as the DENR AO requiring the EGGA, and design guidelines that arerecommendatory need to have the strength of a law to be implementable.
4. Structurally resilient housing involves the integration of site conditions (onsite and offsite) inhousing designs and site development plans, choice of appropriate materials, and compliancewith standards & appropriate method of construction
o Having a resilient low-cost house may not be “so low-cost”. If backyard production ofhousing construction (e.g., CHBs) is not allowed, HOAs or community associations willincur higher costs in acquiring their construction materials.
5. It is important to consider the broader landscape of a site and all environmental factors thatmay affect a site and not focus only on a proposed housing site. For instance, one site inCDO was washed out although it is located some distance from the river.
o Site assessment must be conducted before the purchase of a property intended forlow-cost housing.
6. There is a need for sound checklist for permits. The sets of requirements for permits requiredby LGUs and the processing periods vary from LGU to LGU. Standardizing requirements canhelp prevent confusion among low-cost housing developers and community associations/HOAs applying for permits.
7. Housing is not just about providing housing units but is also about community development,including livelihood opportunities (e.g., case of Eco-ville in Cagayan de Oro).
8. Structural engineers play a critical role in housing development. There is a need to supportASEP’s core activities to expand the reach of their services.
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B. POLICIES AND PRACTICES NEEDING REVIEW AND CHANGE
1. Policies for Review
a. Comprehensive review of all laws, regulations and other policies covering low-cost housingdevelopment, such as Batas Pambansa 220 (Different Levels of Standards and TechnicalRequirements for Economic and Socialized Housing Projects), Batas Pambansa 1096 (NationalBuilding Code), National Structural Code of the Philippines (NSCP), Presidential Decree 957(Subdivision and Condominium Buyers’ Protective Decree), Batas Pambansa 344(Requirements to enhance the mobility of disabled persons in buildings, institutions),Presidential Decree 1185 (Fire Code of the Philippines), etc., to streamline and coordinate theinter-related, overlapping and inconsistent provisions
- To identify specific provisions in each law that needs to be amended or updated, such as butnot limited to:
o One of the provisions in BP 220 that needs to be reviewed in terms of livability is theminimum land area – 18 sqm – for socialized housing.
o The structural standards for socialized housing must be established and implemented,including in areas covered by Community Mortgage Program.
o The provisions under the Fire Code that requires low rise buildings to have closed hallsto contain the smoke within an affected floor from going to the higher floors will resultin closed structures that is not consistent with green architecture planning.
- To find out where the provisions overlap or are incompatible and how these can beharmonized, resolved or streamlined
- To consider the applicability of requirements in the context of onsite developments/ projectsand to maximize community benefits and involvement
b. Disconnect between the engineering, geologic and geohazard assessment administered bythe Mines and Geosciences Bureau and the development permit administered by the LGUs
- This is a critical gap in the regulatory processes for low-cost housing. The LGU tends to focusonly on the checklist within its mandate and may or may no longer consider other pertinentrequirements. The lack of coordination between the LGUs that review site developmentplans, the MGB that administers the EGGA and EMB that administers the EnvironmentalImpact Assessment (EIA) results in the disconnect of these procedures and in turn underminesthe value of the EGGA as input in site planning and development.
- Without adequate appreciation of the importance of integrating geological and hydrologicalfindings in site planning for a project, the EGGA can be complied with merely for compliancesake and thus becomes a futile exercise.
c. Review of legal easements
- The Water Code requires a 3-meter easement from rivers. However, in many urbancommunities, the 3-meter easement does not provide adequate margins of safety from thedestructive overflow of the rivers.
- With regard to the requirement for 40-meter easement from the coastline in the aftermathof Typhoon Haiyan, there are areas along the coast in Leyte and Samar where the storm surgesmoved beyond 40 m inland.
- PHIVOLCS requires 5-meter buffer zones along either side of a fault line. This may be adequatefor houses but it may not be enough for high rise buildings.
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d. Review of permitting process (under PD 1096 and BP 220) and relaxation of permit processingfor socialized housing
e. Review of policies of the Community Mortgage Program and applicability of the standards ofBP 220 given the realities of built up communities
- Loan conditions need to incorporate provisions on geohazard assessment of the sites, sitemanagement and maintenance, and selling rights.
- SHFC can explore instituting special lanes in LGUs for permit processing for CMP projects.- LGUs as mobilizers and partners require capacity building in monitoring and reviewing.
f. Site management regulations for low-cost housing beneficiaries
- Part of social preparation and community organizing of the families that are to be relocated,that acquire units in low-cost housing projects, or that are already established in on-site CMPsites is the establishment of homeowners’ rules and regulations in site management. HOApolicies and the implementation of these can help ensure that sites will not become blightedareas.
- Homeowners must observe said policies when they do improvements on their houses or lots.
2. Gaps in Site Selection and Site Planning
a. Lack of available and affordable lands for low-cost housing
- There is a shortage of affordable and available lands that are suitable (i.e., not highlysusceptible to various hazards) within the cities for low-cost housing development. A numberof sites that LGUs and national agencies are providing for relocation sites are residual (e.g.,fishpond areas that are reclaimed using inferior quality of materials) or in environmentallycritical areas (e.g., mangrove areas). Once these are acquired or allocated for low-costhousing, the challenge of figuring out how to make the site habitable and to accommodate asmany as housing units as possible becomes an engineering challenge.
- Available financing programs to assist low-income urban families undertake in-citydevelopment (land acquisition/reblocking/site development/mitigating measures) arelimited. SHFC provides limited financing, a house-and-lot loan package with a cap of PhP165,000 for each informal settler family. This amount is usually not enough to cover the costof land development or reblocking, and cannot be stretched to cover mitigation measures(e.g., riprap) in sites with high susceptibility to certain hazards.
b. Lack of technical knowledge of stakeholders engaged in land acquisition, such aso LGUs identifying lands for relocation or socialized housingo HOA or community associations engaged in self-initiated housing projectso CMP project beneficiaries in site selection applying for financing from SHFC
c. The implementation of the Community Mortgage Program (CMP) of the Social HousingFinance Corporation (SHFC) in the past, compliance with BP 220 and preliminary assessmentof sites were not prerequisites to the approval of a loan. There are challenges in applying BP220 standards in onsite projects, because the houses are already constructed at the site.
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3. Gaps in Land use Planning and Zoning
- The problem with the comprehensive land use plans and zoning ordinances of many LGUs isthat these
a. are outdatedb. have not integrated geohazard assessment in the allocation of residential and commercial
zones; orc. are not being implemented.
- The CLUP and zoning ordinance are the basis for the LGU’s issuance of a locational clearancefor project sites intended for housing development. If the CLUPs and zoning maps did notundergo due diligence in geohazard assessment, the basis for clearing sites as appropriate forhabitation is unsound. Once approved, CLUP and zoning as bases for reviewing housingproject sites must be free the development permitting process from political influences.
4. Gaps in Policy Implementation
a. Lack of implementation of the 20% balanced housing to
- There is a need to review the implementation of this policy to free up land in urban areas forlow-cost housing. Private subdivision developers are mandated under the UrbanDevelopment and Housing Act (UDHA) to allocate portions of their project sites for thedevelopment of socialized housing, but they are able to evade this requirements.
b. Lack of accountability measures for professionals who prepare site plans and building plansand oversee the construction as well as LGU officials who approve development permits
- For both site planning and house construction, it seems that no one has been sanctioned yetfor malpractice, i.e., for conducting “table plans” that have resulted in or that may lead to lossof lives and/or properties.
c. Lack of monitoring by LGUs of the implementation of site development they approve
d. Lack of coordination of national government agencies SHFC problems with LGUs as they donot coordinate with LGUs and do not require their approval
e. Lack of NHA coordination with LGUs in the monitoring housing projects
5. Gaps in Capacities
a. Limitations in the technical capacities of personnel/offices in the LGUs in:
- Identifying sites for relocation areas and socialized housing projects. There is lack ofawareness among LGUs and end users of the importance of site analysis and assessment.LGUs are encouraged to undertake land banking, but must coordinate with MGB for theassessment of the properties they identified prior to purchase or acquisition.
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- Reviewing site development plans for housing projects as part of the application for adevelopment permit, and monitoring the implementation of projects based on the approvedplans. Some LGUs lack of resources to hire capable staff.
- Integrating geohazard mapping and site geohazard assessment results in CLUP and zoning.The geohazard assessment reports for development projects undertaken for various projectscan be useful input in enriching the CLUP and zoning.
- Developing Disaster Risk Reduction and Management Plans that integrate housing projectsites.
b. SHFC’s requirements for homeowners associations applying for CMP financing include (a)certification from the LGU that a project site is suitable for habitation and (b) MGB’sassessment of the said site. There are cases where the LGU certification and MGB assessmentresult are inconsistent: the MGB finds a site highly susceptible to hazards but the LGU certifiesthe same as a safe site for human habitation.
c. Shortage of geologists in MGB
- MGB is undermanned, resulting in delays in meeting the requests for gaohazard identificationsurvey or geohazard assessment by government agencies, LGUs, private developers andHOAs.
- The geologists hired to undertake geohazard assessment may lack experience and expertise,thus there can be limitations in the findings and recommendations.
- At the same time, there may also be limitations in the review process for the GAR by MGB.
6. Gaps in House Design and Selection of Materials
a. Need for a multi-hazard approach
- Building design and choice of building materials must be informed by multi-hazard approach.For instance, concrete materials can better withstand strong typhoons but may not be idealfor strong earthquakes.
b. Lack of structural standards for low cost housing (including low-rise buildings) in the BuildingCode
- BP 220 does not say anything on structural requirements, but just states that the NSCP mustbe followed. Even NHA housing units are not compliant to the NSCP. On the other hand, theNSCP structural standards are not practical for socialized housing. ASEP is filling in the gap ofstandards for low-cost housing through the drafting of NSCP-Volume 3 (Housing Code) as areference code.
c. Lack of standards for the approval of new/alternative technologies and testing facilities
- There are many ongoing social housing initiatives using alternative technologies, though thesehave not undergone adequate testing. Alternative materials can lower the costs of buildinghouses for low-income families, but these must undergo review and testing by AITECH.
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- The Housing Code being drafted must include standards for bamboo and coco lumber.
d. Need to set standards for wind loads
e. Lack of capacity of local Building Officials, mismatch of qualifications of people assigned/employed as building officials and the skills required
- The Department of Public Works and Highways (DPWH) gives authority to the BuildingOfficials, but this is not clearly established in terms of policy. In a lot of cases, the approval ofprojects is out of the hands of the Building Officials but is dependent on the decision of thelocal chief executives.
- ASEP is forging a memorandum of agreement with the Philippine Association of BuildingOfficials (PABO). There are Building Officials who are not civil engineers, and many of themadmit that they lack the capacity to check structures. ASEP will provide a checklist that theBuilding Officials can use when they receive applications for permits. The Building Officials arebecoming aware of their responsibility.
f. Affordability versus standards
- The budget of certain agencies or organizations for a housing unit can affects the quality ofhouses. Building “low-cost” housing up to standards of a resilient house necessitatesadditional funds; the cost may be out of reach of low-income families.
g. Lack of funds for research and development
- Research and development is not a priority of housing agencies and is thus not allocatedenough funding. For instance, there are no government housing agencies doing bambooresearch in mass housing.
- It is proposed that universities offering engineering and architecture courses can design andbuild different prototypes of houses that can withstand extreme hazards, e.g., earthquakesand/or strong typhoons, for longitudinal study and monitoring of damages.
- Standard procedures for testing of alternative materials may be undertaken by students doingthesis
h. Lack of accountability measures for engineers preparing building plans
i. Monitoring of the quality of construction materials by the Department of Trade and Industry(DTI)
- There is a need to push DTI for more effective regulation of the sale of substandard housingmaterials in the market.
- Relocation and low-cost housing projects must not use thin roofing materials.- Project developers need to require suppliers to conduct material testing the latter deliver the
materials.
C. SOME STRATEGIES TO ADDRESS CRITICAL GAPS AND STAKEHOLDERS INVOLVED
a. Awareness and capacity building for LGUs in:o Site assessment and analysiso Land use planning development through the integration of geohazard and other
hazards in land use plans
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- Strategic collaboration between universities (especially state universities) and LGUs orgovernment agencies can address some of the needed capacity building or data of LGUs.Universities can formulate their extension services, which becomes a basis for students tohave their internships, and research agenda in areas that can respond to the needs of theirlocal contexts. This allows for the bridging and application of academic lessons to actual localsituations. Students, if given adequate training, can be mobilized to gather relevant data orconduct public orientation.
- The needed extension services for capacity building/training LGUs can be provided byuniversities/colleges in the areas of developing thematic maps for planning, technicalregulations and monitoring, etc.
b. Capacity building for Building Officials
- The Philippine Association of Building Officials can be the venue for building the capacity ofbuilding officials and promoting continuing education and standardizing requirements.
c. Multi-sectoral (government agencies, LGU, civil society groups, private low-cost housingdevelopers, etc.) engagement in developing and reviewing policies
- Thematic discussions focused group discussions can be organized regularly on pertinenttopics. Positions papers and technical working papers may be developed in relation to policyreview, standards of construction materials, etc. and presented to concerned governmentagencies and partners in low-cost housing development for the corresponding responses.
- Participation of stakeholders is key in promoting governance in housing-related concerns.
d. Development of education-information campaign materials
- The translation of the IEC material, How safe is your house?, to Filipino allows the have a widerreach.
- ASEP is going to develop a manual to guide the construction of non-engineered houses. Agraphic presentation of “how to’s” allows for more effective presentation of procedures inbuilding a house.
- Local associations can be tapped to explain standards. , translation to comics, TV spots
e. Integration of local indigenous knowledge in site assessment and house construction
f. Increase in government subsidy for socialized housing
- The budget estimate for a disaster resilient house almost doubled the cost of building a house.For resilient housing to be affordable for the poor, there is a need for government to increaseits subsidy.
g. Strengthening of community organizing of families/homeowners to reinforce stakeholdershipin the houses and housing site so that care and maintenance are engendered from the start
- Partner government agencies, LGUs, assisting organizations or private developers need toestablish with communities standards in site management and safety precautions in onsitedevelopment.
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h. Funding support for research and development related to low-cost housing development andbroader communication/dissemination of research outputs
Stakeholders to be Involved in Addressing the Gaps
a. Local government units: Local Building Officials, City/Municipal Planning and DevelopmentCoordinators
b. Homeowners Associations, Peoples Organizationsc. National agencies: National Housing Authority (NHA), Department of Public Works and
Highways (DPWH), Housing and Urban Development Coordinating Council (HUDCC), SocialHousing Finance Corporation (SHFC), Housing and Landuse Regulatory Board (HLURB),PAGASA, MGB, Bureau of Fire Protection – Department of Interior and Local Government(BFP-DILG), Philippine Institute of Volcanology and Seismology (PHIVOLCS), Department ofSocial Welfare and Development (DSWD)
d. Academe: University of the Philippines College of Civil Engineering, Mapua Institute ofTechnology
e. Professional associations: Association of Structural Engineers of the Philippines (ASEP), UnitedArchitects of the Philippines (UAP)
f. Assisting organizations/Networks: TAMPEI, Community Architects Network, Habitat forHumanity-Philippines, Hilti Foundation
g. Research organizations: ESSC-Philippine Working Group
D. EMERGING COLLABORATIVE ACTIONS
The areas for collaboration among the participants and other stakeholders include the following:
1. NHA to host a steering group to finalize the Housing Code (NSCP Volume 3)
2. UAP and ASEP to jointly develop a manual for non-engineered houses, and NHA to promotethe manual
3. Some participants to assist SHFC in reviewing CMP sites
4. ESSC through the Philippine Working Group on Disaster Resilience (PWG) to facilitate focusedthematic discussions and site visits to move the approaches for addressing critical gaps
5. ASEP to facilitate thematic discussions with MGB, PHIVOLCS and PAGASA in relation to NSCPVolume 3
6. Xavier University, Mapua Institute of Technology and University of the Philippines Diliman tointegrate prototype housing testing in curriculum & contribute to testing new technologies
7. NHA to involve ASEP in AITECH
8. ASEP and ESSC to continue work together to follow up and track the collaborative actions
9. National Conference on Safe and Resilient Low-Cost Housing to be held in the last quarter ofyear 2014
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II. HAZARD SCENARIOS
A. SEVERE RISK MODELINGThelma Cinco, Philippine AtmosphericGeophysical and AstronomicalAdministration (PAGASA)
1. Typhoon Trends in the Philippinesfor the Period 1948 - 2013
PAG-ASA’s analysis of a total of 1,641tropical cyclones or typhoons that formedin the Western North Pacific between1948 and 2010, 70 % of which entered orwere formed in the Philippine Area ofResponsibly (PAR), noted the followingtrends:
- Annually, the average number of typhoons that hit the country (19 to 20) has not changed.- There is no month that the country was not hit by a typhoon, though the peak of typhoons
usually happens in the months of July to September.- Based on five-year frequency of tropical cyclones in the last 66 years, variability persists.- There is a trend of increasing typhoons hitting Mindanao: the highest frequency of typhoons
hitting Mindanao in the past 66 years was recorded in the last 5 years. Luzon is seeing adecreasing trend in the frequency of typhoons but it still gets the highest number of typhoons.
- Along with the changes in the frequency, duration and intensity of rainfall events, more andmore people are being affected by hydro-meteorological hazards. Data from the Office ofCivil Defense (OCD) shows that the total damages from typhoons in the last decade grewexponentially. The costs of disasters reached PhP 1 billion or higher in economic losses and300 deaths or more in human losses.
The past five years show the highest accumulated total cost of damage due to destructive typhoonsthat hit the country. Typhoons have associated hazards – namely, strong winds, excessive rainfall thatcan trigger flooding and landslides, and storm surges. A storm surge is wind-driven though people stillliken it to tsunami, and coastal areas with shallow coastlines – such as Leyte – are prone to higherstorm surges than those with deeper coastlines. Typhoon Agnes triggered storm surges in Leyte in1984 that left 985 people dead.
Extreme events are becoming more frequent. The worst disasters caused by tropical cyclones in thecountry include the following:
Typhoon Duration Wind speed(kph)
Deaths Damages inPhP billion
Typhoon Undang (Agnes) 3 – 6 Nov 1984 230 895 1.9Typhoon Rosing (Angela) 30 Oct – 4 Nov
1995260 936 10.829
Typhoon Reming (Durian) 28 Nov – 1 Dec2006
281 709 (753missing)
10.89
Typhoon Milenyo (Xangsane) 25 – 29 Sept 2006 150 45 1.251Typhoon Pablo (Bopha) 3 – 9 Dec 2012 185 1,068 36.9Typhoon Yolanda (Haiyan) 5 – 10 Nov 2013 215 6000 + 50 +
Source: Office of Civil Defense.
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2. Developing Severe Wind Hazard Maps for the Philippines
The ongoing study of PAGASA on severe wind risk assessment, aims to gain an understanding of thelevels of risk from extreme winds. The current understanding of wind hazard, including the returnperiod of severe wind speeds, informs the wind loading standard. The return period of severe windspeed is the average interval of recurrence, although, it can occur randomly and may recur at muchshorter intervals. An alternative way to establish the likelihood of an event is to convert the returnperiods to annual exceedance probabilities (AEPs), which is the chance that a given wind speed will beexceeded in any year.
The data used for the study included the historical tropical cyclone track dataset from 1950 to 2011from the Japan Meteorological Agency, which covers the period from the formation to dissipation ofa typhoon unlike PAGASA’s data that covers the duration when a typhoon enters and exits PAR); winddata from PAGASA’s weather stations; database of the impacts of previous tropical cyclones (forverifying the results of risk analysis); and LIDAR imagery, Elevation Data.
The wind hazard model can calculate the probability of being exceeded in any given year, called theAEP. The calculated AEP wind speeds range from 40% (on average every 2 years) through to 0.001%(occurring on average about once in 10,000 years). In practice, PAGASA then does a damagecalculation for a range of AEPs. This allows PAGASA to assess the damages from both relativelycommon typhoon impacts and from more extreme events.
In the methodology, the role of multipliers were taken into consideration to relate regional windspeeds to local site conditions. One is the height of various terrain (land-cover) types: wind speedincreases with height for different terrain (land-cover) types. Another is the shielding effect in whichtaller buildings reduce the wind speed toward the lower buildings. Also, the terrain roughness or theshape and slope of the ground in undulating topography also affects wind speed. For instance, thepresence of patches of tall trees or buildings scattered across an area can decrease wind speed. Thecombination of topography, shielding and terrain roughness yields a combined multiplier value. Themodeling results, taking topography into consideration, show that the area in Rodriguez, Montalbanis going to have increase in wind speed. There is a need for LIDAR data for local sites to come up withmultiplier values. PAGASA is planning to apply this methodology for the areas affected by TyphoonYolanda, using other sources (not LIDAR), which may take time.
3. Severe Wind Risk Assessment for Greater Metro Manila Area (GMMA)
The components of severe wind risk modeling are: risk = hazard x vulnerability x exposure where
- Hazard refers to the frequency of events, magnitude of events, areas to be affected- Exposure involves the elements that are going to be impacted. The study mainly focused on
residential, commercial and industrial buildings. (There is now a need to look into criticalinfrastructure such as power lines, telecommunications and transport. Other elements thatcan be impacted, though not covered by the study, are people and agriculture.)
- Vulnerability involves how much damage will be caused to each element by the impact of anevent and how a community can anticipate, cope with, resist and recover from a naturalhazard.
The risk estimations can allow one to estimate the damages that a tropical cyclones could cause tobuildings (not people) and the cost of damages by tropical cyclones. The calculation methods require3 key inputs: the (1) wind hazard model, 2) the exposure data, and 3) a vulnerability model. Two
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measures of damage are used. One is physical damage in terms of damaged floor area equivalentvalues for each barangay/municipality (in ha/km2). The study used a vulnerability curve developed byUP that identified 15 building types, in which bamboo houses may suffer 90 % of damage in the eventof 125 kph winds. The estimated damage is expressed in terms of direct building damaged economiclosses on the building structures aggregated by barangay level. The other is economic loss in terms ofdamage/repair cost economic cost in million peso/sq. km. associated with tropical cyclone damage tobuilding.
In case of a 0.2% AEP (1/500) event in GMMA, for the Building Damaged Intensity, Barangay Payatasin Quezon City is one of the areas that will have greatest damage. This is where there is concentrationof light-frame type of buildings (e.g., wood) and makeshift structures and informal settlements.However, translating physical damages to economic loss, Fort Bonifacio surfaces as the area withhighest economic damage. The results are these are still initial and need more data and furthervalidation.
4. Studies as Input in the Housing Code (Data for Establishing Basis for Wind Loads)
The challenge posed to the drafting of the Housing Code is that science is providing data as input inhousing design. It is for the engineers and architects who then decide on what return period to use.High wind speeds such as those of Typhoon Haiyan are rare events, but which result in a high cost ofdamage. Almost every year, the country suffers from catastrophic events. Thus, there is a need tobuild resilient houses.
In the development of the Housing Code, there is a need to establish the basis for wind loads. Thereis a need for 10-year data on the trends of typhoon and wind speed changes. Though there are un-validated reports that DPWH is setting the wind speed standard for houses at 300 kph, the position ofASEP is to first establish the empirical basis for this.
In terms of the regional maps, what PAGASA models is the maximum sustained winds on a 10-minuteaverage. What is damaging to structures is the peak gust: PAGASA considered 3-second peak gust inthe probability.
PAGASA is willing to share raster data with DPWH and ASEP; they can have a discussion on datasharing. PAGASA has the model and the observed data, but PAGASA has reservations about sharingadjusted data. If a tropical cyclone is not directly covered by a PAGASA weather station and data isscarce, PAGASA interpolates. Results from interpolated data and observed data are different.Simulation involves translating from the tracks and transforming the pressure into winds. Thelimitations of the modeling must be clear.
For scenarios for strong typhoons, the events that may be considered are Typhoons Milenyo andHaiyan. For extreme rainfall events, Tropical Storm Ondoy may be considered.
5. Questions, Suggestions and Clarifications
a. Suggestion for the review of vulnerability curve used
In the vulnerability curve used, the building type must not be simply classified in terms of materialsper se. Using the type of materials per se, bamboo houses is predicted to suffer 90 % damage in caseof 125 kph winds. Much of the damage is seen in bahay kubo using lightweight materials that is notwell-built. However, there are different construction methods using bamboo that can also have great
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potential to withstand strong winds. It is not only about the material alone, but it is also about thekind of construction applied.
With regard to housing materials and construction, the cogon houses in Batanes that are of lightweightmaterial proved their resilience to strong winds owing to the quality of construction. The cogon roofsare very thick, consisting of several layers of cogon, knit by the people during bayanihan and replacedafter some years. After Typhoon Odette, there has been no strong typhoon in last 15 years that hitBatanes but there have been some new houses that were reportedly blown away.
b. Wind loads for the energy sector
The project is now looking at possibly developing vulnerability curves for power transmission towers.
The power sector is using a wind load that is quite low. The group says that they are independent ofthe NSCP. For the power transmission lines for power, the Energy Regulatory Commission is theregulating body. The ERC specifies a 50-year return period, although the groups claims that they use270 kph in their design. One concern is that if the standard return period is increased, the cost for thetransmission towers necessarily goes up. There may be a need to change the standard for wind loadsfor transmission towers; PAGASA can perhaps influence them.
B. THE GEOHAZARD ASSESSMENT AND MAPPING PROGRAM OF THE MINES ANDGEOSCIENCES BUREAULiza Socorro Manzano, Mines and Geosciences Bureau-Central Office
1. Objectives and Status of MGB’s Geohazard Mapping
MGB’s nationwide geohazard mapping program started in 2008 although MGB has been doing thissince the 1960s. MGB is conducting geohazard mapping to:
a. Identify areas vulnerable to various types of flood and landslide hazards. The mandate ofMGB is to assess rain-induced landslide and flood hazards but, after the 7.2-magnitudeearthquake hit Bohol, MGB conducted mapping of sinkhole and subsidence hazards.
b. Increase public awareness of such hazards in order to mitigate the negative impacts.
Geohazard mapping was conducted using two map scales: (a) 1: 50,000 scale and (b) 1:10,000 scale.The 1:50,000 scale landslide and flood susceptibility maps for the entire country were completed inDecember 2010. The 1:50,000 scale map for landslide hazards categorizes landslide susceptibility intohigh, moderate, low. The 1:10,000 scale geohazard mapping is ongoing for some parts of the countryand includes mapping of areas prone to subsidence/sinkhole development owing to their underlyinglimestone materials, as well as the mapping of rockfall and soil creep. The 1:50,000 scale maps canbe downloaded for free from the MGB website.
For the more detailed geohazards assessment mapping at 1:10,000 scale, MGB is targeting to do 1,634cities and municipalities. Of this total, 60 % (950 towns and cities) was completed from 2011 to 2013,and the target for this year is 648 cities and municipalities.
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The methodology for geohazard assessmentand mapping included the interpretationand analysis of Remote Sensing data, aerialphotographs and satellite images, and otherthematic maps such as geologic map,drainage (or river system) map, slope map,vegetation map. MGB also conductedground truthing, through geomorphological/geological assessment, ground penetratingradar surveys and gathering of anecdotalaccounts. Oral accounts are particularlyimportant in mapping flood susceptibility, asnot all areas in the country have historicalrecords of floods. Historical records forrainfall are different from historical recordsfor floods.
MGB provided copies of the geohazard maps to LGUs and advisories to barangay officials ofcommunities identified as prone to landslide and flood hazards. Also, MGB conducted information-education campaign (IEC) at the province and municipal levels and produced IEC materials tolaymanize geohazard information.
MGB is part of the warning agencies for the National Disaster Risk Reduction and Management Council(NDRRMC). Aside from PAGASA, MGB also issues advisories for areas under threat of landslide andflooding in case of imminent low pressure areas and typhoons that can trigger these hazards (3 daysprior to landfall). MGB also establishes early warning systems by installing sinages in hazard-proneareas.
In addition, MGB conducts assessment of identified relocation sites of disaster affected areas (e.g.,Compostela Valley province hit by Typhoon Pablo, Region VIII hit by Typhoon Haiyan, and Boholprovince hit by the 15 October 2013 earthquake) in terms of susceptibility to various hazards. MGBdoes not identify the sites for LGUs: what MGB does is to assess the suitability of temporary sheltersand evacuation centers identified by LGUs.
2. Landslide Hazards and Factors to Consider in the Selection of Settlement Sites
Landslide hazards (or mass wasting) is the downward movements of earth materials aided by gravity.Different types of “mass wasting” can move very slowly (< 1 cm/year, creep) to very fast (> 4km/hr,debris avalanche or rockfall). A debris flow (e.g., Compostela Valley in 2012) usually occurs in areasthat no longer have any vegetation and where kaingin is practiced. The speed of movement ofmaterials is dependent on the topography of the area. Debris flows usually start as flashfloods, but ifthe earth materials comprise more than 50 %, it becomes a debris flow. Mudflow (e.g., Infanta,Quezon in 2004) also contains earth materials but, in contrast to debris flow, the materials are fine(mud and silt). Debris avalanche (e.g., Guinsaugon in 2006) can move at a speed of 100 km/hr. Whathappened in Cherry Hills Subdivision in 1991 was a complex landslide that led to theinstitutionalization of the Engineering Geologic and Geohazard Assessment (EGGA) in the applicationfor Environmental Compliance Certificate (ECC) that covers housing projects. Another form oflandslide is a slump.
Field work as part of geological assessmentSource: L. Manzano
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The parameters for landslideassessment are steepness of slope,type of rocks, degree of fracturingand weathering, vegetation andthickness of soil overburden. Signsof impending landslides includetension cracks, terracettes, tiltedtrees indicating creeping andseepages.
In the selection of site, peoplemust avoid:
- steep to very steep slopeswith thick soil overburden
- unstable steep slopes(unless properlymitigated)
- base of mountainousslopes with a stream
- old and recent landslide deposits as these are unstable- near the edge of the outer bank of a meandering river- abandoned river channels (a small stream is still flowing below)- alluvial fan underlain by debris and deposits- mouth of rivers- near escarpments
3. Flood Hazards and Factors to Consider in the Selection of Settlement Sites
Geologists interpret flooding, which is brought about by precipitation and other factors, as part ofgeomorphologic process: flooding is part of how the earth does its natural landscaping. Floodingforms part of the natural fluvial process, and youthful, mature and old-age streams have differentcharacteristics of flooding. Mature and old stream have a developed floodplain where people wouldlike to stay. The floodplain is the domain of the river system and the playground of the river.
There are different types of flooding. There are natural flashfloods and induced flashfloods. Naturalflashfloods are floods of short duration with relatively high peak discharge, circular basin, no forestcover, fractured rocks and highly weathered rocks which can cause temporary damming. On the otherhand, flashfloods can be induced in urban centers because of lack of urban drainages. Sheet floodscover a large area.
Building low-cost housing along flood-prone areas should be avoided because mitigation measuresare expensive and do not give a 100 percent guarantee of safety. There are fluvial processes thatdevelopers need to understand in their designs for low-cost housing projects. People need to respectthe domain of the river systems, and engineers must be aware of the return periods of floods events.The longer the return period, the more extensive the area affected, the higher the flood levels.Because there are no historical records of past major floods, people always says it is the first time thattheir areas are hit by destructive flooding. There are limitations of planning for 50-year return period.What is happening now are flood events with 100-year return period. These are a natural geomorphicprocess with or without climate change. Owing to the absence of written documentation, it isimportant to know the flood marks of recent flood events.
Settlements at the mouth of rivers must be avoidedPhoto credit: L. Manzano
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Flooding is not all about flood level or height, but is also about the behavior of the rivers in a 100-yearreturn period. During these events, rivers can shift their channels. It is important to identify the oldpaths of river systems and avoid building on these. Large rivers can have braiding channels, and thefloodplain where this happens is unstable.
The safest flood mitigation for low-cost housing is hazard avoidance through proper site selectionaway from high flood lines and away from paths of old streams. Buildings must be elevated from thelast flooding level.
Coastal flooding occurs when normally dry, low-lying land is flooded by sea water. Some parts ofMetro Manila are low-lying and were once a tide-dominated delta. Flooding in urban areas issignificantly affected by the urbanization effect, such as changes in the drainage systems.Development significantly reduces water infiltration in an open area from 80 – 100 % prior todevelopment to 1 – 10 % after most of the ground is built on or sealed.
4. Subsidence Hazards
Subsidence hazards are unique in Bohol. Subsidence happens in areas with karst topography orunderlain by limestone. Bohol is underlain by young karst. Sinkholes are technically round, but cancome in various shapes and sizes depending on the age of the karst system. MGB is mapping sinkholesthat collapsed. The signs of subsidence include heaving, spalling, tension cracks, cave collapse andsinkhole collapse. Sinkhole is part of cave features; there is a cave system below.
5. Questions, Suggestions and Clarifications
a. Subsidence in karst topography and subsidence from groundwater extraction
Subsidence in karst topography is different from ground subsidence happening in some parts of MetroManila and other highly urbanized cities being caused by over extraction of groundwater and sinkingof the ground. The weight of the buildings and structures on the soil also contributes to ground sinking.
Karst is a type of topography referring to an area underlain by limestone. Palawan is characteristicallyold karst. Fifty percent of Bohol is young karst. The older the karst, the bigger the cave system. Asinkhole is part of a karst system, either subterranean river or cave system.
b. Whether or not MGB’s assessment is required for building permit
MGB does not have participation in the issuance of a building permit by a municipal or citygovernment. For a housing project, MGB requires the conduct of the EGGA but the findings andrecommendations in site assessment are recommendatory to the issuance of ECC, which is under themandate of the Environmental Management Bureau. Some LGUs strictly require the submission ofthe ECC (which assumes the completion of the EGGA) for applications for development permit. OtherLGUs are not as strict and issue the development permit on the condition that the developer mustobtain an ECC. Compliance with this condition is not necessarily monitored.
c. Use of the geohazard maps in assessing the susceptibility of a site
One of the requirements of the Social Housing Finance Corp (SHFC) for HOAs applying for the loanpackage under the Community Mortgage Program (CMP) is MGB’s assessment of a site. On thequestion of the head of SHFC’s Technical Division whether or not they can use the geohazard maps ofMGB to assess the susceptibility of a site for low-cost housing to flooding and landslide hazards, it was
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clarified that the 1:50,000 scale maps are made for purposes of planning at macro-scale (e.g.,comprehensive landuse planning). For a site-specific development, a site–specific investigation isrequired to assess the susceptibility of the location to geohazards. The Department AdministrativeOrder requiring the EGGA states that assessments should be site specific. MGB conducts a geohazardidentification survey and reports if there is a need for more detailed geohazard assessment and whathazards must be covered by the assessment. It is best to know the geological limitations of a site priorto construction.
The SHFC Board’s requirement is a geohazard assessment. SHFC submitted a long list of CMP sites toMGB for their assessment, but MGB is taking too long in acting on the requests for site assessment.
d. Updating of geohazard maps and clarification on the drainage map used by MGB ingeohazard mapping
Considering that land forms can change over time, are the existing geohazard map still applicable?Ideally, the geohazard maps must be updated every after 5 years. The geohazard maps in 1:50,000scale were prepared in 2008 – 2010 and are thus still usable.
For MGB, the “drainage map” refers to the NAMRIA topographic map showing river systems. Whilethe current editions of the NAMRIA maps can be used, it can be informative to check out oldertopographic maps and old photographs to track changes in the river systems.
C. EARTHQUAKE HAZARDS AND SCENARIOSIshmael Narag, Seismological Observation and Earthquake Prediction Division, PhilippineInstitute for Volcanology and Seismology (PHIVOLCS)
1. PHIVOLCS’s Disaster Risk Reduction Framework
PHIVOCS’s main DRR program identifies the hazard (threats) and the people and assets that are at riskin an area (exposure), and looks into how susceptible they are to physically and socially damagingeffects and what capacity the people have to adapt and cope (vulnerability). What PHIVOLCS wantsto see is a quantification of disaster risks in terms of potential losses through a realistic evaluation ofthe different hazards and identification of the characteristics in a particular area that may be affected.
The measures to reduce disaster risks include:1. Hazard and risk assessment, and monitoring and warning2. Reducing exposure through evacuation; proper landuse planning to lessen the exposure
of people and assets to hazards; and identification of safe relocation sites3. Reducing vulnerability by raising people’s awareness and educating them on the hazards
and corresponding responses awareness building, preparedness, appropriate responses,mitigation (engineering, non-engineering, insurance) and business continuity
In effect, the risk are lessened by concentrating more on planning the positioning of the differentelements and improving coping and adaptive capacities.
2. Earthquake-Related Hazards
PHIVOLCS’s mandate covers earthquake-related and volcanic hazards. The earthquake-relatedhazards are:
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1. Fault (ground) rupture is mostly associated with rupture of the ground and eventuallyrupture of the surface that can cause major displacements, especially for house built righton top of a fault line. Hence, a buffer zone along known active faults is required.PHIVOLCS issued a 5-meter no build zone on both sides of a fault line.
2. Ground shaking can lead to the collapse of buildings. Engineers are concerned withdesigning earthquake resistant buildings.
3. Liquefaction happens when soil behaves like water, causing ground failure and in turndamages to the structures built on top.
4. Landslide can be triggered by earthquakes: a large chunk of materials in sloping areas maylose cohesion and start to fall owing to gravity failure.
5. Tsunami occurs when an earthquake propagates large waves in a body of water.6. Fire can be a secondary hazard.
3. The Quick Unified Inventory for Exposure and Vulnerability for REDAS (QUIVER) Project
The Quiver Project sought to establish a long-term partnership between PHIVOLCS and GeoscienceAustralia. Under this project, PHIVOLCS developed a software to quantify different hazards and alsothe expected damages and vulnerability. The database is integrated into the risk assessment moduleof the Rapid Earthquake Damage Assessment System (REDAS).
4. Metro Manila Earthquake Impact Reduction Strategy (MMEIRS)
One of the previous work of PHIVOLCS is the Earthquake Impact Reduction Study for MetropolitanManila (MMIERS). It involved earthquake hazard mapping that covered earthquake zones andidentified 18 scenario events. Based on the scenario events and using NSO data, a magnitude 7.2earthquake along the West Valley Fault can cause heavy casualties of 33,500 deaths and 114,000injured people, with 18,000 additional deaths due to fire.
The outcome of the project was a Master Plan with 6 goals and 10 objectives, as basis for coming upwith evacuation plans and safe health evacuation plans. A total of 105 action plans were developedfrom the Master Plan and buildings were reviewed by DPWH.
5. Earthquake Scenario: Impacts of Magnitude 8.1 Earthquake in Iloilo City
While people talk about an imminent “big one” in Metro Manila, the “big one” happened in Panay in1948. On 25 January 1948, the magnitude 8.1 Lady Caycay earthquake hit Panay with associatedhazards of severe ground shaking, liquefaction and landslides and tsunami.
The pilot area covered the whole of Iloilo City. PHIVOLCS conducted field survey to validate andsupplement exposure information gathered from the NSO 2000 and Assessor Office’s data sets. Theinformation gathered was used to form statistical assumptions of exposure from first-order datasets(i.e., how a building’s footprint relates to its height).
The project made use building of categories developed by UP PICE based on materials used andframing system. For each building type, UP ICE came up with fragility curve (relationship betweenstructural performance and ground motion). The LGUs were trained on the use of the software, andthey then started to inventory the buildings in Iloilo. The data capture tool gives a snapshot of abuilding.
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In case of a repeat of the Magnitude 8.1 Lady Caycay earthquake, the impacts in Iloilo City arecomplete damage to 8,500 buildings and death of 1,500 people.
6. The Greater Metro Manila Area (GMMA) Risk Analysis Project
This study benefited from LIDAR in creating 2 earthquake scenarios for the Greater Metro Manila Area:one for a magnitude 7.2 and magnitude 6.5. Combining hazard, exposure and vulnerability, one cancome up with a scenario for damages given an earthquake intensity. For the development of theexposure database, using LIDAR data and different imageries, one can now access the name, land use,land area, number of storeys, total floor area, era of construction, population estimates of an area.
It is estimated that the total economic loss in case of a magnitude 7.2 earthquake is PhP 2.4 trillion.In case of a magnitude 6.5 earthquake, the economic loss is approximately PhP 1.9 trillion.
7. NIED Project: JST-JICA (SATREPS)
PHIVOLCS acquired a full-scale shaking table to test Philippines concrete hollow block houses. In anexperiment, a model house that is code-compliant survived 100% of Kobe earthquake input motionwith only minor damage. Good compaction in mortar filling improved CHB-mortar bonding and theuse of standard reinforcement size and spacing improved wall ductility. In comparison, a substandardhouse suffered consistent failure between joint and upper fill mortar on the upper levels of CHBs,indicating poor bonding in between joint and fill. For both models, the gable wall part showed strongershaking as compared to other parts. (The video footage of the shaking experiment will be distributedfor public access.)
8. Recommendations for Earthquake Resilient Houses:
a. Follow the recommendations of the structural code
- Construction materialso Use correct sizes - at least 10mm DSB and 6” CHBo Use correct spacing of reinforcement bars
- Standard construction implementationo Compact properly fill mortaro Observe proper timing of mixing and pouring (for homogeneous bonding of mortars)o Allow proper curing of mortar fill
- Anchorageo There should be no splicing of reinforcement bars at the corners of the structure.o Vertical bars should not be spliced linearly.o Extended CHB to form gable walls is discouraged.o Tie wires on reinforcement bars must be well fastened.
b. Implementation and monitoring of construction standards- Engineers – viable, economical and safe retrofitting methods for existing substandard CHB
houses- LGUs through its Building Officials – monitoring of new construction of substandard houses
and implement recommendations provided by the engineers for existing houses- Contractors (mason, construction leaders) – proper construction implementation for new
houses
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- House owners – adoption of appropriate retrofitting for existing substandard houses and formonitoring of the construction of new houses
9. How safe is my house?
The tool, How safe is my house?, is a self-check checklistto assess the earthquake safety of concretehollowblock houses in the Philippines. A house isscored based on the answers to the questionnaire.
A team from PHIVOLCS applied the questionnaire withsome houses in Bohol during fieldwork to survey thedamages caused by the earthquake of 15 October 2013.The observed major failure patterns include: (a) gablewall partially collapsed/out of plane behavior; (b)foundation-/soil condition-related; and (c) shearstrength of load bearing wall/in plane behavior; and (d)pancake collapse.
PHIVOLCS is planning to come up with a 12-pointquestionnaire for wooden houses and to develop aFilipino version of the questionnaire.
III. EXPERIENCES IN HOUSING CONSTRUCTION, HOUSING SITE SELECTION,PLANNING AND DEVELOPMENT
Ensuring resilient low-cost housing development involves integrating the physical aspect – such as thesite conditions, construction materials and building plans, and site development planning – and socialand economic aspects – in terms of the people’s livelihoods, community organizing and social services,etc. Part of the preparatory process prior to actual site development and house building is complyingwith housing-related regulatory requirements.
A. TACKLING THE NEED FOR RESILIENT LOW-COST HOUSING HOLISTICALLY: INSIGHTS INTO APILOT PROJECTCorinna Salzer, Hilti Foundation
Housing is at the confluence of poverty, urbanization, housing demand, and climate change relatedimpacts, as well as the vulnerability of the poor to disaster risks. This makes housing a crucial entrypoint for action as it can have impacts in many fields.
As part of its work on affordable housing, Hilti Foundation joined forces with United Nations Economicand Social Commission for Asia and the Pacific, together with Homeless Peoples FederationPhilippines, since 2012 to conduct a pilot project on the development of alternative constructionmaterials in the Philippines. The pilot project is implemented in three phases, starting with research
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and business development (Set-up Phase), followed by a semi-commercial application (Start-upPhase), progressing into fully commercial application (Scale-up Phase).
When building a house using conventional technologies on a limited budget, low-income familiesoften end up sacrificing the quality of materials to lower the cost. Hilti Foundation thus turned toalternative construction materials, focusing on bamboo. Bamboo has a long history of traditional usein Philippine houses that then transitioned into a housing material for the poor at present but itsapplication never modernized. Bamboo is still used mainly in rural or temporary settlements and innone-load bearing applications. While concrete materials are ascribed status, bamboo is considereda poor man’s lumber and is not acceptable as a permanent building material. The project aims to liftthis traditional construction material in the modern context with the involvement of key stakeholdersto promote its acceptability.
1. Affordable Housing Initiative in the Philippine Context: Project Vision and Components
The vision of the project is to create sustainable housing solutions for low-income families usingalternative building technologies (i.e., bamboo). Its mission is to create triple bottom line housingenterprises and build ecosystems to enable the sustainability and scalability of the technology: (1) useof locally grown and renewable materials to build houses suited to the design needs of localcommunities; (2) creation of equitable ecosystems along the value chain towards sustainable businessmodels; and (3) creation of livelihoods for famers supplying the alternative building materials. Theproject’s components are:
Technical performance and environmental impact. The initial focus was on the technical performanceof bamboo, but the project also looked into other aspects.
Participatory design and action research with urban poor communities. The project used an interactiveresearch approach as part of the strategy to generate interest in bamboo. The project devoted 18months of research on various aspects of bamboo, from raw material characterization to legalapproval through technical testing and innovation. Bridging the gap between research andimplementation involved a comprehensive understanding and feedback at:
- material scale, i.e., to create material standards to allow engineers to make a structural design- system scale, i.e., interactions and connections. Bamboo houses usually fail because the
connections are opening: thus, the research did testing.- building scale, i.e., some dynamics in lateral loads in case of extreme impacts, such as
earthquakes and typhoons. The research did shaking table tests to determine the seismicperformance of bamboo materials: bamboo houses can be extraordinarily strong.
Overall, the target of the research on raw material characterization and technical testing andinnovation is to achieve structural design and legal approval for bamboo as structural component inhousing according to NSCP standards. The research applied for the first time ISO standards in localtesting facilities. Also, the research learned from the experience of Columbia that has a building codefor bamboo.
Construction of demo houses. To test the performance of bamboo during a strong typhoon, theproject built different kinds of houses using different construction systems, and observed theirperformance in relation to the impacts of wind speed, pressure on the houses, displacement, etc.
Local market research business plan development and impact measurement.
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2. Evaluation of Bamboo Houses during Extreme Impacts
There are a diversity of hazards posing different challenges to housing in the Philippines, and theirpotential impacts on houses require different characteristics. As such, a holistic answer to housingcannot only look at one kind of hazard, but must lookat the multiple hazards posing threats to housing at asite and must include the assessment of the site andproper selection of quality materials. Following theearthquake in Bohol, historic timber houses wereintact while new concrete houses were destroyed. Incontrast, in the towns and cities hit by TyphoonHaiyan, all kinds of structures were affected but it wasthe houses made of lightweight materials that wereseverely damaged.
The question is: Can bamboo be utilized as a modern,affordable building material and contribute to aholistic response for Philippine housing? Yes, thematerial offers this potential. The project’s approachis to show how lightweight houses made of bamboocan withstand seismic impacts with strong anchorageagainst wind forces and careful geohazard assessmentfor the sites. To ensure durability as people investtheir money in their houses, it is important to get theright harvesting time of the bamboo and conductproper treatment.
3. Questions, Comments and Clarifications
a. Status of model houses in Bicol and Iloilo City
Since the construction of the model houses in Bicol (2013) and Iloilo City (2012 – 2013), there has beenno strong typhoon that directly hit these places and that put these houses to test. To establishevidence and a track record on the capacity of the houses to withstand extreme hazards, the projectplans to build more houses in other areas of the country.
b. Ensuring durability of bamboo houses
Ensuring that bamboo houses are going to last – i.e., to have at least 25 years of perfect performance– requires getting the right harvesting time, species, chemical treatment and design. By combining allof these elements, the end result can have the same durability as timber houses. The technology andperformance can be improved further in two more generations of Filipino engineers to make bambooa reliable construction material and give people a confidence to pay houses made of bamboo.
c. Cost per square meter of building a bamboo house
The cost per sqm of a bamboo house depends on specifications and on the set up: e.g., whether thehouse is one- or two-storeys, what roof style is used, etc. The design allows a homeowner to reducethe cost for the building envelope and upgrade, i.e., if the homeowner will have more money in the
A bamboo demo housePhoto credit: C. Salzer
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future, they can plan to improve on the interior. Building with bamboo is cheaper than using concreteby far, but more expensive than bahay kubo. There has to be no compromises on the foundation.
d. Bamboo species used
The project used more than one species of bamboo. The locally used tinik bamboo is a structuralbamboo. Diversifying the species used helps ensure the sustainability of supply.
e. Connections
The project tested different connections and chose the most robust. There are different connectionsfrom foundation to the floor, from the wall to the second floor, from the second floor to the ceiling,etc. Each has a different solution.
B. PERFORMANCE ASSESSMENT OF RESIDENTIAL STRUCTURESRonaldo S. Ison and Miriam Lusica-Tamayo, Association of Structural Engineers of the Philippines
The Association of Structural Engineers of the Philippines conducted inspection of houses and publicbuildings in Bohol on 16 – 17 and 26 – 27 October 2013 after the earthquake of 15 October 2013.ASEP engineers evaluated the different damages in subsequent expeditions to other areas. Photos ofdamages taken show different limitations and problems in housing construction or materials.
Soft-storey failure: A family spent a lot of money on a newly built reinforced concrete 2 storey-house,but which got damaged during the earthquake. The building is not severely damaged, and themainframe structure is still standing, but the back of the house collapsed owing to insufficientanchorage or support, suggesting that the columns might have been insufficiently reinforced.Although one damaged house is new, most reinforcements are corroded already: most concretehollowblocks were made of sea sand that increased corrosion of the reinforcements. The use of closeties or stirrups was inadequate.
Under reinforced houses (non-engineered). A number of houses have small round circular columns,but these are over designed architecturally. Heavy articulations and clusters are added to make thehouses look good. However, these increase the mass of the house and it becomes heavily loaded,increasing vulnerability to earthquakehazards. There were also numerousheavily damaged hollow block wallsthat are under-reinforced and have nolintel posts and beams. A non-engineered house that totally collapsedhas very few structural elements, withno columns or beams to support thewalls and most walls do not havestiffeners. The very slender columnswere heavily loaded with the roof.
Collapse of non-engineered extensions.There are homeowners who addednon-engineered extensions. Acommon practice in the provinces is that
The walls of a non-engineered house fell, leaving only the posts.Photo credit: R. Ison
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people add modules to a structure without thinking about how to connect them properly.
Inadequate roof support (non-engineered). This is a common non-engineered practice. The use ofslender columns can lead to the collapse of the roof structure.
Lack of lateral support (non-engineered). It is expected that houses of light materials would havewithstood the earthquake, but some wooden houses also collapsed. A number of houses made ofreinforced concrete with no lateral support might have deteriorated over the years.
Failed masonry wall support (non-engineered). If the masonry walls are properly constructed, and areadequately connected, these may resist high magnitude earthquakes.
Inadequate anchorage and support to masonry (engineered). Even engineered houses were notspared from the impacts of the earthquake. An engineered house suffered from inadequateanchorage and support to masonry. The construction was only looking at vertical loads, but thevertical walls were not attached laterally so the walls got detach from their supports.
Other houses showed joint failures, absence of reinforcements; buckling, shear failures, soft storeys.In sum, the observed damages included:
- Collapsed or partially-collapsed houses- Leaning or out-of-plumb structures- Houses on “stilts” , damaged first floor levels- Partially or completely shattered wall elements- Falling hazards such as parapets and ceilings
The causes of damage include:- Most, if not all, of the damaged houses were non-engineered; these were constructed by
masons and carpenters.- A common cause of damages was poor quality construction materials, such as substandard
and soft CHBs and small diameter reinforcements with large spacing. There is a need toregulate backyard construction of CHBs.
- There were insufficient frames (beam, column) and sizes of the reinforcements.- Connections of frame elements and anchorages of wall elements were inadequate. For
instance, the roofs that were damaged were not properly connected to the walls. If the roofsare properly connected to the walls, these can act together. However, if the roofs are notproperly connected, it can only aggravate the problem.
- Insufficient frames (i.e., beams, columns) and sizes of the reinforcements were used.- There is poor understanding of earthquake effects to structures and non-structural elements:
o soft-storey effects of houses on “stilts”o use of heavily-plastered articulations or designo use of heavy roofing materials such as clay tiles,o laterally-unsupported parapet walls
- Construction methodology and practices are inadequate or outdated.
A critical consideration in the Philippines is the need to consider the hazards that may affect a housein the choice of materials and house design. Homeowners may prefer light structures to haveearthquake-resilient houses, but light materials may not withstand typhoons. Building on stilts isadvised for houses in flood-prone areas but may lack the strength in relation to possible earthquakeeffects.
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C. REBUILDING POST-TROPICAL STORM SENDONG: CAGAYAN DE ORO EXPERIENCEEliezer Banarez, Habitat for Humanity Philippines – Cagayan de Oro City
1. Responding to Post-Tropical Storm Sendong Disaster Housing Demand
Intense rainfall brought about by Tropical Storm Sendong in the upstream of the Cagayan de Oro Riverresulted in a flashflood on 16 December 2011 that claimed the lives of 674 people. Forty one (41) 41barangays in Cagayan de Oro City were inundated, affecting a total of 38,071 families. A total of 7,317houses were completely damaged and 12,635 houses were partially damaged.
Two weeks after the disaster, many assisting organizations gave out tents. A tent city was establishedin Calaanan 2 that accommodated 1,500 families.
The Cagayan de Oro citygovernment engaged in landbanking prior to TS Sendong. Inthe last week of December, thecity government started sitedevelopment in the 12.23–hectareland in Calaanan. In the first weekof January, a shelter cluster calledthe Local Inter-agency Committee,was formed with the NationalHousing Administration as thesecretariat. On 25 January 2012,the groundbreaking for therelocation site in Calaanan washeld.
Several designs were presented prior to construction. The mayor wanted rowhouses to maximize theland. The NHA wanted duplex units, while the vice president proposed quadruplex houses. For thesite in Calaanan, Habitat for Humanity-Philippines built 686 duplex units. Within three months,Habitat turned over more than 400 units to the LGU.
2. Status of the relocation projects
The various post-TS Sendong disaster relocation sites are summarized as follows:
Relocation Site Location Land AreaNumber of
HousingUnits Built
Site Development andCommunity Facilities
Calaanan 3 BarangayCanitoan
12.23 ha 686 Police outpost
Calaanan 2 BarangayCanitoan
5.96 ha 276 Site development was doneby the DPWH
Calaanan 2B BarangayCanitoan
3.0 ha 66
CalaananTalongan
BarangayCanitoan
1.8 ha 40
Tent city in Calannan 2Photo credit: E. Banarez
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CalaananMahogany
BarangayCanitoan
2.0 ha 160
Indahag 1 Brgy Indahag 3.2 ha 414 Water tank; Sitedevelopment was done byDPWH
Indahag 2 Brgy Indahag 7.78 ha 578 Health center and multi-purpose center
Taguanao Brgy Indahag 0.5 ha 48 (Single-detached)
Oro Bayanihan Brgy Camaman-an, SitioMakapaya
4.7 420 (Duplexunits)
Land was purchased by acongressman in partnershipwith NHA
Xavier Ecoville Brgy Lumbia 5.3 ha 568Pagatpat Brgy Pagatpat 16.0 1,086
(Duplex)Police outpost, day-carecenter
Coopville Brgy Mambuaya 5.0 168Quadruplexand singledetachedunits
(Use of lime compressedearth blocks in houseconstruction)
Divine MercyVillage
Brgy Patag, Opol,Misamis Oriental
12.0 350 (Singledetachedhouses)
In some sites, the capacitybuilding and livelihoodtrainings that were conductedinclude, e.g., block productionfor the 4Ps beneficiaries. Inthe construction of Ecoville,160 families were employedfor block production. Therewere trainings on welding,rebar fabrication and foodprocessing that wereconducted in partnership withTESDA and some schools.
The parameters for resilient structures considered in the relocation sites were:a. appropriate site selectionb. shape of the structures: (symmetrical shapes)c. foundations (must be anchored to the ground)d. roof form and angle (30 – 45 degree angle) and overhangse. roof sheets (0.5 mm thick)f. fasteners (use of galvanized screws with wider heads and member connections
Alternative construction technologies, such as bamboo and compressed earth blocks, were used in afew sites. For the house made of alternative materials, two steel frames were joined and concretewas poured in between to make a column. For the bamboo panels, metal frame with bamboo strips
Calaanan 3 relocation site in Barangay Canitoan, Cagayan de Oro CityPhoto credit: E. Banarez
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were used. Chicken wire was used outside then plaster was added. The panels made of bamboo aregoing to be used in the next installment of relocation houses. There is still a need to construct 1,500houses, and a new design is being planned as the current mayor wants to build single detached houses.The new design, if the cost is the same as the earlier designs, will necessitate adjustment in theconstruction strategies: for instance, gutters were not added in the houses in some sites owing tobudget limitations.
3. Question
a. Whether nor not the sites were assessed in terms of susceptibility to landslide and floodinghazards
All resettlement sites after TS Sendong required a certification from the Mines and GeosciencesBureau (MGB). Isla de Oro, one of the badly hit areas, was a relocation site before.
D. THE EXPERIENCE OF XAVIER ECOVILLEDexter Lo, Xavier University Resource Center
1. Xavier University Engineering Resource Center’s Mapping of January 2009 and December 2011Flood Events
In January 2009, a flood hit Cagayan de Oro City. After this event, Xavier University EngineeringResource Center (XUERC) mapped the flooded areas in case it would rain again in CDO. Studentsdownloaded images of the flood event that were posted online to establish the critical flood heights.XUERC released the map reconstructing the January 2009 a month before CDO was again struck by amore destructive flood in December 2011. The map of the areas actually affected by TS Sendongshowed a more extensive area than the result of a simulation by XUERC in November 2011.
The Cagayan de Oro River Basin is very large, catching water from the provinces of Lanao del Norteand Bukidnon that comes down to the CDO River. It is estimated that the floodwaters flowed at about11,000 m3/sec.
2. President Aquino’s Order
When President Benigno Aquino visited CDO, he announced that “. . . going back to the danger areasis no longer permitted, I want that very clear.” He then ordered the PNP Regional Director at the timeto ensure that people are not going to rebuild in Isla de Oro and the neighboring barangays.Nonetheless, along Ipunan River, where there are many subdivisions and private lands that were badlyhit, no area was declared a no-build zone.
The map generated by XUERC was shared with the President and with the public to increasepeople’s awareness.
3. Xavier University’s Responses to the Disaster
In addition to helping in the relief efforts, the Board of Trustees of XU initiated the establishment ofthe Lumbia resettlement area. Out of the 17 ha of land that Xavier University owns in BarangayLumbia, XU donated 5 ha for the relocation site of displaced families during TS Sendong. Another 5.0ha is temporarily loaned to the city government for temporary shelters.
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XU adopted a holistic approach in the XU LumbiaResettlement Project. It was not just aboutbuilding houses, but it had to consider the watersupply, sanitation, solid waste management, andother elements. Xavier University had to follow SPHERE standards in the construction of houses,including standards on sanitation as part of the conditions for accessing UN funding support. Provisionfor sanitation is an essential component to give people dignity. Habitat for Humanity was selected asthe developer to build the houses and Habitat prepared the site plan.
Again, the effort was not just about building houses; it is also about the stories of the people, includingthe vulnerable groups. Xavier EcoVille houses 550 households, with a total population of 2,660people. The approach recognizes that the physical development and community development mustbe pursued in tandem. The approach has to involve developing solutions with – and not for – thecommunity, within the framework of sustainable development to proceed with gratitude and love.
Physical Development Community DevelopmentTemporary Site- Total land area: 5 ha- No of temporary shelters: 550 bunk houses- Community facilities:
Water filtration system; Child-friendly space;Water treatment facility; Vermicompostingfacility; Community hangar; Sports andrecreation centers
Permanent Site- Total land area: 5.3 ha- No of permanent shelters: 568 houses with loft
Lot area: 50 sqmFloor area: 21.30 sqmCost per unit: PhP 110,000
- Community facilities:St. Francis Xavier Chapel, Livelihood Center,Community Center, Multipurpose Hall, StudyCenter, Toy Library
Programs- Governance: Homeowners
association; Capacity buildingactivities; Leadership trainings; Footpatrol
- Health: Feeding programs; Medicalmissions; Community healthnavigators; Health lectures; Water,sanitation and hygiene
- Values Formation (VF): VF forhousehold heads; VF for youth; VFfor kids; Youth empowerment;Education
- Livelihood: Wholesaling, Credit andloan, Bakeshop, Food processing,Tree nursery, Manpower services,Sewing, TESDA skills training
Left photo: Temporary bunk housesRight photo: Site development plan of EcovillePhoto credits: D. Lo
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E. THE EXPERIENCE OF DE LA COSTA HOUSING V: A PROJECT BY FREEDOM TO BUILD, INCCharlie Tan, Freedom to Build
Freedom to Build, Inc., (FTB) is a social housing developer established in 1976. FTB’s vision is“improving life through decent and affordable housing and community development”.
De la Costa Homes (DLCH) V, located in the town of Rodriguez (formerly Montalban), Rizal, is FTB’slargest low-cost housing project, covering 21 ha of land that is subdivided into 2,400 (row) housingunits. Each housing unit has a floor area of about 20 sqm on a minimum lot size of 50 sqm. The designis that of a core house that a homeowner can expand horizontally and vertically.
1. Selection of the Site: Positive and Negative Features of the Site
When FTB was looking for a site to develop, Montalban was considered because it is close to MetroManila. The land price of the properties where DLCH V was to be established was deemed within thecapacity of FTB to build a social housing project. During ocular inspection of the surrounding areas,FTB noted that Montalban had enough community support and infrastructure to sustain a newhousing development.
Nonetheless, FTB observed challenges in developing the site, considering the presence of quarryingponds and the proneness of the site to flooding. With the site’s low elevation and proximity to theMarikina River, FTB anticipated that there would be a substantial amount of land filling required.Despite this cost, FTB found the housing project feasible and thus proceeded with the processing ofrequirements for a housing project.
2. Findings and Recommendations of the Geohazard Assessment Report
FTB applied for an environmental compliance certificate and, as part of the ECC process, paid for thegeohazard assessment of the site. The geohazard assessment report prepared by a private geologistidentified the following major hazards:
a. The most dreaded hazard that may affect the project site is flood hazard due to the overflowof the Marikina River.
b. The project site is also considered susceptible to liquefaction during strong earthquakesbecause it is located on thick unconsolidated, non-cohesive soil.
Nonetheless, the private geologist assessed the project site for DLCH V as generally habitable providedthat the following recommended mitigation measures were followed or enhanced:
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a. For FTB to fill/backfill theproject area with suitablefilling materials so that thefinal ground elevation is atleast 53 masl at theperipheral area. Inimplementing thisrecommendation, FTBraised the site to 54 masl.
b. For FTB to construct a well-engineered, semi-gravitytype retaining wall alongthe property boundarylines or a well-designedrip-rap. FTB built thisretaining wall.
c. For FTB to ensure that thebuilding foundations andstructures retain integrityin case of inundation.
d. For FTB not to block or fill the present course of Bulubok Creek.
FTB complied with these recommendations, not knowing that the mitigation measures would beinadequate for a major flood like what happened during TS Ondoy. The gaps in the geohazardassessment is worrisome because FTB was putting 2,000 + homes in the area.
An ECC for the project was issued conditionally, subject to FTB’s implementation of all therecommendations in the GAR, construction of adequate drainage, and compliance with the LGU’srequirements.
3. Compliance with LGU requirements
Before the groundbreaking, FTB applied for a zoning certificate at the Municipal Planning andDevelopment Office, certifying that the site is suitable for residential development based on the LGU’sland use plan and zoning ordinance. Prior to issuing a locational zoning clearance certificate,representatives of the municipal government performed an ocular inspection of the property. FTBalso applied for a development permit at the Mayor’s Office; the requirements FTB submitted includedthe locational clearance certificate, housing design, bill of materials, site plans complying withrequirements for open spaces, water outfall, road network, etc. The Sanguniang Bayan approved thedevelopment permit. The LGU requirements, however, made no reference to the ECC.
On the basis of the geohazard assessment findings and issuance of the ECC and development permit,FTB proceeded with the housing project. FTB had the ground breaking for DLCH V in 2002, andcompleted the project in 2007. Because of its proximity to Metro Manila and affordability for middleincome families, all the housing units were taken.
4. Flooding during TS Ondoy and Local Flooding Problems
Two years after its completion, however, DLCH V was submerged under water by the overflow of theMarikina River during TS Ondoy in 2009 despite the mitigation measures. It took two years to clearthe area of mud and completely restore power to the housing units. FTB had no obligation to help in
The retaining wall on the side facing Marikina RiverPhoto credit: ESSC
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clearing the area, but felt responsible to help in the cleanup as the developer. Some homeowners leftand the houses were repossessed by PAGIBIG, while others returned and renewed their loans.
After 2009, the development of a housing project a few meters down from DLCH along Bulobuk Creekcreated flooding problems for some blocks in DLCH V. The developer blocked the Bulobuk Creek withculverts that were relatively small in size and were prone to trapping debris. Consequently, the creekwould get clogged and the water would overflow unto the blocks of DCLH V close to the creek. Theculverts have been removed and replaced with a bridge, but the way that the developer diverted thecreek reduced the creek’s capacity to drain effectively.
5. Disconnect between the ECC and Development Permit Requirements
On the part of FTB as the developer of DLCH V,- FTB relied on the findings and recommendations of the MGB-EMB process and the locational
clearance and site plan review by the LGU. The ECC, however, appeared not to have anyweight, and there seems to be no consistency in what was required of the developers. Forinstance, FTB did as advised that it must not alter the Bulubok Creek. However, anotherhousing developer down from DLCH V site was allowed to divert the creek.
- FTB followed and implemented all the recommendations by the MGB-EMB in order to makethe site “habitable”. No monitoring was done either by the MGB-DENR or the LGU.
- FTB has very little knowledge as to the process taken by these government agencies whenclearing an area for residential development. The landuse plans and maps used by themunicipal government are likely to be outdated.
FTB’s experience clearly shows limitations in the regulatory mechanism intended to ensure thathousing development is done only in safe areas. There exists a disconnect between the nationalgovernment and the LGUs processes, and the gap needs to be addressed to prevent housingdevelopment in high-risk areas. Even after the 2009 flood, development is sprouting in the area.
6. Questions, Suggestions and Clarifications
a. Considerations in conducting site assessment
The case of FTB illustrates a situation where flooding needs to be address at the level of government,not at the level of the developer. Part of site assessment must look at what is upstream of a river thatpass near a site. The project is located along the Wawa River, which stretches upstream to themountains of the Sierra Madre and is affected by the activities upstream of the site, including theupland portion of the Marikina Watershed.
Locating the site on a topographic map, the site is along a meandering river. In the geohazardidentification/assessment, MGB was looking at flood depths at the project site when the project wasstill not yet in place. Geomorphologically, the area has significantly changed already. The site contextwould have necessitated a hydrological study that looked at a 100-year flood event.
Based on ESSC’s review of the developer’s compliance with housing regulations, the geologists whoconducted separate geohazard assessments of the adjoining properties where the DLCH V project wasimplemented in two phases, cited a study of what may happen along the Marikina Valley in case of a100-year flooding event. However, in the conclusion and recommendations, the flood level of themost recent highest flood event (54 masl) at the time was the one considered in the recommendedlandfill height. This is seen as one of the flaws of the geohazard assessment done: the flood scenariofor a worst-case flood event was considered but in the conclusion, a much lower flood height wasadopted as reference point. As such, the recommendations for flood mitigation proved inadequate in
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addressing the severity of the flooding potential. It could not be ascertained whether the geohazardassessment reports for the adjoining project site were subjected MGB’s review. It was suggested thatthat the review process of the geohazard assessment be strengthened.
b. Importance of projections in site assessment
For flooding, it is not enough to consider past events only, but also projections of the volume of rainfallduring extreme events, especially with the trend of more frequent and more intense typhoons andmore frequent extreme rainfall events. During TS Ondoy, the volume of rain in Metro Manila in fourhours was equal to the volume of rain in a month. The projection of storm surge in the areas affectedby Typhoon Yolanda is closer to the mapping done for tsunami.
It may be worth inquiring about the projections for flooding along the Marikina River that wereconsidered in relation to the flood master plan that intends to build a series of dams along theMarikina River.
c. Policy gaps
The gaps in policy and implementation need to be presented at the major conference in October:there has to be a review of the MGB guidelines and the ECC. In relation to drainage planning forhousing developments, there also needs to be a review because what is being used is 1950sparameters for drainage.
F. INTEGRATING THE LANDSCAPE IN HOUSING SITE SELECTION AND SITE PLANNINGDallay Annawi, Environmental Science for Social Change
ESSC is developing a handbook on integrating landslide and flooding hazards in housing site selectionand site planning for stakeholders engaged in low-cost housing developments. It contains lessonsdrawn from ESSC’s site visits to disaster affected areas, different housing and relocation sites,including those acquired by community associations as well as some low-cost housing projects ofpartner developers, LGUs and the National Housing Authority.
1. Site Selection Considerations
Different stakeholders can have different priorities as to what makes for a good housing site. On topof the list for many is affordability. Related to this is accessibility and availability of utilities, as thesecan reduce the cost of developing a site. In many cases, safety from hazards is least in the priority, ifat all it is considered.
A property acquired “cheap” by a community association in Albay but, which turned out to pose majorchallenges in site development owing to its high landslide potential, highlights the need for siteassessment prior to the purchase of a property. The land is bordered along the east and north bysloping sides, which was perceived by some members to serve as a protective barrier in case of strongtyphoons that hit the province from time to time. However, these steep sides were delineated byMGB- Region V as non-buildable, as cutting the slope may initiate landslides. The site topographicmap also reflected a sinkhole that goes down to the elevation of the creek that bordered the propertyon the south. Though this creek does not pose flooding to the southern area, it was undercutting theside. The property turned out as a failed investment: the community association abandoned their
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plans to develop the site for their housing. This case highlights the need for more awareness amongcommunities engaged in identifying sites for their housing.
2. Importance of Initial Site Assessment
Community associations, LGUs, government agencies and assisting organizations that are involved inland acquisition for relocation or low-cost housing development and site development planning needto conduct initial assessment of sites they identify to:
a. Identify site conditions indicating site susceptibility to all possible hazards: flood, landslide,coastal hazards
b. Understand the potential impacts of observed site features to proposed development
A preliminary understanding of a site can serve as basis for considering some important questionsbefore making the decision of whether or not to buy a property, such as:
• Is the site safe from landslide and other hazards? Is there a need for further assessment andadvice by technical specialist?
• Will existing conditions require major engineering measures?• Are additional costs required for mitigation or remediation measures and land preparation to
reduce risks?
As what Ms Liza Socorro mentioned on the need to laymanize technical knowledge for the use of localcommunities, community associations or LGUs looking for a site for housing development must knowwhat site conditions they need to watch out for and what are the questions they can ask wheninspecting a candidate property.
In majority of the sites ESSC visited, there was no assessment made by the MGB or technicalprofessionals. ESSC’s target in the partnership with Homeless Peoples Federation Philippines (HPFPI)and the Technical Assistance Movement for People and the Environment, In (TAMPEI) is to build theircapacity to conduct an initial site assessment even prior to site selection. Not all communityassociations have access to the services of MGB or have the resources to pay technical professionalsfor them to conduct the site assessments. Ideally, their sites must be assessed by MGB and ESSCencourages this, but the geohazard identification survey – geohazard assessment by MGB usuallycomes in after the acquisition of the sites and site plans were already developed.
3. Some Site Conditions to Considerwhen Inspecting a Property
In terms of landslide susceptibility of asite, there are various conditions at asite and in the surrounding areas thatcan be observed to have an initialunderstanding of landslide hazard ornot. The handbook lists questions thatassociations or LGU staff can check onwhen inspecting a site. Slope steepnessis one of the predisposing factors forlandslides to occur: the steeper a slopeis, the higher is its potential forlandslide. Groundwater is an importantcontributor to slope weakness and
A property located on the left bank of the river was progressively erodedduring the river’s strong flows.Photo credit: ESSC
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likelihood of a landslide. Signs of the depth of groundwater in a sloping area that can be noted aresprings and seepages. For surface water, on the other hand, those inspecting a site that is near a creekor river must investigate further on the watershed context of the stream, to know how far they mustset back from the creek or river beyond the legal easements. A site must observe adequate setbackfrom the streams. Where the rivers have a history or potential of flashflooding, a 3-meter easementis not enough margin of safety. Adequate easements are necessary, but can be a hidden constraint indeveloping a property. The characteristics of soil and rock materials may not readily observable insome sites, but it is important for people to be aware of the risks of building houses on soft soils. Somecommunity associations in Iloilo shouldered the cost of hiring engineers to conduct soil tests. Thehazards conditions are also covered under MGB’s geohazard identification survey-geohazardassessment procedure, but since not all community associations and LGUs have access to geologistsand professionals before buying a property, they need to know what conditions they must considerwhen inspecting candidate sites to acquire.
4. Recognizing the Limits of Engineering Measures in Critical Sites
In developing lands that have challenges in site development, there may always be some engineeringsolutions. However, as Ms Manzano stressed engineering measures must be seriously considered inlow-cost housing development. Developers have to realistically recognize the limits of engineeringmeasures in high risk areas, because the measures themselves may not be fail-safe and low-costhousing homeowners lack the resources to maintain or restore such measures to the standardsrequired.
5. Regulating Slope Cutting in Site Development
The case of a subdivision project that created landslide risks for a community association in Rodriguez,Rizal surfaced weaknesses in mechanisms regulating slope cutting. The developer of the propertybelow a community association’s acquired relocation site created a steep cut-slope along almost theentire length of their boundary (about 16 m at its highest). Despite efforts of the affectedhomeowners, with ESSC’s assistance, to establish the bases for stopping the said developer, lack offirm action on the part of the LGU allowed the developer to proceed with flattening a mountain slopeunhindered. The bases established were: 1. the private developer’s violation of its approved slopegrading plan approved by the LGU; 2. the creation of landslide risks for the community association,also backed by MGB’s inspection of the cut-slopes as requested by the community association; 3. thenoncompliance of the private developer with the geohazard assessment and ECC requirement for thesubdivision project it implemented at the site. As the slope-cutting operation eventually cleared theslope, the demand of the affected homeowners shifted to ensuring that the private developer wouldconstruct sound slope protection measure. However, the quality of the “riprap” that the developerstarted to construct – a mere layering of stones with mortar against the cut-slope – does little tostrengthen the exposed slope and reduce the risks for the houses on top of the cliff-like cutslopes.
6. Learning from Past Disasters
The flooding hazards that can cause major destructions are high velocity floods, high impact forces ofa flood and high flood levels. Major flooding disasters that occurred within the physical characteristicsof a watershed can occur again in the future, and what happened in past events must inform siteselection and disaster preparedness efforts, for which site assessment is needed.
One year after families that were relocated to a site in Rodriguez, Rizal in the early 2000s sufferedfrom flooding during TS Ondoy in 2009, some relocated families were surprised see that the land nextto their site, which is relatively lower and was flooded during TS Ondoy, was being prepared for
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relocation site development. During the habagat rainfall in 2012, the newly built houses constructedon this relocation site were flooded to the ceiling. The relocated families no longer wanted to returnto their housing units and entire blocks of houses were abandoned. The response of the developerwas to raise the perimeter wall supposedly to keep off floodwater in case of a similar event. However,the raised wall may very well become a trap if the swollen river overtops the wall or if floodwatercoming from the relocation site or the sides does not have an exit to the river and accumulates at theend of the relocation site.
The event was a reminder for developers to comply with the EGGA requirement of the MGB.Stakeholders in housing/relocation must learn from past disasters in selecting sites and recognize thelimitations of flood mitigation measures during extreme rainfall events.
IV. HOUSING-RELATED POLICIES
In support of the drafting process for the residential Housing Code, housing-related policies wereshared.
A. STANDARDS FOR HOUSING DESIGN AND CONSTRUCTIONMaria Benita Regala, Housing Technology Development Office – National Housing Authority
The National Housing Authority (NHA) recognizes that there is a need to review the relevance andapplicability of existing housing standards in view of the new climatological normals. The Departmentof Housing Design Technologies of NHA developed a disaster resilient house design with theDepartment of Public Works and Highways (DPWH) on President Aquino’s instruction that post-Typhoon Yolanda houses must be resilient.
1. Site Selection Criteria
NHA follows the criteria set by BP 220 in site selection (Sec. 5, BP 220), namely:
Availability of basic needs, such as water, movement and circulation, storm drainage, solid and liquidwaste disposal, parks/playground, and power. NHA coordinates with the local water districts for theprovision of water supply, and with electric companies or cooperatives for the electrification of projectsites. Meralco recently adopted the elevated meter center (EMC) to guard against the tampering ofelectric meters and reduce systems loss. Meralco asked NHA developers not to put the meters on theground, although NHA finds the exposed wires unsightly. In Bagong Silangan, where the meters areon EMCs, some of the meters were removed because the families were unable to pay their bills. Thosewho are disconnected usually tap into their neighbors. Illegal connections and disconnection aresome of the problems in socialized housing.
Conformity with zoning ordinances and city/municipality comprehensive land use plans. A site mustbe classified as residential land based on the approved CLUP. NHA as a national agency complies withthe CLUPs of the LGUs, and all of NHA’s projects are subject to the approval of the LGUs.
Physical suitability. Topographically, the site must be relatively flat, or if it has a rolling terrain, thefilling requirement must not exceed the maximum cost. Slopes must not exceed 15 % gradient. Forhigh density sites, the slope must be below 5%. Further, soil characteristics must conform to the
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suitability standards for construction approved by DENR – MGB. Soil test is not required for one-storey houses, but building officials require at least two bore holes for a 3-storey building. With regardto regional and local context, housing projects must be within suitable sites for housing and outsidepotential hazard-prone and protection areas.
Accessibility. The farther away people move from their former locations, the more that they usuallyhave to spend. Thus, NHA selects sites that are not more than 50 km away from a city. A site musthave an existing legal road right of way connecting to a major thoroughfare.
Further, BP 220 provides for planning considerations in relation to (a) area planning, (b) sitepreservation/ alteration, (c) slope, (d) preservation of site assets, (e) ground cover, (f) easements and(g) circulation. BP 220 standards also covers design parameters in terms of (a) land allocation, (b) lotrequirement, (c) length of a block, (d) shelter component, (e) setback/yard, (f) water supply, (g)electrical power supply, (h) sewage disposal system, (i) drainage disposal system, (j) garbage disposalsystem and (h) firefighting. (Sec. 5, BP 220)
2. Site Planning Principles
Compliance to all existing laws, rules and regulations on housing (local or national). One of the lawsthat NHA has to comply with in the design of houses is the Fire Code. In NHA’s design for low risebuildings (buildings with 2 – 5 storeys that NHA has been constructing as part of the PhP 4 B-fund ofthe national government for the relocation of ISFs in priority waterways), the Bureau of Fire requiredNHA to have closed halls so that in case of a fire at a certain floor, the smoke does not go up to theupper floors. This is supposed to contain the smoke to prevent people in the upper floors from gettingsuffocated. This requirement, however, would lead to very closed buildings, which is inconsistent withgreen architectural planning. Though NHA tried to argue with the Bureau of Fire that people wouldseek to escape from a building and not stay in it in case of a fire, the Bureau of Fire made up theirminds about their requirements.
Adoption of the green infrastructure strategies and preservation of existing natural assets of the land(e.g., trees, ground cover, vegetation, natural waterways). NHA, however, is often defeated in thearea of preservation of the natural ground, because of the need to have more spaces for houses toaccommodate more families. It is hard to debate on this.
Promotion of “walkable communities”.
Promotion of appropriate community facilities and infrastructure. NHA is required to provide theminimum requirements for community facilities, such as schools and materials recovery facility.
Land use allocation per site. The general standard for landuse distribution is to subdivide a site intoabout 66 % saleable or residential housing development and 34 % for non-saleable use, such ascirculation and road network, parks and play grounds and community facilities. Most of the openspaces, however, are eaten up by community facilities. In Visayas and Mindanao regions, wheretopography is rolling, NHA can apply 60 – 40 percent landuse allocation.
For horizontal development (1-storey (loftable) or 2-storey row houses), the maximum allowabledensity per hectare is 160 units/ha. On the other hand, for vertical development (low-rise buildings),the maximum allowable density per hectare is as follows:
• 2-Storey LRB : 225 units/ha. • 3-Storey LRB : 245 units/ha.• 4-Storey LRB : 325 units/ha. • 5-Storey LRB : 405 units/ha.
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Among the changes adopted by NHA are (1) lowering the densities of houses (but not the structuralcomponents) and (2) tripping or allowing families to be relocated to check out available relocationsites from which they can select where they want to be relocated to.
Housing unit design guidelines. For the minimum floor area, NHA is now adopting 22 sqm (loftable,11 sqm) for row houses and 24.0 sqm for low-rise buildings. These are higher than the BP 220minimum of 18 sqm.
A number of proponents are presenting many technologies to the HTD Office and all claim these aredisaster resilient. New technologies or material substitutes being proposed must pass testing by theAccreditation of Innovative Technologies for Housing (AITECH).
3. Design Parameters for a Disaster Resilient House: 22 Row House Model for Typhoon YolandaVictims
A model house proposed for a 22 sqm for Typhoon Yolanda hit areas is one of the outputs generatedfrom consultation meetings held by the NHA Technical Working Group on Disaster-Resilient Housingbetween November and December 2013. NHA submitted designs for a resilient structure to DPWHthat the latter reviewed. The design for a resilient house must have the imprimatur of DPWH. Thedesign was revised on 6 March 2014 and was approved by DPWH in the last week of March. The lotsize is 40 sqm (10 m x 4 m) with a building footprint of 22 sqm (5.50 m x 4 m) and a total floor area of33 sqm (ground floor and loft).
The design parameters are the same for a single storey and a 2- and 3-storey LRBs.- Wind load: 250 kph - Seismic load: Zone 4- Strength of the wall and superstructure: 3,000 psi - Loadings: 50 PSF- Soil bearing capacity: 95 kph - Fire resistance: 2 hours
The idea to construct a loftable housing unit was proposed during country wide discussions that NHAstarted to undertake two years ago in relation to its gender and development program. Severalbeneficiaries expressed the need for privacy for women and children, as too much interaction in thelimited living spaces provides them little privacy. With a loft, a homeowner can add 2 bedrooms andthe design allows them to do this without demolishing any part of the building.
NHA used to construct at PhP 120,000. The improved design almost doubled the cost at approximatelyPhP 220,000.
22 sqm loftable rowhouse 22 sqm rowhouse with loftCost PhP 125,000.00 PhP 219,723.63Total floor area 22 sqm 33 sqm (22 sqm G/F area and 11
sqm loft)Cost per sqm PhP 5,681.81 PhP 6,658.29
The features of the model house include:
a. Introduction of a typhoon shutter (marine plywood typhoon shutters). In case of strongtyphoon similar to Haiyan, splintered glass can also kill or cause injuries. Low-income housingfamilies cannot afford metal shutters, thus, marine plywood shutters are used.
b. Use of roofing material with thickness of .40 mm (not gauge 26 because gauge 26 is notuniform among manufacturers)
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c. Use of J-bolt not tek screws (as recommended by DPWH)
d. Adjustment of the footing from .60 m to .80 m (as recommended by DPWH)
e. Addition of electric lights and outlets (as requested by mothers during past consultations heldby NHA in Bicol region)
DPWH approved the plan based on the review of design concept and analysis submitted by NHA, withthe following recommendations during the construction stage:
a. NHA must conduct close supervision of the construction to ensure compliance to theapproved plans, and
b. NHA must conduct sufficient testing of materials to verify compliance to existing DPWHstandards.
NHA admits they have lapses in ensuring sufficient testing of the materials delivered by suppliers. NHAis supposed to ask suppliers to provide basic testing of the materials they deliver, but this requirementis often set aside. For school buildings that NHA builds, however, DPWH now requires more engineersfor material supervision and testing.
4. Questions, Suggestions and Clarifications
a. Review of BP 220 standards
There is a move to review BP 22. An association called Socialized Housing Developers of thePhilippines made a petition to increase the cost of building a housing unit on an 18 sqm lot at PhP
Rear elevation of the 22 sqm row house model for Typhoon Yolanda victimsCredit B. Regala
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400,000 that was further increased to PhP 450,000. The group’s argument was that the said lot sizewas minimum standard only and that developers can add a loft to increase the floor size.
The presenter made a personal manifestation that the minimum dwelling lot size of 18 sqm needs tobe expanded. There is a debate between national housing agencies and UN agencies on the 18 sqmminimum lot size. This is not humane based on SPHERE standards.
b. Compliance with BP 220 standards in onsite communities applying for CMP
NHA stopped serving as a mobilizer for CMP applications. Implementing BP 220 standards to onsitecommunities applying for CMP is very difficult. The people are already established in these sites andmany families can live on 12 sqm houses. NHA’s project offices say they cannot persuade the peopleto leave. It is the city or municipal Building Officials (or Urban Poor Affairs Offices in the LGUs) thatmust set the minimum standards that the LGUs would allow, though implementing these can bedifficult.
TAMPEI shared about their experience in assisting an informal settler community in Valenzuela Citythat bought the land they have been occupying through auction. There is only one access road forentrance and exit, which has a width of about 4.5 m and has narrow points that can prevent the entryof a fire truck all the way through. TAMPEI facilitated workshops with the community to find solutionsin meeting the requirements of BP 220. The community came up with 2 options: (a) to widen the roadto a width of 5.5 m and, (b) to put hydrants in strategic areas. However, as the community is verydensely built, complying with the required 30 % open space is what is most challenging.
c. Compliance to LGU zoning by NHA projects
Before NHA buys a property or commences a project at a site, it requires a locational clearance fromthe municipal or city government to ensure that the land can be used as a housing site. NHA complieswith local zoning ordinances in all its projects, and all projects pass through a resolution of theSanguniang Bayan/Panlungsod for the approval of the development permit. It is only when thedevelopment permit is issued that NHA approves a project.
NHA conducts its own site evaluation and this is a major component prior to project approval. If theagency does not see that a project is feasible, it would not fund it. However, the problem with somesites arose because even though NHA’s technical staff assessed a site as “not good”, but if a developerwas able to acquire a development permit from the LGU effectively clearing the site for a housingproject, the developers could then proceed with the project. Many LGU staff have not conducted duediligence in mapping the geohazard prone areas and lack technical knowhow in assessing these andallocating sites for residential use. LGU are empowered to approve or disapprove developmentpermits. Sometimes, money works and a project becomes doable. Once a development permit isissued, NHA is compelled to approve a project. There are also cases in which communities that wantto be relocated to a site of their choice make an agreement with a developer. They then process theapplication for the permits. In such cases, the findings of the technical staff are set aside and theoption becomes to undertake mitigating measures.
The effort of NHA to promote social participation started in the 1990s. Recently, NHA introducedtripping to lessen the violent reactions of families to be relocated. For ISFs in the danger areas, theyidentify the properties where they want to be relocated, and NHA tries to guide them.
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d. Coverage area of NHA’s model housing unit
It was clarified whether NHA’s newly approved housing design, which is very expensive for low incomefamilies, is going to be set as the standard across the country, i.e., to be applied even in provinces notcommonly hit by strong typhoons. There are donors that want to build houses but could not affordthe budget for the model house.
The design is not going to be used in inland locations. For coastal areas, the standard of 250 kph isapplicable. NHA is open to new designs within the performance standards. A design for housing unitson stilts for Zamboanga was prepared with a budget of PhP 135,000; the model for this also underwentreview by DPWH.
e. Suggestion for house designs to consider multiple hazards, not only strong typhoons
All the designs being proposed to be built in Typhoon Yolanda-affected areas make use of concretematerials, supposedly to have strong houses that can withstand typhoon hazards. However,considering that Leyte and Samar are also earthquake prone islands based on PHIVOLCS’s map ofactive faults, the performance of concrete houses in case of an earthquake must also be consideredin the design of the houses. The choice of materials and overall design must consider the multiplehazards that may affect a site and not solely react to the strong winds of typhoons.
There are technologies rights now that can allow lower costs of resilient housing and it is AITECH’s jobto review these. NHA can review the donors’ house designs within the performance parameters. Forthe design approved by DPWH, NHA used hollowblocks in the benchmark for the cost. Developersmust not go beyond the approved estimate; they can go lower.
f. Some challenges in NHA’s relocation projects
There is now a need to look at the subsidy framework for post-disaster reconstruction. NHA needs tolook into the cost for the government when reviewing designs for socialized housing.
NHA does not give out the houses for free. However, it is faced with the challenge of collecting themonthly amortization from the beneficiaries. The starting monthly amortization for a resettlementhousing unit is PhP 200. Even with this amount, the collection efficiency rate of NHA is 40 %. Even inmiddle-income housing, there are members who are not paying their monthly dues and amortization.After some time, they would request NHA to pay for the maintenance of their roofs and gutters. Thissituation keeps the NHA always in a subsidy mode. Another challenge for NHA is in getting the LGUto manage the LRBs and to help in the maintenance.
B. DENR ADMINISTRATIVE ORDER 2000-28 – REQUIRING THE CONDUCT OFENGINEERING, GEOLOGIC AND GEOZAHARD ASSESSMENT (EGGA) FOR HOUSINGPROJECTS AS AN ADDITIONAL REQUIREMENT FOR THE ENVIRONMENTAL COMPLIANCECERTIFICATELiza Socorro Manzano, Mines and Geosciences Bureau-Central Office
The issuance of Department Administrative Order (DAO) 2000-28 by DENR (dated 14 March 2000),which requires that a housing project site to undergo an engineering, geologic and geohazardassessment as an additional requirement for the application of the ECC, came in the wake of theCherry Hills Subdivision landslide disaster on 3 August 1999.
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1. Rationale of DENR DAO 2000 – 28
Section 1 states the rationale of the AO.
The Philippines, by reason of its geographic, geologic and tectonic setting, is prone to severalgeologic and natural hazards. The recognition of such hazards, however, is often overlooked byland developers/planners, project proponents and the general public except when a dramatic anddevastating incident occurs, such as a strong earthquake, massive landslide or heavy floodingevent that causes great loss of life and destruction to property.
To therefore adequately and comprehensively address and mitigate the possible effects/ impactsof geologic hazards, it is hereby required that, in addition to the requirement for the issuance ofan Environmental Compliance Certificate (ECC) as provided for under Presidential Decree No.1586, residential Proclamation No. 2146 and its implementing rules and regulations, allproponents of subdivision development projects, housing projects and other land development andinfrastructure projects, private or public, shall undertake an Engineering Geological and GeohazardAssessment (EGGA).
2. Implementing the EGGA
A geological site scoping (also called geohazard identification survey) is done first by a licensedgovernment (MGB) geologist. This is an initial site geological inspection of a proposed project site byMGB geologists. The report includes recommendations on the scope of work to be covered by thedetailed engineering, geological, structural geological, geohazards assessment and geotechnicalengineering tests. Hazards that were observed to be irrelevant for a site can be excluded in the EGGA.
The EGGA can be conducted by a licensed geologist with five years of experience. A private proponentcan hire a private geologist, while a government proponent can engage the services of MGB geologiststo be covered under a memorandum of agreement. The EGGA can also be undertaken by a qualifiedengineer with five years of experience and appropriate training. The EGGA is submitted to MGB forreview then endorsed to EMB for the processing of the ECC.
3. Relevant Policies
DENR Memorandum Circular 2000-21 (issued on 24 October 2000) clarifies the coverage of the EGGAreport. All private or non-government subdivision and housing projects are required to undergo EGGAas additional requirement for ECC applications. Other land development and infrastructure projectsshall likewise undergo EGGA in connection to their ECC applications should this be required by theEnvironmental Management Bureau.
MGB issued Memorandum Circular 2000-33 (signed on 24 March 2000) setting the guidelines and anoutline or checklist for the preparation of an EGGA report as per DENR AO 2000-28 as follows:
a. Project Description (with site plan that is properly located on a topographic map) Location with inclusive coordinates (longitude, latitude), size of project area and its
general setting with respect to major landmarks (e.g., major highway, volcano, lake,etc.)
Methodology Nature and source of information. Suitable explanations should provide any technical
reviewer with the means for assessing the probable reliability of such data.
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b. Regional Setting (covers a wider area and the boundaries are defined by specific geologic ortectonic settings)
Tectonic setting Geologic setting Stratigraphy Structural Geology Geomorphology Climate and vegetation Distribution of exposures
c. Site Geology (covers the area specific to the proposed project) Geology Topography Hydrology Structural Geology Bedrock Lithology (if there are exposed outcrops) Surficial Deposits
Hazard assessment*
Geologic Hazard
- Fault-related/seismichazards
Ground rupture Ground acceleration Liquefaction Differential settlement Landslides Fault creep Lateral spread Tsunami Seiches
- Mass movement Fall Topple Slump Slide Spread Flow Complex
- Mass movement Fall Topple Slump Slide Spread Flow Complex
- Volcanic hazards Pyroclastic surge Ash fall Lava flow Debris flow Debris avalanche Pyroclastic flow Bombs and ballistics Lahar Lateral blast Tsunami Volcanic
earthquake Flooding
Hydrologic Hazard
- Fluvial / riverine Scouring Bank erosion Sedimentation Channel erosion Flooding (overflow) Flooding (sheet flow) Rill erosion Gully erosion
- Coastal Coastal erosion Flooding Storm surge Coastal subsidence Sea level rise Tsunami Submarine landslide
*The EGGAR covers all hazards although MGB’s mandate covers only rain-induced landslides and flooding,including subsidence owing to sinkhole formation.
The EGGA is not a complete assessment. It may recommend specialized studies as necessary. EGGAcontains baseline information pertaining to the hazards that may affect a project site that are notcovered in the environmental management plan. It also contains recommendations identifying thefollowing (if needed):
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- Further assessment work or specialized studies needed (such as, geophysical characterizationof bedrock for sinkholes/caverns, microseismic zoning or seismic risk assessment, floodfrequency assessment, slope stability/liquefaction potential studies, geotechnical evaluationand engineering tests, erosion and sediment transport/budget studies, hydrogeologicmodeling, etc.)
- Mitigating measures (for site planning/realignment of structures; for the design of engineeredstructures, drainage and slope stabilization controls, etc.)
- Monitoring (such as regular inspections or measurements during the construction stage)
The minimum map requirements for the conduct of the EGGA include (a) regional geologic map, (b)site geologic map, (c) relevant hazard map, (d) stratigraphic column, and (e) engineering geologic map.A minimum site topographic map may be in 1: 50,000 scale, but if the project site is less than 5 ha, theproponent must submit 1; 10,000 scale map.
MGB signed a memorandum of agreement (MOA) with EMB and HLURB for the implementation ofDENR AO 2000-28 (dated 22 May 2000). The responsibilities of these government agencies specifiedunder the MOA are:
a. Environmental Management Bureau- requires all housing and land development projects to submit EGGAR report- informs HLURB of projects already with ECC but may need to undergo EGGA- issues certification as to compliance of or exemption from EGGA
b. Mines and Geosciences Bureau- provides expertise on request- conducts GSS- evaluates/verifies pre-DAO 2000-28 EGGAR
(The expenses are to be shouldered by the requesting party.)
c. Housing and Land Use Regulatory Board- requires pre-DENR AO 2000-28 projects with certification of compliance of or exemption from
EGGA- informs EMB and MGB on monitoring of projects that may need EGGA
As set in the process flow of an EGGA application, the EGGA report is reviewed by an MGB TechnicalCommittee before it is submitted to EMB. It is possible for a proponent to go straight to conduct ofthe EGGA and not undergo geohazard identification survey by an MGB geologist.
4. Questions, Suggestions and Clarifications
a. Average processing time for EGGA application
The processing period depends on the submission of requirements, volume of applications receivedby MGB and availability of MGB geologists. The first stage is site scoping with recommendations onwhat is to be covered by the EGGA.
For the CMP sites of SHFC that applied for geohazard assessment, there was one site that did not givea location map thus causing delay.
b. Whether or not EGGA is applied in government projects
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Government projects funded by the national government or international donors are not exempt fromthe EGGA requirement. The DAO is clear that it applies to all housing projects. If it is not compliedwith, a private citizen can challenge the implementing government agency to undertake it.
LGUs are supposed to require the ECC when processing an application for development permit, butnot all are strictly requiring this.
c. Review process of geohazard assessment recommendations within MGB
There may be a need to strengthen the review process of geohazard assessment reports by MGB. Inthe case of Freedom to Build’s housing site, the assessment of the private geologist recognized thehigh susceptibility of the site to flooding. While the private geologist cited studies with projections ofhigh flooding levels in case of high rainfall, the final recommendations was referenced on a muchlower flood height during a recent flood event. Thus the recommendations were not commensurateto the high level of risks.
d. Waiving of the fee for geohazard identification survey for disaster affected areas
A fee of PhP 6,000 is required for the conduct of geologic identification survey by MGB. After TyphoonReming, MGB-Region V waived the fee for self-initiated relocation efforts out of consideration thatthe proponents were disaster-affected families. This is a good practice that is proposed to be adoptedby other regional MGB offices.
C. THE VALLEY FAULT SYSTEM AND SEISMIC GAPS: WHY THE STRUCTURAL CODE OF THEPHILIPPINES SHOULD BE REVISEDRamon Quebral, AMH Philippines
The position paper explains the need to consider seismic gaps, which is a discussion point foramending the NSCP.
Several criteria are used to determine whether a fault is active or not, including seismic data(instrumental), historical accounts, geological evidence.
The Valley Fault System is not associated with any seismic activity. However, there is geologic evidenceto show that the faults are definitely active. It is therefore associated with a seismic gap.
The National Structural Code of the Philippines defines Seismic Source Type A as faults that are capableof producing large magnitude events and that have a high rate of seismic activity. Under thisdefinition, the Valley Fault System is not technically a Type A Fault. That it is creeping or movingaseismically is not a guarantee that it will not move catastrophically. The Anatolian Fault in Turkey, forexample, crept before and after moving catastrophically.
This runs counter to the intent of the Metro Manila Earthquake Impact Reduction Study (MMEIRS) ofMMDA-JICA-PHIVOLCS. In this case, the risk is actually higher despite the absence of seismic activitybecause stress is accumulating and is not being released. However, the structures near these faultsmay be under-designed. It is the low and medium rise buildings that are vulnerable; measures toimprove the resilience of these structures to seismic hazards need to be explored.
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The code should therefore takeinto consideration the concept ofseismic gaps. It should be notedthat certain segments of thePhilippines Fault might also beassociated with seismic gaps.They are candidate sites formajor earthquakes in spite oftheir seismic quiescence. NorthBohol is a good example. All thewhile it is there, but it was notknown until it generated a strongearthquake. It is recommendedthat Type A Faults be redefinedsimply as faults that are capableof producing large magnitudeevents. This is regardless ofwhether they are associated witha high rate of seismic activity ornot.
Questions and clarifications
a. Revision in New Code
Acknowledging the suggestion of the presenter, Engr. Villaraza shared that in the new Code, it wasdecided that faults are not going to be defined into Class A or B. The Code advises project proponentsto consult with PHIVOLCS to identify whether or not a site is close to active faults.
Caution was raised about adopting standards of foreign codes. For the California Code, California isunderlain by continental crust, whereas the Philippines is underlain by oceanic crust. Philippine codesmust not adopted in toto foreign code. The Uniform Building Code (UBC) has own limitations: it doesnot use the seismic code.
The participant from PHIVOLCS agreed on revising the definition for Type A faults. The low- andmedium rise buildings are more vulnerable to West Valley Fault.
b. Whether NHA housing units to are designed to withstand a magnitude 7 earthquake
Based on MMEIRS, the West Valley Fault is capable of generating intensity 8 earthquake. Based onprobabilistic study, it can generate intensity 5.6, but also a 7 magnitude earthquake.
All of the houses built by NHA are designed by structural engineers. The first generation houses (1997-2003) were designed by DPHW. For the LRBs and new generation housing units (last year), NHA doesnot have in-house design structural engineers and consulted DPWH. Compliance to the Code dependson whether or not the engineers involved are knowledgeable of their code.
c. Proposal for PHIVOLCS to increase buffer zone of higher buildings from fault lines
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Engr. Villazara suggested for PHIVOLCS to increase the 5-meter buffer zone from both sides of faultlines for high-rise buildings. The 5-meter buffer may be adequate for houses. For high-rise buildings,the buffer must be at least 1 km.
D. DRAFT HOUSING CODEMiriam Tamayo, Association of Structural Engineers of the Philippines
The Association of Structural Engineers is drafting Volume 3 of the National Structural Code of thePhilippines to come up with a housing code that ensures the safety of people and property againsthazards.
1. Reality-check on Current Housing Construction Policies and Practices
A reality check on house construction practices shows some gaps and weaknesses in people’s know-how.
There are many non-engineered houses in the country, existing and still being built. Even engineeredhouses are non-compliant with prevailing codes. Even after the Bohol earthquake on 15 October2013, the local residents whose houses were damaged were re-building their houses and were doingthe same wrong practices. There is lack of awareness of what caused the damages to the houses. Thecollapse of non-engineered structures during an earthquake or typhoon can be due to:
- Absence/lack of reinforcement- Poor quality of materials, e.g., use of sea sand in concrete mixes, sub-standard CHB- Free-standing parapet walls- Small sizes of structural elements- Absence of lateral-force resisting system- Soft storey (top heavy)- Inadequate anchorage
The National Building Code exempts some houses from earthquake analysis. Under the NBC, housesless than 7.5 m high are not required to submit earthquake analysis. On the other hand, the NSCPrequires earthquake analysis for all structures. The NBC, however, is the “mother code” and thustakes precedence over the NSCP.
The present NSCP Volume 1 is deemed very stringent for houses and is, therefore, not followed. Acommon attitude that one is building “just a house, not a building” makes people less mindful aboutstandards. In the construction of houses, there are “experienced” workers with the wrongexperiences. Also, overloading is common. People think that a concrete house is necessarily strong,thus, they can load it.
There is no strict implementation of product standards for housing construction. To address this, ASEPwas invited by NHA to be member of AITECH to participate in the testing, review and approval ofalternative housing materials.
The typical concerns where professional services are sought include the following:
- Structural configurations, such as unusually long floor spans, unsupported wall heights,large openings or long-span cathedral ceilings
- Loading conditions, such as high winds, high seismic risk, heavy snows or abnormalequipment loads
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- Nonconventional building systems or materials, structural steel, or unusual connectionsand fasteners
- Geotechnical or site conditions, such as expansive soil, variable soil or rock foundationbearing, flood-prone areas, high water table, or steeply sloped sites
- Owner requirements such as special materials, appliance or fixture loads, atriums andother special features
2. Salient Features of the Draft Housing Code
Overall, buildings codes are instituted for the protection of public safety and welfare. The HousingCode/NSCP-Volume 3:
a. is applicable to 1 – 2 storey family dwellings.
b. provides prescriptive limits for column-spacing and floor-to-floor heights (2.83 – 3 height fromthe floor to the ceiling) for more appropriate sizing for houses.
c. covers (a) reinforced concrete construction, (b) wood construction and (c) light gageconstruction.
d. provides a simplified presentation of minimum loads. It has tables and formula for typicalstrengths. There are some engineers who make the computations but come up with wrongvalues. A simplified formula can be used by general civil engineers (who are not specializedstructural engineers).
e. provides minimum sizes and reinforcements for “typical cases”, especially for masonry.
f. contains appendices on the following:
- Detailing for earthquake-resistant structures. At the project sites, people have the correctnumber of bars and columns, but anchorage requirements are not meet.
- Detailing for typhoon-resilient structures. NHA’s requirement of 3000 psi for low-costhouses is high; 2,000 psi can suffice for low-cost houses.
It was reported that DWPH required design wind force to be based on 300 kph. However,ASEP’s position is that any change in NSCP standards must be based on technical data,and not just on a one-time event.
- Site selection. The Housing Code is going to incorporate what is learned from theworkshop on site selection. It includes a portion on soils and site conditions. Not alldevelopers or house owners are willing to pay for soil test, because a single bore hole canbe expensive. It is important to engage credible engineers to conduct the soil test.
- Composite construction
- Alternative materials
NSCP-Volume 3 focuses on critical construction details related to the building envelope, such ascorrect spacing of roof sheathing nails, adequate use of roof tie-downs, window protection. It putsemphasis on construction quality. The Housing Code simplifies wind and seismic design requirements
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to a degree commensurate with knowledge and uncertainty as to how homes actually perform. It alsoemphasizes design precautions against locating homes in steep slopes and weak soils.
Revising and updating the codes does not guarantee that the objective of safety is met. For the codesto be effective, these have to be complied with by the public and effectively implemented by thegovernment.
3. Questions, Suggestion and Comments
a. Inclusion of standards for 3 – 5 storey buildings for low-cost housing
It was proposed for the Housing Code to cover buildings with more than 1 – 2 storeys. Verticaldevelopment is an emerging option for low-income housing in urban areas where there is limitedspace. The low-rise buildings can be three or more levels, but there are no guidelines for these low-rise buildings.
b. Inclusion of consideration of river channels in site selection
It was also proposed that the appendix on site selection must include considerations of the locationof the sites in relation to river channels and sites prone to storm surges. The Housing Code can raiseprecautions against sites that are prone to flood or storm surges. It is easier to get data about slopes;ASEP does not yet know where to get river channel data. Data about channels may need a hydrologist.
c. Process for preparing the Housing Code
In coming up with the Code, ASEP updates with foreign references and customize for applicability inthe Philippine context.
ASEP is going to submit the draft code to DPWH for approval. DPWH serves as the national BuildingOfficial, and this role empowers DPWH to change the code through a Memorandum Circular. DPWHis going to review the draft code and, when once approved, the Housing Code becomes a referral Codefor the National Building Code. It needs to be clarified that the National Building Code is a law, andthe NSCP is a reference code. While the reference codes can be updated and changed, amending theNBC requires legislative act by Congress.
It is targeted that NSCP-Volume 3 be submitted this year with the help of NHA. Arch. Regala, the headof HTDO-NHA proposed that NHA and ASEP collaborate, with other stakeholders, on the finalizationof the Housing Code and getting it approved. Toward this end, NHA and ASEP will consult with DPWHon structural designs and meet with HLURB on the regulations of BP 220.
d. ASEP’s initiatives
Aside from regularly updating the NSCP, ASEP is also planning to develop a manual for non-engineeredhouses. For the manual to be more easily understood by the public, it was suggested that it be writtenin Tagalog and in graphic formats.
Members of ASEP are developing and updating the draft housing code for free. ASEP uses its ownresources when it sends out engineers for field services after disaster events. To help sustain andexpand ASEP’s activities, ASEP appeals for some assistance.