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DISSEMINATION OF SEISMIC RETROFITTING TECHNIQUES

TO RURAL COMMUNITIES IN PERU

J. Macabuag, Building Design Partnership (BDP), UK.

joshua.macabuag@pmb.oxon.org

Prof D. Quiun, Pontificia Universidad Católica del Perú, Peru.

dquiun@pucp.edu.pe

ABSTRACT: (10 pt)

The Andean region demonstrates a high proportion of earthquake-vulnerable adobe (mud-brick) construction amongst poorer communities, whilst being within a highly seismic zone. Several adobe earthquake-retrofitting techniques have been developed by organizations across the world and the appropriateness of each technique is dictated by the local topographical, economical and cultural conditions. However, dissemination of these techniques to the many communities at risk is a very significant challenge. Several community dissemination programmes conducted in Peru are examined. These programmes show that beneficiary participation is key but lessons are lost over time, highlighting the requirement for long-term intervention. Examining the financing of these programmes shows that operational costs of NGOs are a significant barrier to long-term involvement, highlighting that local municipality capacitation is a necessary feature of any community project. Revisiting previous programmes also reveals that communities are not self-funding the reinforcement of homes, showing that greater awareness and financial incentive are required. Finally recommendations are made as to the key features of successful projects and the larger-scale interventions required to support these programmes.

Keywords: Adobe, Developing countries, Non-engineered, Masonry, Seismic engineering

1. INTRODUCTION

The vast majority of earthquake fatalities in the last century have resulted from building failures with a growing disparity between vulnerability of those in developing and developed countries. The greatest risk is by far presented to inhabitants of non-engineered adobe structures (Figure 2) as demonstrated in the 2003 Bam (Iran) earthquake, where many of the thousands of deaths were attributable to vulnerable adobe (sun-dried mud brick) structures. This is due to the nature of the material (high mass, low strength, brittle) and, in the case of non-engineered housing, also the lack of proper design and maintenance.

Figure 1: Examples of typical failure modes for non-

engineered masonry dwellings [Blondet].

Figure 2: Non-engineered adobe in Condesuyos, Peru. Vertical crack typical of poorly bonded orthogonal walls.

Walls are adobe blocks laid in mud mortar. Roof consists of timber planks covered with corrugated sheeting.

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1.1. Housing in Peru

In Peru, 35% of the population still resides in earthen dwellings despite poor performances of these structures in major earthquakes in 2001 (south Peru, Mw=8.4) and 2007 (central Peru, Mw=8). As an example, consider the Provinces of Castilla and Condesuyos, areas of the Peruvian High Andes that were heavily affected by the 2001 Peru earthquake. Most families survive on agriculture with 50% earning less than $115pm including 20% on less than $60pm per household. 72% of homes are adobe with 40% less than 40m2 and of only 1 or 2 rooms. Half of the houses are constructed solely by members of the family, with structural defects common (Figure 2). Many of the houses are built in unsafe zones: e.g. on steep inclines or areas of loose soil with a high risk of land slides or rock falls [Perez-Palma]. In less rural areas there is a growing trend towards confined masonry, consisting of load-bearing unreinforced masonry walls made of clay brick units, confined by cast-in-place reinforced concrete tie columns and beams. Table 1 suggests that engineered confined masonry construction is beyond the means of a large proportion of the population in remote rural areas. However, adobe is often associated with poverty meaning that those with limited means are opting for non-engineered masonry or confined masonry leading to poor quality construction (Figure 3a) or vulnerable hybrid structures, combining materials inappropriately (Figure 3b).

Table 1: Financial and legal comparison of confined masonry and adobe dwellings. Construction type: Engineered Confined Masonry in

Urban Areas

Non-engineered Adobe Dwellings in

Rural Areas

Construction cost $200-250/m! $20-30/m! Built by Developers Village artisans, home owners

Building Regulations Building permits must be issued by Municipal authorities. Four types of technical drawings are required: structural, architectural, services and electrical

Although there is a Peruvian building standard for adobe construction (Norma E.030) there is no process for building code enforcement in rural areas

Typical income bracket of owner

Middle - high income ($12,000 - $60,000 pa)

Very poor – poor ($700 - $1000 pa)

Land tenure and financial loans

Land and properties properly registered allowing access to lines of credit

Often no title deed for properties, excluding people from loan applications

Earthquake insurance Typically available Unavailable

a: Non-engineered confined masonry dwellings

in Chincha that performed badly in the 2007 Peru earthquake.

b: Non-engineered hybrid structure in Lunahuaná displaying slender adobe walls with long clear spans supporting a

concrete ring beam with no vertical tie members. Figure 3: Non-engineered structures using modern construction methods resulting from the negative perception

of adobe but limited means of the homeowner. 2. OBJECTIVES

What are the main technical, social and economical considerations for the dissemination of seismic retrofitting techniques to remote rural communities? This paper aims to:

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• Highlight key successes and failures of previous programs for the dissemination of seismic retrofitting techniques in rural Peru.

• Propose a general model for projects to disseminate seismic adobe construction/retrofitting techniques to rural communities and outline the larger-scale interventions required to support these programmes.

3. COMMUNITY DISSEMINATION PROGRAMMES IN PERU

3.1. Post-Earthquake Reconstruction Programme, Region of Arequipa (2001-2002)

Steel wire mesh reinforcement utilizes strips of mesh often used for fencing in parts of South America, nailed to adobe walls in vertical strips connected to each other by a horizontal strip or ring beam (Figure 5) [Quiun]. As a pilot project, 20 existing houses in six towns across Peru were retrofitted with the steel mesh with five of these being two-storey accommodations. Six retrofitted houses were affected by a major earthquake in 2001 (south Peru, Mw=8.4) and five retrofitted houses by an earthquake in 2007 (central Peru, Mw=8). These houses demonstrated no damage, while neighbouring constructions of traditional adobe houses without reinforcement showed heavy damage or complete collapse (Figure 4). The success of wire mesh reinforced houses during the 2001 Peru earthquake motivated several reconstruction programs for new adobe houses in remote Andean towns within the Region of Arequipa incorporating this wire mesh system.

a: Partially reinforced wall in La Tinguiña. Performed well in the

2007 earthquake.

b: 2-storey reinforced house in Andahuaylillas, Cuzco.

c: Undamaged reinforced house in Moquegua after 2001 earthquake and

neighbouring unreinforced house [Quiun]. Figure 4: Existing adobe houses retrofitted with steel mesh reinforcement.

3.1.1. Phase 1: Post-Earthquake Reconstruction

360 reinforced adobe houses (Figure 5) were built in the Arequipa region as a collaboration between several organizations. The project was funded by the German Technical Cooperation Agency (GTZ), the design of the adobe houses was carried out by the Pontifical Catholic University of Peru (PUCP) and the Peruvian National Service for Capacity Building and Research in Construction (SENCICO), and implementation was carried out in collaboration with the special project of the Regional Government of Arequipa (COPASA). The project aimed to reduce the future vulnerability of the participating communities by engaging them in the construction process, so increasing their capacity to build and reinforce earthquake-resistant houses in adobe, the primary construction material in the region.

Figure 5: House design for reconstruction programme. Incorporates steel wire mesh at intersection of orthogonal

walls, RC ring-beam and timber roof [San Bartolome].

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Members of PUCP conducted a five-day training course in construction of the reinforced adobe houses for 20 SENCICO technicians plus 42 selected rural persons from high-risk communities. The members of the community then built their own houses under the supervision of the trained maestros. Each mason was assigned two assistants and supervised the construction of up to three houses at any one time. COPASA-GTZ technicians supervised the rural construction three days per week and each zone had one permanent SENCICO technical supervisor. The programme was in collaboration with the local government. 360 houses of 36m2 plan area were constructed within 17 months with construction costs of approximately $1700 per house (approximately $50/m2) (Error! Reference source not found.). GTZ-COPASA provided 67% of the cost of the house with the beneficiaries providing 33% mainly through the supply of local unskilled labour and local materials. 3.1.2. Phase 2: “Protection from Natural Disasters with a Focus on Food Security”

Phase 2 sought sustainability of the intervention by motivating the communities to strengthen their homes. Several public workshops showed videos of phase 1 and instructional material was distributed on anti-seismic adobe construction and the manufacture of adobe blocks. The public was then engaged in the construction of public buildings such as school classrooms and small health centres. 30 trained masons from phase 1 were employed to facilitate. 3.2. Pilot Project to Construct a New Town: Ruruca, Arequipa (2007 - 2008)

The pilot project of Ruruca was intended to enable the development of a government model for a program of capacitation and mass dissemination of safe, low cost rural houses to vulnerable communities. The new town of Ruruca consists of 17 adobe houses reinforced with a number of different seismic resistant systems. The local municipality conducted the planning for the new town, collaborating NGOs and technical agencies provided training and materials for reinforcement and the new community constructed their own houses, paying for the basic construction costs (i.e. not including the cost of reinforcement). 7 masons were employed with experience of reinforced adobe through the Arequipa programme (section 3.1). The 64m2 modules had final construction costs of $5270 ($83/m2). 3.3. Reconstruction programme following the 2007 Pisco Earthquake (2008)

Following a major earthquake in 2007 (Mw=8) near Pisco a team from PUCP and the NGO CARE-Peru designed a program for reconstruction and mass dissemination of seismic construction techniques in adobe utilizing a reinforcing technique that uses a polypropylene mesh (commonly used for fencing) to provide confinement of walls [Rubiños]. This project was carried out with the collaboration of SENCICO and the Fund for the Reconstruction of the South (FORSUR), an autonomous fund created by the Peruvian National Government to lead the post-earthquake reconstruction process.

a: Example house reinforced with the plastic mesh, used during the initial training of masons, engineers and

NGO personnel [Rubiños].

b: Fabrication of adobe blocks in Cañete, carried out by hired masons

[Rubiños].

c: Completed house in Chincha Baja, constructed by the public under supervision (after theoretical workshops and practical

exercises). 9 houses were completed throughout Cañete, Chincha and Pisco.

Figure 6: Various stages of the post-2007 reconstruction and capacitation programme.

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Key stages of the project are shown in (Figure 6). The community capacitation programme incorporated literature and videos and taught 883 in theoretical workshops and 276 in practical exercises and live construction. The construction of each 4-roomed, 50m2 house cost $3,155 ($65/m2). 4. DISCUSSION AND CONCLUSIONS

4.1. Main Findings

All adobe houses built in these programmes were intact and performing well, with the exception of some errors due to lack of full-time supervision (Figure 7a). Other NGO and cooperation agency-led programmes in nearby areas followed on from these programmes using similar models. E.g. following the Arequipa programme (section 3.1) 97 houses of the same design were built in the Arequipa region of Yarabamba in a project managed by SENCICO and funded by the Italian Government and UNDP. NGOs and cooperation agencies led and bore the brunt of the costs in the programmes presented. E.g. in Ruruca (section 3.2) the modules had construction costs of $5270: 77% borne by the technical agencies (COPASA-GTZ and COSUDE), 20% by the beneficiaries and 3% by the local government [COSUDE]. Note that for the technical agencies involved, when considering overheads and operational costs they collectively incurred a total cost of $7,841 per module. This represents an additional 93% over the purely construction costs incurred by them, showing that operation costs are a significant consideration for NGOs and technical agencies involved in rural construction projects. Following the programmes no self-funded adobe dwellings have been retrofitted or built with reinforcement. Several non-reinforced adobe structures built by communities after the programmes also showed errors (Figure 7), showing that many lessons had been lost because of no further training input after the initial programmes. One reason that communities members named for not funding the reinforcing of their own homes was that although the reinforced adobe dwellings were considerably cheaper than confined masonry they were still more expensive than unreinforced adobe (Table 2). However, consider the case of the Arequipa programme where the difference in price between reinforced and traditional adobe houses was nearly $1000 but the cost of the reinforcement was only $112. The difference comes in additional features such as a ground slab and foundations, concrete ring beam and more expensive roof construction. Therefore, the basic mesh retrofit to an existing house would cost less than Table 2 would suggest, and fulfil the basic goal of preventing or prolonging collapse provided other structural repairs are not needed. However, this basic cost may still be beyond the means of many families. Another reason named for lack of take-up by the communities was the poor perception of adobe. Many of the wealthier families were reconstructing their homes of masonry or confined masonry, especially in Pisco and Chincha (section 3.3) where materials are readily availability in nearby urban centres. However, many of these confined masonry houses had multiple stories and showed dangerous defects such as exposed rebar and unsupported ring-beams (Figure 3).

a: Rear wall being used as retaining wall to a

public road. b: Holes cut into wall for electrical and mechanical

services, undermining the wall connection and forming a hole in the reinforcing mesh [photo: Chuquimia].

Figure 7: 2001 reconstruction project in Arequipa: Errors in construction or subsequent modifications.

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Table 2: Comparing construction costs for different building methods [Haider]. Total cost Cost/m2 Relative cost Traditional adobe $850 $24 100%

Steel mesh reinforced adobe $1,774 $50 217%

Confined masonry $3,400 $95 408%

Figure 8: Breakdown of construction costs for 36m2 reinforced adobe house in the Arequipa Reconstruction

Programme ($1774/house) [Haider]. 4.2. Recommendations for community dissemination programmes of anti-seismic adobe

construction and retrofitting techniques

The respective roles for community dissemination programmes are summarized in Figure 9 and the necessary features of the programmes are given below:

Preparation phase: • National or regional government by-in, as shown in Figure 9, is required to feasibly conduct a

sustainable, larger-scale dissemination programme.

• Widespread awareness and training programmes must be conducted to promote the lesson that adobe houses must be reinforced.

• Local municipalities must be engaged to support the programme and empowered to repeat aspects of these programmes at regular intervals so that lessons will not be lost.

Capacitation phase: • Training for the NGOs and technical agencies, masons and general population must consider the

level of experience and education of the persons being trained.

Implementation phase: • Participation of the beneficiaries is key. Careful selection of beneficiaries and monitoring of

progress is required to prevent mistakes being made and repeated.

• Technical assistance is required in site selection, selection of soil for adobe and pouring of ring beams if required.

Post-completion phase: • Long-term intervention by local municipalities is required to promote and support safe adobe

construction/reinforcement and reduce unsafe practices.

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Figure 9: Interrelation of organizations for programmes of mass-dissemination of seismic retrofitting techniques [adapted from Rubiños].

4.3. Recommendations for scaling-up the response to vulnerable housing

• Regions must be identified whereby adobe is the predominant material and it is inappropriate to promote other materials (due to local poverty and inaccessibility of the region).

• Building codes for adobe construction in seismic regions must be developed in order for governments to be able to support the construction of public buildings of adobe in remote areas. Some countries do have empirical guidance on adobe reinforcing but not on detailed analysis of adobe structures that would allow accurate, engineered designs.

• Local governments must lead by example in areas of predominantly adobe construction by constructing public buildings (e.g. municipality offices) of engineered adobe and engaging the community in the construction of these buildings.

• Government incentive programmes need to be established to financially assist communities to reinforce existing adobe structures, reducing future vulnerability.

• Given the high operational costs of NGOs and cooperation agencies acting in remote locations and the dangers of unsupervised self-construction in adobe, local municipalities must be empowered to support repeated construction and retrofitting programmes at regular intervals so that knowledge is not lost with time.

National or Regional

Government

Grant or apply for funding for mass-dissemination

programmes

Multilateral Financial

Institutions

Grant funding and advise on programme

Funding Administrator

Administer the funding to the enacting organizations and obtain

materials etc

Private Sector,

Government Technical Departments,

Universities Transfer the necessary technical and procedural

knowledge

NGOs,

Cooperation Agencies

Implement the proposed programme

Masons,

Target Communities Learn the retrofitting technology

and provide hand labor in construction/retrofitting Regional and Local

Government

Support the implementation of the programme,

carry out legal processes of land allocation, planning

permission etc, provide long-term support for continued retrofitting within

community

Retrofitted Homes

Long-term support

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4.4. Key Lessons Learned

• The buildings most at-risk are built without engineering input, so programmes must target communities directly. The “cascade” model (training technicians to teach a larger number who then supervise self-construction) is an effective way of reaching large numbers of the community whilst minimizing cost.

• Remote communities cannot afford well-constructed houses using modern methods of construction. However, these communities are not using reinforced adobe at their own cost due to other basic needs and the poor perception of adobe. This shows that financial incentives are required and that public adobe buildings are needed to raise confidence in adobe as a construction material.

• Lessons taught to communities are lost over time. Therefore, long-term interventions are essential.

• Operational costs are a significant proportion of the total project costs for NGOs and technical agencies, making long-term interventions difficult. Local municipalities have long-term presence but lack capacity and funding. Therefore, capacitation of local municipalities is a necessary feature for the sustainability of any community project.

ACKNOWLEDGEMENT

The research was funded by the Educational Trust of the Institution of Structural Engineers through the Pai Pan Li travel grant 2009. Many thanks to the following for their invaluable assistance and guidance throughout the field investigation in Peru: Arch. Patricia Cardenas of SENCICO, Arch. Edward Chuquimia and Juan Carlos for their guidance in Arequipa; Urbano Tejada, Mr Salustiano García, Alvaro Rubiños and Stefano Bossio for their assistance around Pisco and Chincha; Erik Trigoso and Jesika Rodriguez for their support in Trujillo; Prof Julio Rojas Bravo for his help in Cusco and Nancy Trujillo and the staff of PUCP for hosting the investigation.

REFERENCES

Blondet, Marcial and Garcia, Gladys V. (2006), World Housing Report: Adobe Construction, World

Housing Encyclopedia (electronic report on the Internet).

COSUDE (2008), Sistematizacion del proyecto piloto de vivienda rural en rururca – region Arequipa.

Haider J., Chuquimia E., Huerta J., (2005) “Retos en la Adopción de Tecnología Sismo-Resistente para Viviendas de Adobe en la Sierra Peruana”, proc. SismoAdobe, Peru.

Rubiños A. (2009) Propuesta de Reconstruccion Post-Terremoto de Viviendas de Adobe Reforzado, Civil Engineer (Masters) Thesis, Catholic University of Peru.

Perez-Palma, P. (2004) Estudio socioeconomico de las familias participantes del Proyecto Cuencas

Andinas y Proyecto de Gestion de Riesgo de Desastres Naturales con Enfoque de Seguridad

Aimentaria de la Zona Castilla y Condesuyos – Arequipa, COPASA-GTZ, Arequipa, Peru.

Quiun D. (2009) World Housing Report: Reinforced Adobe, Report Num 107, World Housing Encyclopedia (electronic report on the Internet).

San Bartolome Á., Quiun D., Zegarra L. (2008) “Performance of Reinforced Adobe Houses in Pisco Peru Earthquake”, proc. 14WCEE, Beijing.