day3 10 construction in hazardous environments

8/3/2019 Day3 10 Construction in Hazardous Environments

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Shelter Training 08b – Belgium, 16th –18th November, 2008based on content developed by

based on content developed by

Construction in hazardous environments

This session will look at both the security hazards and the natural hazards

that effect the construction and planning of settlements

65

Bam, Iran, 2003





Session objectives

The key learning objectives of this workshop are to form an understanding of :

1. Workshop: group discussions on hazards affectingconstruction and planning

2. Presentation: security hazards including gender,protection and conflict

3. Presentation: natural hazards including flooding,earthquakes and landslides





Session objectives









Discussion: 1

Each group has been allocated a type of hazard:

Group 1: conflict

Group 2: flooding

Group 3: earthquake

Group 4: storms

Group 5: landslides

Discussion in groups





Discussion: 2

In your groups, discuss and drawthe following measures that can help toreduce peoples vulnerability :

1. any construction details orprocesses specific to the hazard

2. the key planning and siteconsiderations for a plannedsettlement

3. the appropriate preparation or ground works that should becarried out before construction

begins

Key point

1. construction

2. planning

3. ground works

Each group agrees a key point

Discussion in groups





Session objectives






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Security: gender based issues

The following methods can reduce gender based discrimination:

design and construction

• in most communities, women bear the primary responsibilityundertaking household tasks should be reflected in design

• latrines should not be located in poorly lit or remote areas• privacy and security is of primary importance, particularly

during the night when risk of assault is high• in many communities women and girls expect to be provided

with private spaces for activities such as changing clothes

site selection

• sites should not be located near borders as this canincrease the risk of abuse, abduction or forced recruitment

• site planning should ensure accessible services and

resources to lower vulnerability of, for example, childrentravelling long distances to school, women collecting waterand firewood

• overcrowding can increase vulnerability, for exampleviolence against women or young men being recruited intogangs or rebel groups

Women, Girls,Boys and Men (IASC, 2006)



Protection: vulnerable groups

The following groups of people will need specific attention:

• displaced unaccompanied children, are at particular risk

from lack of appropriate shelter, for example, trafficking,violence, abuse and exploitation, therefore safe housingshould be arranged and monitoring procedures initiated

• unaccompanied older persons may also need targetedsupport if they are forced to construct their own shelters

• ethnic or religious minorities may find themselvesmarginalised by the displaced and/or the host population

• displaced families who do not own land or property may beeven more vulnerable due to unclear legal support

mechanisms

Handbook for the Protection of Internally Displaced Persons (Global Protection

Cluster WorkingGroup, 2007)

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Conflict: types of building damage

There are multiple hazards specifically associated with securitythreats that may impact upon the built environment, for example:

direct damage or threats to buildings from:

• small arms, artillery fire, missiles, rockets and aerial bombardment

• unexploded ordinance (UXOs)

military activity for strategic military or political objectives, such as:

• area denial weapons, such as land mines and booby traps• demolition charges• use of bulldozers to clear land• arson

building vandalism caused by:

• illegal building occupancy• civil unrest

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Conflict: vulnerability of buildings

The extent, severity and vulnerability to damage depends on thetype of building as well as the hazard, for example the;

• vulnerability of factories, apartment blocks, detached housesand commercial properties will depend on strategicimportance, proximity to the front line and the topography of the surrounding area

• method of construction will effect a buildings vulnerability to

certain hazards, for example, this may depend on whether astructural frame or load bearing masonry is used

• materials used and their associated properties, such asresistance to fire, tensile and compressive forces

• location of the damage and its effect on the buildingsstructural stability, access and usability

Guidance from a structural engineer is required to determine ifdamaged buildings should be repaired or demolished prior toreconstruction.

S i bj ti



Session objectives





N t l h d i68



p Natural hazards: an overview

The main types of natural hazard that can pose serious risks tothe built environment are:

floods

earthquakes

tsunamis

landslides

volcanoes

fires

storms, and toxic environments

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N t l h d fl d69


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Floods can occur:

• following sudden rainfall or snowmelt

• when rivers break their banks• as a result of surges in sea level• as a result of rising ground water

Building design options include

• raising the building on plinth

• relocating the building locally to higher ground• raising the building on stilts• building strong columns and roof, but sacrificial walls that

are washed out in floods• clear openings on opposite sides of the building parallel to

the likely direction of water flood, such as under raised floors

• strong corners and foundations to resist scouring, beams barriers to divert flows and debris

Support traditional risk management techniques where possibleas this can help identify safer areas that are less likely to sufferfrom flooding.

Natural hazards: floods69

N t l h d th k74




p

Earthquake resistant settlement planning should ensure that:

• settlements are not located on alluvial plains, unstable soils,

reclaimed land, unstable or steep slopes• buildings are spaced to avoid multiple collapse

Earthquake resistant building design should be appropriate to:

• geographic location• economic group• traditional construction

Design components may include:

• a series of 3 ring beams per floor• ‘through stones’ joining front and rear faces of rubble masonry

• columns able to take tension and compression• regular buttresses and dividing walls• continuous structural linkage between all building elements• fatigue stress is taken into account and effects monitored• square or rectilinear plans are used where possible

Natural hazards : earthquakes74

N t l h d t i83




p

A tsunami is a large wave, or series of waves usuallycaused by:

• an earthquake• volcanic eruptions• underwater explosions or landslides

In tsunami prone areas site selection should ensure thattransitional settlements are located on high ground away fromthe sea.

The impact of tsunami on settlements and populations can bemitigated through:

• relocation of communities at risk

• identification of high ground for evacuation• identification of escape routes• reinforcement of flood defence systems including

through natural barriers such as reef, mangrovesand sandbanks

• provision of Early Warning Systems

Natural hazards : tsunami83

N t l h d landslides78




p

The term ‘landslide’ includes rock slides, rock falls, tree slides, mud

slides, debris flows, and avalanches

Past landslides should be assessed, including through consultationwith local communities

Landslides tend to occur on steep slopes or where land isundercut by water

One indication of previous landslides is vegetation at a different

level of growth from surrounding areasFactors which can increase the risk of landslides:• deforestation• overgrazing• heavy rainfall

Foundation design can mitigateagainst the effect of landslidesWhere possible settlements shouldnot be located in areas prone toLandslides. Properly draining a sitecan also prevent landslides

Natural hazards: landslides

less danger oflandslides

damaging thesettlement

bend of river: risks ofwater undercutting land,causing landslide

landslide risk to settlement

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Nat ral ha ards volcanoes82




p

Volcanoes produce various types of hazard:

• hot ash and dust• mud and lava flows• fires• floods• landslides• rock slides

• avalanches• poisonous gases• tsunami• ballistics (rocks thrown into the air)

Settlements should not be located near volcanoes or lava flows

Settlement planning should include escape routes andcontingency plans

Building design should ensure that

• large openings face away from the volcano• roof design allows for ash loading

Natural hazards: volcanoes82

Natural hazards: storms72




p

Storm damage can be lessened by influencing the flow of windthrough the site, for example:

• using wind barriers, such as trees and topography mayhelp to protect vulnerable shelters• the layout of buildings will effect how wind flows through the

settlement• the positioning of windows and openings in buildings can be

used to provide shelter as well as natural ventilation

Building design and retrofitting are measures that may include:

• reducing overhangs, eves and gables• improving the strength of joints through the use of brackets

and cross bracing• introducing cross bracing and ties especially for wall plates

and rafters• improving the fixing of roofing materials• introducing storm shutters for windows and openings

Natural hazards: storms72

p Natural hazards: fire80



Shelter Training 08b – Belgium, 16th –18th November, 2008based on content developed bybased on content developed by

p

The risk of fire is particularly high in dry areas whereforest fires or wildfires are common.Also in cold or temperate climates where cooking and heating

stoves are used inside shelters.

Where possible methods for mitigating risks from fire include:

• fire alarms and fire doors which should open in the directionof the escape

• planning settlements to include fire breaks• providing water points and fire beaters for fire fighting

• ensuring adequate fire escapes from buildings and fire drills

• ensuring fire escapes are marked, clear and accessible

Natural hazards: fire

distance betweenbuildings should be

twice their height

the maximum travel distance to afire escape should not be more than18m from any part of the building

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Natural hazards: toxic environments



Shelter Training 08b – Belgium, 16th –18th November, 2008based on content developed bybased on content developed by

Local knowledge is critical for understanding toxic threats and sources of dangerous pollution

Toxic hazards may include:

• contamination of surface or ground water

- arsenic

- chemical fertilisers or pesticides

- sewage

• carbon monoxide and particulates emitted by vehicles,generators or stoves

• asbestos, this should be removed and its use avoided inreconstruction

salt deposits from sea water flooding

• human or animal bodies

• abandoned lead mines

• depleted uranium weapons

Natural hazards: toxic environments

Bibliography



Shelter Training 08b Belgium 16th 18th November 2008based on content developed bybased on content developed by

Bibliography

‘Women, girls, boys and men’ (IASC 2006)

‘Handbook for the Protection of Internally DisplacedPersons’ (Global Protection Cluster Working Group,2007)

‘Transitional Settlement: Displaced Populations’(Corsellis and Vitale, 2005)

‘Transitional settlement and reconstruction after natural disasters’ (United Nations, 2008)

day3 10 construction in hazardous environments

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