Construction in hazardous environments

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Construction in hazardous environments

• 65

This session will look at both the security
hazards and the natural hazards that effect the
construction and planning of settlements
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Session objectives
!

• The key learning objectives of this workshop are
  to form an
• understanding of
• Workshop group discussions on hazards affecting
  construction and planning
• Presentation security hazards including gender,
  protection and conflict
• Presentation natural hazards including flooding,
  earthquakes and landslides

3
Session objectives
!

• The key learning objectives of this workshop are
  to form an
• understanding of
• Workshop group discussions on hazards affecting
  construction and planning
• Presentation security hazards including gender,
  protection and conflict
• Presentation natural hazards including flooding,
  earthquakes and landslides

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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
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Discussion 2

• In your groups, discuss and draw
• the following measures that can help to
• reduce peoples vulnerability
• any construction details or processes specific to
  the hazard
• the key planning and site considerations for a
  planned settlement
• the appropriate preparation or ground works that
  should be carried out before construction begins

1. construction
2. planning
3. ground works
Each group agrees a key point
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Session objectives
!

• The key learning objectives of this workshop are
  to form an
• understanding of
• Workshop group discussions on hazards affecting
  construction and planning
• Presentation security hazards including gender,
  protection and conflict
• Presentation natural hazards including flooding,
  earthquakes and landslides

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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
  responsibility undertaking 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
  can increase the risk of abuse, abduction or
  forced recruitment
• site planning should ensure accessible services
  and resources to lower vulnerability of, for
  example, children travelling long distances to
  school, women collecting water and firewood
• overcrowding can increase vulnerability, for
  example violence against women or young men being
  recruited into gangs or rebel groups

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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 housing should be
  arranged and monitoring procedures initiated
• unaccompanied older persons may also need
  targeted support if they are forced to construct
  their own shelters
• ethnic or religious minorities may find
  themselves marginalised by the displaced and/or
  the host population
• displaced families who do not own land or
  property may be even more vulnerable due to
  unclear legal support mechanisms

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Conflict types of building damage

• There are multiple hazards specifically
  associated with security
• threats 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

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Conflict vulnerability of buildings

• The extent, severity and vulnerability to damage
  depends on the
• type of building as well as the hazard, for
  example the
• vulnerability of factories, apartment blocks,
  detached houses and commercial properties will
  depend on strategic importance, 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 a structural frame or
  load bearing masonry is used
• materials used and their associated properties,
  such as resistance to fire, tensile and
  compressive forces
• location of the damage and its effect on the
  buildings structural stability, access and
  usability
• Guidance from a structural engineer is required
  to determine if
• damaged buildings should be repaired or
  demolished prior to
• reconstruction.

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Session objectives
!

• The key learning objectives of this workshop are
  to form an
• understanding of
• Workshop group discussions on hazards affecting
  construction and planning
• Presentation security hazards including gender,
  protection and conflict
• Presentation natural hazards including flooding,
  earthquakes and landslides

12
Natural hazards an overview

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The main types of natural hazard that can pose
serious risks to the built environment
are floods earthquakes tsunamis landslides
volcanoes fires storms, and toxic environments
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Natural hazards floods

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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 possible
• as this can help identify safer areas that are
  less likely to suffer

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Natural hazards earthquakes

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• 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

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Natural hazards tsunami

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• A tsunami is a large wave, or series of waves
  usually
• caused by
• an earthquake
• volcanic eruptions
• underwater explosions or landslides
• In tsunami prone areas site selection should
  ensure that
• transitional settlements are located on high
  ground away from
• the sea.
• The impact of tsunami on settlements and
  populations can be
• mitigated 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, mangroves

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Natural hazards landslides

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• The term landslide includes rock slides, rock
  falls, tree slides, mud slides, debris flows, and
  avalanches
• Past landslides should be assessed, including
  through consultation
• with local communities
• Landslides tend to occur on steep slopes or where
  land is
• undercut by water
• One indication of previous landslides is
  vegetation at a different level of growth from
  surrounding areas
• Factors which can increase the risk of
  landslides
• deforestation
• overgrazing
• heavy rainfall
• Foundation design can mitigate
• against the effect of landslides
• Where possible settlements should
• not be located in areas prone to

bend of river risks of water undercutting land,
causing landslide
less danger of landslides damaging the settlement
landslide risk to settlement
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Natural hazards volcanoes

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• 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
  and
• contingency plans

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Natural hazards storms

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• Storm damage can be lessened by influencing the
  flow of wind
• through the site, for example
• using wind barriers, such as trees and topography
  may help 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

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Natural hazards fire

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• The risk of fire is particularly high in dry
  areas where
• forest 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 direction of 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

the maximum travel distance to a fire escape
should not be more than 18m from any part of the
building
distance between buildings should be twice their
height
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Natural hazards toxic environments

• 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 in reconstruction
• salt deposits from sea water flooding
• human or animal bodies
• abandoned lead mines
• depleted uranium weapons

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Bibliography
Handbook for the Protection of Internally
Displaced Persons (Global Protection Cluster
Working Group, 2007)
Women, girls, boys and men (IASC 2006)
Transitional Settlement Displaced Populations
(Corsellis and Vitale, 2005)
Transitional settlement and reconstruction after
natural disasters (United Nations, 2008)