DISASTERDISASTER

TYPES OF DISASTER

Two Types – Natural and Manmade Natural disasters:  

FloodCycloneEarthquakeLandslides

Manmade Disaster

Setting of firesEpidemicDeforestationChemical pollution.WarsRoad / train accidents, riotsFood poisoning Environmental pollution

EARTHQUAKES Ground shaking – back-&-forth

motion , caused by the passing vibratory waves.

Soil failures – caused by shaking e.g. landslides .

Surface fault ruptures, such as cracks , vertical shifts.

Tidal waves ,i.e. large waves on the surface of bodies of water that can cause major damage to shoreline areas.

EFFECTS ON BUILDINGSEFFECTS ON BUILDINGS

As vibrations & waves continue to move through the earth –buildings ,set in motion.

Each building response differently ,acc.to its construction.

When waves strike ,earth moves backward & forward .

The lower part of building moves with the earth.

The upper portion –initially remains at rest.

The upper portion tries to catch up with the bottom but as it does so, the earth moves in the other direction – ‘whiplash effect’.

Taller buildings also tend to shake longer than short buildings.

PROTECTION MEASURES

The building should have a simple rectangular plan.

Long walls should be supported by reinforced concrete columns.

Large buildings having plans with shapes like T,U,L and X.

It should preferably be separated into rectangular blocks by providing gaps in between.

Doors and window openings in walls , preferably be small & more centrally located.

The location of openings should not be too close to the edge of the wall.

Landslides occur because of the interplay of several factors.

1. Natural factors :- Intensity of rainfall, Steep slopes, Poor drainage, Stiffness of slopes etc.

2. Manmade factors:- Deforestation leading to soil erosion etc.

MOST VULNERABLE HOMES

Existing landslides area.Steep natural slopes.Area in or at the mouths of

drainages.Houses constructed near foothills.

PROTECTION MEASURES FROM DAMAGE PROTECTION MEASURES FROM DAMAGE TO BUILDINGSTO BUILDINGS

(a) Site selection: Safe area – that have

not moved in the past . Houses built at the toe

of steep slopes.(b) Signs and warnings: Doors or windows stick

for the first time. New cracks appear on

plaster,tile,brick. Underground utility lines

break. Fences, retaining walls,

utility poles or trees tilt or move.

(c) Preventive action:1. Proper development.2. Sound construction

techniques.3. Seasonal inspections.4. Regular maintenance of

drainage facilities.(d) Protect vulnerable area:Keep surface drainage water

away from vulnerable areas (steep slopes, loose soils & non-vegetated surfaces.)

(e) Intercept surface water.(f) Stabilize slopes:1. Improve soil’s ability .2. Straw, woodchips applied to a

depth of at least one inch.

FLOODS

Water is a source for all life forms . Without water no life is sustainable. ‘How tragic it is’ when water in the form of floods takes away thousand of human and cattle lives. More than one million huts and poor houses are lost every year in floods in India. CAN WE PREVENT THIS LOSS ????????????

Building – constructed with earth –based materials or using stone & brick in mud mortar .

The huts made from biomass materials.

The occupation of areas within the flood plain of rivers has increased vulnerability.

MOST VULNERABLE HOMES

The houses are commonly destroyed so severely that their reconstruction is not feasible.

It is constructed out of light weight material .

Damage caused by inundation of house .

Undercutting of houses.Damage caused by debris.

PROTECTION MEASURES FROM DAMAGE TO BUILDINGSTo avoid residing on river banks

& slopes on river sides.To build at least 250 mts away

from the sea coast .To build proper drainage system

in all flood prone areas.To construct the building with a

plinth level higher than the known high flood level.

To construct the whole village on a raised plat form higher than the high flood level.

To construct buildings on stilts or columns with wall – free space at ground level permitting free flow of water.

CYCLONES

Cyclones pose a major threat to life and property in many parts of the world. Every year these sudden, violent cyclones bring widespread devastation to coastlines and islands lying in their erratic paths. A windstorm's destructive work is done by the high wind; flood producing rains and associated storm surges.

MOST VULNERABLE HOMES

LocationLight weightOlder buildingsPoorly constructed

concrete blocksUrban and rural

communities on low islands

Effected by the velocity of cyclone wind at ground level

EFFECTS ON BUILDINGSEFFECTS ON BUILDINGSUprooting of trees Damage to signposts , electric poles,

etcDamage to improperly attached

windowsDamage to roof/lintel projectionsFailure of improperly attached

parapetsOverturning failures of compound

walls of various types

PROTECTION MEASURES FROM DAMAGE TO BUILDINGS

Site selectionPlatforms and orientationFoundations:- (a) effect of surge or flooding,

(b) Building on stilts

Wall openingsGlass panellingRoof architecture