Class 10 - Social Science : Disaster Management
Chapter - 4 : Safe Construction Practices
Top Block 1
Question : 1 What should be the configuration of an earth quake resistant building?
Answer :
Building should have a rectangular plan to make them earth quake resistant. There should be reinforced concrete columns to support long walls. Large buildings should be fragmented into small rectangular blocks.
Question : 2 How should the foundation be constructed in soft and firm soil?
Answer :
Tilting, cracking and failure of structure can result from soil liquefaction. So the foundation of the building should be strong. Building constructors should ensure that there is no movement of underground soil once the building is built. If the soil is soft the foundation has to be deeper, if the soil is firm the foundation can be moderate.
Question : 3 Which are the most vulnerable homes during floods?
Answer :
Buildings constructed with mud and bricks get damaged easily during floods. Thatched huts and small houses with tinned roofs also get damaged during floods. People who occupy the flood plains of rivers are most affected by floods.
Question : 4 What are the general protection measures for buildings against flood damage?
Answer :
Damage to houses during flood has to be minimised. The first and foremost thing to be done is prevent inundation of flood waters. People should avoid building houses on river banks or near the sea coast. Houses should be built at least 250 meters away from the river banks. The government should ensure proper drainage system.
Buildings should be built on an elevated platform. Buildings in flood prone areas can be built on stilts or columns.
Question : 5 What are the considerations for selecting the site in areas prone to landslides?
Answer :
The site most suited to build houses in landslide prone areas are where the land has not moved in the past. Flat surfaces away from sudden slopes and areas at the top or along the ridges are also suited for building houses.
Question : 6 Write about the slope stabilisation methods by drainage.
Answer :
Surface drainage system should be kept away from steep slopes, loose soil and non-vegetated land. Water that drains from the roof and other areas like the portico should not be allowed to flow down the slopes. This water should be drained through the drain pipes.
Question : 7 What are the desirable plan forms and orientations for cyclone resistant buildings?
Answer :
The shape of an individual building should be either circular or polygonal in cyclone prone areas. Rectangular or square shapes are not suited. A symmetrical building with a compact plan is most suited to withstand cyclones.
Mddle block 1
Additional Questions
Question : 1 How is damage caused to buildings during an earthquake?
Answer :
During an earthquake the ground shakes back and forth due to the plate movement under ground. The surface of the earth ruptures causing huge cracks; landslides occur; and sometimes tsunamis are generated during earthquakes. All these cause severe damage to building. Collapse of buildings, lead to loss of life.
Question : 2 Where are land slides common in India?
Answer :
Landslides are a major natural disaster all over the world. In India landslides are common in the hilly regions of the south and in the Himalayan regions of the north. These landslides cause a lot of damage to life and property
Question : 3 Mention the damages caused during a cyclone.
Answer :
During cyclones, electricity cables and transmission towers can be damaged causing immense hardship to people. Live electricity wire on the road can prove to be a death trap to people walking on the road. Sign posts on the roads can be damaged.
Question : 4 What causes landslides and what are the warning signs of a landslide?
Answer :
Landslides occur due to heavy rainfall, steep slopes, seismic activity and poor drainage.
Landslides are also caused due to deforestation and soil erosions. Unrestricted excavation, mining and quarrying also cause landslides.
Warning signs before a landslide are ……..
Landslides usually occur in the same place again and again. Doors and windows jam for the first time New cracks appear on the walls and floors Gaps form between the pavement and the building outside the house. Fences and compound walls tend to tilt Underground water and electricity lines break When these warning signs occur people have to take precautions.
Question : 5 What kind of damages are caused to buildings, during floods?
Answer :
Small houses and huts are most vulnerable during floods as they get washed away in flood waters. These houses are totally destroyed in the flood waters. Houses which do not have a firm foundation also get washed away or tend to float. Houses in low lying areas get inundated with water. There is great loss to property in this case. Flood waters can damage the foundation and walls of buildings and this will make the construction weak. Houses may get affected due to floating debris, like huge trees.
Question : 6 What are the features of an earthquake resistant building?
Answer :
Features of an earthquake resistant building are as follows:-
Building should have a rectangular plan Reinforced concrete columns should support long walls Large buildings should be fragmented into small rectangular blocks The foundation of the building should be strong. Building constructors should ensure that there is no movement of underground soil once the building is built. Doors and windows should be small and centrally located. This will ensure more stability to the walls. Reinforces concrete bands are essential for all buildings. These bands have to be at the plinth level; floor level; lintel level; and roof level. Vertical reinforcement should be provided at the corners and wall junctions.
Question : 7 How can houses be protected from cyclones?
Answer :
To protect houses from cyclones one should select an appropriate site to build a house. The site should be above the inundation level. The shape of an individual building should be either circular or polygonal. Rectangular or square shapes are not suited. A symmetrical building with a compact plan is most suited to withstand cyclones. As cyclones are accompanied by torrential rain inundation is inevitable, so houses should be elevated. Houses should be constructed on stilts or columns.
Doors and windows should have strong closing and locking systems to with stand the force of the wind. Openings just below the roof should be avoided. Glass panelling can be avoided in buildings situated in cyclone prone areas. If there are glass panels they have to be protected with paper strips or metallic mesh pasted outside. The size of the panels can be small so the damage is minimal. The roof is the most vulnerable part of the building during a cyclone as it is at a higher level and exposed to the wind. Roof projections should be minimal. A pyramidal roof is most suited in cyclone prone areas.
Question : 8 What causes landslides and what are the warning signs of a landslide?
Answer :
Landslides occur due to heavy rainfall, steep slopes, seismic activity and poor drainage. Landslides are also caused due to deforestation and soil erosions. Unrestricted excavation, mining and quarrying also cause landslides. Warning signs before a landslide are ……..
Landslides usually occur in the same place again and again. Doors and windows jam for the first time New cracks appear on the walls and floors Gaps form between the pavement and the building outside the house. Fences and compound walls tend to tilt Underground water and electricity lines break. When these warning signs occur people have to take precautions.
Question : 9 What kind of damages are caused to buildings, during floods?
Answer :
Small houses and huts are most vulnerable during floods as they get washed away in flood waters. These houses are totally destroyed in the flood waters. Houses which do not have a firm foundation also get washed away or tend to float. Houses in low lying areas get inundated with water. There is great loss to property in this case. Flood waters can damage the foundation and walls of buildings and this will make the construction weak. Houses may get affected due to floating debris, like huge trees.
Question : 10 What are the features of an earthquake resistant building?
Answer :
Features of an earthquake resistant building are as follows:-
Building should have a rectangular plan Reinforced concrete columns should support long walls Large buildings should be fragmented into small rectangular blocks The foundation of the building should be strong. Building constructors should ensure that there is no movement of underground soil once the building is built. Doors and windows should be small and centrally located. This will ensure more stability to the walls. Reinforces concrete bands are essential for all buildings. These bands have to be at the plinth level; floor level; lintel level; and roof level. Vertical reinforcement should be provided at the corners and wall junctions.
