By Razvik Schwadev
The Sidekick
From a simplistic standpoint, an earthquake places a sideways load on a building. So in addition to making a building, bridge or any other structure, capable of holding up forces of gravity caused by the weight of the structure and its contents, an earthquake resistant structure can withstand a considerable sideways force, this is done by tying the walls, floor, roof and foundations into a rigid box.
Masonry Woes
The worst building, from an earthquake point of view, is made of non-reinforced masonry such as brick or concrete blocks. Generally the walls are made of bricks stacked on top of each other and held with mortar. The roof is then made of beams of wood or steel laid across the top of the wall. The roof's weight is carried straight down through the wall to the foundations. When the type of building gets sideways jolt, the masonry walls tip over or crumble and the roof falls in on the occupants like a stack of cards. Since this type of structure is prevalent in poorer countries, the death toll from earthquakes can be many times higher than in places with strict building codes such as Japan or California.
Fundamentally Strong Foundation
As the buildings get bigger and taller, the challenge becomes more difficult. The harmonic characteristic of the building and ground have to be considered. For instance, even if the building is very strong, the foundation can settle for fail leading to sinking or tipping over the structure. A classic example occurred during the 1964 earthquake in Nigata, Japan. The Kawagushi-cho apartment buildings toppled over like a series of dominoes. The buildings themselves were super strong and remained intact but their foundations failed to counter the quake. Though 2000 homes were destroyed, only 28 people perished in that quake. Hence building codes undoubtedly saved many lives.
From a simplistic standpoint, an earthquake places a sideways load on a building. So in addition to making a building, bridge or any other structure, capable of holding up forces of gravity caused by the weight of the structure and its contents, an earthquake resistant structure can withstand a considerable sideways force, this is done by tying the walls, floor, roof and foundations into a rigid box.
Masonry Woes
The worst building, from an earthquake point of view, is made of non-reinforced masonry such as brick or concrete blocks. Generally the walls are made of bricks stacked on top of each other and held with mortar. The roof is then made of beams of wood or steel laid across the top of the wall. The roof's weight is carried straight down through the wall to the foundations. When the type of building gets sideways jolt, the masonry walls tip over or crumble and the roof falls in on the occupants like a stack of cards. Since this type of structure is prevalent in poorer countries, the death toll from earthquakes can be many times higher than in places with strict building codes such as Japan or California.
Fundamentally Strong Foundation
As the buildings get bigger and taller, the challenge becomes more difficult. The harmonic characteristic of the building and ground have to be considered. For instance, even if the building is very strong, the foundation can settle for fail leading to sinking or tipping over the structure. A classic example occurred during the 1964 earthquake in Nigata, Japan. The Kawagushi-cho apartment buildings toppled over like a series of dominoes. The buildings themselves were super strong and remained intact but their foundations failed to counter the quake. Though 2000 homes were destroyed, only 28 people perished in that quake. Hence building codes undoubtedly saved many lives.
Extracted From TOI, DIY Conservatories
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