Earthquake resilience of Pol houses in Ahmedabad
4. Symmetrical structures (in both the directions) perform better during an earthquake, as an asymmetric structure would experience torsion10 5. Simple rectangular shapes in plan behave better than the one with many projections. 6. The building should be constructed using good quality of materials. 7. When the built structures are adjacent to each other there should be a gap between the two blocks like an expansion11 joint to avoid the hammering12 action. If the gap is not there, there can be a filling of weak material. 8. An earthquake responsive structure should be simple in terms of least compromise on structural integrity. The decoration should not hinder the main crucial joinery responsible for earthquake resistance. 9. Horizontal reinforcement is required in the walls to transfer the out of plane forces to the shear walls, else the walls can suffer from collapse. 10. Extra support must be provided to the main beams or columns, which will be responsible for the complete collapse in case of an earthquake.
2.2 Ahmedabad as a world heritage city Ahmedabad – “Ahmed” – “Aabad”, a bustling busy city today was founded by the Sultanate ruler Ahmed Shah, in the year 1411. The city is located on the banks of river Sabarmati. Ahmedabad's old city is a walled city with its unique urban settlement and architectural styles. The city got its title of UNESCO World Heritage City in the year 2017. It is the first world heritage city in India. The settlement and self-sufficient house form were one of the most important criteria for the world heritage city nomination. The following is the criteria (v) description from the outstanding universal value document of UNESCO – “Criterion (v): Ahmadabad city’s settlement planning in a hierarchy of living environment, with streets as also community spaces, is representative of the local wisdom and sense of strong community bondage. The house is a self-sufficient unit with its own provisions for water, sanitation, and climatic control (the courtyard as the focus). Its image and its conception with religious symbolism expressed through wood
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Torsion – Twisting due to applied forces Expansion joint – or movement joint that allows the contraction and expansion of the building materials, also allows the structure to move. 12 Hammering action – due to non-availability of adequate space between the buildings, they tend to collide with each other during an earthquake, that action is termed as hammering action (or pounding). 11
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