Role of Floor Diaphragms and RCC Shear Walls in Earthquake Resistant Buildings

Abstract

In the current scenario, many buildings have irregular structural configurations. These irregularities may be present in both section and plan. In the event of earthquakes, such buildings may be subjected to poor performance due to such irregularities. The performance of the structures when subjected to such disasters should be identified for new as well as existing buildings. Openings in floors and discontinuities in diaphragms are very common now-a-days for the sake of lighting, aesthetics, staircase, lift shaft, etc. Such diaphragm discontinuities can affect the performance of the building. Majority of the buildings in our country are constructed in reinforced concrete. Beyond certain height, sufficient lateral stiffness cannot be provided by only beam-column moment resisting frame. To provide sufficient structural stiffness, in combination with the moment resisting frames, concrete shear walls are used. Shear walls are very efficient in resisting the lateral loads and a large amount of lateral loads on a building are assigned to it. All recent softwares give facility to assume the diaphragm as rigid and flexible/semi-rigid. In this thesis, an attempt has been made to find out the correct assumption for the type of diaphragm i.e. whether a diaphragm should be considered rigid or semi-rigid in the analysis, based on different conditions of diaphragm discontinuity. Also, an attempt has been made to find out the optimum location of shear wall such that it participates in resisting sufficient amount of lateral load. Comparison of parameters like storey displacements, base shear, storey stiffnesses, storey shears, etc. has been done with different conditions of diaphragm discontinuity and shear wall locations.