A Study of Effects of Different Bracing Systems on an Open Ground Storey Building

Most of the urban multistoried buildings in India today consist of an open ground storey. This is practiced and adopted to accommodate parking or reception lobbies in the first storey. With urbanization and increasing shortage of required space, it is becoming imperative to provide open ground storey in commercial and residential buildings. But open ground storey provisions reduce the stiffness of the system and a progressive collapse becomes inevitable in a severe earthquake. Studies have shown that lateral displacement at the open ground storey roof level is 4 to 6 times of that of a normal continuous building having walls in the ground storey also. Thus, the vulnerability of soft storey effect resulted structural engineers to rethink the design of a soft storey building in areas of high seismicity. The present study investigates and compares the effect of soft storey with different bracing systems. Three different steel sections were used for the purpose. The position of bracing is provided in two different arrangements. The modeling of the whole building is carried out using the computer program STAAD.Pro v8i and SAP 2000.For all cases bracing reduces the lateral displacement at the roof level of open ground storey, but judicious selection makes the results in better efficiency.