Risk Targeted Seismic Design of RC Buildings

Abstract

Earthquake is one of the most destructive forces, for any type of structure and needs special attention during design. Over the year’s earthquake resistant design methodology has improved significantly. Throughout the world, researchers and engineers are tirelessly working towards more realistic consideration of seismic force to improve the structural performance during seismic events. This has led to extensive research and development in the field. Moreover, due to the significant improvement in the computational facilities in the last decade or so, it has now been possible to simulate complex structural behaviour and better understand the structural response during such events. However, we are still in the early stage of development of seismic design and the current design methodology comes with many limitations. To overcome these and develop a reliable and universally accepted design methodology, researchers are working continuously and as an outcome of this, ‘Risk Targeted Seismic Design’ concept has evolved which is argued by many as a futuristic seismic design methodology. In the first part of this dissertation, the seismic design using the Risk Targeted Seismic Design methodology is studied. Three different building models with the same plan but different heights are considered in order to study the effect of fundamental period on the collapse risk. All the buildings are considered to be located in the Zone-V of Indian Seismic Zoning map. Buildings are designed as per IS 456:2000 with seismic provision as per IS 1893:2016 (Part 1) and IS 13920:2016. Initial target performance levels for all the buildings are obtained using the methodology given in ASCE-41 (2017). Seismic fragility assessment is carried out using incremental dynamic analysis method. Site specific hazard curves for three different sites corresponding to Zone-V are obtained using the OpenQuake Hazard Assessment tool. Collapse risks for the buildings are then estimated by convoluting fragility curve and site specific hazard curve for each of the sites. Obtained collapse risks are compared with the target collapse risk to understand the sufficiency of the code based design in achieving the target collapse risk.