Performance Evaluation of 9 Storey RC Building Located in North Goa

Abstract

It is observed from the past major earthquakes in India, Turkey, China, Nepal and other countries, numerous medium to high rise buildings suffered major damages including life and safety of people. There were devastating effects on life and property in the recent Nepal Earthquake of April 2015. There were also numerous collapses of RC buildings in the Imphal earthquake that hit north east India on 4th January 2016, as most of the buildings could not sustain the forces imposed by demand earthquake. The current seismic design practice stops at demand estimation, analysis and design and consequently cannot guarantee that the design structure meets the objectives set at the start. The required approach should therefore be performance based design. Goa falls in seismic zone III that indicates that Goa has moderate probability for occurrence of earthquakes. Goa forms part of moderate seismic zone in the country, namely, zone III of seismic zoning map of India. Though Goa has not directly witnessed any earthquake, it was affected by tremors from devastating earthquakes from neighboring states; with magnitude 5.0 or more that hitted “Koyna” and “Latur” In Maharashtra in the year 1967 and 1993 respectively; affected the routine life of the people of Goa as many of the residential as well as public structures; infrastructures were damaged severely; although no casualties were taken place. Although the vulnerability is low, towns are more at risk than rural areas due to higher density of population. The present paper highlights the importance of carrying out performance based seismic design for the RC buildings and investigates the seismic performance of 9 storey residential apartment building located in the Panaji city of Goa. The building is designed as per IS 456:2000 and seismic evaluation is carried out using Non linear pushover analysis. The analysis for pushover is carried using ETABS v9 software. The program using VBA is developed for carrying out moment curvature analysis based on stress-strain models for concrete and steel given in IS 456:2000, for modeling plastic hinge properties of beams and columns. The design base shear of the building is compared with the base shear at demand earthquake. Also the global response of the building in terms of capacity curve, hinge location and ductility ratio is studied for predicting the safety of the building at demand earthquake loading.