Seismic Vulnerability Assessment and Retrofitting Techniques for MRT Compliant RCC Buildings

Abstract

From 1970 to 2015, there was a rapid growth in Reinforced Concrete Cement (RCC) building construction in Kathmandu valley. Ready to use dimensions and details provided in Mandatory Rule of Thumb (MRT) issued in 1994 was primarily used for up to three storey ordinary residential buildings. This MRT was adopted to achieve the minimum seismic safety requirements specified by NBC 105:1994. The minimum dimensions and detailing were updated in the draft code of MRT in 2012. Later in 2020, NBC 105 code for seismic design of buildings in Nepal was revised. This study aims to quantify the seismic vulnerability of MRT compliant buildings in Lalitpur Municipality City (LMC) and analyze their behavior in future earthquake (MCE). Sixty-eight samples of building drawings of RCC structures were collected from LMC and was categorized into various typologies based on dimension of structural members, number of bays, number of storeys, height of the building, grade of concrete, compliance to MRT codes. Structural analysis of final ten typologies was done and retrofitting strategies were applied to the structures as per guidelines of IITK GDSMA and Seismic Retrofitting Guidelines of Buildings in Nepal (RCC) -DUDBC and the ones satisfying performance level of Life Safety was concluded acceptable. All typologies except for typology I required intervention for retrofitting.