Seismic Performance Assessment of Typical Residential RC Frames of Kathmandu with Beam to Beam Connections

Abstract

Nepal is located in one of the world’s most seismically active zone and predicted that big earthquake occurred within certain repetition of time. It is predicted that if the earthquake of 6 Richter scale happened in Kathmandu, minimum death will be 69,000 which is due to declining construction practices, uncontrolled urban planning and violating building codes. Thousands of the concrete houses have been constructing every years with/ without proper engineering design. Among them beam to beam connection without column is one of them. This type of connection occurred when the column under crossing of the beams get removed. Some of them are occurred during the design due to architectural requirement of rooms, land shapes and closeness of two columns where as some of them occurred by removing close column during construction. In order to know the influence of beam to beam connections, 150 building drawings of KMC-16 which were sanctioned from KMC in fiscal year 2063/2064 B.S. (2005/2006 AD) were collected and analyzed. It is found that 67 percentages of those buildings have beam to beam connection and most of them have connection at center. Then, the plan of beam to beam connection at the center is taken and from that other four different models are made by adding and removing beams and columns. All these buildings are firstly modeled in SAP2000 for pushover analysis and then to COM3 for nonlinear dynamic analysis by using Kobe Earthquake. From the analysis from COM3, it is found that beam to beam connection at the center have large top displacement, low base shear, maximum internal stresses (BM, and SF) and damage occurred in minimum strain in comparison to other model which shows that beam to beam connection without column deteriorate the strength of building and should be avoided as far as possible.