A Comparative Study on Different Seismic Zone in Bangladesh Based on BNBC-2020

Abstract

Bangladesh is located in a seismically active area. The ground shakes during an earthquake. As a result, the base of a building sitting on it will move. So it is necessary to ensure the adequacy of the structures against the horizontal load effect. With the help of BNBC's guidelines, the risk of failure in newly built infrastructure exposed to wind and earthquakes can be minimized. The latest BNBC code is Bangladesh National Building Code 2020 (BNBC 2020). In BNBC-2020, the seismic zone of Bangladesh has been divided into categories, such as Zone-I (seismic intensity: low), Zone-II (seismic intensity: moderate), Zone-III (seismic intensity: severe), and Zone-IV (seismic intensity: very severe). They have different seismic coefficients. This paper compares different seismic zone analyses of a multi-storeyed (G+5) residential building in all four seismic zones. This paper's primary goal is to examine how this building responds to earthquakes in the updated seismic zone and coefficient. The analyses, in this case, are limited to four seismic zones, with the same size structural frames (beam, column, slab, and stair, joint) and the same dead and live loads applied. But in the case of environmental load, it is changed according to the location of the building. For different zones, wind speed and the seismic coefficient have been changed, and it mainly impacts the buildings. To compare these impacts based on environmental loads, we used four different locations in four different seismic zones. The locations of the different zones are Rajshahi (Zone-1), Dhaka (Zone-2), Rangpur (Zone-3), and Sylhet (Zone-4). Structural analysis is done by using ETABS (Extended Three-Dimensional Analysis of Building Systems) software to find storey drift, storey displacement, base shear, stiffness, etc., and compare these factors with the help of a graph in Excel, which will be discussed later. All the drafting is done using AutoCAD software.