Analytically and Numerically Predicting Base Shear Coefficient of Building Structure with the Variations of Response Reduction Factor based on BNBC 2020 by using ETABS

Abstract

Response reduction factor (RRF) influences the building base shear. Soil profile and seismic
zone factors affect the variations of RRF. According to Bangladesh National Building Code
(BNBC 2020), three (ordinary, intermediate, and special) different values of RRF for the
moment-resisting frame are used for four seismic zones. In the present research, analytical
(BNBC 2020) and numerical (ETABS) base shear coefficient ratio (BSC) are evaluated by
the variations of RRF (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12) and seismic zoning factors (Z 1 =
0.12, Z 2 = 0.20, Z 3 = 0.28 and Z 4 = 0.36). BSC values are very close for analytical and
numerical analysis. The maximum value of analytical and numerical base shear coefficient
ratio (BSCR) is 100.29 percent for seismic zone – 1 (RRF = 7). Similarly, the minimum value
of BSCR is 99.97 percent for seismic zone -1 (RRF = 10). For all values of RRF and seismic
zone factors, numerical BSC is lower than analytical BSC except the location of minimum
BSCR.
KEYWORDS: Base shear coefficient, Response reduction factor, Analytical formulae,
BNBC 2020, Numerical analysis.