Assessment of Near-Field Directivity Effects on Seismic Behavior of Tall Moment Frames comprising of Identical Stiffness and Different Bays Configuration

Document Type : Original Article

Authors

1 MSc Graduate Structural Engineering

2 Assistant Professor khu.ac.ir

3 Assistant Professor, Kharazmi University, Tehran, Iran

Abstract

In this paper, the non-linear behavior of height-rise rigid moment frames comprising of small and large bays in the configuration of three dimensional skeletons in order to assess the seismic response parameters were studied. To perform the non-liner analyses, a group of near-field ground motions contains various directivity effects has been chosen. The most important characteristic of the chosen ground motions is the existence of high-amplitude and powerful coherent velocity pulses in recorded time history. The 20-story studied structures were designed by using the three dimensional bundled-tube frame system. The seismic response parameters of the studied structures were calculated and obtained based on conducting a number of non-linear time history (NTHA), inelastic modal pushover (MPA) and incremental dynamic analyses (IDA). This analytical process was completed in order to assess the seismic response parameters and the differences between nonlinear behaviors of the two structural models. Moreover, some of inter-story drift time histories show permanent values under applying a number of scaled earthquake records which contain forward directivity effects. This research results indicate considerable differences between the calculated drift parameter related to the both studied structures under effect of high-amplitude velocity pulses. The maximum drift demands are mainly focused in middle levels than to higher ones of the resistant skeleton. The results, show more acceptable seismic responses in small bays model than large bays one.

Keywords


Volume 21, Issue 56
December 2020
Pages 5-18
  • Receive Date: 08 September 2018
  • Revise Date: 14 April 2020
  • Accept Date: 20 September 2020