Influence of Angle of Incidence on Seismic Demands of Eccentric Braced Frames Subjected to Near-Fault Ground Motions

Document Type : Original Article

Authors

1 MSc in Structural Engineering, Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran

2 Associate professor, Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran

3 MSc in Earthquake Engineering, Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran

10.22065/jsce.2023.393097.3096

Abstract

The effect of the angle of incidence on the structural damage and the seismic demand in far-fault earthquakes has been taken into consideration by many researchers for several decades. However, this issue has recently received more attention from researchers and design codes for near-fault earthquakes. This issue is due to the pulse-type motion caused by forward directivity phenomena in near-fault earthquakes which increases the influence of the angle of incidence on the seismic demand. Due to the importance of the issue, several researches have been conducted in the past years to improve the design criteria for near-fault regions. For example, for Nonlinear Time History Analysis (NTHA), ASCE/SEI 7-16 design code recommended that the selected near-fault ground motions should be first rotated in the fault-normal/fault-parallel directions and then applied to the main axes of the structure. This paper aims to investigate the accuracy and efficiency of the proposed method for design of structures in near-fault regions. For this purpose, using nonlinear macro modeling of an Eccentrically Braced Frame (EBF) and applying near-fault ground motions with different angle of incidence, the seismic demands of structures were evaluated. The analysis results show that not only the direction of maximum response changes with the change of near-fault ground motions and the types of seismic demand parameters, but also it varies in different stories of a building. Nevertheless, the fault-normal response usually provides an acceptable estimate of the maximum response, which is suitable for design purposes. So that in almost 70% of the cases, the ratio of the fault-normal response to the maximum response is more than 0.75.

Keywords

Main Subjects

Files

History

  • Receive Date: 23 April 2023
  • Revise Date: 01 July 2023
  • Accept Date: 15 July 2023

Share

How to cite

Statistics