City Research Online

Abstract

In recent earthquakes, structures near seismic sources have suffered severe damage due to near-fault ground motions. When compared with ordinary ground motions, these ground motions create high demands on structures. The presence of a strong energy pulse has been observed in near-fault ground motions. This impulsive motion, propagating towards the site, will result in forward-directivity effects. This study is intended to assess the structural effects of mid-rise Modular Steel Building (MSBs) under the near-fault pulse-like and non-pulse-like records and to investigate design procedures that explicitly comprise near-fault effects. The main objective of this paper is the nonlinear seismic responses of MSBs to near-fault forward-directivity (FD) and non-forward-directivity (NFD) ground motions, as well as whether the equivalent pulse present in forward-directivity earthquake ground motions dominate the structural response. This paper discusses the key properties that can be used to characterize near-fault ground motions with forward-directivity effects and non-forward-directivity effects on the engineering demand parameters. For this purpose, using 72 pulse-like ground motions and 120 non-pulse-like ground motions, a Cloud analysis is conducted to obtain statistically significant results. Nonlinear time history analysis is performed using OpenSees based on distributed plasticity approach to develop a finite-element model of a 6-story mid-rise MSB. The results depict that near-field pulse-type ground motions generate larger demands to the MSB compared with the non-pulse ground motions. In addition, when correlated with simple intensity measures such as PGA, PGV, and spectral acceleration at the first mode period, the structural response to forward-directivity ground motions exhibits a higher dispersion than the structural response to non-forward-directivity ground motions. The representative equivalent pulses of the considered forward-directivity ground motions were decomposed using the continuous wavelet transform method to explore their effects on the MSB response. Finally, the influence of the pulse parameters, including period and amplitude of the forward-directivity, are ascertained.

Publication Type:	Article
Additional Information:	© 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
Publisher Keywords:	Modular Steel Buildings; Inter-connection; Near-fault ground motions; Forward-directivity; Distributed plasticity; Equivalent pulses
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TH Building construction
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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