Ground motion rotation for mainshock-aftershock sequences: Necessary or not?

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 130; p. 105976
• Main Authors: Wen, Weiping, Ji, Duofa, Zhai, Changhai
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.03.2020; Elsevier BV
• Subjects: Aftershock; Aftershocks; Critical angle; Engineering demand parameter; Ground motion; Ground motion rotation; Performance evaluation; Rotation; Seismic activity; Seismic design; Seismic response; Ground motion rotation; Aftershock; Critical angle; Engineering demand parameter
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2019.105976

This manuscript studies the effects of rotating mainshock-aftershock (MSAS) sequences to different orientations on the seismic performance of structures. A total of 222 recorded MSAS ground motions are additionally rotated the given angle away from the fault-parallel direction. Four different engineering demand parameters (EDPs) are used to quantify the seismic performance. The results indicate that the aftershock would change the critical angle of ground motions with respect to the mainshock, and the change in the critical angle can exceed 30°. The effect of ground motion rotation is significant for MSAS sequences, and can exceed 25% for all EDPs considered. The effects of aftershocks on the maximum and median EDPs over all rotation angles are generally comparable. Rotating MSAS sequences into the critical angle is necessary for seismic design and performance evaluation. •The effects of rotating mainshock-aftershock sequences on EDPs are studied.•Aftershocks can change the critical angle in a maximum value of 30°.•Effects of rotating MSAS sequences can exceed 25% for all EDPs considered.•Effects of aftershocks on the maximum and median EDPs are generally comparable.•Rotating MSAS sequences into the critical angle is necessary for seismic design.