Damage spectra of global crustal seismic sequences considering scaling issues of aftershock ground motions

Abstract

Summary Recent studies and earthquakes have shown that the mainshock‐aftershock (MSAS) sequences would induce significant cumulative damage, and it is urgent to incorporate the MSAS sequences into performance‐based seismic design and resilience assessment. For this purpose, one of the key problems is how to accurately and quickly estimate the cumulative damage induced by MSAS sequences. This manuscript investigates the damage spectra of global crustal MSAS sequences and proposes a prediction equation of damage spectra as a tool to quantify the cumulative damage caused by MSAS sequences. The recorded MSAS ground motions from global crustal seismic sequences are collected. The structures are modeled by 4 different kinds of single degree of freedom systems with/without degradation and pinching behavior. The scaling indicator and scaling factor SF of aftershock ground motions are studied from the point of view of efficiency and accuracy. The results indicate that scaling aftershock ground motions with spectra acceleration Sa present the best efficiency. Applying the condition of SF smaller than or equal to 5.0 (ie, SF ≤ 5.0) can clearly reduce the bias induced by over‐scaling and meanwhile has no change on the dispersion of results. Strong aftershocks (eg, relative Sa greater than 0.8) can increase the damage spectra by the minimum level of 20% for non‐degrading systems, and quantitative effects of aftershocks strongly depend on the period of vibration, strength reduction factor, hysteretic behavior, and intensity of the aftershock ground motions. The proposed prediction equation shows high accuracy on the estimation of the cumulative damage induced by MSAS sequences.

Vulnerability assessment of a high‐rise building subjected to mainshock–aftershock sequences

“…The mainshock ground motions are selected to match the target response spectrum. The MSAS ground motions are selected from the database used by Wen et al, [ 8 ] which collected a total of 274 recorded MSAS ground motions. Besides, the following criteria are used: (i) both two horizontal record components are available; (ii) at least one component of the horizontal record pair shows good compatibility with target response spectrum.…”

“…For another, the response spectra of aftershocks decrease more quickly than those of mainshocks at medium to long periods. [ 3,8 ] The fundamental natural period of the model structure (i.e., 3.162 s) falls in a long period range and thus results in greater PGAs in aftershocks when adopting S a ( T 1 ) as the IM.…”

“…Ruiz‐García, [ 2 ] Goda, [ 3 ] and Goda et al [ 4 ] studied the differences in characteristics between a mainshock and major aftershock records, providing useful insights into the MSAS records selection or generation. The response spectra of MSAS sequences were proposed for the performance evaluation [ 5–9 ] and seismic design [ 10–14 ] after considering the effects of aftershocks. The influence of MSAS sequences on the seismic response of buildings, mainly including steel frames [ 15–18 ] and reinforced concrete (RC) frames, [ 19–21 ] was also investigated with recorded or artificial MSAS sequences.…”

Experimental investigation on the damage accumulation of reinforced concrete columns under mainshock‐aftershock sequences

“…Moreover, ordinary shaking table tests generally select a specific record as input and excite the shaking table by gradually scaling up the amplitude of this record. This method indicates that the duration (and frequency content) of multiple earthquakes in the ordinary shaking table tests are identical, while the differences in duration (and frequency content) between the mainshock and aftershock ground motions are obvious 9,30,31 . Therefore, the results of ordinary shaking table tests cannot be used to estimate the damage accumulation of structures under MSAS sequences.…”

“…2 The effects of mainshock-aftershock (MSAS) sequences on building performance have aroused great concern in the last two decades. Some researchers (Amadio et al, 3 Luco et al, 4 Hatzigeorgiou and Beskos, 5 Goda, 6 Yaghmaei-Sabegh and Ruiz-Garcia, 7 Zhai et al, 8 and Wen et al 9 ) have focused on the effects of aftershocks on a single degree of freedom system. Several investigations have been conducted on multiple degrees of freedom systems, such as steel structures, 10,11 reinforced concrete (RC) frame buildings, 12,13 and wood structures.…”