Characteristics of Strong Ground Motions and Its Corresponding to Questionnaire Survey to Damage of High-Rise Residential Buildings During the 2018 Mw 6.4 Hulien, Taiwan, Earthquake

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

During the 2018 Hualien earthquake, the main shock of a seismic sequence originated offshore of the eastern Taiwan, long-period pulse-like motions near the Milun fault under the Hualien City were observed. Though the CMT focal mechanism showed that this event had mainly a strike-slip focal mechanism with a minor thrust component dipping to the west, the field investigation of surface ruptures announced another possibility that the main ground motion generation areas should belong to the Milun fault and the Lingding fault dipping to the east. High amplitude and pulse-like velocities with period of 2 to 4 sec were recorded near the Milun fault, which are considered to be dangerous to high-rise buildings. Indeed, fourbuildings with week lower stories were totally collapsed along the Milun fault. In this study, we constructed a characterized source model with the purpose to explain the generation of long-period pulse-like motions near the Milun fault. Then using the proposed source model, ground motions at the sites of damaged buildings were numerically simulated based on the thin-layer method. We selected 9 high-rise RC residential buildings locating at the southwest side, the northeast side, and the central part of the east side of the Milun fault to examine the response characteristics of buildings in Hualien City and perform questionnaire of the feeling of shaking, indoor damages, structural damages, etc. Predominant frequencies of the ground within Hualian City are about 1 Hz which are close to the inferred fundamental frequency of damaged buildings. We found that the shakings of the buildings at the northeast part was longer and stronger than those at other places. Correspondingly, the damages of these buildings were more severe. For the buildings at the central part, the shaking duration was short and building damage is relatively light. The shaking pattern at the buildings at the southwest side was more complicated and the indoor damage was the most severe.

Presenting Author: Xin Wang

Authors