Construction Stage Seismic Vulnerability Evaluation of a Continuous Girder Bridge with the Cast‐in‐Place Cantilever Construction Method

Abstract

To evaluate the vulnerability of bridges at various construction stages under the action of strong earthquakes, the incremental dynamic analysis (IDA) method is applied, and the vulnerabilities of a continuous girder case study bridge with the cast-in-place cantilever construction method, which owns five main construction stages, are evaluated and compared. The results show the following: With the increase in the peak ground acceleration (PGA), the vulnerabilities of bridges at different construction stages all increase. The fragility and vulnerability are mainly determined by the structural mechanical system condition and the mode shapes but not the modal frequency. For the working condition of seismic PGA of 0.4 g, (1) the bridge at the substructure construction stage may only experience slight or moderate damage with the exceedance probability of 8% to 5% and the mean loss ratio being only about 5%; (2) the vulnerabilities of bridges at the middle cantilever construction stage and the long cantilever construction stage are similar, the collapse damage exceedance probability is about 80%, and the mean loss ratio is about 65%; and (3) the vulnerabilities of bridges at the middle span closure construction stage and the bridge completion construction stage are nearly the same, the collapse damage exceedance probability is about 98%, and the mean loss ratio can reach 80%. The research results explore a new method for evaluating the vulnerability of bridges at different construction stages, which can provide suggestions for seismic damage defense and seismic insurance risk evaluation.

Construction Stage Seismic Resilience Evaluation of a Continuous Girder Bridge with the Cast-in-Place Cantilever Construction Method

“…The flow chart of the vulnerability evaluation process is introduced in Li et al [35,36]. The flow chart of the resilience evaluation process starting from the vulnerability is shown in Fig.…”

“…The case bridge in this paper is the same as that in Li et al [35,36], and it is a continuous girder bridge with the cast-in-place cantilever construction method. The case bridge was designed conforming to the relevant design specifications of China.…”

“…The construction stage seismic vulnerability has been researched by Li et al [35][36][37] and it has been suggested to apply in the seismic insurance by Li et al [36]. On the basis of Li et al [35,36], the construction stage seismic resilience will be further studied in this study. The construction stage seismic resilience evaluation process will be proposed.…”

“…The height of piers is 9 m. The cross section of piers is a rectangle with the size of 3.5  7 m. The bridge has three spans with the length of 51 m, 85 m and 51 m. The girder cross section is a single box single chamber variable section. The more detailed information about the case bridge was introduced in Li et al [35,36].…”

Seismic Vulnerability Analysis of Long-Span Prestressed Concrete Composite Box Girder Bridge with Corrugated Steel Webs under Construction

“…Hsu et al [10] proposed a construction classification and vulnerability analysis framework for existing buildings from the perspective of earthquake insurance. Both Huang et al [11] and Li et al [12] conducted studies on the seismic vulnerability analysis method and calculation process for cast-in-place cantilever continuous girder bridges under construction. Besides, Shi et al [13] chose an irregular long, span-continuous rigid frame bridge with a high pier as the case, inputted velocity pulse type near fault seismic waves, calculated the seismic vulnerability during the cantilever construction, and compared and analyzed the influence of considering the internal force state on the seismic vulnerability of components.…”