An offshore long-span continuous rigid-frame bridge is taken as an example to study the effect of degradation of bond-slip behavior on the seismic performance of bridges in an offshore environment during a service period. On the basis of a numerical simulation analysis using the OpenSeeS platform, the influence of durability degradation of concrete carbonization, steel corrosion, and degradation of bond-slip performance is considered collectively using incremental dynamic analysis method to examine the time-varying seismic fragility of the offshore bridge. Results show that when bond slip is considered, the exceedance probability of the bridge components and the system increases significantly, and the durability degradation caused by concrete carbonization and chloride ion erosion in the whole life cycle increases the seismic response of the bridge structure. The results of the proposed time-varying seismic fragility analysis indicate that, considering the degradation of bond-slip behavior of reinforced concrete after the durability degradation of materials, the exceedance probability of the pier, bearing, abutment, and system increases with the extension of service period and the increase in seismic strength under earthquake action. In addition, with the extension of service time, the effect of bond slip on the seismic fragility of components and system gradually decreases.

The bond-slip effect has a great influence on the seismic performance of reinforced concrete structures and ignoring it will overestimate the seismic performance of the structures. Based on the low-cyclic reversed loading experiment of a reinforced concrete column, this paper uses OpenSees to establish a nonlinear finite element model considering bond-slip and verify its correctness. In this paper, a multispan continuous girder bridge with varying pier heights is taken as an example. Considering the effect of the bond-slip behavior of steel bars, a refined finite element model based on the OpenSees platform is established to do the numerical simulation analysis. 10 seismic waves are selected from the Pacific Earthquake Engineering Research Center (PEER) according to the site condition and modulate the amplitude to 150 waves. This paper uses the incremental dynamic analysis (IDA) and the second-order reliability method to analyze the seismic fragility of bridge components and systems, respectively. Results show that the exceeding probability increases obviously when considering bond-slip, and with the increase of seismic spectral acceleration, the influence of bond-slip on the exceeding probability of components also increases; when bond-slip is considered, the difference of system fragility between the upper and lower limits under four damage states is greater than that without bond-slip.

At present, most of the research studies on the seismic performance of the durability degraded reinforced concrete structure only consider the influence of a single factor. This paper comprehensively considers the factors such as concrete carbonization, steel corrosion, and bond slip performance degradation caused by other durability factors and durability damage repair and studies the influence of the above factors on the seismic performance of bridge structures. Based on the finite element model considering the bond slip and the material parameters of time-varying durability damage, the seismic performance analysis model of the pier is established considering material durability damage repair in different service periods. Then, the effect of material durability damage repair on the seismic performance of the pier is examined. The results show that the displacement of the pier top increases, the curvature of the pier bottom decreases, and the moment-curvature curve pinching phenomenon is further evident when considering the bond slip. When considering the durability damage repair of materials, the curvature considerably decreases (the maximum value is approximately 16.04%) with the extension of the service time of the bridge, and the pier damage is substantially reduced.