Research On The Seismic Performance Of RC Bridge With Local Corrosion Of Reinforced Bar

Bridge is an important component of the traffic network, and it plays a key role in the regional earthquake prevention and disaster reduction. However, as the service time increases, due to the influence of the natural environment, the materials of the bridge gradually decay, which leads to the deterioration of its seismic performance. In China, along with the aging of bridges and the increasing importance of the security of national land, it is imperative to establish an evaluation method for the seismic performance of bridges in-service.In this paper, through the numerical simulation on the Opensees platform of an existing experiment, which studied the performance of corroded columns under low-cycle load, the materials’ constitutive models with both higher computational accuracy and efficiency were confirmed. Taking a concrete continuous girder bridge as an example, through the simulation of different extent and location of reinforced bar’s corrosion, the effects of pier’s local corrosion on the seismic performance of the bridge were analyzed. Thirty ground motions were chosen and adjusted according to the target acceleration response spectrum, and were used to study the effects of strong motion duration on the seismic performance of corroded reinforced concrete bridge. By the end, the corrosion process of reinforced bar in coastal bridge’s pier was analyzed, and adjusted ground motions based on the equal exceeding probability theory were applied to study the life-cycle seismic performance of a coastal bridge.The main conclusions in this paper can be drawn as follows:(1) The combination of Steel02 reinforced bar model and ConcreteOl concrete model has higher computational accuracy and efficiency to perform the numerical simulation of the corroded columns’performance under low-cycle load on the Opensees platform.(2) With the exacerbation of reinforced bar’s corrosion, the flexural capacity of the bridge pier decreases gradually, and the damage degree of the bridge pier under the same ground motion increases gradually.(3) Under seismic action, the local corrosion of pier’s bottom leads to a greater plasticity degree or a larger plasticity range, the local corrosion near the pier’s bottom may change the location of plastic zone, and the local corrosion far from the pier’s bottom will influence the distribution of plastic zone only when the corrosion is severe.(4) Strong motion duration index RUju, which is based on the structure’s seismic response, has a better correlation with pier’s energy dissipation. The corrosion of reinforced bar increases the sensitivity of pier’s energy dissipation to strong motion duration.(5) With the erosion of chloride ion, under the ground motion of equal exceeding probability, as the increase of service time, the plastic zone of coastal bridge’s pier will rise from the bottom of the pier to the bottom of tidal zone. The pier’s damage degree reduces gradually when calculated according to the initial pier’s mechanical property, but firstly remains almost constant and then increases rapidly when calculated according to the corroded pier’s mechanical property.