Civil Engineering Association

SIMULATION TECHNIQUES FOR COLLAPSE ANALYSIS OF RC BRIDGE UNDER STRONG EARTHQUAKE

Collapse analysis is becoming increasingly significant as the performance-based design is being gradually adopted in the seismic design of bridges. To deal with the strong nonlinearity and large deformation of the structure, dynamic simulation methods were introduced in this paper. Some
simulation techniques were used to realize the fracture of structural member; and the contact and impact of broken reinforced concrete member with each other were also taken into consideration in the methods. The simulation of the whole collapse process of Cypress Double-deck Viaduct in 1989 Loma Prieta was performed with the above method. The analysis results agree well with the damage observed in site and this indicated that the simulation method and techniques proposed is capable to be utilized for collapse analysis of RC bridges. With simulation results of collapse analysis, failure modes and potential collapse mechanism of RC bridge under strong earthquake can be illustrated. A new double-deck viaduct with Y type pier was built in Shanghai recently. Its upper deck is urban arterial highway and the lower deck is urban light railway system. With the proposed simulation techniques, the response of this viaduct under earthquake was analyzed and the simulation results were verified by a pseudo-dynamic test with this bridge. With the analysis result, the seismic vulnerability of the double-deck viaduct was assessed and suggestion was proposed to improve the seismic
performance of bridge. Many high pier RC bridges are been constructed crossing deep valleys at mountain areas in the western China, where the geotechnical condition is more complicated and the earthquake is more active. To
verify the seismic response performance and to predict the damage mechanism of a high pier bridge under strong earthquake, a high pier RC at a typical mountain area was investigated as an example. The bridge is a multi-span continuous frame structure with high piers. Its deck consists of two parallel separate girders with curve. In this simulation, first, detail nonlinear analysis for bridge elements those
might be heavily damaged during earthquake were analyzed using advanced elasto-plastic constitutive model. Then, based on that, a simplified constitutive model were established for the collapse analysis of the whole bridge. The methodology and results of the simulation in this paper are expected to be helpful for the seismic design and analysis of RC bridge.