Evaluation of Dynamic Response Analysis Comparing with Actual Behavior of Concrete Bridge Damaged by Earthquake

在兵库县南部地震中，许多钢筋混凝土桥梁遭到严重破坏。但也有一些桥梁几乎没有受到任何破坏。使用相同的分析工具分析这两座桥梁并评估模拟和观察到的损伤差异非常重要。本研究的目的是通过实际行为与模拟行为的对比来验证分析工具，主要进行了以下研究：（1）利用断层模型对兵库县南部地震中山阳新干线混凝土桥墩破损部位的地震波进行了研究。根据场地土的特性，利用激发的地震波计算了三维输入地震动。(2)利用计算得到的地震动对山阳新干线9座受损桥梁和2座未受损桥梁进行了三维非线性动力分析。在模拟这些桥梁时，梁/柱单元定义的平面理论被用来代表钢筋混凝土桥墩和三维实体弹性单元代表钢筋混凝土板。假设楼板在地震中没有损坏。根据经验公式计算了桥墩的抗剪承载力。通过比较每个时间步的响应剪力和承载力来进行失效分析。结果表明，在所有受损桥梁中，桥墩的反应剪力都略大于其抗剪承载力。(3)进行混凝土结构地震反应分析存在三种不确定性：地震动、结构模型和分析工具。从这项研究中发现，三维非线性反应分析，使用输入数据的三维地面运动的位置的结构是必要的，以预测在严重地震下的行为。

Many reinforced concrete bridges were severely damaged by the Hyogo-ken-nanbu Earthquake. However, there were also some bridges that suffered almost no damage. It is important to analyze both these bridges using the same analytical tools and to evaluate the differences in the simulated and observed damage. The purpose of this study is to verify the analytical tool by comparing between actual behavior and simulated one.The following studies were conducted in this research:(1) The seismic wave at the locations of damaged concrete bridge piers at Sanyo Shinkansen under the Hyogo-ken-nanbu Earthquake obtained using the fault model was developed. Three dimensional input ground motion was calculated in the basis of the soil characteristics using the developed seismic wave.(2) Three dimensional nonlinear dynamic analysis was conducted using the calculated ground motion at nine damaged bridges and two non-damaged ones in Sanyo Shinkansen. In modeling these bridges, beam/column elements defined by the inplane theory were used to represent the reinforced concrete piers and three dimensional solid elastic elements represent the reinforced concrete slabs. It is assumed that the slabs are not damaged during the earthquake. The shear capacity of the pier was calculated based on the empirical equation. The failure analysis was performed by comparing the response shear force and capacity at each time step. As a result, it is clear that the response shear forces of the piers are a little larger than the shear capacities at all of the damaged bridges.(3) There are three kinds of uncertainty to conduct the seismic response analysis of concrete structures; the ground motion, modeling of structures and analytical tools. From this research it is found that three dimensional nonlinear response analysis using the input data of three dimensional ground motion at the location of the structure is necessary to predict the behavior under severe earthquake.