Quantitative Evaluation of Seismic Countermeasure Effects Focusing on Lost Transportation Volume of Railway Networks

Abstract

To improve railway resilience against earthquakes, we verify and apply a developed support system to evaluate the effects of seismic countermeasure, focusing on the lost transportation volume of the railway networks. The system calculates the recovery process of the transportation volume which decreases after an earthquake, using optimization calculation by which the lost transportation volume is to be minimized. This makes us evaluate quantitatively the effect of the countermeasures. In addition, a different recovery process can be relatively evaluated. In this study, first we evaluate the performance of the system based on past earthquakes. Then comprehensively compare the effects of several seismic countermeasures such as struc tural and operational countermeasures. This paper describes that the evaluated recovery process of the lost transportation volume with the developed system is useful to implement strategic seismic countermeasures. Earth retaining structures, such as bridge abutments and retaining walls, are con-structed at the boundary of bridges or embankments. There are a variety of earth retaining structure failure modes, therefore in order to be able to ensure rational aseismic reinforcement, it is necessary to develop a range of different aseismic reinforcement methods adapted to the relevant earth retaining structure’s failure mode. Moreover, there are many cases where construction work is severely restricted due to various limitations, such as land boundaries, available space, and time available for construction work. Therefore, the authors propose an aseismic reinforcement method, which can both improve seismic performance of earth retaining structures and be carried out efficiently. This paper outlines this research and describes some examples of the practical application of the newly developed reinforcement method.