Exposition of Revision of Seismic Design Guideline for Overhead Contact Systems

In Japan, in order to prevent supports (referred to poles and portal structure etc.) in overhead contact systems from collapsing at the time of an earthquake, we design them according to the Seismic Design Guideline for Overhead Contact Systems and Commentary (hereafter referred to as the OCS Guideline). We revised the OCS Guideline in 2013 to evaluate seismic performance of supports more precisely. The paper shows the process of revising OCS Guideline until now and details of the latest revision of the OCS Guideline. and the separat ed model. In case of the unified model based on the consideration of unifying supports and civil engineering structures, we evaluate the response acceleration of supports to the ground motion. However, it is difficult and complex to evaluate the response acceleration of supports. On the other hand, the separated model is easy to evaluate of RTRI, 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.