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Substructure seismic strengthening method

1. Overview

The substructure seismic strengthening method is a construction method which involves wrapping an existing substructure in concrete and steel or other materials to ensure its current seismic performance. The substructure seismic strengthening method includes different methods like the wrapping method, i.e., the RC wrapping method and steel plate wrapping method, and the PC&PA method, which utilizes PC cable. The wrapping method requires excavating around the substructure up to the footing; hence, consideration must be given to the construction method and other details when performing this work in rivers or the ocean.


2. Key Features

  • The RC wrapping method involves adding reinforced concrete around the existing concrete in order to improve toughness and load capacity.


  • The steel plate wrapping method involves installing steel plating around the existing concrete and filling the space between the existing concrete and the steel plating with shrinkage-compensating mortar and epoxy resin or other such material to join together and reinforce the concrete and steel plating. Member thickness can be made thinner with this method compared with the RC wrapping method.


  • The PC&PA method is an earthquake-proofing method which involves running tensioned PC cables between the opposite ends of the substructure, thereby reducing pier deformation during earthquakes and reinforcing not only the vertical wall but also the foundation. In terms of scope of application for this method, it is essential to take into consideration such factors as the solid structure of the existing abutments and the straight line planar shape of the bridge.


3. Our Construction

  • National Route 251 bridge repair work
  • Suzuta Bridge bridge repair work


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