ENSURING OF GIRDER EDGE SPACE AT EARTHQUAKES WITH LARGE DEFORMATION BLOCKS

Abstract

  Gaps between superstructures and abutment parapets should be small for increasing the life of expansion joints and for reducing noise from joints. However, to prevent the collision of superstructures with seismic-isolation bearing into parapets, the gaps should be large. In this study, the noise from expansion joints and load bearing capacity of abutment parapet of bridges were investigated. On the basis of the results, concrete blocks with unique shapes were made with high performance fiber reinforced cement composite and foamed polystyrene for aiming at giving the following functions to the blocks: Having sufficient load bearing capacity for the vertical wheel load at ordinary times. Following the seismic displacement of the superstructure by deforming largely in horizontal direction. Enabling the restoration of damaged members easier by having an easy-replaceable module structure. The loading tests of the blocks revealed that they had highly anisotropic mechanical performances and high deformability of compressive strain of more than 20%, as had been expected. In addition, it was clarified that fibers could prevent spalling of concrete fragment after the fracture of the block. Polystyrene form helped to decrease the residual strain of blocks after being unloaded less than the half of its maximum strain during loading test.