PRESTRESS INTRODUCTION TECHNOLOGY USING PC STEEL STRANDS EXTENDING FROM PRE-TENSIONED MEMBERS

Abstract

 In order to expand the application range of precast method, we have proceeded with development the “hybrid PC (HPC) structure”, that is jointed pre-tensioned member to additional post-tensioned member by re-tensioning PC steel stands extended from pre-tensioned member. In this study, we carried out experiments on the development length and re-tensioning in pre-tensioned member. Experimental parameter are concrete strength and with or without the epoxy coating of PC steel strands. And we considered the adhesive mechanism of PC steel strands when introducing prestress and re-tensioning in pre-tensioned member from result of these experiments. The relationship between the adhesive stress and slip of PC steel strands obtained from these experiments were introduced into the nonlinear FEM analysis, and tried reproduction analysis the adhesive behavior of PC steel strands.

 As a result, The adhesion mechanism are different in the introducing prestress and the re-tensioning, and with or without epoxy resin coating on PC steel strands. And we have found high strength concrete are suitable for HPC structure. In addition, FEM analysis are able to reproduce the adhesive behavior of PC steel strands to a certain degree.