Half-PC보에 적용된 비인장 강연선의 부착응력-슬립모델 및 정착길이 평가

Abstract

The purpose of this research is to obtain the development length and bond slip relationship of the untensioned wire strand, applied to the PC beam-column joint system developed recently. For this the pull-out tests were performed, in which the main test parameters are diameter of strands (9.3mm, 12.7mm, bundle), embedment lengths, and the covering depth from precast concrete (PC) surface to the strand. The development length estimation equation was proposed based on the test result. Herein 5% fractil value with 90% reliability was considered. The development length estimated by the proposed equation is comparable with that of the untensioned wire strand suggested in CEP-FIP Model Code 1990. The bond-slip model was established by means of the strand strain obtained from the pullout tests. The development length obtained by numerical analysis using this bond-slip model agree with the test result. This shows the validity of the bond-slip model developed in this research.