Anchorage length and bond stress-slip model of an untensioned wire strand placed at the interface between a half-PC beam and topping concrete

Abstract

The purpose of this research is to obtain the anchorage length and the bond stress-slip relationship of an untensioned seven-wire strand placed at the interface between a half-precast beam and topping concrete, applied to the precast concrete beam-column joint developed recently. From a pullout test with various embedment lengths, the anchorage lengths were determined for strands of diameters 12.7 and 15.2 mm, and also for a bundle of two 12.7 mm strands. Additionally, the bond stress-slip model was established by means of a numerical algorithm applying the strand strains measured in the pullout test. The anchorage lengths estimated numerically using the bond stress-slip model agreed well with the test results. For the interface between a half-precast concrete beam and topping concrete, a new bond condition coefficient $$\eta_{2} = 0.875$$ was proposed for use in the design equation for the basic anchorage length suggested in the CEB FIP Model Code.