Evaluation of Strand Transfer And Development Lengths In Pretensioned Girders With Semi-Lightweight Concrete

摘要

In a study sponsored by the FHWA, the current AASHTO equations for the calculation of transfer and development lengths of prestressing strand were found to be unconservative in the case of lightweight concrete members with unit weight less than 1920 kg/m³. This finding raises a question regarding the applicability of the same equations to semi-lightweight concrete members.nThe objective of this study co-sponsored by the Indiana Department of Transportation and the Federal Highway Administration is to determine if the current AASHTO Specifications are applicable to semi-lightweight pretensioned concrete bridge members. The study addresses the transfer and development lengths of 13.3 mm and 15.2 mm pretensioned strand in semi-lightweight concrete girders with concrete compressive strength of 48 MPa for the 13.3 mm strand and 69 MPa for the 15.2 mm strand. Two strand types were considered in this study.