Development length of prestressing strands in precast/prestressed girders using self compacting concrete

Self-consolidating concrete (SCC) has become of high interest to the precast concrete industry due to the benefits it offers in enhancing construction productivity. In spite of this interest and rapid developments on SCC technology, its acceptance in the U.S. is lagging due to material and structural performance concerns; among these is the issue of bond. An on-going study is thus evaluating the bond of prestressing strands on precast/prestressed girders. The study is based on experimental evaluation of transfer and development lengths of 13mm (0.5 in.) diameter seven-wire strands on small-scale T-beams. Three different SCC mix designs, which bound the approaches to achieve SCC behavior, and a reference normally consolidated concrete mix were considered. Preliminary results indicate that transfer lengths for SCC deviate from those for normal concrete depending on its composition. In all cases, however, the experimentally determined transfer lengths are within code recommendations. Flexural tests for determining development length are on-going.