Crack width evaluation in post-tensioned prestressed concrete bridge-deck slabs

The purpose of the present study is to investigate the cracking behavior and crack width of transversely post-tensioned concrete decks in PSC box-girder bridges. For this purpose, full-scale box-girder members were made and tested. Major test variables include the amount of prestressing and prestressing steel ratios. The crack width, strains and deflections of deck slabs were measured automatically according to the increase of applied loads. The bond effectiveness of prestressing steel was determined from the test data and it was found to be about 0.468 compared with non-prestressed ordinary rebar. A realistic formula for predicting crack width of PSC deck slabs has been derived. The comparison of proposed equation agrees very well with test data while the existing Gergely-Lutz equation and CEB-FIP code equation show large deviation from the test data. The proposed equation can be efficiently used for the realistic analysis and design of prestressed concrete decks in box-girder bridges.