Transverse post-tensioning arrangement for side-by-side box-beam bridges

Abstract

While side-by-side box-beam bridges have numerous structural advantages, a serious drawback for this type of bridge is the longitudinal deck cracking over the shear keys. These cracks are observed as early as a few years after initial construction, even where transverse post-tensioning is applied. Associated distresses are well documented in the literature. Two hypotheses were established: longitudinal deck cracking in side- by-side box-beam bridges may be mitigated through an optimized transverse post-tensioning arrangement and traffic is not the sole load factor controlling longi- tudinal deck cracking. This broad study, encompassing field observations as well as experimental and numeri- cal investigations, demonstrates that a transverse post- tensioning system can be determined as a function of bridge geometry such that deck cracking due to temperature and traffic loads is mitigated. The recom- mended transverse post-tensioning system is defined by the number of diaphragms and the force applied at each diaphragm.