Shear strength at the interface of precast bridge concrete decks and girders subjected to cyclic loading with varying speeds

Abstract

Since its inception, the full-depth precast concrete deck panel system has attracted the attention of the bridge construction community. This alternative system constitutes a cost-effective solution that solves some of the issues associated with the traditional cast-in-place concrete decks. To ensure an adequate composite action, shear connectors are required at the interface deck-girders. Previous studies dealt mostly with the shear behavior of the interface between precast girders and cast-in place decks. Studies dealing with the alternative system are limited and were based on static push-off tests. In this paper, 12 cyclic loading tests were carried out to understand the cyclic behavior of the interface deck-girder of the alternative system and estimate its shear strength. Test variables included the number of shear connectors and speed of loading (i.e., loading rate). We observed that the common mode of failure of the interface is due to debonding of the deck from the girder. Test results showed that the shear strength increases with the number of shear connectors but decreases with the speed of loading. Moreover, the test results of specimens without shear connectors were used to estimate the cohesion factor at different loading speeds. Comparison between AASHTO LRFD code provisions and test results showed that the code provides an acceptable estimate of the shear strength provided that the cohesion factor is accurate.