Influence of intensity & eccentricity of posttensioning force and concrete strength on shear behavior of epoxied joints in segmental box girder bridges

Precast concrete segmental bridges have the advantages of rapid construction speed, excellent quality control and low cost. The structural behavior of segmental bridges largely depends on the behavior of the joints between segments. In this study, a series of specimens with epoxied joints, were tested to assess shear behavior of box girder segmental bridges, under direct shear loading. The study parameters were: confining stress level, prestressing eccentricity, and the concrete compressive strength. Shear behavior, shear capacity, and crack patterns of the joints were investigated as well. Mechanisms of sequential shear failure and a detailed analysis of failure events are also presented. It was found that the shear capacity of the joints increased approximately 40% for each increased 50% of the confining stress. Eccentricity of prestressing force wasn't affecting the elastic behavior of the joints, but its role was appeared obviously at the plastic stage. By increasing concrete compressive strength up to 70 MPa, the joint shear capacity can be increased significantly. The experimental results of the current study and results of other researchers were compared with design provisions. It was seen that the relationships tended to underestimate the shear strength of keyed epoxied specimens by an average value of 11.3%. (C) 2018 Elsevier Ltd. All rights reserved.