Experimental Study on Shear Behavior of Precast High-Strength Concrete Segmental Beams with External Tendons and Dry Joints

Precast high-strength concrete segmental beams with external tendons and dry joints (ED-PHCSBs) have become a potential alternative for achieving accelerated bridge construction due to their lighter self-weight and easier installation. In order to investigate the shear behavior of ED-PHCSBs, eight precast concrete segmental specimens were fabricated and tested to failure. For comparison purposes, one externally prestressed high-strength concrete monolithic beam was also investigated. The primary parameters, including concrete strength, shear span-depth ratio, stirrup ratio, joint number, and joint location, were adopted. Test results indicated that increasing the concrete strength or stirrup ratio can effectively improve the shear capacity of the ED-PHCSBs. The shear span-depth ratio was inversely proportional to shear strength for all specimens. The results also revealed that the joint number had a marginal effect on the defections and stresses of the external tendons of ED-PHCSBs. AASHTO 2017 and Chinese code 2018 can conservatively estimate the shear strength of ED-PHCSBs. Considering the actual failure modes of the precast beams, a calculation method based on a modified strut-and-tie model was proposed. The average and standard deviation of the ratios of the test results to the predicted value of the proposed method were 0.98 and 0.08, respectively. It indicated that the proposed formula was more accurate.

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