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Computers and Concrete
  Volume 26, Number 2, August 2020, pages 161-173

Shear strength of match-cast-free dry joint in precast girders
Haibo Jiang, Jiahui Feng, Jie Xiao, Mingzhu Chen and Weibin Liang

    Shear keys in precast concrete segmental bridges (PCSBs) are usually match-casting which is very labour intensive. In this research, an innovative match-casting-free construction was proposed by leaving small gap between the convex and the concave castellated shear keys in the joints of PCSBs. Specimen experiment, shear strength analysis and numerical simulation were conducted, investigating the loading performance of this new type of dry joints, the gap dry joints. Compared with matchcasting joint specimens, it has been found from experiment that shear capacity of gap joint specimens significantly decreased ranging from 17.75% to 42.43% due to only partially constrained and contacted in case of gap dry joints. Through numerical simulation, the effects of bottom contacting location, the heights of the gap and the shear key base were analyzed to investigate strength reduction and methods to enhance shear capacity of gap joint specimens. Numerical results proved that shear capacity of gap dry joints under full contact condition was higher than that under partial contact. In addition, left contact destroyed the integrity of shear keys, resulting in significant strength reduction. Larger shear key base remarkably increased shear capacity of the gap joint. Experimental tests indicated that AASHTO provision underestimated shear capacity of the match-casting dry joint specimens, while the numerical results for the gap dry joint showed that AASHTO provision underestimated shear capacity of full contact specimens, but overestimated that of left contact specimens.
Key Words
    direct shear; matching joint; gap joint; strength reduction; code evaluation; numerical simulation
Haibo Jiang, Jiahui Feng, Jie Xiao, Mingzhu Chen and Weibin Liang: School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006, China

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