Experimental Investigation of Shear Keys for Adjacent Precast Concrete Box Beam Bridges.

Xiaojing Ni,Ahehehinnou Ougbe Anselme,Yuan Xing,Rongqiao Xu,Guannan Wang

doi:10.3390/ma15041459

Xiaojing Ni, Ahehehinnou Ougbe Anselme + Show 3 more

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https://doi.org/10.3390/ma15041459

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Abstract

Longitudinal cracking in shear keys is one of the most frequently recurring problems in the adjacent precast concrete box beam bridges. The relative displacement across the shear key (RDSK) under loads has been used as a direct indicator for shear key cracking. Therefore, accurately simulating the interface between the shear key and beam or providing the correct relationship between shear transfer and RDSK is key to evaluating the damage of the shear key. In this study, the shear transfer properties of four types of composite specimens were studied by static displacement-controlled bi-shear (SDS), cyclic force-controlled bi-shear (CFS), and cyclic displacement-controlled bi-shear (CDS) tests. Two finite element models (FEMs) were established to calibrate and validate the interfacial material parameters. The results showed that adding reinforcement bars over the joints that connect the block and the overlay could improve the bearing capacity of the shear key. Formulae were proposed for the relation between shear force transfer and RDSK in engineering applications. The values of the interfacial material parameters used in the traction–separation model to simulate the interface between the shear key and beam were recommended.

Highlights

Adjacent precast concrete box beam bridges are widely used in short- to medium-span bridges
The following notation of specimen names was used throughout this study: the first three letters stand for the test type; the number following the first three letters represents the type of specimen, and the last digit indicates the replicate number of the specimen
The curves are similar to that of Type I and Type II; the interface of block and joint cracked during this stage, and the upper end of the crack extended to the bottom of the overlay

Summary

Introduction

Adjacent precast concrete box beam bridges are widely used in short- to medium-span bridges. One of the most significant issues for this type of bridge is the longitudinal cracking of the shear keys. It is believed that cracked shear keys compromise the load transfer between beams [1,2]. The load on a single beam exceeds its designed allowable load, leading to accidents [3]. Field observation found that the load transfer between beams could still be maintained for partially cracked shear keys [4,5,6]. It is necessary to reasonably evaluate the damage and load transfer capacity of shear keys to predict the remaining service life of bridges and select appropriate maintenance and reinforcement strategies

Objectives

Results

Conclusion