Experimental and numerical investigations on shear performance of key tooth joints of precast concrete segmental bridge under repeated loading

Precast concrete segmental bridge (PCSB) has developed rapidly because of its advantages of fast construction speed, little environmental impact, easy quality control, and low cost. The key tooth joint (KTJ) is the critical connection part of PCSB. Limited research on performance of KTJ under repeated loading is available. This study includes experimental and numerical investigations on the behavior of adhesive KTJ under repeated loading. Five scenarios of KTJ with different configurations, including geometries of keys, number of keys, reinforcement in key, and steel fibers in concrete, are included. It is found that KTJ with small keys and KTJ with a single large key present similar behavior when the contact areas are kept the same, and the behavior of the large key is stiffer. Compared to monotonic loading, the load-bearing capacity and stiffness of KTJ are significantly reduced under repeated loading due to the damage accumulation in concrete. Adding steel fibers (in concrete) can evidently enhance the ductility of KTJ and adding reinforcement (in large key) can reduce the damage accumulation effects. The developed finite element models of KTJ under repeated loading agree well with the experimental results regarding the cracking development, load-displacement behavior, and load carrying capacity.

Automated summary

Precast concrete segmental bridge (PCSB) has gained rapid development due to its advantages of fast construction speed, minimal environmental impact, easy quality control, and cost-effectiveness. Key tooth joint (KTJ), as the critical connection part of PCSB, has limited research on its performance under repeated loading. This study conducts experimental and numerical investigations on the behavior of adhesive KTJ under repeated loading. The study includes different configurations of KTJ, such as geometries of keys, number of keys, reinforcement in the key, and steel fibers in concrete. The results show that KTJ with small keys and a single large key exhibit similar behavior when the contact areas are the same, but the large key is stiffer. Compared to monotonic loading, KTJ's load-bearing capacity and stiffness are significantly reduced under repeated loading due to damage accumulation in concrete. Adding steel fibers in the concrete can enhance the ductility of KTJ, while adding reinforcement in the large key can reduce damage accumulation effects. The developed finite element models of KTJ under repeated loading align well with experimental results in terms of cracking development, load-displacement behavior, and load carrying capacity.