Experimental and PARAMETRIC Numerical Investigation on Punching Shear Behavior of RPECC Link Slabs in Joint-free Bridges
Cheng Zheng, Shuai Hu, Shaohua He, Zheng JiangIntroduction:
Link slabs incorporating Rubberized Polyethylene Engineered Cementitious Composite (RPECC) exhibit excellent axial performance, making them a promising solution for joint-free bridges. However, the structural reliability of RPECC link slabs under localized wheelload- induced effects, particularly with respect to punching shear resistance, remains insufficiently understood. To fill this research gap, this study investigates the punching shear behavior of RPECC link slabs through a combination of experimental and numerical tests.
Methods:
Four link slab specimens were fabricated and tested to failure, comprising one Engineered Cementitious Composite (ECC) slab and three RPECC slabs with different reinforcement types, namely Glass Fiber-Reinforced Polymer (GFRP), basalt fiber-reinforced polymer (BFRP), and HRB400 steel reinforcement. Damage patterns, crack propagation, load-deflection behavior, and strain development obtained from the slabs were presented and analyzed. A Finite Element (FE) model was developed to examine damage mechanisms and conduct a parametric study of critical design variables.
Results:
Experimental results reveal that RPECC slabs undergo ductile punching-shear failure featured by progressive crack propagation and moderate load degradation. Of the three reinforcement types, GFRP bars achieve the best mechanical performance. Adopting HRB400 steel rebars slightly lowers ultimate punching-shear capacity, while BFRP rebars exhibit poorer resistance owing to low rebar strength and insufficient interfacial bonding with the RPECC matrix.
Discussion:
Compared with the GFRP-reinforced ECC slab, the RPECC slab with matching GFRPs achieved 9% higher punching-shear resistance. Regarding reinforcement influences, GFRP- and steel-reinforced RPECC slabs yielded similar resistance, 55% higher than that of their BFRPreinforced counterparts. For GFRP-reinforced RPECC slabs, increasing slab thickness (40 mm to 80 mm) and reinforcement ratio (0.51% to 3.11%) improved ultimate capacity by 241% and 308%, whereas reducing the width-to-length ratio from 1:1 to 1:2 decreased the resistant capacity by 40%.
Conclusion:
The findings highlight that RPECC link slabs reinforced with GFRP rebars can satisfy the punching-shear performance demands of jointless bridges, and the obtained results offer reliable design guidance for jointless bridge link slabs.