Experimental study of high-strength steel-precast prestressed concrete composite beams under hogging moment

To study the bending behavior of high-strength steel (HSS)-precast reinforced concrete (PRC) slab composite beams with clustered studs under hogging moment, five prefabricated composite beams were tested under single-point loading. The key parameters are shear connection degree, shear pocket spacing in the PRC slab, and applying precompression to the concrete or not. The results showed that two failure modes appeared in the composite beam, including flexural failure and shear failure. The composite beams made of Q550 steel and C50 concrete have full composite action and good overall bending behavior. In addition, applying the prestressing force in the PRC slab can effectively increase the cracking load of the slab and slightly improve the bending behavior. When the shear pocket spacing is increased from 360 mm to 800 mm (the limit value in the AASHTO LRFD Bridge Design Specifications is 610 mm), the composite beam can still maintain the full composite action. The existing specifications can be used to predict the bending capacity and stiffness of the HSS-PRC slab composite beam under hogging moment, the result is relatively conservative for the former but is consistent for the latter. •Single-point loading tests on the HSS-PRC slab composite beams.•HSS composite beams have good bending behavior under hogging moment.•Prestressing in PRC slab is effective in improving the anti-cracking behavior.•Evaluating the rationality of enlarging the shear pocket spacing.•Existing codes are conservative in bending capacity but accurate in stiffness.