Shear behavior of hybrid seawater sea-sand concrete short beams reinforced with BFRP reinforcements

•A new type of hybrid SWSSC beam-type member was proposed.•Transversely placed BFRP grid units were used as shear stirrups.•A BFRP-wrapped steel tube (BWST) was placed in the bottom tensile zone.•Shear behaviors of short beams were experimentally tested and numerically simulated. A new type of hybrid seawater sea-sand concrete (SWSSC) beam-type member was proposed and tested in this paper. It adopted transversely placed basalt fiber-reinforced polymer (BFRP) grid units as shear stirrups, and its bottom tensile zone was hybrid reinforced with BFRP bars and a BFRP-wrapped steel tube (BWST). The shear behaviors of short beams (shear span-to-effective depth of 1.35) reinforced in shear with only BFRP grid stirrups, only the BWST, and with both BFRP grid stirrups and the BWST were tested and compared. Besides, a finite element model (FEM) was established based on the test results, and numerical simulations under more parameters were carried out. The results showed that the existence of the BWST can improve the shear resistance of the proposed hybrid SWSSC beams. In addition, the combined use of BFRP grid stirrups and the BWST can achieve the best overall shear performance. This new type of hybrid SWSSC beam has broad application prospects in future ocean engineering construction.