Shear testing of steel fiber reinforced expanded-shale lightweight concrete beams with varying of shear-span to depth ratio and stirrups

摘要

Aiming at achieving the beneficial effects from the lightened self-weight of structures, steel fiber reinforced expanded-shale lightweight concrete (SFRELC) is promoting to be applied in structural engineering. In this condition, proper design method needs to be built up for the reinforced SFRELC structures. In view of the shear performance of reinforced SFRELC beams, ten test beams were fabricated and tested by four-point bending test in this paper. The major variables were selected as the shear-span to depth ratio from 2 to 3 and the stirrups ratio of 0.19 % and 0.25 %. The shear-cracking resistance, the shear crack width and distribution, the mid-span deflection and the shear capacity of test beams were measured. Results indicate that the shear failure mode of reinforced SFRELC beams relied on the shear-span to depth ratio and can be modified to ductile with the increase of stirrups ratio, the shear-cracking resistance and the shear capacity reduced with the increase of shear-span to depth ratio. The beneficial effects of steel fiber and stirrups on the shear performance of SFRELC can be comprehensively reflected by the shear capacity provided by SFRELC of reinforced SFRELC beams. Based on test results and previous studies, formulas were proposed to calculate the shear-cracking resistance and shear capacity of reinforced SFRELC beams. Finally, the formulas expressed by the lower envelop curves of test date for conservative design of shear capacity of reinforced SFRELC beams are also suggested. In this condition, the shear crack width can be limited within 0.2 mm and 0.1 mm at normal serviceability.