The study of shear capacity of steel reinforced concrete deep beams based on modified softened strut-and-tie model

In order to study the shear capacity of steel reinforced concrete(SRC) deep beams, the static test and finite element analysis of 7 SRC deep beams was completed.The influence factors include shear-span ratio, section steel web height and flange width are considered.The failure modes of the specimens are diagonal compression failure and shear failure.The shear-span ratio has a great influence on the failure mode.The larger web height and flange width of section steel significantly increase the shear capacity of specimens.On the basis of experimental study and finite element analysis, the softening effect of reinforced concrete, the coordinated deformation of unsoftened concrete and flange, the shear contribution of web are considered.A modified softened strut-and-tie model is established, and a calculation method for shear capacity of SRC deep beams is derived by using the superposition principle.The result shows that the modified softened strut-and-tie model can better reflect the failure characteristics and stress mechanism of SRC deep beams.The proposed calculation method of shear bearing capacity is in good agreement with the experimental data, and the factors affected by shear are considered more comprehensively.The method in this paper can well predict the shear capacity of SRC deep beams.