Mesoscopic analysis for shear behavior of reinforced ultra-high performance concrete beams
The shear tests of eight reinforced ultra-high performance concrete(UHPC)beams were carried out to explore their shear failure mechanisms.The designed variables included steel fiber content,shear-span ratio,reinforcement ratio and stirrup ratio.The test results showed that the shear strength of UHPC beams could be significantly increased due to the bridging-effect of fibers,accompanied by controlling propagation and decreasing spacing of cracks.A decrease in shear strength but an increase in deformation capacity of UHPC beams could be obtained,as their shear-span ratio increased.An increase in the shear strength of UHPC beams took place with the stirrup ratio.Simultaneously,the improvement in their shear behavior after peak load and decrease in width and length of the diagonal cracks could be observed after adding stirrups.The diagonal deformation(concrete deformation perpendicular to the direction connecting the support and the loading point)decreased and post-cracking stiffness of UHPC beams increased after using steel fibers and stirrups.According to the shear force characteristics of UHPC beams,the contributions of steel fibers at the critical shear crack interface,dowel action,concrete in the shear compression zone and stirrups to shear strength were determined.Furthermore,a mesoscopic multi-parameter shear strength calculation formula of UHPC beams was proposed.Based on test results of 102 UHPC beams,a better prediction of shear strength of UHPC beams could be obtained using the proposed calculation formula,compared with five previous formulas.Therefore,the effect of some common design parameters on the shear strength was investigated.It found that the shear strength contributed by concrete in the shear compression zone decreased significantly with the increase of shear-span ratio.The increase in fiber characteristic value enhanced both the shear strength provided by the steel fibers at the critical shear crack interface and dowel action.
国家科技期刊平台
NSTL
万方数据
维普
