海水海砂ECC梁的抗剪性能试验及有限元模拟

Experimental study and finite element analysis of seawater sea-sand engineered cementitious composites beams

为研究海水海砂高延性纤维增强水泥基复合材料(SSE)梁的抗剪性能,进行了SSE材料的研制,并对玄武岩纤维增强树脂复合材料(Basalt fiber reinforced polymer,BFRP)筋增强海水海砂高延性纤维增强水泥基复合材料(ECC)梁(BFRP/SSE梁)进行剪切试验,分析了配箍率和剪跨比对梁抗剪性能的影响。试验结果表明:SSE的单轴受拉应变最大可达8.3%,平均裂缝宽度约为0.2 mm。BFRP/SSE梁剪切破坏时没有发生剥落破坏。在正常使用极限状态下,BFRP/SSE梁裂缝宽度小于0.3 mm,满足相关规范要求。在少箍筋和无箍筋的情况下,采用SSE制备的梁抗剪承载力反而提高59.32%~99.25%和6.37%~73.68%不等,且刚度也有一定程度的提升。在BFRP/SSE梁的结构设计中可以考虑不设置最小配箍率。采用有限元软件进行数值模拟,探讨了SSE的力学性能对无腹筋BFRP/SSE梁抗剪承载力的影响规律。计算结果表明,随SSE抗压强度提高抗剪承载力增加明显;随SSE抗拉强度提高抗剪承载力缓慢增加;SSE拉伸应变能力对梁抗剪承载力基本没有影响。本研究可为海水海砂ECC梁的工程应用提供参考依据。

To study the shear performance of seawater sea-sand engineered cementitious composites(SSE)beams,SSE material was developed.The shear tests of basalt fiber reinforced polymer(BFRP)bars reinforced SSE(BFRP/SSE)beams were carried out,and the effects of shear span ratio and stirrup ratio on the shear performance of BFRP/SSE beams were analyzed.The experimental results show that the maximum tensile strain capacity of SSE is 8.3%,and average crack width is about 0.2 mm.When BFRP/SSE beams fail in shear,no spalling failure occurs.The crack width of BFRP/SSE beams at serviceability limit state is less than 0.3 mm,which meets the requirements of relevant code.In the case of few stirrups and no stirrups,the shear capacity of beams prepared by SSE is increased by 59.32%-99.25%and 6.37%-73.68%,and stiffness also increases.Minimum stirrup ratio may not be required in the structural design of BFRP/SSE beams.Through finite element software,the influence of mechanical properties of SSE on the shear capacity of BFRP/SSE beams without web reinforcement was analyzed.The results of finite element analysis show that with increasing the compressive strength of SSE,the shear capacity increases obviously.With the increase of tensile strength of SSE,the shear capacity increases slowly.The tensile strain capacity of SSE has little effect on the shear capacity.This study can be used as a valuable reference for the applications of SSE beams in civil engineering.