初始静载对不同剪跨比BFRP筋混凝土梁动态剪切性能的影响  

Effects of initial static load on dynamic shear performance of BFRP-RC beams with different shear span ratios

作　　者：雷宇霜 金浏[1] 杜修力[1] 余文轩 LEI Yushuang;JIN Liu;DU Xiuli;YU Wenxuan(The Key Laboratory of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市减灾与防灾防护教育部重点实验室,北京100124

出　　处：《振动与冲击》2023年第9期36-46,共11页Journal of Vibration and Shock

基　　金：国家自然科学基金(51978022,51822801)。

摘　　要：为揭示初始静载对玄武岩纤维增强(basalt fiber reinforced polymer,BFRP)筋混凝土(BFRP-RC)梁动态剪切性能的影响,建立了考虑混凝土非均质性、混凝土与BFRP筋间相互作用及各材料应变率效应的三维细观数值模型。在验证了该模拟方法合理性与准确性的基础上,分析了初始静载对不同剪跨比BFRP-RC梁破坏过程与失效机制的影响。研究结果表明:BFRP-RC梁的抗剪承载力及变形能力均随应变率增大而提高;应变率对梁抗剪承载力的增强作用随剪跨比增大而减弱;在峰值荷载前应变率突增,BFRP-RC梁的刚度增加,抗剪承载力提高;在峰后软化段应变率突增,BFRP-RC梁的峰后软化转变为峰后硬化,而后出现第二峰值荷载;BFRP筋混凝土梁的动态抗剪承载力均随初始静载增大而降低,但梁抗剪承载力的降低量是否与后续应变率有关取决于初始静载水平;在各应变率下,BFRP筋混凝土梁的变形能力及损伤程度均随初始静载的增大而减小,但增大后续应变率会削弱初始静载对梁动态性能的影响。Here,to reveal effects of initial static load on dynamic shear performance of basalt fiber reinforced polymer(BFRP)-reinforced concrete(BFRP-RC)beams,a 3D meso numerical model considering heterogeneity of concrete,interaction between concrete and BFRP reinforcement,and strain rate effects of various materials was proposed and established.On the basis of verifying the rationality and correctness of this simulation method,effects of initial static load on failure process and failure mechanism of BFRP-RC beams with different shear span ratios were analyzed.The results showed that 1)anti-shear load-bearing capacity and deformation capacity of BFRP-RC beams increase with increase in strain rate;2)strengthening effect of strain rate on anti-shear load-bearing capacity of beams decreases with increase in shear span ratio;3)before peak load,strain rate suddenly increases,stiffness of BFRP-RC beam increases,and its anti-shear load-bearing capacity increases;in post peak softening stage,strain rate suddenly increases,and post peak softening of BFRP-RC beam changes to post peak hardening,and then the second peak load occurs;4)dynamic anti-shear load-bearing capacity of BFRP-RC beam decreases with increase in initial static load,but whether the reduction of anti-shear load-bearing capacity of BFRP-RC beam is related to subsequent strain rate depends on initial static load level;5)under each strain rate,deformation capacity and damage degree of BFRP-RC beam decrease with increase in initial static load,but increase in subsequent strain rate can weaken effects of initial static load on dynamic performance of BFRP-RC beam.

关 键 词：玄武岩纤维增强(BFRP) 筋混凝土梁(BFRP-RC) 初始静载 动态加载 应变率 剪跨比 细观模拟 

分 类 号：TU375.1[建筑科学—结构工程]