【摘要】 通过12榀不同混凝土强度等级、剪跨比、配箍率的实腹式型钢高强高性能混凝土简支梁试验,得到了各级荷载作用下沿梁长度(即跨度)方向型钢应变、型钢与混凝土界面粘结应力与相对滑移分布规律。结果表明:在界面粘结应力尚未达到局部粘结强度之前,型钢应变和界面滑移近似呈指数变化;此后界面出现粘结软化,且粘结软化区段随荷载的增加逐渐向试件自由端扩散,型钢与混凝土协同工作的能力降低。通过对界面粘结滑移行为与诸影响因素的分析,从机理上揭示了粘结软化的形成与演化过程,分析了局部粘结强度与其主要影响因素的关系,并由试验结果统计回归得出了型钢高强高性能混凝土局部粘结强度的计算公式,进而提出型钢高强高性能混凝土梁局部粘结应力与加载端粘结滑移本构关系的数学模型。最后建立了型钢与混凝土界面粘结滑移分析的理论模型,求解了各级荷载作用下粘结应力的传递规律。研究成果为改进型钢高强高性能混凝土梁设计计算理论和有限元分析提供了试验依据。更多还原

【Abstract】 Based on the experiments of twelve simply supported steel reinforced HSHP(high strength and high performance) concrete composite beams with various concrete strength,shear span ratio and stirrup ratio,the distribution of bond stress and relative slip between shaped steel and concrete in HSHP concrete composite beams is obtained.Steel strain and relative slip increase exponentially from the free end to the loading end before bond stress reaches the local bond strength;with the load increasing,the strain difference turns to be insignificant on steel surface near loading position.This is called interfacial bond softening,and it will lead to progressive reduction of shear transfer capacity between steel and concrete.By analyzing the influence of the main parameters on interfacial bond-slip behaviors,the occurrence and evolution of bond softening as well as the relationship between local bond strength and its influential parameters are explained mechanically.In the light of the test results,the regressive formulas of local bond strength are established and the constitutive model of the bond stress versus slip at loading end is proposed.At last,a mechanical model is established to account for the bond stressdistribution and the theoretical result agrees well with experimental result.更多还原