考虑位置函数的木材表面嵌筋粘结滑移本构关系

BOND-SLIP LAW BETWEEN TIMBER AND NEAR SURFACE MOUNTED REBAR CONSIDERING LOCATION FUNCTION

木材表面嵌筋加固是提升木结构构件力学性能的有效加固方法,木材与筋材之间良好的协同工作性能是保证其加固效果的基础,内嵌筋材与木材的粘结滑移本构关系是理论计算与有限元分析的重要依据。该文基于6组18个原木木材表面内嵌钢筋试件的拔出试验结果,首先分析计算试验中量测得到的钢筋应变以及钢筋相对于试件端部的滑移值,得到了局部粘结应力和相对滑移量沿锚固长度的分布曲线,由其分布规律可知局部粘结应力呈双峰状分布,相对滑移量分布与锚固长度相关;进而分析了不同位置处的粘结滑移曲线以及同一滑移值下的粘结应力分布曲线,可知不同应变测点处的粘结滑移曲线分布规律不同;之后采用归一化的方法给出了描述粘结滑移关系的位置函数,并讨论了钢筋直径以及锚固长度对位置函数分布的影响;最后建立了考虑位置函数的木材表面嵌筋粘结滑移本构关系。

The mechanical properties of timber structure components can be improved significantly with the near surface mounted technique,and the strengthening effects depend on the collaborative working performance between timber and rebars.The bond-slip constitutive relationship is the necessary basis for the theory calculation and finite element analysis.On the basis of the pull-out test results of 18 timber specimens(6 groups)with near surface mounted rebars,the distribution of the local bond stress and local relative slip-displacement along the anchorage length of steel rebars were obtained by analyzing and calculating the experimentally measured strain of steel bars and the relative-slip values of steel rebars to the end of specimens.The distribution law of local bond stress indicates that it is bimodal and the local relative slip-displacement curves are related to anchorage length.Further,the local bond-slip curves,the distribution of which varies along the measurement position and the bond stress distribution curves under the same slip value are analyzed.Then,a location function describing the bond-slip relationship is derived by the normalization method,and the influences of diameter and anchorage length of steel rebars on the distribution of the location function are discussed.Finally,the bond-slip law between timber and near surface mounted steel rebar considering the location function is constructed.