型钢轻骨料混凝土粘结强度研究

Experimental study on bond stress of steel reinforced lightweight concrete

通过正交试验设计,由推出试验研究了型钢轻骨料混凝土的平均粘结强度和局部粘结强度。根据试验结果,拟合了平均粘结强度表达式,得到了局部粘结应力最大值和混凝土立方体抗压强度的关系。基于所得平均粘结强度,推导了临界锚固长度和极限荷载表达式。临界锚固长度计算中提出了临界锚固长度系数,当混凝土保护层厚度、配箍率和混凝土强度不变时,不同型号工字钢临界锚固长度系数取值趋于一致,临界锚固长度系数的引入可用于计算锚固长度的上限值,并对影响临界锚固长度的因素进行了探讨。极限荷载的理论值和试验值吻合较好,可用于型钢轻骨料混凝土构件自然粘结力估算。

Based on the push-out tests of steel reinforced lightweight concrete specimens,average bond strength and local bond strength are studied by orthogonal experimental design.According to the test consequences,equations of average bond stress,relationship between the maximum local bond stress and concrete cubic compression strength are proposed.The critical anchorage length and ultimate load functions are derived in response to the average bond stress.The coefficient of critical anchorage length is introduced in calculation the critical anchorage length,and major factors that affect the critical anchorage length are also analyzed.The coefficient varies in a small range for different I steel when concrete cover,stirrup ratio and concrete strength are constant values,then it can be used to calculate upper limit of critical anchorage length.The ultimate loads from formulas agree well with the test results and nature bond load can be estimated by the theory function.