超声波检测残余预应力的理论探讨

残余预应力是预应力构件的重要特征参数,关系到构件的承载力大小和安全状况。残余预应力与诸多因素有关,且关系很复杂,准确计算残余预应力是非常困难的。因此,对已建成结构进行现场检测是获得残余预应力的有效方法。在这样的背景之下,文中引入超声波来检测预应力钢筋或钢绞线的残余预应力。根据声学和力学的理论知识,推导了残余预应力的计算公式。在推导过程中考虑了温度补偿。在测量承载构件的残余预应力时需要测量纵横超声波的声时和计算外荷载产生的弯矩分布。

Explore and discussion on theory of ultrasonic testing residual prestress

Residual prestress which has much to do with bearing capacity and security condition of the structure is an important parameter of the prestressed component.Residual prestress relates to many factors and the relation is significantly complex.Calculating the residual prestress accurately is very difficult.Therefore,testing the built structures on site is an effective way to get the value of residual prestress.Under such background,ultrasonic technology is introduced to test residual prestress of pretensioned steels or strands.The computation formula for residual prestress is derived according to phonics and mechanics theories,and temperature offset is considered in this paper.The time of transmission of longitudinal ultrasonic and rotational ultrasonic need to be tested and the moment distribution which was generated by external loads need to be calculated,when using this method to test residual prestress of the load-bearing structures.