基于频率法的PC桥梁锚下有效预应力检测技术影响因素

Influence factors of effective prestress detection technology for PC bridges based on frequency method

针对采用频率法检测预应力混凝土(PC)桥梁锚下有效预应力时锚具振动频率易受外界测试因素影响的问题,以实际工程中预制PC梁片为试验对象,进行了激振锤锤头材料、激振锤敲击点位、加速度传感器加固方式与安装位置的影响程度研究,进而总结归纳形成了锚具振动频率测试的合理、规范操作流程。结果表明采用频率法检测PC桥梁锚下有效预应力时,建议采用易于操作且测试信号稳定的尼龙锤头,将加速度传感器安装在锚板正下方且采用不锈钢卡箍进行加固,使激振锤的敲击位置与加速度传感器的安装位置保持正对方向。研究成果可提高频率法检测PC桥梁锚下有效预应力检测精度,为后续该方法的推广应用打下基础。

Aiming at the problem that the vibration frequency of anchor was easily affected by external test factors when using frequency method to detect the effective prestress of prestressed concrete(PC)bridge,the prefabricated PC beam in the actual project was taken as the test object,the influence degree of shock hammer head material,shock hammer point position,reinforcement method and installation position of acceleration sensor was studied,then the reasonable and standard operation flow of anchor vibration frequency test was concluded.The results showed that when the frequency method was used to detect the effective prestress of PC bridge,it was suggested to use nylon hammer head which was easy to operate and stable test signal,and install the acceleration sensor directly under the anchor plate and reinforce it with stainless steel clamp,the percussion position of the vibration hammer was directly opposite to the installation position of the acceleration sensor.The research results can improve the accuracy of frequency method for detecting the effective prestress of PC bridge,and lay a foundation for the subsequent popularization and application of this method.