基于频率法对系杆拱桥吊杆索力测试的分析

Analysis of Determining Suspender Tension of Tied-arch Bridges Based on Frequency Method

根据系杆拱桥吊杆的振动特性,建立了考虑吊杆弯曲刚度影响的振动微分方程,基于弦振动理论,得出了频率法测试吊杆索力的实用计算公式.研究了单侧安装阻尼器对吊杆振动模态的影响,进而提出了消除阻尼器对索力测试精度影响的计算方法.将此方法应用于某钢管混凝土拱桥的施工监控中,对比分析了各阶段吊杆索力的测试结果与千斤顶标定测量值,结果表明:上述分析方法能够满足实际工程的需要,可广泛应用于频率法测估各种系杆拱结构的吊杆索力.

According to the vibrating characteristics of tied-arch bridge,the differential equation with considering the bending rigidity of the suspender as well as the calculating formula using frequency method for tension test was established. Based on the theory of chord vibration, the influence of single-side damping to the vibration of suspender was analyzed,consequently. The influence of damping to tension test was eliminated by modifying the calculating length of the suspender. The above method was used in the construction monitoring of a concrete filled steel tube bridge by contrasting the practical tension with the tension from tension jack method. The conclusion can be attained that such method could fulfill the requirement of factual project and be widely used for determining suspender tension of tied-arch bridges.