The Method And Application For The Determination Of The Reasollable Tensile Foree In Tied-arch Bridge Suspender

Tied arc bridge is a kind of beam arch combination structure, which is external statically determinate and statically indeterminate structure inside, and its main stress components are arch rib, tied-beam and suspenders. The tied-beam under bridge deck load directly, then pass most of the load to the arch rib by the suspender, again by the integration of arch rib and tied-beam to the bearing and the lower structure. It’s visible that suspender is the main power transmission component, which connect tied-beam and arch rib. Whether suspender cable force distribution is reasonable, will directly affect the linear of the tied arc bridge structure and uniformity of the distribution internal force, Seriously,it also relates to normal operation of a bridge, and even affect its service life. Therefore, to a tied arc bridge, how to determine reasonable suspender cable force, how to get suspender to the design target state in the construction process of tension, is one of the key problems in the process of design and construction.In this paper, combined with practical engineering, on the basis of existing methods of determining reasonable suspender cable force, we use the unknown coefficient method in MIDAS software to determine reasonable cable force of Yudai bridge in construction stage. By the suit iteration method, the tension cable force of the Yudai bridge in the construction stage was calculated, and three types of tensioning sequence and its corresponding tension are determined. No matter adopt which type of the three methods, the suspender can be tensioned to the ideal state at a time, which provides the convenience for construction. Based on the established calculation model, analyzed the side beams of local constraints to the suspender near the arch springer. By the method of influence matrix calculation of the vector, this paper also calculated the Secondary transfer of cable force and adjustable order to the Dongfeng bridge after the replacement of suspender, and applied it to the field monitoring, by comparison with field monitoring data, the correctness of this method was verified.Finally, based on the theory of vibration frequency lasso solution and the finite element method, the main factors affecting the vibration frequency of suspender arc analyzed, and can be used as a reference of vibration frequency method to detect the suspender cable force.