Studv Of Construction Control In Cable Replacement Project For Single Pylon Cable-stayed Bridges

As one of the most important stressed member of the cable-stayed bridge, the stay cables always happen PE pipe corroded, steel strand(or steel wire)rust heavily or even broken because of the severe work condition, the unreasonable stress state and the shortage of repairmen, it is more likely to drop the carrying capacity of the stay cables, also threaten to the safety of the cable-stayed bridges. In recent years, home and abroad take measures that replacing the stay cables in order to fix them one after another. The cable replacement has made increasing progress while theoretical research has lagged behind. Thus, this paper did a research on key issues in the construction of cable changes as follows:(1) On the basis of restoring the stress state of the stayed-cable bridge before replacing cables, three typical cable replacement plans’finite element model was built respectively, which are replacing single cable, replacing two cables symmetrically and replacing two cables asymmetrically. Through coMParing plans from bridge’s stress indicators like cable force increment, bridge linear, girder strain, got the optimal cable replacement plan which is replacing two cables symmetrically. Eventually, coMPared the bending strain energy of girder under the cable replacement construction state, chosen the optimal cable replacement sequence which is from the shorter cable to the longer.(2) Took the damper into account while analyzing the vibration of the cable system, simulated the mechanical property of damper, a energy equation of vibration which considering the effects of damper was established, and a new cable force calculation formula was summarized, whose precision is higher than traditional formula while applying it to the stay cables of People Bridge, and also more satisfy the demands of practical accuracy.(3) By coMParing the calculation of temperature load code between countries, chosen the right one which was suited to People Bridge to analysis the temperature effect by the finite element software MIDAS/Civil. The result shows that the system non-isothermal and the tower temperature gradient has less influence on the stress state of the bridge, while the difference temperature between cable and girder (tower) and the girder temperature gradient has a greater one. At the end, a preliminary revision suggestion was put forward to revise temperature effect on the cable force and main girder stress monitoring in the cable replacement construction.