Study On Completed Bridge Cable Tension Optimization And Rational Construction Of Longwan Bridge

Cable-stayed bridge is a kind of highly redundant and complex structure，the cabletensions have greatly tremendous influence on the distribution of internal stress in thestructure system and they have become the key to control to the internal forces of the wholebridge. How to determine and optimize the cable tensions in order to make the cable-stayedbridge in good condition，and how to determine the rational construction state—thereby theconstruction to achieve the target of rational finished dead load state in design，have becomeone of the key problems about design and construction technology of cable-stayed bridge.In this paper, the Longwan Bridge in FoShan is taken as engineering background，adopted constrained Minimum Energy Method which combied the Minimum Bending EnergyMethod，the Influence Matrix Method and two Planning Theory to determine and optimize thecompleted bridge tensions. First，the constrained minimum energy method was chosen tofound the mathematical model that determine the optimum preliminary cable-stayed tensionsat reasonable status of completed bridge，with the whole deformation energy of the towerand the girder minizing as the objective function，and the upper and lower limits of specifiednodal displacement、bending moment and cable force as the constrains，using the quadraticprogramming method to adjust the completed bridge cable tensions， solving by theoptimization toolbox of MATLAB，ultimately，the reasonable completed cable tensions willbe worked out.Then，computed the construction cable force according to the characteristic of guyedbasket by establishing the construction stage model，and adjusted the cable tensions with theInfluence Matrix Method after the whole bridge was built，in order to achieve the reasonablecompleted bridge state. This paper used a construction program of single cable，which needs asmaller construction cable force than the original construction plan by two cables，and can beimplemented more easily. At last，the static and dynamic behavior at operation stage wasanalyzed，we clarified the stress and deformation of the structure，obtained the vibrationcharacteristics of the bridge，validated some common features of cable-stayed bridge aboutstructure vibration characteristics.The parametric sensitivity analysis of the cable-stayedbridge was carried out and some useful conclusions were obtained.