| With the development of the bridge structure analysis theory and construction techniques,single and tilt pylon cable-stayed bridge,which is elegant,great tension and reflecting the vigor and vitality,is often the preferred bridge in city bridge design. Although the cable-stayed bridge gives visual pleasure, the structure of the internal force state has become a challenge to be faced by the designer. And the choose of design parameters has become a key issue.Based on the design information of He-hua Bridge in Ya’an, Sichuan, China, the bridge finite element model was established to analyze the finished stage. For the finished stage,certain load effect such as live load and temperature. The most disadvantageous combination were also studied.The reasonable finished state and optimization of cable force of the single and tilt pylon cable-stayed bridgewere studied by using Influence Matrixand MATLAB quadratic optimization method. Optimization method is making optimization of cable force into solving a constrained quadratic programming problems,which objective function is the tension and compression and bending strain energy of the beam and steel pylon and restriction,taking into account the live load,is setting a reasonable range of beam and stay cable stress.Optimization of cable force is divided into preliminary and final optimization phase.Because cable-stayed bridge is statically indeterminate system, cable tension affect bridge structure force state. Once the cable tension changes,its structure will respond.At last, the design parameters comparison analysis should be based on whole internal forces as the goal and meet the constraints of the optimization of cable force, then the structure of the force state is compared. Based on this type of bridge, this paper studied the influence of the range and distribute loads of weights in side span,the ratio of beam and pylon stiffness and the pylon angle on static structural characteristics.According totheanalyzing, when the weights are in a small range, it is beneficial for the structure to increase the set of weights and when the weights are in a large range, it is from beneficial to negative for the structure to increase the set of weights. With the increase of beam-column-stiffness-ratio,structural strain energy decreased first and then increased, and steel pylon strain energy and the beam moment sum of squared increased. With the increase of pylon angle,structural strain energy, beam strain energy, pylon strain energy,beam moment sum of squared and pylon moment sum of squared decreased first and then increased. |
