Decision Method On Reasonable Design State Of Self-anchored Suspension Bridge With Spatial Cables

Self-Anchored suspension bridge with spatial cables main cables and slings as the formation of a three-dimensional system,which make it have good landscape effec, strong wind resistance and excellent dynamic performance,at the same time the self-anchored suspension bridge without massive anchor can well to adapt to harmful Geological bridge site area, subject to restrictions on small terrain features, making it more and more in the attention in the small and medium span bridge. Suspension bridge design, general layout of the first under the bridge and experience in determining the overall state of the parameters into a bridge, such as the main cable control points (including the anchor point and the IP point, etc.) coordinates span ratios, slings linear layout and bridge, etc. then calculated into a bridge state cable shape, cable power, cable length, sling length, and finally into a bridge with the intrinsic link between the state (non-stress length of each component remains the same), cable finished iteration obtained , saddle base fallback content, stress-free length of the main cable as well as the construction phase structure of the state of regression analysis. Therefore, to determine the state of suspension bridges is essential.The thesis is a numerical study of decision method on reasonable design state of self-anchored suspension bridge with spatial cables based on the Hangzhou Jiangdong Bridge.The main work is summarized as the follows:1)According to the inherent requirements of self-anchored suspension bridge with spatial cable subjected to loads, the global flow to determine its reasonable design state was clarified. Proceeding from that the internal force state (especially bending moments) of the girder should be reasonable, the method to calculate the vertical component of suspender's force was obtained. Based on expatiation the fundamental analytical equations of spatial main cable shape finding and method to calculate the vertical component of suspender's force, the analytical program and method to find the shape of spatial cable in design state with high speed come into being. According to condition that the suspenders only crosswise inclined in the design state, the recursive formulas to calculate the stiffness of spatial cable while it's shape changing were derived, the specific processes to find the shape of spatial main cable and calculate the parameters of suspender was given. And then, the method to calculate the design state of self-anchored suspension bridge with spatial cables with high efficiency and precision and with good idea was established. The example of Jiangdong Bridge in Hangzhou proved that the method of this paper is very efficient and precise.2)Based on the saddle's theoretical apex which is defined as extensive catenary crossing point.The method of level busbar saddle's position is explored greatly.The eleven nonlinear equations are derived from mechanical relationship and geometrical relationship,which are solved by the Newton-Raphson iterating method.The step and iterating method are introduced.The Jacobian Matrix is deduced,the method which iterative initial value be defined is discussed and which ensures the iteration quickly to converge at the true solution.at last,the sample in which saddle's position and the unstressed length of cable on the saddle is calculated,and the sample show that the method is feasible and preferable precision.Get the precision unstressed length of cable through the saddle's position Amendments to the main cable length .3)Based on the above theory, Writing the software of decision method on reasonable design state and construction process calculation for Self-Anchored suspension bridge with spatial cables main cables.The example of Jiangdong bridge in Hangzhou proved that the method of this paper is very efficient and precise.