Sectional Optimization And Procedures On Steel Truss Arch Structure

The purpose of structure optimization design lies in seeking both the security and the economical structural style. The optimized design can use material performance reasonably, and be enable various units of structure to obtain the best coordination, and can satisfy each restraint condition—the intensity, the displacement and so on. The practice proved that the structure optimization can reduce the design cycle and the enhance design quality and design level. The structure optimization design has the remarkable economic efficiency and the social efficiency. This article carries on the section optimization design to under-type steel truss arch bridge, to seek most superior design proposal which the structural design condition permits. Applying specifically full stress design criteria and full displacement design criteria to rationally define the structure of the cross section of the bar area so that the structure can withstand a given load and meet a variety of conditions are bound, to minimize the weight of the structure. structural design allows for the optimal design conditions.Currently, the correlation structure internal force computational procedure mostly is compiled with Basic or the Fortran language . By finite element analysis, procedures of the steel truss arch internal force calculation are compiled and debugged with C language structure in this article, then making a variety curve for corresponding with Matlab, AutoCAD etc. software in order to facilitate analysis of internal forces, support force, and the cost of structure changing when the vector cross-over of the steel truss arch changes continuously.In this article, mainly using full stress optimization design and full displacement optimization design two methods to comply and debug corresponding section optimization procedure on the base of meeting the strength, stability, displacement etc. constraints, and then to the steel truss arch structure to carry on the section optimization design to figures out the optimum cross-sectional area of each bar.The conclusion of the study in this article is that under the same load conditions, the maximum pressure, the average pulling force, the average pressure, the average axial force, support level reaction, the structural weight (cost) has gradually become smaller; the maximum pulling force, support vertical reaction remain unchanged when the span of steel truss arch structure is unchanged but the arrow is increasing high— that is when the vector cross-over continually growing larger. Through calculated the example analysis, the cross-sectional area of each bar after section optimization is relatively smaller, and the structure stressful condition is also better when the structures are under the same load conditions and the vector cross-over is in the scope from 1/4 to 1/9. The cross-section area of the bar obtaining by the full stress optimization design not only can give full play Materials and can meet strength, stability and geometry constraints, but also can meet the structural stiffness requirements when the span, the panel length of the structure and the load conditions is smaller. However, it can't meet the structural stiffness requirements when the span, the panel length of the structure and the load conditions is larger; the cross-sectional area of the bar further adjustments using the full displacement optimization design.In this article, the section optimization procedures of the steel truss arch structure have the important instruction function to the actual design and safety assessment of the steel truss arch structure. The optimization design mentality of steel truss arch can be used similarly to optimize the structure of other planar structure, such as rib arch, truss, rigid frame and so on.