A New Cable-arch Structure’s Mechanics Performance Analysis And Optimization Design

Cable-arch structure is a new kind of structure form which hybridized by the cable and the arch hybrid. Through the reasonable combination of arch, brace lasso and poles, the structure utilizes supporting effect provided by cable tension or poles to improve the internal force’s distribution and limit the development of its deformation, and improve its rigidity and stability effectively. In the light of this new type of cable-arch structure, its classification, mechanics performance, optimum design and parameter analysis has been studied.First of all, according to the connection node of cable and brace, cable-arch structure could be divided into three types:sliding cable node type, fixed type (also the sectional type) and fixed rope tension after the node type. The basic mechanical properties of the above were studied. A new sliding cable’s calculation method, namely equivalent roller method was put forward, and its validity was verified by an example. The result showed that the sliding cable nodes is not suitable for the cable-arch structure, but fixed line and tension after fixed nodes could be applied to the cable-arch structure, the former has better mechanical performance while the latter’s tensioning construction was more convenient.Based on ANSYS, this paper put forward multiple load steps solution technology combined with the optimized design module of optimization method, respectively, for the fixed line node type new cable prestressed cable-arch structure optimization and cable prestress and cross section size optimization problem, has established the optimization goal, design variables and state variables, optimization mathematical model is established, considering the combined load is optimized. A optimization program has been compiled by using ANSYS and APDL software which is helpful to solve practical engineering problems.The parameters analysis of the cable-arch structure has been made and studied the lower level of bearing stiffness, number of poles, the rise-span ratio of arch and cable, steel arch section, and the size of the prestressed cable section’s influence on the structure’s strength, stiffness and the overall stability. The result shows that:when the cable-arch structure is hinged at both sides, its stress level reachs the lowest while the overall stiffness reachs the highest; A certain number of poles is adjusting the internal force distribution of the steel arch lasso, control the important assurance of structural deformation, improve the overall stability, but unfavorable and overmuch. The mechanical properties is optimal when arch rise-span ratio values 0.3; Arch’s size has great effect on the mechanical properties of cable-arch structure; Cable cross section size have less effect on the internal forces of the arch body; High pre-stress increases arch body and internal force of lasso, adverse consequences, and did little to the promotion of rigidity and stability. These conclusions could provide references for practical engineering design.