A Study On The Development Of Construction Simulation FEA System For 3-Dimensional Cable-Supported Structures

Nowadays cables are widely used in a variety of long-span structures such as cable-stayed bridges, suspension bridges, cable roofs, and etc. The rapid development of cable-supported structures not only raises challenges to design engineers, but also puts forward new requirements of technology for construction. This thesis aims at developing a set of Finite Element Analysis(FEA) system for construction simulation of 3-dimensional cable-supported structures. The present studies are mainly focused on concrete creep and shrinkage effect, geometric nonlinear effect, beam and cable elements. And the derived formula and algorithms are successfully applied to the development of the FEA system for construction simulation.Firstly, the exact beam-element theory is extended from the plane case to the 3-dimensional case. Explicit expressions of element elastic stiffness matrix and geometric stiffness matrix are derived based on Updated Lagrange(UL) formulation. In addition, the transformation matrix between local coordinate system and global coordinate system for 3-dimensional beam element is established with UL formulation. The nonlinear geometric analysis is then carried out via Newton-Ralphson iteration algorithm and with the unbalanced force as convergence index.Secondly, the material nonlinear problem commonly met in concrete structures, i.e. concrete creep and shrinkage effect, is taken into account. The elemental equivalent load increment method for analyzing such effect is extended from the plane case to the 3-dimensional case. And the corresponding algorithm is integrated into the FEA system.Thirdly, new type cable elements are studied. Based on detailed investigation on the mechanical properties of cables in different working scenarios, cables can be categorized into two types, i.e. those with given unstressed length and those with given tension force. Two new cable elements are then developed by using first-order expansions of the analytical solutions for the elastic catenary cable and introducing appropriate constraint conditions, and explicit expressions of element tangent stiffness matrices are derived. Again, the corresponding algorithms are incorporated into the FEA system.Finally, with the cable roof of Shenzhen Bao’an Stadium as an example, the developed FEA system is applied to simulate the construction process of the roof, and a comparative simulation analysis is also done with the general FEA software package Strand7. Comparisons of the numerical results show the satisfied accuracy and high computational efficiency of the proposed FEA system.In the conclusion, main contributions of the present study are summarized, and possibly future work is identified.