Pre-stress And Span Height Optimization Of The Beam String Structure

Beam String Structure, short for "BSS", with bar connecting flexural and compression structural members and tensile members, is a developing structure form which fully utilizes the mechanic properties of arches and cables. It has been applied in variable domestic and oversea project practice these years.Firstly, the article has a non-linear static properties analysis with BSS. In example of single-direction BSS, due to biggish space between adjacent shares of BSS, different pre-stress is applied with each share, which can hold down structure deflection and internal force. In example of dual-direction BSS, in the interest of strengthening structure border stiffness, non-uniform section beam is applied which helps reduce effectively border deflection and optimize structural capability.Secondly, the article presents in detail pre-stress action and introduction method. Then it has a non-linear analysis separately with single-direction BSS and dual-direction BSS with adopting "pre-strain method" to introduce pre-stress into structure. Influence acted by pre-stress to structure internal force and displacement is definitely concluded and the method seeking for reasonable pre-stress is obtained with basis of pre-stress definition and function eventually.At present, design personnel commonly assume experientially structural design parameters such as beam section, pre-stress and span height in BSS design process, and then analyze structure stress and displacement restriction conditions, check computations whether it satisfied with practice conditions or not. If results can't match conditions, new parameters will be necessarily redefined, which is too numerous even can't find best project because of its non-consecutive property. Aiming at the fussy problem, the article has an emphases on BSS structural optimization. With the clue of parameters enactment, optimization approach, optimization procedure and result sets deposed, the article takes an optimization analysis on a single-direction BSS. Considering the span height as design variables, structure displacement and internal force as state variables, structure gross weight asoptimizing objective, the article achieved some useful conclusions with simulation of ANSYS software.At last, this article gives a conclusion of optimization of BSS structure analysis and points out what should be done to further the theory of BSS structure.