Papers by Keyword: Beam String Structure

Abstract: The Beam String Structure was in short-side direction. This paper simulated Beam String Structure in long-side direction. Through SAP2000 analysis of vibration mode and stress of single and overall structure, some features of the structure were obtained. The single structure has small rigidity disadvantage, while the overall structure has reasonable stiffness. Then the paper draws a conclusion that disadvantage in long-side direction can be remedied by overall structure.

Abstract: Initial imperfections on beam string structure (BSS) include geometric imperfections and residual stresses, which negatively influence the mechanical properties of BSS. This paper analyzed the mechanical influences of initial imperfections on BSS by FEA, pointed out that initial imperfections do not remarkably influence the properties of BSS in stage of prestressing, but geometric imperfections obviously influence the displacement out of plane in stage of use, which should be controlled to improve the safety of BSS by installing enough lateral supports at the upper chords of BSS in construction.

Abstract: A vibration reducing system of seismic isolation bearings is introduced into beam string structures. The vibration control on seismic response of beam string structures (BSS) with seismic isolation bearings is discussed. Firstly finite element models for different analyses are established by using explicit dynamic analysis program LS-DYNA. Then the seismic response analyses are performed on a single beam string structure with and without seismic isolation bearings to investigate the effectiveness of the seismic isolation bearings in reducing vibration response of BSS. Furthermore, parametric analyses are conducted to examine the effects of lateral stiffness and damping of the seismic isolation bearings on seismic isolation. The analytical results indicate that the vibration reducing system can effectively reduce the vibration response of BSS against seismic force, and be applied in the vibration control of BSS.

Abstract: Modal parameters are widely adopted to identify structural damages. This paper explores the mode jumping problems in damage identification for Beam string structure (BSS). The characteristics of structural mode are discussed firstly. It is found that the modal concentration is obvious for BSS, and this may cause modes after damage not in the same order as those corresponding ones before damage due to proper structural damages. The reasons for mode jumping are analyzed in detail. Based on the principle of relativity, the correspondence of the structural modes before damage and after damage can be determined by calculating the mode correlation coefficients. Numerical experiments show that this method is of higher precision, and can be applied successfully in structural damage identification for BSS.

Abstract: Three dimensional seismic responses of an isolated spatial beam string structure are studied by applying the non-linear finite element theory. The filtering effect of the main structure, which amplifies the ground input, is investigated. The results indicate that the vertical rare earthquake has great influence on the isolated spatial beam string structure, and stresses of cables, frames and slab shells under vertical rare earthquake are all much greater than that under gravity load. Results of non-linear time history analysis show that elements’ stresses are in elastic stage, thus the spatial beam string structure with isolation keeps safe under rare earthquake.

Abstract: There have been few researches on the reliability of prestressed steel structure, especially the study on the reliability considering the failure of key components. In order to study the impact of the component failure on the structure reliability, the response surface method based on central composite design is adopted and APDL language is applied to write a corresponding program, thereby carrying out reliability calculation and analysis to the model. The system reliability and parameters sensitivity of the beam string structure under different failure of components are provided. The results indicate that the impact of cable failure on the reliability is large, but it is weak by the failure of brace rod. The results may serve as a reference for the health monitoring and safety assessment of the prestressed steel structure.

Abstract: Beam string structure (BSS), which is a new kind of semi-rigid hybrid system, composed of arch, strut and string, has been developed rapidly in long-span steel structures in recent years. Based on the principle of virtual work and Updated Lagrange, the formulas of geometric nonlinear F.E.M. for spatial beam element, cable element and truss element are derived respectively in this paper. Taking the one-way BSS model of the steel roof in Guangzhou International Convention and Exhibition Center as a computational example by using both linear and nonlinear analysis method, the analytical results show that it is appropriate when adopting the straight truss element with two joints and equivalent elastic modulus to simulate the cable element with small sag. Although the linear analysis can meet the requirement of practical engineering due to its weak nonlinearity of BSS, the nonlinear method is also important to improve the precision theoretically. The conclusions obtained may be helpful for the designers in similar projects.

Abstract: In this paper, taking a practical project for the study, using the finite element analysis software ANSYS, static analyses under different load conditions are performed on a single beam string structure (BSS) and a one-way beam string structure with the cooperation of the supporting structure, respectively. Moreover, influence of factors on mechanical properties of the one-way BSS with the cooperation of the supporting structure is investigated. The factors include grouting, support form, corrosion. The results can provide a reference for design and construction of the same type of structure.