Theoretical Research On Spatial Beam String Structure And Its Application

Spatial beam string structure is a type of prestressed hybrid structural system, which is composed of beam, cable and strut. For its functions of self-balancing, internal force controlling, stiffness controlling, and its diversiform shape suitable for different kinds of architectures, it has a widely practical perspective. In this paper, Beijing University Gymnasium, Quanzhou Gymnasium and Anhui University Gymnasium are taken as spatial beam string structure project background. The characters of this kind of structural system are analyzed systemically.In this paper, the features of spatial beam string structure are summarized and categorized by the types of engineering projects. Based on the theory of eigenvalue buckling analysis of linearly elastic structure and prestressed hybrid structure, the method to get eigenvalue of prestressed hybrid structure with the existence of constant load is given.Model test of Anhui University Gymnasium is completed. The construction process of prestressing cables and the process of loading are carried out. The features of this structure are analyzed. The results of the tests proved the correctness of theoretical analysis and can be regarded as the guidance for the construction of the project.Radiating planar truss string structure of Beijing University Gymnasium, parallel spatial truss string structure of Quanzhou Gymnasium and cable-strut-supported shell structure of Anhui University Gymnasium are regarded as the project background of spatial beam string structures. The composition and features of spatial beam string structures are analyzed. Parameters that influence the property of the structures are analyzed too. Common features of this kind of structure are summarized, and the conclusions can be taken as design reference.In this paper, elastoplastic ultimate capacities of different kinds of beam string structures are analyzed with the nonlinear finite element method. The yield mechanism and collapse mechanism are analyzed. The performances of the beam string structures are evaluated according to the two level performance goals and the development of plasticity. Performance goal of those structures whose life span is over 100 years is discussed. Parametric analysis, which includes deflections of the structure, asymmetry of load, types of support, height of struts and magnitude of prestress are also made. Common features of yield mechanism and collapse mechanisms of structures with similar structural formations are analyzed. Influences of parameters on the elastoplastic ultimate capacity of beam string structures are summarized.Elastoplastic ultimate capacity analyses of beam string structures with some element failing to work are made. The development of plasticity and ultimate capacity of the structures are clear after the analysis. The importance of the element is clarified. According the analysis, advices to enhance the safety of structure are given. The redistribution of inner force in the long-span spatial structures are summarized. A universal method used to evaluate the importance of the elements is achieved. The relationship between the safety of members and the safety of whole structure is discussed. Redundant structures are also analyzed and the corresponding conclusions, which can be referred in structure designing are drawn.Based on the parametric analysis of dynamic features of cable-strut-supported shell structure, Seismic features of pin-supported structures under horizontal, vertical earthquakes are analyzed with the time history method. Earthquake responses of structure with elastic supports and structure of small height are analyzed too. Distribution of seismic inner force coefficient and displacement of joints are analyzed. Influence of supporting structures and geometry character on seismic features of spatial beam string structures are generalized.After summarizing the methods of construction process simulation of spatial beam string structure and prestressed string structure, inverse analysis method of construction process is extended on the basis of the definite status of structures. It is suitable for linear or geometrically nonlinear structures. This method can also be used to simulate one or more steps of construction process. Influence of later tensioned cables on the former tensioned cables can be considered in this way. The construction process of Anhui University Gymnasium cable-strut-supported shell structure is simulated with the inverse analysis method. Tensioning sequence from outer cable to inner cable and from inner cable to outer cable finished in one and three steps are compared, conclusions corresponding to it are drawn.