| The prestressed steel structure is an advanced, scientific, high-effective new branch of engineering structure subject. It can not only create modern steel structure system, but also can increase strength ultimate bearing capacity effectively, improve integral stability, increase rigidity, reduce self-weight, save material, decrease cost. The long-span suspend-dome belongs to the advancing subject of modern prestressed steel structure and modern spatial structure. A research on the current situation of the prestressed steel structures was taken in this paper, also a summary was completed based on the domestic and foreign academic documents. On the background of engineering construction for 2008 Olympic Games, supported by the National Natural Science Foundation of China and Beijing Scientific Committee, by the spirit of"High-tech Olympics"and"Independent innovations", innovations were made to the new-type long-span suspend-dome structure and applied in the real project of Beijing Olympic Games. The main conclusions in this paper are as follows:The joint and structure system innovations of New-type long-span suspend-dome include the authorized patents of the adjustable stay-bar joint for prestressed steel structure, the suspend-dome with V-type radial cable, the cable-link suspend-dome, the assembled cable-stayed joint of prestressed steel structure and multi-prestressed suspend-dome. These innovations of suspend-dome can release the end moment of the stay bars, prestress the structure by extending the stay bars, improve force bearing performance, make construction more convenient, enhance integral stability and ultimate bearing capacity, utilize strength of material sufficiently, save material and decrease cost. These joint and structure system innovations break through the limit that the maximum span of suspend-dome is 46m in the world, and they do much contribute to design and construction of the first longest-span suspend-dome of the world in China.The improved particle swarm optimization method which is used for prestressed steel structures was proposed firstly. The problem of the coupling of state variables and geometric variables was solved, the goal which the geometrical shape, prestress degree, sectional dimension are optimized simultaneously was achieved, and The optimization model and program were built according to the current code and specification, in which, besides the strength standard of steel members and cables, the stability of members, the maximum displacement of shell and the multi-load case are considered too. The whole research integrates the optimization method and significant engineering application, which achieves the engineering application level, and it was applied in the plan selecting and structural design of the badminton gymnasium for 2008 Olympic Games successfully. The steel cost of the designed out new-type longest-span suspend-dome is optimized to 62kg/m2, save steel by 38%, which achieved concordance and unification of the reasonable light steel structure system and graceful architectural sculpt, and the double excellent aim of safety and economic is realized.Based on probability theory, an initial defect probabilistic method is proposed, which is suitable for the integral stability analysis of suspend-dome structure with initial defects. With this method, the impact of initial defects, such as the position deviation of joint caused by construction, the initial eccentricity of members, the deviation of cable's tension, the deviation of Young's modulus, on the nonlinear integral stability and ultimate bearing capacity were studied generally in the paper, and compared the analysis results of this method with the traditional eigenvalue buckling modal method. It indicates that the probabilistic method can fully display the impact of initial defects on the integral stability of suspend-dome structure, the shape and size of initial defects are more reasonable, and is inclined to security. The probabilistic method has been used in the integral stability analysis of suspend-dome of the badminton gymnasium for 2008 Olympic Games successfully, which verifies the applicability of this method.The 1:10 reduced scale model of the badminton gymnasium for 2008 Olympic Games was studied on static, stability and construction tension simulation research. The mechanical properties of model under the weight of single-layer shell before tensioning, the state during construction tensioning, the state under both the design load and triple design load after tensioning, and the state until being loaded to damage were studied. Comparing the results of the numerical simulation and the model test, the variation regularity of the internal forces, the displacement of joints and the horizontal displacement of support are obtained. The theoretic and experimental values of the ultimate bearing capacity which represent integral stability were gotten too. The influence of asymmetrical layout of live load to integral stability was studied, in order to find out the buckling form and the buckling mechanics. Four kinds of construction tensioning plans were selected for finite element numerical simulation, and the best two values were selected to be model tested, at last the optimum plan was selected. The model tensioning test verifies the construction tensioning plan, proves the safety and convenience, and provides a useful reference for the construction tensioning of correlative structures.A new construction simulation method, the pre-relaxation of cable tension method, is proposed. This method is suitable for construction simulation of prestressed steel structure. The influence, such as the construction deviation of joint's position, the construction temperature, the construction temporary supports, the friction of cable-stay joints, to the constructional tensioning is studied generally. Combining this method with friction elements, nodes coupling technology and regional hypothermia method, the whole construction process of suspend-dome was simulated accurately, and the influence regularity of various factors to the design and construction was got. With the method proposed in the paper, an accurate construction simulation of whole construction process was carried out to the badminton gymnasium for 2008 Olympic Games, which provides important data for the selection of construction plan and the confirmation of engineering acceptance standard.According to the composition and the layout characteristic of the badminton gymnasium for 2008 Olympic Games, a real time health monitoring system was designed. The whole variational process of the force of members, the tension of cables, the displacement of joints during the phase of construction tensioning and usage was monitored. It provides important data for acceptance of construction, verifies the structural safety in the service period, and ensures the security and health during the project's whole life. The changing rule of inner-force of the long-span suspend-dome would be gathered by a long-term monitoring, which help to forecast the last life of the structure and supply prestress maintenance at right time.The wok and achievement of the paper run through whole process of the structural system innovation, the optimization design, the model test, the construction tensioning and control, the tensile, the whole life health monitoring of prestressed suspend-dome structure. The theory researches have been used in the grave project, some key problems of structural design and construction were settled successfully. The achievements of the paper exceed the 46m span limit of suspend-dome, and provide innovative achievements for the realization of 93m large-span suspend-dome structural system real project. These achievements have been used in the steel structural design, construction and whole life health monitoring successfully, make great contribution to build the longest-span new-type prestressed suspend-dome of the world in China. At the same time, much theory research and engineering experience were accumulated, the works of the paper motive the engineering application of long-span suspend-dome in large projects, also meet the spirit of"High-tech Olympics"and"economic Olympics", make a lot to accelerate the development of the steel structure in our country.
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