Research On The Constructional Unloading Process And Model Experiment Of A Steel Roof Stadium

With the development of society and culture, the demand for large public buildings is increasing. More complicated structure forms emerge at a historic moment to meet the requirements of the use and appearance, structural design and construction technique are developing because of the construction of large span spatial structure. In conventional design the model is built according to space coordinates of final displacement without considering construction methods, the changing process of the stress and morphology during construction. The forms of large-span spatial structures are complex, thus the analyses of their construction processes become more complicated. Unreasonable plan may lead the construction process unsafe, and that is the reason why analysis of the construction process is necessary no less than the design of large scale structure. The analysis is very significant to analyze mechanical behavior during construction and achieve accurate designed configuration. Construction simulation is one of the key technologies of structural design and construction forming.Temporary support towers are usually set up during the construction of large span structure in order to reduce the internal forces and deformation of permanent structure, which could improve the safety of the construction process. Unloading is one of important procedures of the whole construction. Reasonable unloading process will contribute to the smooth transition to design state.First this paper summarizes the current research in the field of constructional unloading of domestic and then it introduces mechanics analysis theory and numerical simulation methods of spatial structures’constructional stage. Basic on the Shaoxing stadium, the following problems are studied:(1)The simulation of unloading process was made by finite element software with different boundary constraints, different ways of unloading control and pre-stress methods. Different kinds of unloading were compared.(2)An1:15scale model of steel roof structure was designed, then the grading synchronous unloading process was simulated under the circumstance of elastic boundary constraints and experimental data was analyzed to verify the rationality and feasibility of the unloading plan.(3)Considering the retractable roof is close, open and half-closed, the displacement and variation of stresses were studied. Then the calculated values was compared with the monitoring values and the correctness and reliability of finite element analysis were verified. References are given for the design of similar projects.