| With the improvement of comprehensive national strength and the progress of science and technology.In recent decades,A large number of large-span spatial structures had emerged in China.As the span of the structure becomes larger and larger,the shape becomes more and more complex.Accidents in construction are also common.Therefore,it is necessary to study new theories and methods to improve the existing theoretical system of construction mechanics to guide for the safety of structures construction.At the same time,it is very necessary to track and simulate the structure in the construction stage.This paper is based on the overall lifting construction process of Tianshui Sports Center gymnasium project.The following work has been done:(1)The finite element model of reticulated shell structure was established.The maximum stress of members,vertical displacement of structure and support reaction force at9 construction stages were analyzed by ANSYS life-and-death element method.At the same time,the mechanical properties of temperature-sensitive structures were studied when they experience possible temperature difference during construction period.(2)The reticulated shell joints at the lifting point were subjected to the support reaction of the support structure in the construction process.In order to study the influence of the support reaction on the joints,the key joints of the structure were selected according to the simulation results of the lifting process.And the three-dimensional solid model of the selected joints was established for finite element analysis.The ultimate bearing capacity and the stress process based on the non-linear analysis were studied.Finally,it is suggested that the support point should be chosen at the lower chord spherical joint during construction.(3)The elastic-plastic stability of the temporary braced structure at the construction stage was studied.First,establishing the finite element model.Then,eigenvalue buckling analysis and non-linear buckling analysis were carried out for the four different cable-wind ropes.The corresponding buckling critical load,buckling mode and load-displacement curve were obtained.The results showed that at least three cable-wind ropes should be installed during construction.And set spacing from bottom to top is from dense to sparse.The position is as far as possible.The number of settings should not be too much,otherwise more space should be occupied to bring inconvenience to the construction.(4)In order to illustrate the effect of asynchrony on the mechanical properties of the structure,the reticulated shell structure of the construction stage SG5 with the largest number of members and vertices was selected as the calculation model of asynchrony analysis.According to the symmetry of the model,the basic working conditions which only consider the influence of stiffness were determined.And then the reaction forces of lifting points support were calculated from the basic working conditions.After linear combination of somelifting points,the adverse working conditions corresponding to the basic working conditions were obtained.Considering the self-weight effect,the structure was analyzed under different jacking displacement differences.It was found that the difference of displacement during jacking up less than 10 mm could ensure the safety of the construction process.(5)The key members and displacement control points of the structure were selected to carry out on-site monitoring.Comparing the measured and simulated stress values,the results showed that the measured and simulated stresses basically coincided with each other.The stress levels of the members were in the elastic range.The displacement values of the structure changeed smoothly in the construction stage without sudden change. |
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