Analysis Of Static Stability And Construction Simulation For Long-span Suspended Dome Structures

The suspended dome structure, which is a new kind of hybrid spatial one composed of the upper single layer reticulated shell and the lower cable-strut system, has been widely used in long-span structures in recent years. Taking the suspended dome structure under construction of Houjie Gymnasium as the engineering background, the static behaviors, static stability and construction simulation of long-span suspended dome structures are investigated in this paper. The main contents are summarized as follows:(1) The research on the prestress-determining method of suspended dome structures is carried out, and the feasibility of self-balanced prestress-determining ring-by-ring method is proved. On the basis, the static behaviors of elliptical and round suspended dome structures are investigated respectively by considering half-span distribution of live loads, changes of topological form of the upper single layer reticulated shell and cable-strut system arrangement. The results show that choosing the horizontal radial displacement of supports as the calculation controlling parameter for the prestress-determining method is reasonable. Therefore, it can achieve the goal of the horizontal radial displacement of supports being almost zero. Due to introducing of the lower cable-strut system, the structural deformation is decreased obviously, and thus the stiffness of the structure is enhanced. Moreover, the structural vertical displacement is more unfavorable under half-span distribution of live loads. In order to avoid the relaxation of radial steel rod located in the inner ring, calculation of asymmetric loading distribution should be conducted. Relatively, both nodal vertical displacement and the internal force of members are not affected remarkably by the topological form, while those near the inner ring of the upper single layer reticulated shell are greatly influenced by the cable-strut system arrangement.(2) The analysis of static stability for suspended dome structure is performed by comparing the differences between the suspended dome and the corresponding single layer reticulated shell as well as probing the effects on stability arisen by several parameters and different initial geometric imperfection modes. Besides, the applicability of consistent mode imperfection method is discussed. The research shows that the stability bearing capacity of suspended dome is remarkably higher than that of the corresponding single layer reticulated shell, and the material nonlinearity might have significant effect on the stability of suspended dome. It is obtained that stability bearing capacities of both structures under half-span distribution of live loads are more unfavorable. So we suggest that it is available to choose K8+Lamella hybrid grid of the upper single layer reticulated shell, and Rib+K8 of the cable-strut system arrangement for elliptical one and K8 for round one in engineering practice. In addition, the improved stochastic imperfection mode method is applicable to the stability analysis of the structure. However, to some degree, the consistent mode imperfection method overestimates the structural stability bearing capacity. Furthermore, the stability bearing capacity is not minimal when the initial geometric imperfection configuration is taken as the first-order buckling mode. The structure is sensitive to the variation of initial geometric imperfection. A 1/500 of span as the reasonable maximum value of imperfection is more suitable for the suspended dome structure.(3) The effects of different tension methods and initial geometric imperfection modes on the construction simulation analysis of suspended dome structure employed in Houjie Gymnasium are respectively compared. The results indicate that the multi-step tension method is more available than the one-off tension method for structural erection simulation. The improved stochastic imperfection mode method has higher reliability, while the consistent mode imperfection method usually underestimates the structural deformations and internal forces of members. Besides, the structural deformations and internal forces of members are not minimal when the initial geometric imperfection configuration is taken as the first-order buckling mode. Thus, it is proposed to consider the effect of initial geometric imperfection on the analysis of construction simulation.