Study On The Stability Of Single-layer Lattice Dome As The Roof Structures Of Oil Tanks

With the increasing demand for oil, oil storage facilities are put forward higher request. One of the restricting factors of large-scale oil tanks is the realization of large span of the roof. Due to the economy and the construction convenient, the application of single-layer lattice domes with hub-shape inlay joints is gradually getting attention now.But hub-shape inlay joint was considered as rigid joint in most designs, which resulted in some engineering accidents. Based on the actual situation, the hub-shape inlay joint is a typical kind of hinge joints in the dome surface and can not transfer bending moment among members. So in this paper, the hub-shape inlay joint was treated as the rigid-pin-joint. To ensure the universality of the results, two single-layer lattice domes with different spans were taken as cases.The static behavior and the stability of the single-layer lattice domes were studied. The critical load was determined for the dome with rigid-pin-joints, including the ideal models and the models considering geometric nonlinearity and initial imperfection of the structure. By comparison between the single-layer lattice domes with rigid-pin-joints and those with common rigid joints, the adverse effects of the rigid-pin-joint on the overall stability of single-layer lattice domes was discussed. Then sensitivity of the rigid-pin-joint to the initial imperfection was studied by comparing the critical loads of the domes with different initial imperfections. In this paper, the initial imperfection was considered by the consistent imperfect buckling analysis method.In addition, in the cylindrical arc length technology, two parameters including the length of initial steps and the maximum of the arc length need to be set. It was found that the parameters have a significant impact on the critical load of the ideal models, but little on the models with initial imperfection.The effects of the lower supporting structure on the single-layer lattice domes were studied. In order to simplify the analysis, the elastic support method was proposed and proved to be feasibleAt last, whether the single-layer lattice domes with hub-shape inlay joints could use the method of simulated shell was discussed.