| The single-layer reticulated shell is a cured space-grid structure with the advantages of uniform stress distribution, large span, economic, convenient construction etc. and it is widely used in large public constructions. With the rapid development of construction technique and computer science, the range of its applications is getting wider and wider and the span is becoming much larger, as a result, greater demands are being placed on the accurate calculation of its bearing capacity of stability. Present analyses are formulated on the assumption of rigid connection, which may be invalid for various joints. The existing norms has not raised the relevant provisions about overall stability calculation of semi-rigid joint shells.Therefore, it is necessary to study the mechanical properties of semi-rigid joints and its influence on bearing capacity of stability of the single-layer reticulated shells to provide some reference for the semi-rigid joint single-layer reticulated shells design.Firstly, this paper makes an introduction of the classification of most common joints and reviews current study situation of semi-rigid joints and stability of reticulated shells. Some computing theories or methods are summarized and then the research contents and methods of this paper are proposed.In order to study the semi-rigid properties of different joints, loading tests of three kinds of joins, hub type, bolt-sphere and ring-type, with 5 groups respectively, are carried out and the corresponding moment-rotation curve of each joint is achieved. As for hub type joins, numerical simulations for loading tests are also verified and the effects of some factors on the moment-rotation curve are concluded, through which, a simplified numerical model is presented to describe the relationship between joint stiffness and rotation. In addition, model parameters of each test joints are reduced.The joint semi-rigidity has a great influence on the overall stability of reticulated shells, to consider which, this paper derives a reduction coefficient of bearing capacity based on the overall stability analyses with different semi-rigid models and the effect laws of semi-rigid parameters are also drawn.Additionally, the joint semi-rigidity has varies impacts on different reticulated shells, whose bearing capacity of stability and reduction coefficients under different parameters are analyzed in this paper. Also the effect laws of initial imperfection, span and rise-span ratio are obtained. The parameters of semi-rigid joint model from loading test are introduced to the reticulated shells of different spans or rise-span ratios to get their reduction coefficients. |
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