The Experimental Research And FE Analysis On Steel-Concrete Composite Shells For Enclosing Large Spaces

Steel-concrete composite shells, for enclosing large spaces, may be a progress in development of concrete shell structures. Theses composite shells are formed by steel base shell and in-situ cast concrete on it. The steel base shell is constructed by a lot of bolting together semi-box modular steel units. The thin stiffened steel base shell can serves as both the permanent formwork in construction stage and the strengthened steel reinforcement in service stage. The new structural system possesses all the advantages of the widely used thin concrete shell roofs, eliminates completely the need for the temporary formwork for concrete casting and greatly reduces the shoring requirement. At present, the investigation for this new composite structural system is ongoing and developing.In this article, the research aims to the stability and load-carrying properties of composite shells during service stage. So two experiments is described: one is the scaled model test under a four-point loading to get the overall bearing performance and the other is bolted connection test, the nonlinear properties of the shell, including the form and development of cracks , invalidation of bolted connections and buckling characteristic of steel plates, can be learned from the tests, then the general differential equation in curvilinear coordinate to analyze and calculate the shell structures. In addition, the overall and local stability behavior is also discussed using the principle of energy.As the development of finite element theory and corresponding numerical method, it is possible to accurately carry on nonlinear analysis to the steel-concrete composite shells, including the geometrical and material nonlinearity. In this paper ,based on finite element method, the possibility of modeling the discrete connections between composite shell units by springs was investigated, then considering the nonlinear properties of concrete, steel plate and bolts, author derived the element stiffness matrix and whole stiffness matrix using plane element, and established the equilibrium equation between nodal displacement and nodal load of the structure, which are convenient to write the program for the shell.At last, making use of the universal 3D nonlinear finite element software------ANSYS, choosing proper element and parameters, author set up a finite element model and made full numerical simulation for the composite shell. The analysis with finite element method is accord to the experimental results basically, and invalidates the correctness of the model. The analysis results indicate: if making proper...