MODEL-BASED SIMULATION OF STEEL PLATE CONCRETE MEMBRANE STRUCTURES
Composite Steel plate Concrete (SC) have been widely used in nuclear industries as a primary component for the construction of safety shells and nuclear containment vessels, considering its advantages of cost-efficiency and enhanced structural behavior. SC wall-type structures are usually visualized as assemblies of steel plate concrete plane stress elements, whose behavior can be simulated with the help of the finite element method. The accuracy and reliability of the numerical analysis relies on two major aspects, namely the two-dimensional in-plane model and the uniaxial constitutive material laws.
In this research, a mechanics-based Membrane Model formulation of SC elements (MM-SC) has been developed using the “smeared-crack” concept, which includes surface steel plates, infilled concrete, and optional embedded reinforcements as main components of the SC element. The fixed-angle theory has been adopted, considering the principal direction of the applied stress as the governing stress state for both the steel plate and the concrete elements. Meanwhile, based on the experimental observation of full-size SC specimens subjected to in-plane tensile, compressive, and shear loadings, the corresponding analytical constitutive material laws of SC steel plate and infilled concrete have been developed. By adopting the MM-SC formulation and the object-oriented framework OpenSees, a nonlinear finite element computer program “Simulation of Concrete Structures – Steel Plate Concrete Module (SCS-SC)” is developed, which enables the prediction of the nonlinear behavior of SC plane stress structures under complicated loading conditions. The SCS program is then validated with different types of structures in the literature and meanwhile, an experimental database of all the literature cases has been established, summarizing critical design parameters and loading details.
Finally, parametric studies of the two newly-conducted SC panel shear tests at University of Houston has been performed. Three major variables of steel content ratio, slenderness ratio, and shear connector spacing-diameter ratio are investigated regarding their influences on the structural behaviors of SC elements. Current design specifications of ACI-349 and AISC-N690 are statistically validated using the SC panel cases, as well as SC database cases. The whole study in this research can be summarized into five steps: experiments, modeling, implementation, validation, and application. The working flow of this research program is interpreted as model-based simulation of steel plate concrete membrane structures.