Simplified numerical model and optimal design of steel-concrete composite panel

Abstract

The steel-concrete composite panel(SCP) is being seriously considered for modular construction of storage tanks or containment vessels installed at harsh environments because of their short construction time and low cost. Upon this background, this paper proposes an efficient numerical model for steel-concrete composite structures and suggests an improved design guideline for SCP panels based on parametric studies. First, this paper introduces a simplified numerical model to consider the bond-slip effect in steel-concrete composite structures. The use of shear studs usually placed in the form of mechanical shear connectors makes it possible to adopt composite steel-concrete structures in various applications. Therefore, in the analysis of composite structures, the partial interaction behavior should be considered according to the characteristics of the connectors. However, adopting the classical bond-link/zone elements or modeling the details of connectors may cause problems in analysis of complex structure due to the complexity of the model and overlapping boundary conditions at the interface. In the proposed model, the slip behavior is defined and the equivalent modulus of elasticity and equivalent yield strength for steel is derived on the basis of a linear partial interaction theory to construct a simplified model. A solution procedure to evaluate the slip behavior along the interface of the composite flexural members is also proposed. After constructing the transfer matrix relation at an element level, successive application of the constructed relation is conducted from the first element to the last element with the compatibility condition and equilibrium equations at each node. Finally, correlation studies between numerical results and experimental data are conducted with the objective of establishing the validity of the proposed numerical model. In addition to numerical model, improved design guideline of stud and tie-bar arrangement in steel-concrete composite panel (SCP) is proposed. Manufacturing of SCP must be based on the application of existing design guidelines which require very close arrangement of shear studs. This means that the direct application of current design guidelines usually produces very conservative results and close arrangement of shear studs precludes placing concrete within exterior steel faceplates and increases the self-weight. In this light, an improved guideline to determine the stud spacing should be introduced, and this paper proposes an improved ratio of the stud spacing to the thickness of steel plate on the basis of numerous parametric studies to evaluate the relative influence of the stud spacing on the stability of the SCP. Moreover, placing of concrete usually develops very high pressure which cause excessive deformation on the steel plates and it will affect the ultimate resisting capacity. Nevertheless, the influence of the steel form deformation on the evaluation of the ultimate resisting capacity, which is deeply related to the determination of the stud spacing, has not been considered in determining the stud spacing. In this context, parametric studies on SCP with initial imperfection are performed to introduce the efficient spacing of shear studs and tie-bars to satisfy both the serviceability and stability criteria.