Steel-concrete Composite Panels Research Articles

Cyclic tests of unbonded steel plate brace encased in steel–concrete composite panel

Cyclic loading tests for the panel buckling-restrained brace (panel BRB) comprising an unbonded steel plate brace encased in a novel type profiled steel sheet–concrete composite panel were carried out to mainly investigate the effects of construction details of profiled steel sheets and perforated steel channels on the hysteretic behavior of the panel BRBs. Two loading stages, including increasing and constant amplitudes of horizontal displacement in the first and the second stages respectively, were used for six panel BRB specimens. Tests reveal that the perforated channels can prevent the composite panels from failure by punching shear. When stiffening ribs of profiled sheets were installed parallel to the axis of the brace, the composite panels remained intact in general after two loading stages. When the stiffening ribs of profiled sheets were installed in the horizontal or vertical direction, the specimens in which welds were used for the grooves of profiled sheets near the brace can also prevent panels from failure in the two loading stages, and bending failure of panels occurred in the first loading stage for the specimens without welds for the grooves of profiled sheets. The specimens, in which failure of panels was avoided, achieved great ductility and energy dissipation capacity before tensile fracture of steel braces occurred. Due to strain hardening and frictional action, the ultimate axial compressive strength of each specimen significantly exceeds its yield strength.

Performance of Fiber Reinforced High-strength Concrete with Steel Sandwich Composite System as Blast Mitigation Panel

The study investigated the response of steel-concrete composite panels subjected to air-blast loading. The composite panels consist of fiber-reinforced high-strength concrete on the incident face, together with a specially configured steel sandwich as the distal layer, which functions to dissipate the imparted blast energy. The performance of the novel composite panel is compared to a conventional steel concrete steel (SCS) panel and an ordinary reinforced concrete panel. The dynamic response of the composite panel is obtained numerically using finite element analysis adopting a simplified modeling approach. Parametric studies are carried out by varying the charge weight, the concrete type, and a number of steel sandwich core structures. Furthermore, the energy absorption capacity is found by calculating the area under the resistance-deflection curve of the proposed composite panel. The relationship between the steel sandwich core structure and the energy absorption capacity, as well as the core design and total panel deflection subjected to various blast charges, are then derived. The combination of fiber reinforced high-strength concrete and cellular steel sandwich demonstrated good potential for use as blast mitigation panel due to the high weight-to-performance ratio and the high energy absorption properties of the composite system.

Effect of confinement on steel-concrete composite light-weight load-bearing wall panels under compression

The strength of composite wall panel depends on plain concrete strength, degree of confinement and the composite action of steel and concrete acting together. This paper presents details of an experimental study on the effect of confinement on axial capacity and behaviour of steel-foamed concrete composite panels. Five small scale load tests are carried out on wall panels with different configuration of studs and sheet edge boundary conditions. Light weight foamed concrete (LFC) is used as infill material and the interaction between sheeting and concrete is achieved by using through–through studs. The loading is primarily distributed over the concrete surface, so as to avoid early/brittle local buckling of sheet under direct compressive loading of wall panel. Failure modes such as vertical separation and diagonal shear failure of concrete are observed and the axial resistance of wall is found to increase with the degree of confinement provided by studs and sheet edge conditions. Also the controlled lateral deformations of confined concrete by steel sheeting due to interconnecting studs exhibited ductile deformations after the post peak behaviour. Based on the failure modes obtained from the tests, a new method is proposed to determine the axial resistance of composite walls.

Response of steel-concrete composite panels to in-plane loading

Steel-Concrete Composite (SCC) panels consist of steel faceplates with welded shear studs and concrete infill. The shear studs, which perform a similar function to bond of rebars in reinforced concrete, act as springs resisting the shear slip between the faceplates and concrete. In spite of extensive research in the 1980s and 1990s due to the interest in using SCC in offshore construction and in nuclear power plants, and recently related Codes, there is no analytical method to-date to predict the shear studs response to in-plane loading. Shear connectors are sized according to various criteria unrelated to their actual forces under in-plane loads, such as prevention of faceplate buckling or out-of-plane shear resistance. This paper presents a closed analytical solution of the equilibrium and compatibility differential equations for steel and concrete displacements of SCC panels, based on distributed shear springs idealization. Analytical results presented in this paper are validated by test results of SCC panels loaded by pure shear forces and can be used as practical design formulas for the in-plane portion of the design loads.

Research Situation of the Unilateral Contact Buckling of Thin Wall Steel-Concrete Composite Panels

Thin wall steel-concrete composite wall panels can be used as bearing member and also as maintenance structural plates, which can satisfy functional requirements of building including bearing capacity, heat insulation and preservation. The problem relating unilateral contact buckling of thin wall steel composite panels has received attention from many construction engineers. The investigation progress is analyzed in general and the investigation questions are illustrated. The research approach and technical routes of delaminated critical load are also presented.

A Novel Modelling Technique for Blast Analysis of Steel-Concrete Composite Panels

Blast resistant structures usually undergo large plastic deformation and absorb energy before collapse. There are many structural forms that have improved blast resistance are reported in literature. Among these, steel-concrete composite panel has been considered as extremely resilient to blast loading. Conventionally, steel-concrete composite panels are analysed using solid element model for plates, concrete as well as shear connectors. In this paper, a novel modelling technique is proposed for analysis of steel-concrete composite panels under blast loading. As per the proposed technique, shell, solid and link elements are used to model cover plates, concrete and shear connector respectively. Validation and performance studies are carried out with a problem available in literature. The proposed model is found to be better with less demand on modelling requirements. It is also computationally efficient, while retaining the accuracy of results. Parametric studies are carried out using the proposed model on steel-concrete composite panel with through-through connectors subjected to air blast loading. Steel plate thickness, concrete core thickness, connector spacing and diameter of connectors are varied to study their influence on the response behaviour of the panel. It is observed from the study that connector diameter and spacing and core thickness significantly affect the response than the plate thickness.

Nonlinear Dynamic Analysis Of Profiled Steel-concrete Composite Panels Under Blast-induced Excitations

This paper presents the nonlinear dynamic behavior of profiled steel-RC composite panels subjected to blast-induced excitations using a finite element package, DIANA v7.2. An appropriate finite element model is fwst formulated and then parametric studies are performed to evaluate the strength and deformation characteristics of selected composite slabs. In the numerical model, perfect bonding between concrete and steel is assumed. The steel elements include the profiled steel deck and the reinforcement. Nonlinear behavior of steel with isotropic hardening using the Von-Mises yield criterion is adopted. The inelastic behavior of concrete is described by the Drucker-Prager model with varying yield surfaces to simulate compression softening, Under tension, a smeared crack model with softening and shear retention is employed. Results confirmed that numerical difficulties encountered using the brittle crack model may lead to inconsistent displacements and strains for the problem considered. The linear and nonlinear softening models give better results but the linear model needs considerably less effort and is attractive for large problems. The use of a variable shear retention model is more realistic as opposed to a constant shear retention model. The behavior of composite panels under blast-induced excitations is studied numerically for various combinations of reinforcement ratio r and panel thickness t. The nonlinear trend exhibited in terms of maximum deflection, concrete strain and crack distribution with respect to r and t indicate that further study must be performed to formulate comprehensive guidelines for the design of such composite elements in protective structures.