Shear Resistance Of Composite Slabs Research Articles

Vertical shear capacity of steel–normal concrete-UHPC composite slabs with steel ribs in the cantilever

UHPC is utilized to enhance flexural performance of tensile zone of composite slabs, which will enable reducing slab height. The vertical shear resistance of composite slabs in the cantilever might become insufficient with the reduction of slab height. In the paper, the vertical shear performance of steel-normal concrete-UHPC composite slabs in the cantilever is investigated based on five composite slabs tests, numerical simulation, and theoretical analysis. The results indicate that UHPC layer changes the failure mode of steel concrete composite slabs. The bearing capacity and ductility of composite slabs are effectively enhanced with the application of UHPC. The addition of a 10 cm UHPC layer makes the bearing capacity of composite slabs increase by 69.97%. And the reinforcement ratio of UHPC layer and the type of steel ribs exert a significant influence on the shear resistance. Additionally, an analytical model derived from modified compression field theory can well predict vertical shear bearing capacities of composite slabs in the cantilever.

The Effect of Adding Shear Connectors to the Composite Slabs with Different Geometry of Profile Steel Sheet

The aim of this research is to investigate experimentally the effect of adding shear connectors to the composite deck slabs which have various geometries of steel sheeting. The behavior and resistance of composite slab is basically depending on the development of longitudinal shear resistance. In this study six specimens of composite deck slabs which have different types of geometries of steel sheets (trapezoidal, triangle and T-shapes) with dimensions (1850mm x 500mm x 110mm) were casted and tested under four-point load in presence and absence of shear connectors in order to evaluate the behavior and longitudinal shear resistance of composite slabs. The results show that the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to increase ultimate load capacity by 22.2% and 17.8% respectively as compared with composite slabs without shear connectors while effect of adding shear connectors to the composite slab with T-shape was very little or can be neglected. As well as the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to decreasing the deflection as compared with the same load also act to enhance the general performance of slabs

Vertical shear behaviour of steel‐concrete composite slabs

ABSTRACTThe design of short span steel‐concrete composite slabs, or even the spans currently used in building construction but with the longitudinal shear behaviour improved by some type of reinforcement system, usually tends to be governed by the vertical shear resistance. Nevertheless, the design model for vertical shear resistance of composite slabs, according to European standard EN 1994‐1‐1, because it is based on the design model for reinforced concrete slabs predicted in standard EN 1992‐1‐1, does not take the contribution of the steel sheeting into account adequately. In this paper several vertical shear design methodologies are presented and compared. The results of an experimental programme, composed by 4 tests on composite slabs with short spans carried out at the University of Coimbra, are shown and discussed. In order to induce a collapse by vertical shear, the composite slabs tested were provided with a longitudinal shear reinforcement system. The experimental results showed that the design model prescribed by EN 1994‐1‐1 is conservative as it neglects the contribution of the steel sheet resistance to the slab's vertical shear resistance.

An Experimental and Numerical Study of the Load Distribution Effect on Composite Slab Shear Resistance

The design codes prescribe “a close simulation” of the uniformly distributed loads for bending tests, since, applying an ideal uniform load on the slab surface, is not technically as simple as applying concentrated loads by spreader beams. The 4-point bending test used in both standard methods m-k and PCM to determine the shear resistance of composite slabs is currently the most conventional loading arrangement. This article presents the comparison between the 4-point bending and uniform load results, obtained from both experimental tests and numerical simulations. Two groups of specimens, made with a common trapezoidal steel profile and concrete, including short and long spans, have been tested under the two loading setups. The numerical analysis of these slabs has been carried out through modelling the realistic interaction of steel and concrete. For the 4-point bending simulation, predefined vertical cracks are modelled representing the real crack inducers, whereas, for the uniform load case, the Willam-Warnke model is used. Both the experimental and the numerical results indicated that the 4-point bending test provides higher shear strength than uniform load. The experimental part was conducted by LERMA (Universitat Politecnica de Catalunya – BarcelonaTech) in collaboration with AdMaS-BUT at Brno University of Technology. The 3D FEM of composite slabs has been made through ANSYS software.

ANALYSIS OF THE VERTICAL SHEAR DESIGN MODEL FOR STEEL‐CONCRETE COMPOSITE SLABS

AbstractUsually, the design of composite slabs with short spans, or with current spans with the longitudinal shear behaviour improved by reinforcing systems, is governed by the vertical shear resistance. Nevertheless, the vertical shear resistance of composite slabs, according with european standard EN 1994‐1‐1, is calculated in the same way as reinforcing concrete slabs, being the contribution of the steel sheet not taken into account adequately. In this paper, a reflection and a comparison between vertical shear design models according different standards or methodologies are presented. It is also presented the results of a short experimental programme, composed by 2 experimental tests in composite slabs with short spans, carried out in the Department of Civil Engineering of University of Coimbra.

Experimental study of the influence of friction at the supports on longitudinal shear resistance of composite slabs

Abstract The aim of this work is to evaluate the behavior and strength of composite slabs considering the influence of the friction at the sheeting-concrete interface in the region of the support. Results from tests conducted in the Structural Engineering Department of Federal University of Minas Gerais (UFMG) were used. A Steel Deck 60 system was considered, which consists of a trapezoidal profile with “V” shaped embossments. Deflections, end slips and strains of the steel decks were measured, allowing for the analysis of the behavior of the composite slab system and for the determination of its failure mode. The influence of friction of the region of support in the longitudinal shear resistance was evaluated through the partial shear connection method, which also allowed for establishing criteria and determination of analytical expressions for calculating the ultimate load. Comparative analyses reveal that the influence of the friction of the region of support in the shear-bond resistance is more significant in composite slabs with short shear spans. Design expressions which incorporate friction will also be presented. Their application have demonstrated the efficiency of the method for evaluating the longitudinal shear resistance.

Longitudinal shear resistance of composite slabs

Composite slabs using cold-formed profiled steel sheeting are widely used in multi-storey steel-framed buildings. This paper presents the results from a comprehensive test programme that considers the longitudinal shear resistance of composite slabs with two types of trapezoidal profiled sheeting, where the only parameter that was varied was the yield strength of the steel. Although the ductility of high-strength steel material used in two of four test series was low, the longitudinal shear behaviour for all of the composite slabs was deemed to be ductile according to Eurocode 4, which meant that the partial connection method was permitted. However, the longitudinal shear resistance was shown to be significantly lower in the specimens that used the higher-strength steel, which clearly demonstrates that the rules given in Eurocode 4, annex B.3.1 for reducing the number of tests lead to unconservative design values. To remedy this situation, an amendment is proposed.

Longitudinal shear resistance of composite slabs containing crumb rubber in concrete toppings

This paper investigates the behaviour and longitudinal shear capacity of metal deck composite slabs with the inclusion of crumb rubber in the concrete toppings.The ability of the slabs to act compositely is governed by the shear interaction between the concrete topping and the profiled steel deck. Results here show that crumb rubber concrete (CRC) improve the overall shear bond capacity between the steel deck and topping following an experimental study on full scale loading tests in accordance with Eurocode 4.The results confirm that composite slabs incorporating crumb rubber had no effect on the longitudinal shear resistance with similar failure loads and behaviours to plain concrete. It also demonstrates a practical use for recycled tyres in the form of crumb rubber which are an environmental problem.