Behavior Of Concrete Sandwich Panels Research Articles

Experimental and numerical investigation on the behavior of concrete sandwich slab panel for a structural system

This paper proposes a simplified methodology based on a concentrated plasticity model to develop numerical analysis of concrete sandwich slab panels for structural systems. Also, a proposal for the determination of experimental damage and its evolution within concrete sandwich panels is formulated. To validate the proposed methodology, an experimental study was carried out on full-scale slab panels to analyze the flexural behavior. Eight specimens were subjected to three- and four-point bending tests. A cycle loading protocol with unloading up to zero load was performed. These specimens, constructed with either one or two joined panels, were used to assess the group action. Mechanical properties for structural analysis—such as strength, stiffness, degree of composite action, and effective moment of inertia—were determined. The tested specimens exhibit significant stiffness degradation, indicating a notable evolution of damage even at small plastic displacements. The proposed methodology proves to be effective and reliable for predicting the behavior of concrete sandwich panels under bending moments. The numerical simulations performed show an adequate description of slab panel behavior until the ultimate load, regardless of its simplicity.

In-plane shear behaviour of concrete sandwich panels reinforced with various geogrids

Seismic occurrences have caused severe damage and even the collapse of fragile unreinforced masonry structures. New technologies are replacing these conventional methods of construction; concrete sandwich panels (CSP) are one such technique gaining popularity. In-plane diagonal shear strength of concrete sandwich panels is studied experimentally, and the effect of incorporating geogrids on the deformation capability and load-bearing capacity is reported. Two forms of geogrid material, plastic uniaxial geogrid (PUG) and polyester biaxial geogrids (PBG2 and PBG3) are used to improve the strength and ductility of concrete sandwich panels. Diagonal compression tests have been carried out better to understand the behavior of CSP under in-plane strength. This paper also discusses the effect of the different mixes, the effect of geogrids, load-deformation behaviour, shear capacity, deflection ductility factor, mode of failure, shear strength, and energy dissipation. In contrast to the control specimen, specimens cast with plastic geogrid had a 13.7% and 26% improvement in shear capacity and load-bearing capability for the two types of micro-concrete mixes used in this study. The conclusion reached is that plastic uniaxial geogrid is effective in improving the concrete sandwich panels’ load-bearing capacity, shear capacity, and deformation ability. Polyester biaxial geogrids enhanced the ductility of the concrete sandwich panels.

Behaviour of Innovative Concrete Sandwich Panels with Pervious Concrete Core under Flexural Bending

Research studies investigating the possibility of using new core material (other than polystyrene) in concrete sandwich panels are being reported in the literature. In this paper, lightweight pervious concrete core is proposed as a new alternative. In this paper, the flexural behaviour of concrete sandwich panels with pervious concrete core is investigated under three-point and four-point bending conditions. The geometrical variables considered are core thickness and number of shear connector lines. Test results showed that, sandwich panels without shear connector trusses failed due to separation of wythes, and the panels with shear connector trusses achieved composite action. The variables considered were found to influence the initial stiffness, cracking moment, ultimate moment, load-deflection behaviour and load-strain behaviour of the panels. Analytical study indicated that the equation given in ACI 318 underestimated the strength of the tested panels. The equation have to be modified by explicitly including the shear connector details in the equation for predicting the flexural strength with reasonable accuracy. Further experimental and analytical studies on prototype concrete sandwich panels with pervious concrete core produced using lightweight aggregates are required in view of developing design guidelines for practical applications.

In-plane Behavior of Concrete Sandwich Panels Bounded by Steel Frames: A Numerical Analysis Approach

In-plane Behavior of Concrete Sandwich Panels Bounded by Steel Frames: A Numerical Analysis Approach

Out of plane performance of novel concrete sandwich panel using different geosynthetics

The main objective of the study is to investigate the flexural behaviour of concrete sandwich panels strengthened with geosynthetics. Two types of geosynthetic material are being used viz. plastic geogrid and polyester geogrid. An attempt has also been made to enhance the strength by using two different mixes. The panels are tested under a monotonically increasing load using a hydraulic jack. The load–deflection curves of the panels were examined to evaluate the effect of geosynthetics on the strength, stiffness, and deformability of panels. The result shows that plastic geogrid reinforced sandwich panels enhanced the flexural strength and ductility of panels compared with control specimens. Polyester geo-grid as reinforcement is also found to be relatively better in restoring the deformability and energy absorption of panels. The results show a gain of about 28% in plastic geogrid (SPGG); 36.8% in the case of polyester geogrid (SGi200), in comparison with the control specimen. The moment–curvature curves were also examined.

Experimental and numerical investigation of the creep response of precast concrete sandwich panels

A numerical model is developed in this paper for investigating the time-dependent creep and shrinkage response of precast concrete sandwich panels made with diagonal-bar shear connectors. The material model uses the fixed smeared cracking approach and the modified principle of superposition in its integral form. It is incorporated into the finite element package ABAQUS to build a structural model that considers concrete cracking, tension stiffening, aging, creep, shrinkage and geometric nonlinearity. The time-dependent behaviour is described via a time-stepping analysis. An experimental study that includes testing of four panels under sustained loading for a period of four months is reported. Two panels were subjected to 4-point bending and the other two were loaded under eccentric axial compression. The test results show that creep has led to a reduction of up to 27% in the residual capacity of the axially loaded panels. A good correlation between the numerical model and the experimental results is obtained. The numerical model is further used for conducting parametric studies. The results provide an insight into the critical parameters that govern the time-dependent behaviour of concrete sandwich panels, which include the diameter of the shear connectors, sustained load level, loading eccentricity and concrete strength. It was found that global creep buckling of the investigated panels can occur under eccentric axial load levels that are as low as 60% the load carrying capacity.

Thermal behaviour of concrete sandwich panels incorporating phase change material

ABSTRACT In this study, the influence of phase change materials (PCM) on the thermal behaviour of concrete sandwich panels was investigated. Sandwich panels are known for their high thermal efficiency however, this research proposed the integration of a PCM concrete layer to maximize the ability of PCM to store heat and slow down the rate of heat transfer. The thermal behaviour was tested by supplying heat energy to specimens until the core temperature reached 60°C. Specimens were allowed to cool until the core temperature returned to 40°C. The thermal behaviour was recorded and analysed. Three specimen types were tested: solid panels (SL), sandwich panels (SW) with and without a PCM concrete layer. For all SW panels, a 10-mm air gap was introduced between two layers at three different locations. Results showed that the air gap behaviour was modified with the heat transfer process by creating temperature lagging, thus resulting in a slower rate of heat transfer across the specimens. The temperature lagging was observed in SW panels and varied depending on the location of the air gap. The application of PCM in SW panels further reduced the rate of heat transfer and decreased the fluctuation of temperature lagging magnitude.

Behavior of Concrete Sandwich Panels under Eccentric Axial Compression�Testing and Finite Element Analysis

Behavior of Concrete Sandwich Panels under Eccentric Axial Compression�Testing and Finite Element Analysis

Precast concrete sandwich one-way slabs under flexural loading

The behavior of precast concrete sandwich panels consisting of two thin R/C layers (wythes) separated by an expanded polystyrene core is examined through experiments on prototype panels subjected to four-point bending, for different values of panel thickness and mesh size, with/without either shear-resistant ribs or conventional steel rebars (besides the wire mesh) in the bottom wythe. The test results indicate that all the panels behave as composite member until failure, and the panel behavior is similar to conventional R/C one-way slabs under flexural load. Due to the presence of wire mesh, cracking behavior in terms of number of cracks and crack spacing of concrete sandwich panels is similar to that of ferrocement cracking behavior. Volume ratio and specific surface of reinforcement affect the cracking behavior of concrete sandwich panels similar to that of ferrocement panels. The crack spacing based on predictive models for concrete slab reinforced with wire mesh agrees with the experimental results. Presence/absence of shear-resistant ribs and/or rebars in the bottom wythe significantly affects the flexural behavior of the panels. Presence of conventional rebars in the bottom wythe together with the wire mesh increases the ultimate flexural load capacity of the panels. The load-deflection response of the concrete sandwich panels exhibits trilinear behavior, and is similar to ferrocement behavior under flexural loading. Analytical study includes strength predictions based on conventional R/C beam analysis.

Flexural behavior of precast concrete sandwich panels under different loading conditions such as punching and bending

Precast concrete sandwich panels having two wythes separated by a core may serve dual purposes of transferring load and insulating. Research studies with respect to flexural behavior of these panels under four-point bending are available in the literature. Nevertheless, experimental and analytical studies with respect to flexural behavior of concrete sandwich panels under punching load are not found. In this paper experimental and analytical studies carried out to understand and compare flexural behavior of concrete sandwich panels under two different loading conditions such as punching and four-point bending are presented and discussed. Experimental study indicates that, type of loading conditions affects the flexural behavior of the concrete sandwich panels significantly. The panel subjected to punching load failed in flexural mode, and its behavior is similar to conventional RC slab. Under four-point bending the panel failure is attributed to failure of concrete by combined effect of shear and flexural stresses. For both types of loading conditions, analytically predicted cracking moment is comparable to the experimental cracking moment. Further experimental and analytical studies are required in this area to develop design guidelines for practical applications of these types of panels under different loading conditions.

Experimental and numerical studies on the behaviour of concrete sandwich panels

ABSTRACT Precast concrete panels are often used for the façades of modern warehouses and commercial malls. During the last two decades, they have generally been made of two concrete layers with interposed thermal insulating polystyrene boards. Traditionally, perimeter concrete ribs allow the weight of the external concrete layer to be transferred to the internal thus causing unavoidable thermal bridges which reduce the energy performance of the building. In the sandwich cladding panel, the two concrete layers can be linked by low-conductivity shear connectors crossing through the insulation layer, thus ensuring the overall thermal efficiency of the building. In this paper, the results of a wide numerical study on the behaviour of concrete sandwich panels realized with glass fibre-composite pultruded connectors are presented, focusing on the stresses and deformations caused by dead load, thermal actions and shrinkage.

Experimental and numerical studies on the behaviour of concrete sandwich panels

ABSTRACT Precast concrete panels are often used for the façades of modern warehouses and commercial malls. During the last two decades, they have generally been made of two concrete layers with interposed thermal insulating polystyrene boards. Traditionally, perimeter concrete ribs allow the weight of the external concrete layer to be transferred to the internal thus causing unavoidable thermal bridges which reduce the energy performance of the building. In the sandwich cladding panel, the two concrete layers can be linked by low-conductivity shear connectors crossing through the insulation layer, thus ensuring the overall thermal efficiency of the building. In this paper, the results of a wide numerical study on the behaviour of concrete sandwich panels realized with glass fibre-composite pultruded connectors are presented, focusing on the stresses and deformations caused by dead load, thermal actions and shrinkage.