Concrete Sandwich Panels Research Articles

Flexural behavior of Expanded Polystyrene core Reinforced Concrete Sandwich Panels with different construction methods and end conditions

The effect of construction methods and end conditions on flexural behavior of Expanded Polystyrene (EPS) Core Reinforced Concrete Sandwich Panels (RCSP) under out-of-plane flexure loading is studied, experimentally. Total 21 specimens are constructed using factory made corrugated EPS panels and wire mesh. The specimens are constructed using different construction (pouring and spraying of concrete) methods, with varying combinations of wythe thicknesses, boundary conditions (presence and detailing of RC beams along the supported edges), and alignment of corrugations in the EPS core. Specimens are tested under four-point bending, with simply supported condition, in displacement control mode. The influence of the considered parameters on cracking pattern, failure mode, strength, moment-rotation curve and ductility are studied. The failure mode of the EPS core RCSP specimens is mainly governed by the edge condition at supports, whereas, the method of construction and thickness of wythes do not have much influence of the failure mode. The thickness and construction method of the wythes has significant effect on the initial behaviour of panels up to cracking, but has only limited effect on the ultimate load capacity, as it mainly resisted by the wire-mesh reinforcement in primarily catenary action, in most of the tested specimens.

Risk Assessment of Joint Sealing Tape in Joints between Precast Concrete Sandwich Panels Resilient to Climate Change

Lately, a new technical solution, pre-compressed joint sealing tapes in precast concrete sandwich panel facades, has been introduced in Sweden. Although the consequences of performance failure can go far beyond the component, affecting the building, the introduction has gained little attention in terms of risk assessment in the literature and in industry. Instead, reference cases are used as verification without formal evaluation, potentially leading to serial failure. The aim of this paper was to provide guidance on how a design–build contractor should handle this new technical solution. A risk assessment framework using a design–build contractor’s perspective was applied to the case. The framework addresses new technical solutions or adaption to new conditions (e.g., climate change) with the aim of preventing serial failures. Moisture conditions within the joints were simulated using present and future climates, and probabilities of failure were assessed using the Monte Carlo method. The results of the study included identified risks of failure associated with the solution and factors influencing the probability of failure. A main issue was the exposure of the facade to driving rain but also run-off areas and imperfections in the application of the joint sealing tape. Future climate changes affect performance negatively. In conclusion, the new technical solution might be possible to use if draining potential is ensured in all detailed designs and a set of recommendations, including full-scale testing, is provided for the design–build contractor.

Experimental investigations and design method on a lightweight bamboo-concrete sandwich panel under axial load

Bamboo is well known as a kind of environment-friendly and sustainable material with superior mechanical properties such as high strength to weight ratio. Generally, it is accepted that bamboo has wide application possibilities in the construction sector. In the present development of the processing technology, engineered bamboo has gradually entered the field of modern structural engineering since the beginning of present century. This paper proposed a novel sandwich panel composed of engineered bamboo face and aerated concrete core. Investigation and analysis of the mechanical properties of this novel engineered bamboo–concrete sandwich panel under axial load was conducted through experiments and theoretical equations. The influence of different factor like face type, thickness of face and core; connection type between the face and the core was discussed as well. The result showed that the bamboo face significantly affected the panel mechanical properties and demonstrated that the sandwich panel proposed in this paper is promising due to its distinguished recorded structural performance.

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.

Composite behaviour of wide sandwich panels with thin high performance recycled aggregate concrete wythes with fibre reinforced polymer shear connectors

ABSTRACT The traditional means of using precast concrete sandwich panels are restrictive in terms of applications, where thick wythes result in heavy panels which are often unsuitable in retrofitting domestic and commercial buildings. As concrete sandwich panel technology has evolved to make it more widely accessible, recent research work has demonstrated that it is possible to achieve thermally efficient partial composite action within a thin wythe panel provided non-conductive shear connectors are used. This paper examines high performance recycled aggregate concrete in heavily insulated non-load-bearing panels for retrofitting domestic and commercial buildings. A series of concrete mixes were tested to develop one which would be more sustainable than the widely accepted standard mixes for wythes. Different 220 mm thick concrete sandwich panels were tested consisting of 20 mm thick fibre-reinforced recycled aggregate concrete wythes and a 180 mm layer of XPS insulation. Unconnected and shear connected panels were tested in flexure in a displacement control test. The effects of composite action and post-cracking toughness were examined and it was concluded that a shear connected panel comprising sustainable thin recycled aggregate concrete wythes enclosing a thick layer of insulation is a feasible product to use for light high-performance sandwich panels.

Seismic Performance Test of Double-Row Reinforced Ceramsite Concrete Composite Wall Panels with Cores

The research objective of this study was the seismic performance of double-row reinforced ceramsite concrete sandwich wall panels. The feasibility of upgrading a new wall panel from a non-load-bearing partition wall to a load-bearing seismic wall was examined by conducting cyclic load tests on five wall panel specimens. The test piece was a sandwich thermal insulation structure that could achieve a good protection distance between the thermal insulation material and the fire source so that the fire prevention problem could be solved. At the same time, the problem of easy fall-off of the insulation system was also solved. The specimens were divided into three groups, including three double-row reinforced ceramsite concrete sandwich wall panels with different dosages of alkali-resistant glass fiber, a double-row reinforced ordinary concrete sandwich wall panel, and a solid concrete ceramic wallboard. The effects of different dosages of alkali-resistant glass fiber, construction forms, and bearing side plate materials on the seismic performance of the sandwich wall panels were investigated separately for the specimens. From the analysis of the specimen results (damage characteristics, hysteresis curves, energy dissipation capacity, bearing capacity, ductility, longitudinal reinforcement strain, and stiffness degradation), it could be seen that among the five types of wallboard, the double-row reinforced ceramsite concrete sandwich wall panel with 0.3% fiber content had the best ductility and energy dissipation capacity. Adding fiber could solve or improve the problem of the low ultimate bearing capacity of ceramsite concrete as the wallboard’s bearing material. Compared with the same size solid ordinary concrete wallboard, the bearing capacity of the double-row reinforced ceramic concrete sandwich panel was slightly reduced. However, the additional seismic performance indexes were relatively superior. Through the analysis of the test results, it was shown that, when considering the thermal performance and seismic capacity, the new wall panel had good prospects for engineering applications.

Thermal performance of concrete sandwich panels incorporating phase change materials: An experimental study

The employment of phase change materials (PCMs) in the construction of concrete building components has engaged many researchers’ interest. In this study, a novel reduced-scale experiment is employed to perform a parametric investigation of the thermal performance of PCM-integrated wall specimens considering two types of concrete, two types of PCM, and different thicknesses of the concrete and PCM layers. Moreover, three different ambient temperature profiles of a summer day in three different cities were considered as the outside ambient temperature to evaluate the performance of each PCM under different temperature conditions. The test procedure is capable of evaluating the thermal performance of different wall configurations under various temperature conditions. The inside temperature variations of the wall specimens were monitored as the thermal performance criteria. In consequence, integrating the PCM layer with normal concrete or with slimmer concrete layers resulted in better thermal performance of PCM in absorbing heat in comparison to lightweight concrete or thicker specimens due to the considerable effect of density and specific heat capacity of different types of concrete. Moreover, the compatibility of the melting temperature of PCMs with the ambient temperature of the considered cities in summer is assessed and discussed.

Structural performance and section optimization of precast concrete sandwich panels with pin-type GFRP connectors

A precast concrete sandwich panel (PCSP) offers a good potential in the application of façade wall due to the improved energy efficiency. In this study, the structural performance of PCSP with pin-type glass fiber reinforced polymer (GFRP) connectors was investigated, and an optimization characterized by ribbed structural wythe was proposed and studied. Firstly, the pull-out and shear capacity of the pin-type connector were evaluated through direct tensile test and direct shear test, respectively. Thereafter, seven PCSP specimens were fabricated and tested under four points flexural load. The investigating parameters included the structural wythe thickness, loading direction, insulation bond, and section type of the structural wythe. The load-deflection relationship, crack pattern, failure mode, load-strain relationship, and degree of composite action of the PCSP were studied and compared. It was concluded that: (1) the tested PCSPs presented ductile failures; (2) the structural wythe thickness, loading direction and insulation bond would influence the cracking, yielding, and peak loads of the tested PCSP; (3) the PCSP with pin-type GFRP connectors could be designed as non-composite type owing to the low composite action; and (4) the proposed ribbed structural wythe could achieve a lightweight PCSP while considerable flexural stiffness and capacity could be retained.

Structural performance of concrete sandwich panels under fire

This paper investigates the structural performance of load-bearing precast concrete sandwich panels subjected to one-sided fire. It focuses on panels made with FRP diagonal-bar connectors. Heat transfer analysis is conducted for characterizing the temperature gradient within the panel and a structural model is developed. The model considers the composite action between the reinforced concrete (RC) wythes, the transient creep of concrete under fire, strain softening in compression, cracking and tension stiffening, yielding of the steel reinforcement and geometric nonlinearity. The heat transfer analysis is conducted using a finite element approximation, and the governing differential equations of the structural model are solved using the nonlinear shooting method following an iterative procedure. The model is validated through comparisons with test results and other models in the literature. A numerical example and a parametric study that show the capabilities of the proposed model and clarify the structural behavior are presented. The results reveal progressive failures of the FRP-bar connectors and buckling failures of the panels under fire. It is revealed that the load eccentricity of the applied load greatly affects both the structural performance and the fire resistance of the panels. The diameter of FRP bars, the thickness of insulation layer and the load level are also found to play key roles in the fire resistance of the panels.

An experimental and numerical study on the in-plane axial and shear behavior of sprayed in-situ concrete sandwich panels

The paper deals with the experimental and numerical characterization of the in-plane axial and shear mechanical behavior of sprayed in-situ reinforced concrete (RC) sandwich panels, used as structural walls. Axial compression tests were carried out on specimens with different slenderness ratios to study their behavior under axial vertical loads. While the diagonal compression test and shear load with constant compression test were respectively performed on squared panels, analyzing their response to in-plane horizontal lateral forces. Ultimate axial and shear loads have been experimentally determined and the most significant load–displacement diagrams have been reported. The obtained results have been compared with other experimental campaigns on RC sandwich panels and with conventional RC walls equations, available in codes of practice and literature. The structural potentialities of RC sandwich panels as load-bearing and shear walls are highlighted. The experimental investigation is corroborated by a 3D nonlinear finite element (FE) numerical analysis, considering the influence of the insulation layer, the efficiency of steel connectors, and the involved material nonlinearities.

Low-Velocity Impact Experiments and Modeling of TRC Skin-Aerated Concrete Core Sandwich Composites.

Mechanical response of textile-reinforced aerated concrete sandwich panels was investigated using instrumented three-point bending tests under quasi-static and low-velocity impact loads. Two types of core material were compared in the sandwich composite consisting of plain autoclaved aerated concrete (AAC) and fiber-reinforced aerated concrete (FRAC), and the stress skins were alkali-resistant glass (ARG) and textile reinforced concrete (TRC). The textile-reinforced layer promoted distributed cracking mechanisms and resulted in significant improvement in the flexural strength and ductility. Digital Image Correlation (DIC) was used to study the distributed cracking mechanism and obtain impact force-crack width response at different drop heights. A constitutive material model was also developed based on a multi-linear tension/compression strain hardening model for the stress-skin and an elastic, perfectly plastic compression model for the core. A detailed parametric study was used to address the effect of model parameters on the flexural response. The model was further applied to simulate the experimental flexural data from the static and impact tests on the plain aerated concrete and sandwich composite beams.

Shaking table test on insulated sandwich concrete wall building structure

To solve the problems of concrete sandwich panels such as cold bridge, weak connection, and poor ductility, a new configuration, namely the insulated sandwich concrete wall (ISCW) is proposed in this paper. Shaking table test is performed on a 1:3 scaled model of 3-storey ISCW building structure to study the seismic behavior of an ISCW structure. Results indicate the ISCW building structure has large stiffness and can work in elastic state under small earthquakes. The stiffness degrades continuously and the structure arrives in a plastic state as the PGA increases, but the degradation process is relatively slow. The cracks or damages mainly occur on the wall with big opening of floor one, but they do not spread through the walls and no collapse happens. With a rational arrangement of the cold-formed thin-walled steel tube columns, the structural integrity and ductility are significantly improved. Three types of seismic waves were input in the test, and significantly different structural responses were caused. Hence the ground motion spectrum characteristics cannot be ignored when the seismic response of an ISCW building structure is analyzed.

High Temperature Performance of a prefabricated concrete sandwich panel

The innovative sandwich wall panel studied in this paper can be used as the load-bearing member of the structure. In addition to the traditional sandwich panel structure, the new panel system also has the characteristics of spiral stirrups along the section of the core column, 650mm column spacing, foam concrete for insulation layer and self-compacting concrete for outer layer. In addition, in order to improve the overall strength and stiffness of the panel, a unique wire system consisting of two vertical wire mesh connected by a short horizontal steel bar is adopted in the concrete layer. In order to study the mechanical properties of the new panel system at high temperature, ABAQUS simulation was carried out. The simulation results show that the new precast concrete sandwich wall system has good resistance to high temperature and still has good bearing capacity after high temperature.

In-Plane Shear Behaviour of Novel Concrete Sandwich Panels Reinforced with Various Geosynthetics

In-Plane Shear Behaviour of Novel Concrete Sandwich Panels Reinforced with Various Geosynthetics

Long-term behavior of precast, prestressed concrete sandwich panels reinforced with carbon-fiber-reinforced polymer shear grid

Long-term behavior of precast, prestressed concrete sandwich panels reinforced with carbon-fiber-reinforced polymer shear grid

Structural performance of textile reinforced concrete sandwich panels under axial and transverse load

AbstractThe performance of textile reinforced concrete composite panels (TRCCPs) under the action of pseudo-static load up to collapse was evaluated. The test of TRCCPs under axial and transverse loading was conducted, and the results were compared with those for steel wire mesh reinforced-concrete composite panels (SMRCCPs). Ceram-site concrete was utilized as the panel matrix owing to its lightweight and insulation characteristics. The ultimate load bearing capacity, load-deformation and load-strain relationships, and failure modes were discussed and investigated in comparison with the findings of non-linear finite-element-model (FEM) analysis and the analytic method on the basis of the reinforced concrete (RC) theory. The analysis results indicate that TRCCP is suitable for use as a potential structural member for a wall or slab system of buildings, and the typical RC theory can be applied to predict the ultimate load bearing capacity if modified suitably.

In-plane behaviour of expanded polystyrene core reinforced concrete sandwich panels

The structural behavior of Expanded Polystyrene (EPS) core Reinforced Concrete Sandwich Panels (RCSP) under axial and in-plane shear loading is studied, experimentally. An experimental study is conducted on RCSP consisting of factory made corrugated EPS core, welded wire mesh, and orthogonal shear connectors. Total 14 specimens (six of axial compression and eight of diagonal compression) are constructed and tested. The specimens are tested in displacement control mode with Digital Image Correlation (DIC) to measure displacements and strains. The mode of failure, propagation of cracks, ultimate axial load carrying capacity, in-plane shear strength, and stress–strain curves are presented in this article. The experimentally obtained axial load capacity and shear strength are also compared with those calculated analytically. The axial load capacity obtained analytically is in good agreement with experimental results, but the shear strength obtained from experiment is much higher than that estimated using the design codes for reinforced concrete.

Development Length of Small-Diameter Basalt FRP Bars in Normal- and High-Strength Concrete

Abstract Small-diameter fiber-reinforced polymer (FRP) bars have great potential in certain applications, such as concrete sandwich panels, ties, and shear connectors. In this study, the developmen...

Precast Concrete Sandwich Panels for Mass Housing Systems: Plan and Design Strength Requirements

Ambitious mission mode project ‘Affordable Housing for All’ proposed by the Government of India requires an innovative technology for speedy construction of cost-effective residential housing systems. Precast concrete sandwich panels with reinforced concrete wythes, expanded polystyrene core and truss shear connectors can be considered as a suitable alternative to conventional brick masonry walls and reinforced concrete floors. In this paper, a typical plan for mass housing systems is arrived and concrete sandwich panels are proposed to be used in the mass housing systems. In the proposed housing plan, the dimension of each room was selected based on length and width of the concrete sandwich panels (achieving dimensional co-ordination). The design strength of concrete sandwich panels is obtained from the experimental studies available in the literature and compared with actual loading effects on the mass housing system with the proposed plan. The study shows that concrete sandwich panels can be used for acting as load bearing walls and floors in housing systems. The study also indicates that dead weight of the housing systems could be reduced significantly by using concrete sandwich panels. Further experimental and analytical studies are required for assessing the structural behavior of the housing systems with concrete sandwich panels under lateral loads.

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.