Steel-concrete Composite Panels Research Articles

Design of steel-concrete composite panels under low-velocity impact: Local punching failure

Steel-concrete composite panels (SC panels), consisting of two layers of steel plates and one layer of in-filled concrete, have excellent impact resistance. Currently, the proposed impact-resistant design methods of SC panels under low-velocity impact only consider the overall bending failure mode, but are unsuitable for the more common local punching failure mode. This study establishes an ideal tri-fold line resistance function and theoretically derives the stiffness and resistance of SC panels for the local punching failure mode. Furthermore, from the energy perspective, a design method is proposed in the study with impact-side steel plate tearing and SC panel penetration as safety criteria, and a design process covering two types of failure modes is provided. The design process is applied to the SC panel of the AP1000 nuclear station, and its practicality is validated, providing a simple tool for researchers and engineers.

Mechanical properties test of plant fiber reinforced cementitious composites

In this paper, a new type of plant fiber-reinforced cementitious composite (PFRCC) is developed. Compared with ordinary cement-based materials, its toughness is greatly improved. To investigate the tensile and bending mechanical properties of PFRCC, four kinds of PFRCC panels with different thicknesses were developed, and the axial tensile test and bending test of the PFRCC panel were designed. The results show that with the increase in the thickness of the PFRCC panel, the bearing capacity increases gradually. The peak tensile strain is about 0.022 %, which is 1.47-2.2 times that of the matrix cement mortar. The average tensile strength is about 2.52 MPa, which is slightly higher than that of the matrix cement mortar. The bending failure load of the PFRCC panel increases with the increase in thickness, but its peak displacement decreases gradually. The bending strength of the PFRCC panel is about 13.5 MPa, which is 2.7 times that of the matrix cement mortar. It shows that the addition of plant fiber can not only increase the toughness of cement mortar but also improve its tensile and bending strength. The above research provides a theoretical basis for the application of PFRCC panels in practical engineerings such as permanent formwork of foundation beams and light-gauge steel stud concrete composite external wall panels.

Analytical Study on Profiled Steel Sheet – Concrete Composite Sandwich Panel under Axial Load

Steel-concrete composite panels have been proposed and developed for applications in various types of structures A sandwich panel is a typical structural form with good structural performance and excellent material advantages, such as high-specific strength, stiffness, light weight, high thermal insulation, and better performance under shock absorption. The project investigated the response of profiled steel sheet – concrete composite sandwich panel subjected to axial loading. Steel-concrete-steel sandwich structures consisting of two steel face plates infilled with concrete composite material has been developed. Sandwich panel consists of profiled steel sheet as the outer skins(face) and concrete as the infill, connected by using through bolts and the concrete portion is called core. Further, numerical study has been conducted to assess the integrity of the connection between skin and core and to find the effectiveness of connection on overall strength of the panel. Three-dimensional finite element (FE) simulation model is created for the parametric study to investigate the effect of several parameters on overall strength of the panel. Parametric studies are performed and numerical analysis using ANSYS Workbench results are analysed including failure mode, load–deflection curves and strength capacity.

Contribution of Corrugated Steel Plate on the Blast-Resistance Performance of Steel-Concrete Composite Panels

Contribution of Corrugated Steel Plate on the Blast-Resistance Performance of Steel-Concrete Composite Panels

Dynamic response and failure mode of steel-concrete composite panels under low-velocity impact

There are two types of failure modes when a steel-concrete composite panel (SC panel) is subjected to low-velocity impact, local punching failure mode and overall flexure failure mode. Current studies have mainly focused on the former. To analyze the dynamic response process and mechanism of local punching failure, drop hammer impact test of seven SC panels, and static loading test of one SC panel have been completed. With increasing in impact energy, five types of damage patterns under the local punching failure mode appeared in turn. Comparing the residual deformation and the peak value of the membrane force, it could be concluded that reducing the spacing of tie bars improved the impact resistance of SC panels. The impact force-displacement curve of the drop hammer could be divided into five stages. Based on the dynamic response characterized curve and static loading test, a five-segment resistance function model for the entire process of impact response was proposed. The difference between the two failure modes of an SC panel under low-velocity impact reflected the different abilities to resist overall flexure failure and local punching failure. It also reflected the different method of energy dissipation. The criterion and formulas for distinguishing failure modes were proposed in this paper, and the calculation results were in good agreement with tests.

A simplified equation to determine stud spacing in SCP member

Steel-Concrete composite Panel (SCP) broadly used in storage tanks are modularized construction members that are made by placing concrete within two exterior steel plates. Placing of concrete, however, usually develops very high pressure which may cause excessive initial deformation on the exterior steel plates, and the developed deformation will affect the ultimate resisting capacity of the SCP member by an increase of instability in the steel plates. Nevertheless, the influence of the steel plate deformation on the evaluation of the ultimate resisting capacity has not been systematically reviewed. Especially since the ultimate resisting capacity of the steel plate is deeply related to the stud spacing, the initial deformation of exterior steel plates must be taken into consideration in determining the optimum stud spacing. In this context, finite element (FE) analyses on steel plates considering the initial shape imperfection are performed, and a design guideline to determine the stud and tie-bar spacing is proposed on the basis of numerous parametric studies.

Structural behaviour of composite panels made of profiled steel sheets and foam rubberised concrete under monotonic and cyclic shearing loads

Abstract This research investigates the effect of using lightweight foam rubberised concrete as an infill material for double-skinned profiled composite panels under pure shear load through experimental and analytical modelling. Three concrete mixes were used as infill materials in this study: one control foam concrete (FC), and two foam rubberised concrete (FRC) with rubber contents of 8.5% and 17% by total mix volume. The pure shear behaviours of the profiled concrete and profiled steel-concrete composite panels were investigated by testing nine small-scale square panels. Three profiled concrete panels and three profiled steel-concrete composite panels were tested under monotonic pure shear load. In addition, three profiled steel-concrete composite panels were tested under repeated cyclic pure shear load. The monotonic test results showed comparable ultimate loads for both FRC and FC panels. Moreover, the FRC panels experienced a higher number of cracks and higher ductility. The cyclic shearing behaviour of FRC composite panels with 8.5% and 17% rubber contents outperformed the FC panels through increased capacities of about 10.3% and 8%, respectively. The increase in ductility of FRC panels with 8.5% and 17% rubber contents over that of FC panels was about 19.5% and 2.4%, respectively. The cumulative energy dissipation for FRC panels also showed a distinct increase over that of FC panels.

Strain rate effect of steel-concrete composite panel indented by a hemispherical rigid body

This paper presents numerical and theoretical investigations on the strain rate in steel-concrete composite (SC) panels under low-velocity impact of a hemispherical rigid body. Finite element analyses were performed on five specimens with different loading rates. The impact energy was kept constant to eliminate its influence by simultaneously altering the velocity and mass of the projectile. Results show that the strain rate in most parts of the specimens was low and its influence on bearing capacity and energy dissipation was limited in an average sense of space and time. Therefore, the strain rate effect can be ignored for the analyses of global deformation. However, the strain rate effect should be considered in local contact problems. Equations of the local strain and strain rate were theoretically derived.

Displacement response analysis of steel-concrete composite panels subjected to impact loadings

Steel-concrete composite (SC) panels consist of two steel faceplates and a concrete core. The past studies have shown that the SC panels are effective against impact loadings. This paper presents a method for evaluating the displacement response of SC panels subjected to impact loadings using the equivalent single-degree-of-freedom (SDOF) model. The resistance and stiffness of the SC panels are theoretically derived and validated to develop an idealized trilinear resistance function model. The validations against the past experimental results show that the proposed model provides a basis for the dynamic response analysis of SC panels and lays a foundation for further design methods.

Performance of Precast Prestressed Steel-Concrete Composite Panels Under Static Loadings to Replace the Timber Transoms for Railway Bridge

Timber is widely used as transoms in numerous railway networks all over the world and currently in use on the existing Sydney Harbour bridge railway system. Now-a-days, the timber transoms, in numerous railway networks, are edging towards the end of their design life. Moreover, often these timber transoms are subjected to repeated mechanical loadings, chemical degradation and prolonged environmental exposures. As a result, frequent maintenance and sometimes complete replacement to ensure the functionality of the railway network significantly increases the track maintenance cost. Therefore, the paper aims to presents alternative solutions to replace the timber transoms with other more durable and virtually maintenance free materials that will improve the long-term functionality of the transoms in Sydney Harbour bridge railway system. To achieve the goal of the study, an experimental investigation was carried out on the precast prestressed steel-concrete composite panels using two different connectors like AJAX ONESIDE blind bolts and LINDAPTER blind bolts. The experimental results of precast prestressed steel-concrete composite panels under two-point bending test were also compared with the conventional reinforced concrete. It can be concluded that the prestressed panels performed better and exhibited less cracking, less deflection and higher stiffness compared to the conventionally reinforced concrete panels. Moreover, the prestressed panel with AJAX ONESIDE blind bolt connectors shows slightly higher deflections and lower uncracked stiffness in comparison to the prestressed panel with LINDAPTER blind bolt connectors. Therefore, LINDAPTER blind bolts connectors, are preferable in connecting the bridge stringer steel and the prestressed composite panel, could be a viable solution to replace the existing timber transoms of the Sydney Harbour bridge railway line.

Flexural behaviour of alternate transom using composite fibre pultruded sections

Abstract Timber transoms have been installed in railway tracks around the world. These transoms are subject to frequent maintenance and replacement due to the degradation of timber. To reduce the maintenance issues associated with timber transoms, this paper will assess the behaviour of a virtually maintenance free material under static loading. This would provide financial and practical benefits to the Sydney Harbour Bridge's railway network by reducing the need for replacement and frequency of maintenance. Conventional alternative materials including steel and concrete have been extensively researched but are not viable for use in the Sydney Harbour Bridge railway system due to maintenance and weight issues. Composite steel-concrete panels utilise the best attributes of both materials to provide a solution that is lighter, reduces depth and will reduce installation time. While precast steel-concrete composite panels reduce the weight of concrete transoms, they are still quite heavy. Composite fibre material is a constantly developing material that is promising for use in transoms. The material possesses strong mechanical properties while reducing the weight and installation time relative to concrete solutions. There is limited research regarding the feasibility of composite fibre material for use in transoms due to the relatively recent development of the material. This paper presents a theoretical panel design solution using Wagners Composite Fibre Technology (CFT) pultruded hollow sections to cater for applied rail loads. Two composite fibre panels were fabricated and assembled using AJAX ONESIDE blind bolts and LINDAPTER blind bolts, and experimentally tested to investigate the panel's response to static railway design loads. The two blind bolts and the static experimental methodology were chosen to replicate previous experiments investigating composite steel-concrete panels for use as transoms. The composite fibre panel design successfully resisted a maximum load of 900kN and deflected less than the serviceability deflection limit. The results from experimental proved the flexural behaviour and deflection of the composite panel design is suitable for use as a railway transom under static loading. Further studies into the composite fibre panel such as impact testing and fatigue testing are required to make a supported conclusion regarding the feasibility of the composite fibre panel for use as a transom in the railway industry.

Experimental study on impact and post-impact behavior of steel-concrete composite panels

This paper investigates the impact and post-impact behavior of steel-concrete composite (SC) panels. Impact tests were carried out on eight specimens in an instrumented drop hammer rig. The parameters studied in these tests include the impact energy and axial compressive preload prior to impact. Test results such as dynamic response process, impact force-displacement relation, and permanent deformations were discussed. After impact, the specimens along with two undamaged ones were tested under quasi-static compressive loads. Based on the relation between the residual compressive strength and the dimension of the damage region, a model was proposed to evaluate the residual compressive strength of SC panels with impact-induced damage.

Tests of chevron panel buckling-restrained braced steel frames

Two specimens were tested to investigate the effects of constructional details, including panel buckling-restrained braces (panel BRBs), connections, strengthening measures, etc., on the hysteretic behavior of two-story chevron-shaped panel buckling-restrained braced frame (PBRBF). Each panel BRB is an unbonded steel plate brace encased in either an assembled steel panel or a steel-concrete composite panel. Tests revealed that obvious yielding of panel BRBs and framing members occurred after an average inter-story drift of approximately 1/375 and 1/75 respectively. Generally, both specimens from the capacity design exhibited stable hysteretic behavior within story drifts of 1/50, while large local bucking, low cyclic fatigue cracks and tension fracture of steel components, which result in eventual failure of the PBRBFs, occurred at the drifts far larger than 1/50. The PBRBF1 with moment-resisting beam-to-column connections has trilinear skeleton curves within story drifts of 1/30. The PBRBF2 with non-moment-resisting beam-to-column connections, along with the panel BRBs, has bilinear skeleton curves prior to failure of panel. Although local failure of a composite panel occurred at story drifts of 1/68 in the first test, the PBRBF2 still exhibited stable hysteretic behavior in the second test and finally failed at story drifts of 1/33. The constructional details are generally acceptable to ensure good performance of the PBRBFs. Furthermore, if 1/200 is considered as a permissible residual drift level, the residual drifts would challenge function of use when the PBRBFs underwent peak inter-story drifts larger than approximately 1/100.

Influence of shear bolt connections on modular precast steel-concrete composites for track support structures

Through extensive research, there exist a new type of connection between railway bridge girders and steel-concrete composite panels. In addition to conventional shear connectors, newly developed blind bolts have been recently adopted for retrofitting. However, the body of knowledge on their influence and application to railway structures has not been thoroughly investigated. This study has thus placed a particular emphasis on the application of blind bolts on the Sydney Harbour Bridge as a feasible alternative constituent of railway track upgrading. Finite element modeling has been used to simulate the behaviours of the precast steel-concrete panels with common types of bolt connection using commercially available package, ABAQUS. The steel-concrete composite track slabs have been designed in accordance with Australian Standards AS5100. These precast steel-concrete panels are then numerically retrofitted by three types of most practical bold connections: head studded shear connector, Ajax blind bolt and Lindapter hollow bolt. The influences of bolt connections on load and stress transfers and structural behaviour of the composite track slabs are highlighted in this paper. The numerical results exhibit that all three bolts can distribute stresses effectively and can be installed on the bridge girder. However, it is also found that Lindapter hollow bolts are superior in minimising structural responses of the composite track slabs to train loading.

Impact response of steel-concrete composite panels: Experiments and FE analyses

A steel-concrete composite (SC) panel typically consists of two steel faceplates and a plain concrete core. This paper investigated the impact response of SC panels through drop hammer tests and numerical simulations. The influence of the drop height, faceplate thickness, and axial compressive preload was studied. Experimental results showed that the deformation of SC panels under impact consists of local indentation and overall bending. The resistance of the panel significantly decreased after the local failure occurred. A three-dimensional finite element model was established to simulate the response of SC panels under low-velocity impact, in which the axial preload could be considered reasonably. The predicted displacements and impact force were in good agreement with the experimental results. Based on the validated model, a parametric study was conducted to further discuss the effect of the axial compressive preload.

Flexural studies on profile sheet-embedded steel concrete composite sandwich panels: Part I—Experimental research

The use of shear connectors in a composite system tends to impart heterogeneity and needs an expert workmanship as well as special equipment for fabrication. In order to avoid such necessities, the present study is focused on developing steel concrete composite sandwich panels without use of any shear connectors by embedding flanges of the profile sheet in the concrete. Two configurations, (i) P1, where both the skins are a composite with flanges of profile sheet embedded in self-compacting concrete and (ii) P2, where the top skin alone is a composite with flanges of profile sheet embedded in self-compacting concrete, are studied experimentally under four-point bending and are compared with an Reinforced cement concrete (RCC) slab of same dimension. In both the configurations, the webs of the profile sheet act as core in providing shear stability to the panel. The configurations P1 and P2 have 38% and 22% weight of an RCC slab and exhibited 77% and 60% strength of the RCC slab respectively. Apart from good strength-to-weight ratio, the configurations P1 and P2 exhibited better ductility, stiffness and flexural rigidity posing to be a better alternative.

Cyclic tests for steel frame with unbonded steel plate brace encased in panel

Quasi-static tests for two panel buckling-restrained braced frames (panel BRBFs), each of which consists of one two-story steel frame and two diagonal or chevron-shaped panel buckling-restrained braces (panel BRBs), were done to examine the impacts of constructional details on hysteretic response of the panel BRBFs (PBRBFs). Each panel BRB consists of one unbonded steel brace and either one assembled steel panel or one steel-concrete composite panel. Obvious yielding of panel BRBs and framing members developed from inter-story drifts of approximately 1/375 and 1/75 respectively. Local buckling of unreinforced segments of beams occurred when story drifts nearly reached 1/50. Local buckling of columns and tension fracture of steel components occurred at story drifts far larger than 1/50. The PBRBFs didn’t fail within story drifts of 1/30 in the first load stages and still exhibited stable behavior before eventual failure, which was attributed to tension fracture of either encased braces or other components, in the second load stages. The skeleton curves of each specimen are close to a trilinear model and those of both panel BRBs and frame are close to a bilinear model. All panel BRBs exhibited good ductility and qualified cumulative inelastic deformation capacity. The tests revealed that the capacity design generally confines most inelastic action in panel BRBs within story drifts of 1/50. The constructional details, including configurations of panel BRBs, width-to-thickness ratios of elements that meet moderately ductile requirement for H-shaped framing members, strengthening measures and connections, were generally acceptable to ensure good performance of the panel BRBFs.

Free vibrations of precast modular steel-concrete composite railway track slabs

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel

Damped frequencies of precast modular steel-concrete composite railway track slabs

This paper presents unprecedented damped oscillation behaviours of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an innovative slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both undamped and damped eigenfrequencies and eigenmodes have been extracted using the Lancsoz method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel\'s modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

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.