Metal Deck Research Articles

Cyclic moment-rotation model for bolted double-angle connections with composite floor systems

This paper presents a simplified moment-rotation model for cyclic response of bolted double-angle beam-to-column connections in composite steel frames with concrete on metal decking floors. The proposed model employs mechanics-based equations to determine model parameters, along with empirical observations from previous studies and data from recent large-scale multi-bay frame experiments. Several design variables and construction details, such as orientation of the metal decking, concrete reinforcement layout, and deck splicing details around the connection, were considered in the proposed model. Comparisons between the connection model and experimental results showed reasonable agreement in moment-resisting capacity up to 8% interstory drift. Notably, the proposed model adequately simulated varying responses based on connection details not captured by existing moment-rotation models. Analyses of 2- and 4-story frames using the proposed model showed up to 1.3 times higher ductility and 47% lower initial rotational stiffness compared to those using the existing ASCE 41 connection models with strengths of 20% and 35% of the plastic moment capacity of the girder. These results indicate the potential overestimation of stiffness and moment-resisting capacity, and the underestimation of ductility when using existing moment-rotation models due to insufficient modeling parameters to represent actual behavior. Therefore, the proposed model demonstrates its applicability in incorporating various design variables and construction details of bolted double-angle connections with composite concrete on metal deck floors. This model can be used to account for the non-negligible strength and stiffness of bolted double-angle connections in steel gravity framing under seismic loads.

TECHNOLOGICAL ASPECTS OF PRODUCTION OF EPOXY ASPHALT CONCRETE BY ADDING CARBON ADDITIVES

Epoxy asphalt concrete is a durable, high-quality material consisting of epoxy resins, hardeners, and the mineral part itself. Accordingly, slow-hardening epoxy asphalt concrete has high physical properties and low sensitivity to temperature changes, which makes it usable as a rigid pavement and applicable even on metal and concrete bridge decks. However, a downside of epoxy asphalt concrete is its ability to gain strength over a long period of operation (up to 1 year). It is a disadvantage when using such coatings in the upper layer of the road surface. In addition, a long period of strength gain during intensive use of the road pavement leads to critical destruction of the pavement itself, plastic deformation, and a reduction in the service life (which may differ much from the standard). Using metal fibre substantially increases the strength and keeps the area from collapsing. The use of metal elements can significantly reduce the performance of the tires of vehicles that will drive on the road and even create a hazard in the event of destruction of the epoxy asphalt concrete area. Using epoxy binders notably increases the strength characteristics of road materials, especially at high temperatures, and boosts their ability to resist rutting. At the same time, the characteristics of epoxy concrete do not decrease during operation and at low temperatures, which indicates the versatility of such a material. The only drawback that cancels out all the positive features of epoxy asphalt concrete is its long strength gain. This disadvantage not only led to the problems mentioned above but also delayed the opening of traffic, which, especially on roads of higher categories, caused traffic disruption and inconvenience to the movement of vehicles. The authors proposed a solution to this problem by developing an improved epoxy asphalt concrete composition by introducing fibre ash into the developed composition as a reinforcing and structuring additive that accelerates the pavement formation time and strengthens the asphalt matrix in epoxy asphalt concrete. Keywords: epoxy asphalt concrete, additive, fibre, fly ash, combustion products.

Energy consumption, power generation and performance analysis of solar photovoltaic module based building roof

Building energy intensity (BEI) of typical office buildings in Malaysia ranges from 200 to 250 kWh/m2/year, wherein a substantial portion is due to the cooling system. This study evaluates of the performance and suitability of double-laminated monocrystalline solar photovoltaic (PV) glass in comparison to traditional solar PV systems installed on roofs in Malaysian conditions. To address this aim, simulation studies have been conducted to examine the efficacy of Building Attached Photovoltaic (BAPV) and Building Integrated Photovoltaic (BIPV) systems. Key parameters such as heat transfer across the building envelope, cooling demand, daylight utilization, and solar irradiance were analyzed. Additionally, an evaluation of economic viability, including Return on Investment (ROI) and payback period (PBP), was undertaken. Analysis showed that more heat was transferred through the roof on the BIPV building as the U-value of the solar PV glass was higher than the metal deck roof on the BAPV building. The lighting energy in the BIPV building can be saved by up to 80 % as sufficient daylight was entering the building. More than 30 % of the building area had a daylight factor of 1.0 %–3.5 %. From economic viewpoint, the double-laminated monocrystalline solar PV glass had a longer payback period as the initial capital cost was much higher even though the one-off savings and annual savings in the BIPV building were more than the BAPV building.

Performance of recycled aggregate concrete composite metal decks under elevated temperatures: a comprehensive review

ABSTRACT This comprehensive review explores the performance of composite metal decks and structural elements incorporating recycled aggregate concrete (RAC) at elevated temperatures. Despite the acknowledged environmental benefits of using recycled aggregates in concrete production, there is a notable gap in the literature regarding their behaviour under fire conditions. The investigation delves into studies encompassing fire resistance, physio-thermal properties, mechanical attributes, and structural performance of composite metal decks constructed with RAC. The analysis reveals that the inclusion of recycled aggregates has both positive and negative impacts on these elements when exposed to high temperatures. The fire resistance of metal decking composite slabs is significantly influenced by material properties, composition, and RAC mix design. Experimental findings indicate that RAC slabs showed larger midspan deflection under load and fire exposure compared to their counterpart NC slabs. After 120 min. of duration, the mid-span deflection of RAC-0 was recorded to be 19 % higher than the corresponding deflection of NC-0 slab. While temperature-time curves show comparable performance between RAC and natural concrete (NC) slabs, RAC slabs exhibit a notably lower ratio of soffit temperature to the upper surface temperature, resulting in increased spalling. In conclusion, this study advocates for the broader utilization of RAC in constructing structural elements, particularly composite slabs facing extreme temperatures. However, it emphasizes the need for additional research to optimize fire resistance and gain a comprehensive understanding of their behaviour. The findings provide essential guidance for structural engineers and researchers involved in the design of sustainable and fire-resistant structures.

Corrugated Structural Metal Decking System under Tensile Strength Test

Corrugated metal decking has been widely used in the construction industry for many years due to its benefits towards the sustainability, improve time performance of the projects and environmental aspects. This article includes the investigation of tensile strength and identify the failure behaviour of different corrugated surface profile of the metal decking that innovated for structural slab. Novelty of this research is the discovery of the tensile performance of a cold rolled corrugated metal decking profiles at various points of interest for a composite flooring system. Tensile strength specimen preparation complies with the ASTM E8 Standard. A total of 60 specimens with different thicknesses and different parts of metal deck have been tested by the universal testing machine (UTM). The findings on how Base Metal Thickness (BMT) affects the tensile strength and the unique roll formed of the corrugated metal decking system, with 0.75BMT & 1.00BMT, are discussed and analysed in this article. Results showed that the average tensile strength value for 0.75BMT and 1.00BMT from part A was 592.47MPa and 554.41MPa, respectively, and the metal decking is up to the designed strength and the unique roll forming embossment provides better bonding quality between concrete and steel to be used in the industry.

A design stage, multi-objective assessment: material selection with environmental life-cycle analysis, labor, and material health considerations for building structure

During the schematic design stage of a building, assessing trade-offs of lifecycle impact of building elements and materials is crucial for the decision-making process when aiming to reduce negative impacts holistically. A multi-objective assessment is proposed, for environmental, labour exploitation risk (LER), and material health lifecycle impact of the structure and foundation elements in the schematic design stage. Using a real, mid-size, mass timber, educational building in Philadelphia, United States as a case study, we deployed multi-objective optimization (MOO) to consider the range of global warming potential (GWP), LER rating, and material health impact of nine product types over 1602 structure and foundation elements. The parametric workflow paired with Building Information Modelling (BIM) objects aims to provide designers a holistic overview on the cumulative, per material, and per building element impact upstream in the supply chain. The Pareto front solutions reveal that concrete floor with metal deck, hollow structural section framing, and concrete foundation slab, footing, and column pose the greatest risk overall for the case study building, and warrant design consideration to substitute with less impactful alternatives.

Structural Behavior of Concrete Slabs with Profiled Metal Decking: Experimental and Analytical Study

Structural Behavior of Concrete Slabs with Profiled Metal Decking: Experimental and Analytical Study

Test and design of built-up cold-formed steel-lightweight concrete (CFS-LWC) composite beams

Cold-formed steel (CFS) products are extremely versatile and can be used in multiple applications. To further extend their applicability, this investigation assesses the structural behaviour of innovative built-up CFS-lightweight concrete (LWC) composite beams through experimental testing and numerical modelling. First, four full-scale CFS-LWC simply supported composite beams were tested. The specimens included two distinct configurations of the innovative CFS built-up composite beams. The tested CFS-LWC composite beams comprised a lightweight concrete slab supported by profiled metal decking, connected to a CFS built-up beam using bolted shear studs. Following EN 1994-1-1, the degree of shear connection attained in the specimens ranged from 21 % to 57 %. The test procedure, setup, and collected results are described in detail, including load-bearing capacity, deformation, flexural stiffness, and failure modes. Numerical simulations and calibration against the experimental data were then performed, and the CFS-LWC composite beams with different degrees of shear connections were investigated using the calibrated finite element model. The validity of the available design code for the innovative CFS-LWC composite beams was assessed by comparing experimental findings and analytical predictions using EN1994-1-1 (equilibrium and simplified methods) and AISC 360 methodologies. The results showed that the maximum bending resistance of the composite beam obtained from the equilibrium method of EN1994-1-1 and AISC 360 was unconservative due to the overprediction of shear resistance for the bolted shear connectors. Consequently, a calibrated finite element modelling technique determined the bolted shear connectors’ shear resistance. Finally, the bending resistance design prediction of CFS-LWC composite beams following EN1994-1-1 and AISC 360 methodologies, incorporating the shear connector resistance obtained from simulations, was compared with experimental and numerical results from the parametric study. An excellent agreement was observed between experimental and numerical results with the design predictions according to EN1994-1-1.

Flexural resistance of Cold‐formed steel‐lightweight concrete (CFS‐LWC) composite beam

AbstractThis paper discusses the flexural behaviour of innovative built‐up cold‐formed steel lightweight concrete (CFS‐LWC) composite beams through an experimental study. Two full‐scale CFS‐LWC composite beams were tested. The specimens included two distinct configurations of the innovative CFS composite beams. The tested CFS‐LWC composite beams consisted of a lightweight concrete slab supported by profiled metal decking, connected to a CFS built‐up using bolted shear connectors. Two degrees of shear connection were considered. The specimens were uniformly loaded, and the load was increased until failure occurred. The test procedure, setup, and results were recorded in detail, including load‐bearing capacity, deformation, and failure modes. The validity of the design predictions following EN 1994‐1‐1 for the innovative CFS‐LWC composite beams was investigated. Both equilibrium and simplified methods were used to predict the bending resistance of the CFS‐LWC composite beam. The results showed that the design predictions following EN 1994‐1‐1 (equilibrium method) accurately predicted the bending resistance of the CFS‐LWC composite beam, while the simplified method underpredicted the experimental results.

Design Recommendations for Concrete Pryout Capacity of Headed Steel Studs and Post-Installed Anchors

Current formulas to assess the shear capacity of headed steel stud anchors and post-installed (PI) anchors in case of pryout failure (sometimes known as pull-rear failure) have been derived either based on the indirect-tension resistance model or are fully empirical based on push-out test results. In both cases, the predicted pryout capacity is clearly conservative and underestimates the true pryout capacity of anchorages, especially for stiff anchors with low embedment-to-diameter ratios (hef/d < 4.5). This paper proposes an empirical and a semi-empirical formula to predict the concrete pryout capacity of headed steel studs and PI anchors. They were derived based on an improved indirect-tension model which accounts for the stud diameter and the stud spacing in a group of anchors. Furthermore, a database of 214 monotonic shear tests from the literature, including own tests (push-off and horizontally shear tests), is reevaluated and compared to the provisions of EN1992-4. The scope of this assessment proposal includes single and group of headed steel studs and PI anchors attached to a stiff steel plate as well as shear connectors in composite structures without metal deck embedded in normal-weight concrete.

Practical Investigation on the Strengthening of the Built-Up Steel Main Girder of a Metro Station with Carbon-Fiber-Reinforced Polymer on the Inside Part of the Tensioned Flange

This study investigates the effectiveness of a carbon-fiber-reinforced polymer (CFRP) in enhancing the load-carrying capacity of a steel main girder in a metro station. The objective is to evaluate the applicability of CFRPs in sustaining increases in applied loads and assessing their effectiveness on curved surfaces. Finite element analysis (FEA) identified the most stressed areas of the girder under design loads. Based on the FEA results, a targeted strengthening procedure using CFRP sheets was proposed. Various arrangements of CFRP sheets were tested, including different orientations and thicknesses up to 60% of the girder’s flange thickness. To validate the FEA accuracy, two small-scale specimen beams were prepared and tested in the laboratory. One beam was strengthened with CFRP sheets on the tension part of the inner flange side, similar to the suggested strengthening method for the girder. The FEA results show that the CFRP increases stresses by an average of 8% to 10% for the steel main girder, with strengthening effects up to 19% at the center of the CFRP strengthening positions, differing from a regular straight flange shape. Significantly reducing stresses required a total CFRP layer thickness of at least 50% of the flange’s total thickness. Applying a CFRP on the inner face of the girder preserves its usability without the need for openings in finishes or the metal deck surface. The findings highlight CFRP’s potential to enhance load-carrying capacity on curved surfaces and sustain increased applied loads, offering a promising solution for strengthening infrastructure and similar applications.

Development of an indoor solar simulator for the evaluation of the thermal roof performance for commercial buildings in Malaysia

Past researchers have expressed the difficulty in assessing the empirical thermal performance of an entire roof assembly in terms of thermal resistance (RSI value) under hot conditions. This research discussed the development of an indoor solar simulator to assess the thermal performance of commercial building roofs under steady-state conditions. The indoor solar simulator has 40 halogen lamps to simulate solar radiation. Thermocouples and heat flux transducers are mounted at various points across the roof assembly to measure the heat transfer through the roof assembly. From the error analysis, the RSI values obtained experimentally using the indoor solar simulator and ASHRAE Standard agree with a MAPE value of 6.13%. This paper compares the thermal performance of radiant barriers, bubble foil reflective insulation, polyurethane (PU) foam, and mineral glass wool in a roof assembly. The measurement results showed that the radiant barrier and bubble foil reflective insulation has high RSI values ranging from 1.22 m2K/W to 2.19 m2K/W for enclosed air gap thicknesses from 25 mm to 125 mm. In contrast, the metal deck roof with PU metal resulted in RSI values from 0.55 m2K/W to 1.62 m2K/W for PU thicknesses from 20 mm to 50 mm. The combination of radiant barrier and glass mineral wool of 50 mm and 100 mm resulted in RSI values of 0.83 m2K/W and 1.60 m2K/W, respectively. The results from this research can be used to identify the optimum insulation for different roof configurations commonly used in the Malaysian building industry.

Flexural performance of concrete composite metal decking with different base-metal-thickness new smart system

Industrial Revolution 4.0 has led to the age of automation and industrialized building systems. Composite slabs gain its popularity in the modern construction industry due to its speed of construction and cost saving features with lightweight structure. However, from time to time the manufacturer will introduce new corrugated roll forming cold formed steel metal decking systems, which cause the end user to ponder if the product is up to desired performances. The aim of this research is to study the structural performance of SMARTDEK composite slab composed of 0.75 mm and 1.0 mm thickness compared to the conventional reinforced concrete slab under flexural strength, deflection, and failure mode. Concrete slab with thickness of 130 mm was constructed to uncover the ultimate load capacity of the slabs. The novelty of this research is the discovery of longitudinal shear resistance constant through derived equations and the new SMARTDEK profiled composite slab performs better than the conventional slab. Four-point flexural tests were conducted according to ASTM C293 standards to determine the performance of the slabs, and three linear variable displacement transducers (LVDTs) were used to determine the deflection of the slabs. Load-Deflection graphs were plotted for the specimens to determine the yielding point and ultimate point of the slabs. The composite slab with 1.0 mm Base-Metal-Thickness (BMT) had the highest ultimate strength at 75 kN, followed by the composite slab with 0.75 mm BMT at 65 kN, and finally the conventional slab at 39 kN. The failure mode of the conventional slab was pure flexural; while the composite slab first failed in flexural, followed by longitudinal slip failure due to flexural and flexural-shear cracks, which disabled the composite action between the concrete slab and metal decking. The finding showed that the increasing thickness of the metal decking improves the slab strength which results in higher ultimate strength and reduces the overall deflection of the slab. Moreover, the breakthrough of this research is that increasing the overall thickness of the slabs increases the performance in loading’s capacity which could result in higher ultimate strength.

Strength prediction of composite metal deck slabs under free drop weight impact loading using numerical approach and data set machine learning

Strength prediction of composite metal deck slabs under free drop weight impact loading using numerical approach and data set machine learning

Numerical study of steel–concrete composite cellular beam using demountable shear connectors

Steel concrete composite beams have been increasingly used in practice due to their advantages with respect to their structural features and constructability. However, in conventional composite beam systems composite action is applied via shear connectors welded at the top flange of the down-stand steel beam and embedded in the concrete slabs, making it less favourable for the beam system to be disassembled and reused. This paper presents a numerical study of a new composite beam system consisting of a cellular steel beam, metal deck flooring and demountable shear connectors. According to the experimental study, this composite beam system made the demounting, reassembly, and member reuse possible, and did not compromise the loading capacity. In the numerical study presented in the paper, a finite element model was developed and validated against the results obtained from the previous experimental study. The parametric study further examined the effects of concrete strength, shear connector arrangements and asymmetry ratios of steel beam section to the load capacity of the composite beam system. The analysis and comparison provided a deeper insight into the behaviour of this type of shear connector. Through this numerical study, the structural merits of the composite beam system using demountable shear connectors were highlighted. Finally, the mid-span plastic moment of the composite beam was predicted using the direction method provided in SCI publications and compared with the moment–deflection relationship obtained from FE modelling.

Finite element analysis of TPO membrane- retrofitted metal roof system subjected to wind loads

Metal roofing is a common system for low-slope and flat roofing systems such as those used in industrial and storage facilities. Despite its longevity, a metal roof will require a retrofitting when it displays a functional deficiency or reaches to the end of its service life. One of the common retrofitting methods is to use a thermoplastic polyolefin single ply membrane due to its ease of installation, economic efficiency, and lightweight. A single ply membrane typically relies on the existing metal deck system as a structural deck and provides insulation and protection against wind uplift. This paper presents a high-fidelity finite element model to investigate the behavior of a single ply membrane retrofitting metal deck roof under wind uplift. The developed finite element models (FEMs) were validated with experimental results of three full-scale retrofitted metal deck systems using Thermoplastic Polyolefin (TPO) membrane. Parametric study was carried out to investigate the effect of different fastener patterns, transverse and longitudinal fastener spacing, and membrane strength.

DEFORMATION CAPACITY AND DUCTILITY OF SHEAR CONNECTORS

AbstractDeformation capacity and slip range (eventually called “ductility”) of shear connectors are key parameters for the design of shear connectors in composite beams, especially in partial shear connection. Existing design rules require a deformation capacity of at least 6 mm for the use of shear connectors with plastic design methods. This rule is combined with the assumption of rigid‐ideal plastic behaviour of the shear connectors. Still, the real characteristics of most of today's usual shear connectors differ considerably from these assumptions, even more for shear connectors used in combination with metal decking. The paper describes the results of a literature research conducted in order to obtain reliable values for the deformation capacity and the slip range of headed stud shear connectors. Based on these results, advanced design methods can be used to realise composite beams with more realistic lower limits for the degree of partial shear connection and thus better economic performance.

Full-Scale Floor System Testing for Future Hot-Rolled Asymmetric Steel I-Beams

The presented study conveys the initial full-scale experimental study for future hot-rolled asymmetric steel I-beams, termed A-shapes. The primary use for these beams is residential building floor systems. Current systems commonly utilize concrete solutions, which achieve a shallow depth for optimal floor-to-floor heights. However, these floor systems are relatively slow to construct because of the amount of formwork, rebar and post-tensioning placement, and shoring needed. The shallow-depth steel-concrete floor system concept explored in this research aims to improve the speed and efficiency of residential building construction. This increase in speed is achieved through hot-rolled steel A-shapes, which reduce the fabrication time for beam production. These steel shapes have a wide bottom flange that can support precast concrete panels or deep metal decking. Therefore, a relatively easy to assemble shallow-depth system can be achieved. The research study presented herein includes the experimental feasibility testing of a full-scale shallow-depth steel-concrete floor system to further the knowledge of A-shape performance in such systems. The floor system concept evaluated consisted of three steel A-shapes, precast hollow-core concrete panels, and a cast-in-place concrete topping slab. The testing involved taking measurements during construction, service live loading, and loading of the system to failure. The major unknowns were constructability, stability during construction, live load performance, and composite behavior. This experiment revealed that the system was constructed easily and rapidly and also remained stable during construction. The system performed well under service live load, experiencing deflections equivalent to L/3,000. The system failed due to the bond breaking between the concrete and steel, going noncomposite after experiencing partially composite behavior. This occurred at an actuator load equivalent to five times the design service live load. All of this indicates that the floor system concept using A-shapes is a legitimate path forward to faster construction of residential facilities. This validates the need for the research toward standardized A-shapes in the United States.

Standard versus natural fire resistance for partially restrained composite floor beams: 2-Analysis

A thermo-structural reduced-order finite element modeling approach is used to evaluate the results of two fire tests (presented in Part 1 of this study) on identically designed, highly composite floor beam specimens with SFRM protection, shear tab connections at each end, a lightweight concrete slab on a corrugated metal deck, and partial restraint of both axial thermal expansion and connection rotation. Model validation is performed for both an ASTM E119 standard fire and a parametric natural fire, with a constant load applied to the specimens via four-point bending to a maximum service condition. Predictions of temperature increase in the protected steel beam and the composite slab show good agreement with experimental measurements by implementing a series of weighted averaging strategies on thermal FE results for 2D cross-sections at the thick and thin portions of the composite slab. Predictions of temperature-induced deflections, which used the results of thermal FE analysis as input, also show good agreement with experimental results when little-to-no rotational stiffness is applied to the connections. The numerical models are then re-analyzed at a reduced loading level (representing a middling service condition) and with varying rotational stiffness in the shear tab connections. The results of parametric analysis are used to draw correlations between standard fire resistance and natural fire robustness as a function of applied loading and temperature increase in the steel beam. Simplified modeling strategies and recommendations for performance-based structural-fire design are discussed, and opportunities for future research are highlighted.

Performance of Composite Slabs Using Profiled Steel Decking Reinforced with Cold-Formed C-Channel Steel

There are several different types, shapes and geometries of profiled steel decking that are available in the market for composite slabs construction. The application of the system in construction industry usually depends on the design tables provided by the manufacturer of steel decking. Engineers and builders use the design tables according to the required spans and thicknesses in order to facilitate the design of composite slabs for their construction. However, architectural designs might be an obstacle toward applying the system directly because of the limitation toward spans and thicknesses that can be provided by the design tables. In this research, reinforced profiled steel deckings using cold formed C-channel were used to construct full-scale composite slabs with a purpose to increase the span provided by manufacturer design tables and the capacity of the system for in-situ construction. The full-scale composite slabs system was simply-supported and tested in four-point bending with single control shear spans. The structural behaviour of the reinforced slabs system was investigated. The test comprises 12 specimens which include control (CD slabs) and reinforced decks (RD slabs) samples. The composite slab flexural behaviour was monitored using the LVDT instruments toward bending deformation at the critical points and toward slip displacement between the metal decks and the concrete. The load was applied until total damage was observed for the composite slabs system. The performances of the tested RD slabs were comparable with the corresponding CD slabs which indicated by the samples load carrying capacity, end-slippage, and concrete-steel composite action.