Steel Profiles Research Articles

Optimization of Structural Steel Used in Concrete-Encased Steel Composite Columns via Topology Optimization

Concrete-encased steel composite columns are preferred for their exceptional ductility and strength, particularly in high-rise buildings. This research aims to enhance both the strength and ductility of these composite columns by increasing the height of the steel profile. Typically, hexagonal or circular openings, referred to as castellated elements, are incorporated into the steel profile to achieve this height increase. This study employed a topology optimization method to identify the ideal opening shape for the steel profile in concrete-encased steel composite columns. The analysis revealed a sinusoidal-like opening shape, which was then refined for manufacturing. The optimal opening shape was used to increase the height of the existing steel profile, and nonlinear analyses were conducted to evaluate the effectiveness of this new optimized steel profile in concrete-encased steel composite columns. Two concrete-encased steel composite columns were designed: one with the optimal steel profile and the other with a standard steel I profile. ANSYS APDL 19.0 software was used to simulate an experiment based on an existing concrete-encased steel column to validate the nonlinear analysis. The verification analysis demonstrated a remarkable similarity between the experimental and numerical load–displacement graphs, indicating that the numerical analysis was reliable. In the analysis of the composite columns, both axial and lateral forces were applied in the nonlinear analyses. The axial force was applied at 15% of the column’s capacity, while the lateral force was applied until the composite column reached a state of failure. The results of the nonlinear analyses allowed for a comparison of load–displacement curves and the performance of the composite columns. In comparison to the standard steel I profile, the steel profile with the optimal opening shape increased load-carrying capacity by approximately 19% and energy absorption capacity by approximately 24%.

Modeling surface roughness profiles generated by the belt finishing process of a 27MnCr5 carburized steel

Belt finishing is a superfinishing process that enables to reach fine surface roughness. This paper proposes a numerical model, predicting belt finishing roughness profiles of a 27MnCr5 carburized steel. It utilizes belt topographies that are then numerically deformed thanks to a specific morphological filter. A method for determining the morphological filter parameters is proposed and depends on the size of the grains. Then, the deformed topography of the belt virtually scratches the workpiece at a given depth of indentation (computed by a rough contact model). The model predicts surface roughness profiles in the steady state regime. The paper shows a reasonable agreement between experimental and numerical results. The model captures the main trends: the higher the grain size the higher the roughness of the workpiece. Computational time needed for this model is a few minutes, making it a useable solution for the industry.

Ensaios de push-out: conexões por aderência no contexto de lajes treliçadas

Abstract Composite structures and precast solutions stand out because they lead to simple, fast erected and economic constructions. In steel-concrete composite construction, shear connectors are used to assure the shear transfer between the steel profile and the concrete slab, enabling the composite action to develop. This paper discusses an innovative technology for connection by adherence, whose resistance is due to friction on various steel-concrete interfaces. The authors consider that this type of shear connection is suitable for composite beams with latticed joists slabs, and the study developed intends to analyze the behavior of the proposed connection, in this application's context, through experimental and numerical approaches. For this purpose, push-out specimens were fabricated and tested in accordance with Eurocode-4 requirements, where the connection behavior is analyzed in terms of its load-slip relation, and the failure modes are identified. Experimental and numerical results allowed to induce that the connector by adherence made with a checkered steel plate is appropriate to be used in composite structures, as it exhibits satisfactory shear resistance and ductility performance. Also, specimens with latticed joist slabs presented average load capacity values with the same magnitude as the average load capacity obtained in models with solid slabs, despite being more prone to cracking. From the parametric study, an increase of 100% in the connector height implied strength increase from 16% to 25%, depending on slab type.

Experimental performance of CA-50 steel shear connectors for composite structures in steel profiles and reinforced concrete

Experimental performance of CA-50 steel shear connectors for composite structures in steel profiles and reinforced concrete

Methodology for Improving Manufacturing and Assembly of Lightweight Prefab Systems

The increasing adoption of prefabrication in the Global North reflects a response to the urgent demand for safe and affordable housing. This demand is compounded by the necessity to meet contemporary standards for aesthetic quality, structural safety, and energy performance, all within the context of the current climate and safety challenges. Prefabrication, underpinned by the principles of design for manufacturing and assembly (DfMA), offers a pathway toward modernizing construction practices. Specifically, lightweight steel profile technologies, particularly suited for low- and mid-rise buildings, offer an efficient solution to meet these evolving demands. However, to achieve widespread adoption, further optimization is necessary. The reduction of material use, fabrication waste, and production time, alongside cost reduction, will be critical in aligning prefabrication technologies with sustainable development goals. This paper presents an eight-step methodology in which manufacturing and assembling strategies are considered since product development and according to which materials and components are selected, prototyped, and tested to optimize both mechanical and environmental performance. The methodology has been validated through an academic and industrial venture that aimed to optimize a lightweight cold-formed steel volumetric system for housing applications. The study demonstrated to achieve a system that fully met the structural requirements while also minimizing the use of material, waste, and production time. In doing so, this work contributes to a broader effort to modernize construction practices and address the dual imperatives of safety and climate resilience.

Characterization of the elevated temperature behaviour of demountable shear connectors in steel-concrete composite beams through push-out tests

Demountable shear connectors are a key component of reusable structural systems. The intention behind the development of these systems is substituting, or at least providing a valid alternative to the widely utilized beam-to-slab connection via shear studs, which are welded to the flange of the steel profile and embedded in the concrete slab, therefore eliminating the possibility for the slabs to be reused in a new structure. To ensure that these demountable connectors are a valid option in practice, it is necessary to analyse them under different actions, including the fire situation. This is the primary purpose of the experimental campaign presented in this investigation, where a series of push-out tests at elevated temperatures are performed to extend the previously available results at ambient temperature, as a response for the need of characterization of the behaviour of the proposed demountable shear connectors in the fire situation, thus facilitating their applicability in the construction sector. This study shows how temperature affects the shear resistance of the connectors, their ductility, and the slip resistance. The available design provisions in EN 1993–1-8 and the reduction factors in Annex D of EN 1993–1-2 for bolts loaded in shear are tentatively applied to high temperatures, as a way to assess their validity for fire design.

ПРОЧНЫЙ АНАЛИЗ ОПАЛУБКИ С ПРИМЕНЕНИЕМ ЛЕТНОЙ СИСТЕМЫ НА ПЛИТНО-СВАЙНОЙ КОНСТРУКЦИИ

The Semarang-Demak Toll Road was planned with detailed procedures to address disorganized road networks, increased traffic volumes, congestion, land subsidence, and tidal floods. It has toll entrances in Semarang, Genuk, and Sayung sub-districts and ends in Demak City. Its purpose is to minimize traffic jams, provide access to tourist cities, and serve as a tidal barrier sea embankment. The formwork support system's proper design is crucial to ensure the safe construction of the main structure. A unique disk lock and steel tubular scaffold are utilized for a slab-on-pile structure employing a flying falsework system. This approach results in a structurally sound and secure construction that is not susceptible to twisting, providing quick erection and disassembly, significantly improving construction efficiency. The system was employed in a portion of the Semarang-Demak toll road project, and its efficacy was evaluated using finite element analysis software. The software provides security and convenience in analyzing structures, paying attention to the nominal strength of each steel profile and the internal forces at work. All components are safe as their actual deflection falls within the maximum limit.

Numerical investigation of steel beams with web openings obtained from topology optimisation

The use of web openings in I-section beams has become increasingly common in recent years, and these elements can be observed in various civil engineering applications. This design approach results in an improved weight-to-stiffness ratio in steel beams, enabling their use over longer spans without a significant increase in material cost and deflections due to self-weight. It also avoids the cutting of holes in inappropriate locations for electrical, hydraulic, and air conditioning installations. Steel beams fabricated with web openings also represent an important solution when height constraints are imposed on multi-story buildings due to design regulations and economic considerations. It is recognised that the use of the traditional web opening shapes - namely, circular, rectangular, and hexagonal - in civil structures can lead to issues associated with high stress concentration. The presence of these web openings can induce local instability or yielding due to inadequate shear force transfer across the openings, allowing plastic hinge formations, also known as Vierendeel mechanism, for instance. In this sense, researchers have investigated novel shapes to mitigate the impacts of the web openings in both structural and economic terms. In this sense, this work has been developed aiming to evaluate the structural performance of I-section beams obtained using structural optimisation, for a reference distributed load and different boundary conditions, compared with the cellular beams. An evaluation of the structural potential of the obtained topologies has been performed by linear elastic, buckling and complete nonlinear analyses. Results were obtained in terms of stresses, displacements, and ultimate loads for all investigated cases. It was found that when compared to a cellular beam, the optimised beams increased the ultimate resistance with superior stiffness resulting in lower displacements and presented a more adequate stress distribution with lower stress concentration. However, in some cases a poor structural performance was observed due to large zones with holes obtained from the optimisation process. Based on these results and on the work of Tsavdaridis et al., authors proposed a configuration for the openings, and its structural performance proved it to be a promising solution to be employed on beams with web openings, especially when the expected failure mode is lateral-torsional buckling. A parametric study was conducted to assess the efficiency of the proposed configuration for different steel profiles and span lengths; results indicated equivalent or superior load capacity when compared to the reference cellular beam. The configuration suggested by the authors can be easily fabricated, and, considering the constant patterns along the length, finding an expression to determine its design load is possible, like what is usually done for other shapes (circular, hexagonal).

Analysis of foundation solution for the noise protection walls on the reinforced earth

This paper brings the introduction of the analysis of foundation solution for the noise protection walls on the reinforced earth along the Highway Corridor Vc, a road and rail transport corridor that connects Hungary, Croatia and Bosnia and Herzegovina, included in the network of Pan-European transport corridors. A solution with pile foundations made of steel IPE profiles is presented in detail. During the design and modelling, as well as the calculation of the structural foundation, the modern software program PLAXIS was used, and the calculation was made in accordance with EN 1997 Eurocode 7, Geotechnical Design. Special attention is devoted to the analysis of the impact of driving IPE steel profiles, as foundation piles, on reinforced earth. The presented solution was then verified by an additional control calculation and a field test of the impact of the horizontal load on the bearing capacity of the IPE steel profile driven into the reinforced slope. Based on the conducted analyses and testing, it has been proven that it is possible to build noise protection walls on the reinforced earth without disturbing the internal stability and functionality of the reinforced earth.

A Deep Learning‐Based Approach to the Estimation of Jominy Profile of Medium‐Carbon Quench Hardenable Steels

The possibility to estimate the Jominy profile of steel based on its chemical composition is of utmost importance and high practical relevance for industries, which enables a preliminary assessment of the suitability of a specific steel grade to a particular application or to the requirements of a customer, by saving time and resources as the Jominy end‐quench test is costly and time‐consuming. More importantly, an estimator can be used in steel grade design, by supporting the investigation of the most suitable chemistry to meet some given specifications. The article proposes a novel approach to estimate the hardenability profile of medium‐carbon quench hardenable steels, which exploits the potential of deep learning to correlate the steel metallurgy to the entire shape of the curve rather than to its single points, by thus being adaptable to a wide range of steel grades while providing very accurate estimates. Moreover, the proposed approach is suitable to implement a transfer learning paradigm, as it can exploit the knowledge acquired by training on a specific dataset to adapt the model to different steel grades for which less data or data holding different features are available.

Community Skill Development for the Use of Galvalume Composite Concrete Materials for Building Structural Parts

Galvalume material is often known as Cold Formed Steel material. Galvalume is one component that is often used by the people of Indonesia as a building structure material. Galvalume is easy to use, easily available in the market, and relatively inexpensive. Mild steel profiles can be used instead of roof trusses made of wood and concrete. The problem so far is that innovation regarding the use of Galvalume material has not been widely used for building structures without being wrapped in concrete. In this study, a trial was conducted and the introduction of the application of the use of Galvalume to building structural materials. The methodology is carried out using galvalume which is made as a composite concrete stiffener. Composite concrete testing is only at the concrete compressive strength test stage. The results of the concrete panel test show that the galvalume material can be used and the workers who work on it are not too difficult to do.

Analisis Profil Atap Baja WF dengan Metode LRFD Menggunakan SAP 2000 dan Idea StatiCa

The roof is one of the main components in a building to protect it from heat and rain. The roof is also an architectural component that adds to the beauty of a building. Therefore, every building must have a roof. Currently, many steel roofs are used as the structural frame. Considering that wooden materials are considered expensive to use nowadays. Apart from that, steel material has a longer durability than wood material, so steel is considered the best alternative at the moment. The title of this article is "Structure Analysis of WF Steel Profile Roofs Using the LRFD Method". This analysis was carried out to determine the strength of the WF steel truss structure and its connections. The analysis method used in this research is the LRFD method which is carried out with the help of the SAP 2000 v20 program to calculate the statics of the roof construction and using the help of the Idea StatiCa program to calculate the connections. Based on the results obtained, the trusses that use the WF 200.100.5,5.8 profile are able to withstand the forces acting on the truss structure, and the connections are sufficient to withstand the forces that occur.

Post-fire performance of circular steel tube confined steel-reinforced concrete slender columns: Testing, simulation and design

Steel tube confined steel-reinforced concrete (STCSRC) stub columns offer good residual bearing capacity, great ductility, and large stiffness after fire exposure because inner steel profiles are unaffected by exterior temperature. Nonetheless, instability issues exist in STCSRC slender columns, and study into the mechanical characteristics of post-fire slender specimens is critical. At present, no relevant study on the axial performance of STCSRC slender columns after fire exposure has been reported. In this paper, nine circular STCSRC slender columns that had been exposed to fire were tested under axial load. The failure modes, axial load–displacement relationship, and lateral deflections of STCSRC columns were discussed. Furthermore, heat transfer analysis models and mechanical analysis models were established, and the effects of crucial variables on the buckling responses of STCSRC slender columns were explored. Among the parameters studied, sectional diameters and steel profile to concrete area ratio have a significant impact on buckling capacity. To calculate the buckling capacity of the post-fire STCSRC slender column, a simplified calculation method according to JGJ/T 471–2019 was proposed.

I-section stainless steel portal frames: Loading tests and numerical modelling

Austenitic stainless steel is an attractive structural material due to its high ductility, appropriate toughness, significant strain hardening and good fire resistance. Also the laser welding technology for fabrication of structural stainless steel profiles has recently become increasingly popular. However, there is still only a limited amount of experimental data on laser-welded stainless steel members. And loading tests of whole structures made of these sections have still not been published. Therefore, loading tests were performed on two austenitic stainless steel frames made of laser-welded I-sections. The frames had pinned columns and were loaded both vertically and horizontally. The objective of the loading tests was to capture the effects of material nonlinearity on the global sway behaviour of the stainless steel frames. In fact, material nonlinearity leads to a gradual loss of stiffness, which results in higher deformations and thus a higher second-order effect. The resulting load-displacement diagrams of the experiment are tabulated, allowing their further use. A numerical model of the studied frames was developed and validated on the basis of the performed experiments. Based on the elastic buckling load factor and the modified elastic buckling load factor, a large influence of material nonlinearity on second-order effect has been demonstrated.

Flexural behavior of composite ribbed slabs employing cold-formed steel lipped channels

By means of a series of full-scale laboratory tests, this research studied the flexural behavior of a composite ribbed slab employing cold-formed steel profiles as formwork before and after concrete casting. An experimental program was devised and separated in two sets of tests. The first set consisted of the execution of four-point bending tests on eight specimens to represent the system during construction, featuring three specimen types; isolated profile, profile with plastic spacers along the channel and a full assembly including the profile, the plastic spacers and a rebar truss. Displacement and strain as a function of load were measured and the data was used to analyze the influence of the different components on the flexural strength and stiffness of the system. On the second set of tests, three ribbed composite slab specimens featuring steel profiles were subjected to four-point bending. Displacement was registered along with strain on the concrete layer. A formulation to determine the flexural strength of the slabs based on Eurocode is presented and compared to experimental observations. The first phase indicates significant increases of flexural strength and stiffness by coupling a truss to the profile and varying the height of the former, namely a maximum increase of 708% in stiffness and 357% in strength. Isolated profiles and profiles with plastic spacers all failed by distortional buckling, while the full assembly specimens failed by instability of the top chord on the trusses. Second phase results show that the analytical prediction is adequate to determine the flexural strength of the prototype slabs, with approximately 95% accuracy for this sample size. All slab specimens failed by plastic hinge formation within the pure moment span. Furthermore, strain measurements on the concrete indicate that the formulae chosen to determine the effective width of the concrete “tee” section is also adequate.

Geometry optimization of steel formwork for steel–concrete composite slabs

The use of steel formwork incorporated into composite steel–concrete slabs stands out for contributing to sustainable development in civil construction. However, this construction system still has limited usage in Brazil, which may be due to the restricted availability of formwork geometries in the national market. As such, this study aims to determine the optimal steel geometry that results in the lowest steel consumption during manufacture of the composite slabs, taking into consideration the initial construction phase, in which the formwork is under the highest load demand. The Direct Strength Method (DSM) and the traditional Effective Width Method (EWM) are applied for designing the steel formwork during the construction phase, where the cold-formed steel profile resists the applied forces independently. For DSM, the critical buckling moments are determined using the elastic stability analysis program CUFSM, via Finite Strip Methods. The solution of the optimization problem was implemented in MATLAB® using Particle Swarm Optimization and considering two design variables: the thickness and the bend angle of the formwork web. In addition, the reliability of the proposed formulation was evaluated in the implementation phase of DSM and EWM. Numerical analyses are carried out on four different steel geometries currently available in the Brazilian market. The main results showed that the developed computational program was successful in finding optimal solutions for said geometries, as the optimization reduced steel consumption by an average of 21.6%. Thickness had a greater effect on the steel savings, and this variable decreases in the optimal solution, while the height and bend angle increase.

Evaluation of Project Budget Due to Price Fluctuations Based on Digital Technology in Factory Construction Projects

The development of industrial construction requires adequate resources to avoid the failure and risk of the project. The resources required are materials (building materials), human resources (human resources), machines (equipment), capital (money), methods (methods of implementation), timing, and information on the implementation of the construction. According to data from the Central Statistical Agency (BPS), wages of labor in Indonesia of Rs. 2.89 million increased by 1.12% by 2022. In addition, the price of construction materials has also increased, such as steel, steel bones, concrete, and other construction materials. Especially steel price increases, starting in the second year of the pandemic, have risen about 30%–40%. Generally, the construction of factory buildings uses more steel profiles for the construction of warehouses—storage of raw materials or warehousing of production sites. This has a huge impact on the project budget that has been estimated prior to material price fluctuations. Therefore, the re-evaluation of the project budget in PT. XYZ, which has been estimated by the company at Rp. 219.5 billion, has a total budget change to Rp. 276.1 billion.

Performance and strength analysis of shear walls with vertical steel encased profiles under tensile-shear load

This study investigates the behavior of composite steel reinforced concrete (SRC) walls under tension-shear (TS) coupled stress state during earthquakes. Quasi-static tests on five SRC shear walls with a shear span ratio of 1.42 were conducted. The experimental results demonstrated that the SRC shear wall retained its high shear capacity and good ductility in shear failure mode. The stiffness analysis revealed that the concrete provided most axial stiffness before cracking but gradually withdrew from the work as the cracks developed and extended rapidly in the tension loading phase. And the effective lateral stiffness was approximately 10%–15% of the elastic lateral stiffness. Parametric analysis was conducted on the shear capacity, including the axial tensile ratio, steel profiles content, concrete strength grade, and horizontal distributed bar diameter. Additionally, the predictive formulas for the shear capacity in the codes of various countries were compared. It was found that the European and American code inadequately predict the shear capacity of specimens, and the Chinese code has higher safety. These findings can provide references for the practical engineering applications of SRC shear walls in earthquake-prone regions.

Numerical analysis of the global stability of simply supported cellular steel columns under axial compression

The influence of geometry and materials on the instability of cellular columns has still not been clearly defined in the literature, research, and existing standards in the field. Studies on cellular profiles acting as beams can be found more frequently; however, studies are scarcer for these profiles acting as columns. Some authors have investigated the influence of physical and geometric imperfections on the strength of cellular profiles, while others have focused on the shear and bending effects that act simultaneously with compression in these profiles. The analytical procedures adopted in the main standards do not include calculation of geometric properties of the cellular profiles, which have their area reduced significantly, mainly in relation to the major axis, due to openings. In this context, a parametric study of 576 cellular columns was carried out using the ABAQUS software to investigate the behavior and resistance of these profiles in greater depth. The ultimate load results were compared and contrasted with the results of the standard procedures contained in EN 1993–1–1:2005 [1] and ABNT NBR 8800:2008 [2], using four different methods for calculating the geometric properties. It was concluded that the degree of influence of the diameter of the openings and the spacing between them decrease, along with the consideration of more slender columns.As for standard procedures based on EN 1993–1–1:2005 [1], the analytical method of surface weighting obtained the best results for S355 and S690 steel. Regarding ABNT NBR 8800:2008 [2], the “2T” section method obtained the best results for S355 steel and the line weighting method for S690 steel. However, the discrepancies among some results indicated the unpredictability involved in applying ABNT NBR 8800:2008 [2] for high-strength steel profiles. Therefore, the present study has attempted to provide a better understanding of the behavior of cellular columns, thereby contributing to the technical knowledge in the field.

Full-scale fire resistance tests of lightweight steel framed floor systems

As cold-formed steel profiles are increasingly used for load-bearing structural systems, their fire design requires specific attention due to their thin-walled nature and high slenderness. In some specific applications such as in storage hall floor systems, these structures are used without sheathing or thermal protection on the fire-exposed side. Yet, there is a lack of data from fire resistance tests on full-scale load-bearing thin-walled steel structures, especially with directly exposed steel. This article describes two standard fire resistance tests on full-scale light gauge steel frame floors made of cold-formed steel lipped channel girders and joists topped by chipboard panels. The experimental program was designed to investigate the fire resistance of the unprotected girders. A specificity of this program was that the girders were subjected to a low load level to probe the ability to achieve without passive fire protection a 30-min fire resistance rating typical for storage hall structures in the Czech Republic. The absence of protection resulted in differences in thermal gradients and bracing compared to common fire tests, as well as a very low degree of utilization leading to an expected failure temperature higher than 800 °C. The results showed that the two floors remained stable during the 30 min with limited deflections, but failed the deflection rate criteria after 24 and 22 min, respectively. Comparison is provided with the calculation methods from the Eurocodes. The presented results provide new data on the response of full-scale, unprotected cold-formed steel floor systems subjected to fire, which can be used to calibrate numerical models and fire design methods outside of the range currently covered by the codes.