Steel Construction Research Articles

Конструктивно-технологический аспект возведения сталежелезобетонного пролетного строения автодорожного моста через реку Ветлугу

Purpose: To consider structural and technological aspects of construction of steel reinforced concrete span of road bridge over the Vetluga River. To consider the issues of creating a computational model in the Midas Civil program complex with regard to the presented requirements to meet the requirements of GOST and SP. To give a detailed analysis of the stress-strain state of the model on the basis of calculation of the created model. Methods: Analysis of the design and allocation of the main parameters; comparison of the calculation models obtained taking into account the stage of concreting of the monolithic reinforced concrete slab of the roadway and without taking into account the stage of work. Results: The stress-strain state has been analyzed, and the structural and technological features of the erection of a road bridge over the Vetluga River have been considered. It is established that stresses in metal main girders increase significantly in comparison with the model that does not take into account the stages of erection. The combined operation of steel and reinforced concrete section starts only after the monolithic reinforced concrete slab of the roadway has gained strength. It is established that the development of cracks in concrete in the support zones caused by negative moments can be accounted for by reducing the elastic modulus of concrete in the support zones by 8 times. The change of stresses and strains in the structure by stages has been analyzed. The stresses and deformations arising in the structure during its erection are "inherited" from one stage to another when calculating by stages. Practical signifacance: The methods of creating a reliable calculation model of steel-reinforced concrete spans, reflecting the actual nature of the work of the structure both at the stage of construction and at the stage of operation, are shown. The methods described in the article can be recommended for creating a calculation model in the Midas Civil software package with consideration of the presented requirements to meet the requirements of GOST and SP, as well as to avoid accidents at all stages of the life cycle of the structure.

Development of a novel suction cylinder exploitation device for marine natural gas hydrate and the feasibility studies

Natural gas hydrate (NGH), a novel clean energy with enormous potential, has drawn the attention of many countries for research and development. In recent years, exploitation theories and technical capabilities have advanced quickly. However, commercial production, in terms of current exploitation equipment and tried tests, is still challenging to implement. In this paper, a novel suction cylinder exploitation device (SCED) was proposed based on marine NGH depressurization exploitation technology and suction anchor to replace conventional wellbore. The SCED is a prefabricated steel construction that enters the NGH reservoir by suction and gravity and has the potential to be recycled after exploitation. Through indoor experiments, the SCED penetration mechanisms and characteristics were investigated to confirm whether it can smoothly penetrate the NGH reservoir. Simultaneously, the gas production situation of the SCED was explored by CMG software. Results show that: (i) the super sizeable length-to-diameter ratio SCED model can complete the penetration from the experimental results. Although the “soil plug” height increases with the increase of the length-diameter ratio, it can be solved by taking appropriate methods for specific engineering; (ii) Due to the larger diameter and higher strength of the SCED, it can achieve greater pressure reduction and exploitation range, making the efficiency of gas production roughly 5.7–11.77 times greater than that of a conventional wellbore. In summary, it is anticipated that the SCED will open up new opportunities for the early commercial exploitation of marine NGH due to its advanced advantages of high equipment strength, big exploitation diameter, and easy construction.

Investigating seismic behaviour of cold-formed steel moment frames with the welded through-plate flexural connection

The Cold-Formed Steel (CFS) construction in seismic regions requires carefully selecting and designing an approved seismic-force resisting system. Among the available seismically-resistant structural systems, the bolted CFS moment frames have recently gained some attention. However, given the currently existing design issues associated with the bolted connections in CFS moment frames, this paper seeks to conduct a numerical investigation into the potential substitution of bolt fasteners with the weld materials in CFS frames. The objective is to explore the possibility of including the welded connection as an alternative to bolted connections in subsequent editions of the ASCE 7 code. To this end, finite element models, consisting of two built-up CFS beams and twenty-three flare-bevel-groove and fillet weld specimens, are initially validated against the cyclically and monotonically loaded tests with data available in the relevant literature. Subsequently, the verified weld and CFS beam models are incorporated in the simulation of thirty-four CFS beam-to-column welded moment connections, each differing in beam dimension, weld length and size, and gusset plate thickness. The built-up beams comprise back-to-back and lip-to-lip double C-section profiles. Stress variations along the weld lines, derived initially from nonlinear finite element analyses and then computed from the theoretical elastic analysis, are compared to establish a basis for categorizing stress distribution patterns in the longitudinal welds. Finally, six CFS frames assembled with the welded moment connection and subjected to a combined column axial compression and cyclic lateral drift are examined, resulting in an estimated seismic modification coefficient, R, equal to 3.8. Overall, the welded moment connections demonstrate a stable seismic response with an average ductility ratio, μ, of 2.7. The dominant failure mode is a locally developed ductile fracture in the two end segments of the longitudinal welds, identified as critical regions.

Numerical analysis of GFRP rebar embedded concrete beam

The use of glass fiber-reinforced polymer (GFRP) in construction has several sustainability benefits that make it an attractive alternative to traditional reinforcement materials. One of the main sustainability problems faced by steel is its carbon footprint, 1.89 tonnes of CO2 is being released into the atmosphere for every tonne of steel produced. Another wellknown problem faced by steel in construction is corrosion which is the leading cause of failure of a building. the use of GFRP in construction offers several sustainability benefits that make it an attractive alternative for use in a variety of applications. The combination of improved performance, reduced waste, and lower carbon footprint make GFRP a sustainable choice for the construction industry. This paper presents a numerical analysis of a concrete beam reinforced with glass fiber-reinforced polymer (GFRP) rebar. The study aims to investigate the mechanical behaviours and performance of concrete beams embedded with GFRP rebar under 2-point loading conditions. Ansys 2023 software was utilised for the modelling and analysis of the developed model. Two models were created in the Ansys workbench, one with GFRP rebar as reinforcement and other with steel rebar reinforcement. The numerical results were then analysed to determine the load-carrying capacity and deformation behaviours of the GFRP-reinforced concrete beams compared to that of regular steel reinforced beam.

Achieving sustainable built-environment using bamboo composite frame system with cow-dung masonry infills

In today's rapidly urbanizing world, there is dire need for adopting the principles of green/ sustainable built-environment so as to mitigate the ill effects of environmental degradation and climate change. However, demand for housing is on rise in developing countries like India, where sizeable population, especially the low-income strata, still lacks decent quality structurally safe housing. Extensive use of concrete and steel in construction over more than a century has led to detrimental environmental effects such uncontrolled release of greenhouse gases/ pollutants, deforestation and erosion, leading to now visible outcomes of climate change. Bamboo, on other hand provides a sustainable alternative to concrete and steel as a building material since it absorbs the atmospheric carbon dioxide, produces more oxygen than timber producing trees and is a lightweight and renewable building material. Unlike timber, it matures in four to five years and being grass family, is replenishable in nature. However, from structural point of view, the main drawback of bamboo culm is its large slenderness ratio, which renders it weak in resisting bending and compressive loads. This paper presents an alternate structural system utilizing fibre reinforced bamboo composite (FRBC) to overcome the structural deficiency of a single shoot bamboo and build a prototype structure after detailed laboratory evaluation and structural analysis. Structural elements made from FRBC are utilized for fabricating a prototype 3D frame structure, measuring about 24 m2 in plan, representing a modular unit amenable to horizontal and vertical expansion. Eco-friendly materials like cow-dung based bricks and mortar, which offer net zero additional carbon dioxide emissions and circumvent reliance on cement and river sand, have been utilized as masonry infills after structural evaluation. The built structure provides a proof-of-concept demonstration of the feasibility of using bamboo and cow-dung, sustainable building materials, for achieving a structurally safe built-environment. The technology is especially suitable for countries like India which are endowed with tropical climatic conditions. By adopting such environmentally friendly alternatives, the construction industry can create a healthier environment while addressing housing and infrastructure needs in sustainable manner.

Agency, co-creation and environmental advocacy in lens-based practice.

Tahāroa is a tiny settlement to the South-West of the Kawhia harbor, in the North Island of Aotearoa-New Zealand. N.Z Steel first brokered an agreement with local tribe Ngāti Mahuta ki-te-Hauāuru in the 1970’s to extract the titanomagnetite from the sands and ship it offshore for use in the construction of steel. This film asks what prolonged mineral extraction and the re-introduction of that material into the global manufacturing chain might mean for the mauri (or spirit) of the land, and for our planetary relationships.

Welding of P355NH steel for the construction of a medium-pressure gas pipeline

AbstractThere is an increasing demand for welding of steel pipes meant for pressure purposes. P355NH (1.0473) steel became an important construction material used for structuring and restructuring of a medium-pressure gas pipeline due to its properties, such as significant tensile strength at the level of 600 MPa and increased yield point. These properties ensure appropriate service life of the principal pipeline structures. When welding P355NH steel, processes that enable high-quality welds without significant changes in the chemical composition of the base material, are applied. It is recommended to use the TIG welding process to produce joints, although P355NH steel joints are considered as difficult to weld. During welding, various welding defects might appear, which mainly include sticking and lack of fusion. Creation of joints with the desired properties, including those used in the construction of medium pressure gas pipelines, with the required class B quality, requires selection of appropriate parameters and compliance with the welding process practice. This is very important for the service life of the structure. Therefore, the article aims to select the most appropriate parameters and thermodynamic conditions for welding P355NH steel in order to obtain the best mechanical properties. The most important of the tested welding parameters of P355NH steel is welding speed, welding current, preheating temperature, interpass temperature and, above all, the role of various shielding gases. (Three different shielding gases containing argon and helium additives were tested.) The obtained joints were tested by: non-destructive tests, such as VT—visual examination; MT—magnetic particle testing, PT—penetration tests, UT—ultrasonic testing and by the destructive methods, such as tensile strength, impact toughness, bending test, light microscopy and scanning electron microscopy. The cause-and-effect relationships between the obtained joint structure and its mechanical properties were determined. The considerations were supported by the nucleation model and the mechanisms of formation of the acicular ferrite phase in the joint material. The chosen parameters of TIG process allow to obtain joint with adequate strength for the production of the gases pipeline, without welding defects. The results have a practical implication, the developed production technology for the obtaining the joints. The presented solution gives the possibility of producing correct welded joints, which can be used in the responsible steel construction. The originality of manuscript is the presentation the newly, uncomplicated solution of obtaining joint with good mechanical properties included the thin-walled tubular structure with a thickness of 3.6 mm. A novelty in the article is a clear indication of the importance of detailed thermodynamic welding conditions and obtained weld structure on the mechanical properties of the P355NH steel joint, which lead to the formation of various non-metallic titanium inclusions, which have a decisive impact on the mechanical properties of the joint, especially its strength and impact strength.

Customary light-gauge steel framing construction with flat strap bracing: seismicity limits for low to mid-rise buildings in Europe

AbstractOrdinary (customary) light gauge steel framing is a convenient construction technology; however, given the studs low axial capacity, it has been considered mainly for low-rise buildings in low seismicity regions. This paper investigates the boundaries of application of this type of steel framing (in moderate and high seismicity areas) by designing the structures of three representative 5, 7 and 10-storey buildings in order to examine their feasibility. The necessity of using built-up columns consisting of two or more sections is investigated. The axial capacity of studs is estimated by code-type analyses. The critical buckling stress is determined with well-known closed-form expressions; as they do not contemplate the flexibility of the screwed connections (in built-up sections), the obtained results are complemented with those of the finite strip method and generalized beam theory formulations.

The Application Research of BIM Technology in the Construction Process of Yancheng Nanyang Airport

The application of BIM technology in building construction provides the possibility to realize design accuracy, to visualize the construction details, to optimize construction schemes, and to enhance cooperation among various professionals. The Yancheng Nanyang Airport terminal 2 project, with its large span of steel roof structure, complex installation in mechanical and electrical pipeline (MEP) engineering, and difficulty in construction organization, is taken as the engineering background. The whole process application of BIM technology in the construction process is introduced. In structural engineering construction, the application of BIM technology can provide guidance for plane layout of the construction site, and can also assist in deepening the designs of irregular steel components. In steel construction, the application of BIM technology gives a commendable visual demonstration of the construction process of the metal roof system and the single-layer reticulated shell. In MEP engineering, the application of BIM technology provides a great approach to establish a synthesis of pipeline drawings to further form pipeline section diagrams and operation drawings. By integrating the dimension of time, precision control, and deviation rectification, a recursive construction drawing can be built. With respect to synergistic management, the quality and safety management in the construction site can be implemented on the basis of BIM terminal equipment as well. This paper will give a great reference on the application of BIM technology in the airport terminal construction.

Shear Testing of Topologically Optimised Web Cover Plates in Splice Connections-Experiment Design and Results.

Testing shear-resisting plates in steel connections is one of the most challenging laboratory undertakings in steel construction, as the most common experimental layout design includes simulating the connection with its adjoining members. This significant hindrance gained particular magnitude as the need to test prototypes of topologically optimised shear cover plates became more pressing. Indeed, new code-compliant topology optimisation approaches for steel construction have recently been offered, and physically non-linear analyses have been demonstrated to be vital for assessing these elements. Hence, a rapid and reliable experimental process has become a fundamental necessity. To answer this need, a novel layout is herein proposed, in which topologically optimised and previously numerically examined bolted shear plates of a well-known steel joint were tested. The results allowed for the definition of the material trilinear model for use in subsequent numerical analysis, as well as the validation of the numerical simulation results. The discrepancy between the previously mathematically anticipated and empirically determined ultimate resistance did not exceed 1.7%.

Lateral torsional buckling of unsymmetric beams by FEM with linear elements

As the exact solution of lateral torsional buckling of elastic prismatic beams is practically limited to the simple case of simply supported beams under equal end moments, other loading conditions and boundary conditions require more practical solutions to the problem. As the general solution of lateral torsional buckling of unsymmetric beams is a function of the sign of the bending moment along the axis of the beam, i.e. location of the shear center concerning the compression zone of the cross section, application of the current traditional empirical expressions such as coefficient of the moment, Cb, becomes highly inconsistent and unwarranted to capture the correct critical moment as acknowledged by the American Institute of Steel Construction, AISC. The finite element method, FEM, offers a feasible alternative to overcome these shortcomings. FEM is formulated in its simplest form of linear elements for the general case of lateral torsional buckling of unsymmetric cross sections. Finite element development shows that the characteristic equation is of the nonlinear quadratic eigenvalue problem type. Using the classical polynomial shape functions for beams, FEM proves to be extremely accurate and can overcome the high inconsistencies and discrepancies embedded in the application of the classical methods.

Connecting performance evaluation of the Quick-Connector for modular steel construction

This study presents the Quick-Connector, a new self-fastening joint system designed specifically for modular steel construction. By eliminating the need for a dedicated workspace during the connection process, the Quick-Connector minimizes disruptions to finishing work. A comprehensive set of tests, including pull-out, shear, and cyclic tests, was conducted on a full-scale prototype to evaluate its structural performance. The experimental results demonstrate that the Quick-Connector exhibits exceptional connecting performance, meeting the shear and tensile strength requirements for high-tension bolts. The seismic performance of the Quick-Connector was also evaluated through cyclic testing, highlighting its potential as a viable replacement for high-tensile bolts. Furthermore, a push-over analysis was carried out to develop an elastic structural design model specifically for buildings incorporating the Quick-Connector. The analysis results closely aligned with the experimental findings, validating the accuracy of the proposed model. Overall, the Quick-Connector offers a promising alternative to traditional bolted connections in modular construction, with the potential to enhance construction efficiency, quality, and safety.

Research on the application of prefabricated green steel structure in public buildings

The construction industry is a pillar industry to improve people's quality of life and promote social and economic development. It has the characteristics of high energy consumption and high pollution, which deviates from the requirements of green development advocated by people at present. In view of healthy long-term development, the building industry needs to take effective measures to reduce energy use. The components used in prefabricated steel construction projects are mainly processed in factory batches. After transportation to the construction site, they only need to be assembled in accordance with standard specifications and processes, which can shorten the construction period, reduce the generation of construction waste, and fully meet the development requirements of energy conservation and emission reduction. Therefore, prefabricated green steel structure has been widely used in the construction of modern public buildings. Firstly, this paper summarizes and analyses the development status and main types of prefabricated green steel structure. The practical application in public building construction is also discussed. It is hoped that the results can provide a valuable reference for the construction of similar projects.

Design method for determining appropriate stiffness for end point braces

The high dependence of end point braces on rotational restraint conditions differentiates them from intermediate point braces. Although the point brace stiffness equation of the American Institute of Steel Construction (AISC) design specifications applies to both braces, it restricts the stiffness to only the buckling load based on the unbraced length and an effective length factor of 1, which is too conservative for end point braces. This study investigated the relationship between end point brace stiffness and column buckling loads through buckling analyses using slope–deflection equations with stability functions, considering diverse supports, end rotation constraints, and column counts. Irrespective of the column count, the columns with end point braces exhibited a non-sway elastic buckling load of up to four times the Euler buckling load depending on the rotational restraint at the column ends. The proposed procedure enhances the AISC regulations by introducing a new equation that allows up to 90% utilization of the buckling load based on the unbraced length and an effective length factor of 1 or less, considering column end rotational constraints. The procedure was applied to six frames undergoing elastic or inelastic buckling and validated by assessing the buckling loads and related point brace stiffness. The proposed procedure significantly enlarged the load-bearing capacity of the column compared with the AISC design procedure, although both approaches obtained comparable point brace cross-sectional areas. It extends the buckling load limit for columns or frames with an end point brace, providing predictive insights into brace stiffness to improve structural design.

Content: Steel Construction 4/2023

Content: Steel Construction 4/2023

Cover Picture: Steel Construction 4/2023

AbstractOver the last couple of years, several research projects have developed systems which allow for the design of demountable composite structural elements. A pilot project, ‘la Petite Maison’, has been designed and built next to the University of Luxembourg in Belval, Luxembourg. Source: Dragos Ghioca © at Uni.Lu. (s. paper Charlier, M.; Vassart, O., p. 209)

Experimental investigation on seismic performance of cold-formed steel strap-braced stud walls under lateral cyclic and vertical loading

Cold-formed steel (CFS) construction offers several benefits over traditional construction, including being lightweight, sustainable, recyclable, quick to build, insect and rot-resistant, and suitable for computer-aided design and manufacture. Despite extensive research on CFS elements, there are still gaps in our understanding of the behaviour of CFS structural systems, particularly their response to severe earthquake events. This experimental program aims to provide a better understanding on the seismic behaviour of strap-braced stud-walls as a lateral force resisting system for residential medium-rise buildings. An innovative test rig is developed that is capable of applying a constant vertical load during lateral cyclic testing, replicating the loading conditions expected during an earthquake event in such cases. For the first time, seven full-scale tests are conducted on CFS walls under vertical and horizontal loading using standard sections in New Zealand. The vertical capacity, lateral stiffness, ultimate strength, ductility, and failure mechanisms of the specimens are investigated. Subsequently, a modified detailing is suggested, which allows CFS walls to exhibit considerably better seismic behaviour compared to the systems with conventional detailing. It is shown that by adopting the modified detailing, CFS walls exhibit an ideal elastic-plastic curve with negligible degradation in successive cycles and a high ductility factor exceeding 5. The results of this study should prove useful for more efficient design of CFS strap-braced stud walls for mid-rise buildings.

Analisis Faktor Produktivitas Kerja Menggunakan Smart PLS pada Industri Konstruksi Baja

Changes in work patterns after the COVID-19 pandemic have an impact on CV's daily productivity. Superior Jaya. Companies engaged in steel construction have decreased work productivity which has resulted in a decrease in company performance. This study aims to determine the relationship between work motivation, occupational health and job satisfaction on work productivity and to determine the relationship between work productivity and employee welfare. This research was conducted with a quantitative descriptive approach using Smart Pls software for SEM modeling. The results of this study found that there is a significant influence between occupational health on work productivity and there is a significant influence between work motivation on work productivity. Then there is no effect of job satisfaction on work productivity and work productivity does not have a significant effect on employee welfare. Efforts to increase work productivity can be done by improving the ergonomics of the workspace, striving for a balance between salary and workload, and increasing employee job satisfaction by providing bonuses. This research can provide efforts to improve the work environment to be more productive and also scientific confirmation of the relationship between occupational health, work motivation, and work productivity in the context of the steel construction industry.

The Effects of Corrosion and Fire Damage on the Steel-Bolted T-Section Connections Used in the Steel Construction.

The most common type of connection in steel structures is the T-section connection. Steel structures can be damaged due to environmental effects such as earthquakes, fires, corrosion, etc., in real applications used in industry. Therefore, in this study, the corrosion and fire condition effects that occur in the T-section connection on the behavior of the connection zone were investigated. The study was carried out with 18 T-section connections with various corrosion (hydrochloric acid and sulfuric acid) in different layers at 5, 10, 15, and 20% corrosion levels, and fire (ISO834) conditions after corrosion have been evaluated and compared. T-section-bolted joints examined in the study were produced using IPE300 standard profiles. In the first part of the study, the behavior of the 18 T-section connections under an axial tensile load has been determined experimentally. The second part created a finite element model with the ABAQUS program for all models. It was seen that the finite element model analysis results converged with the results obtained as a result of the experimental study. As a result, compared to H2SO4 corrosion, HCl corrosion has little effect on the load-deformation characteristics of the connections. Also, if corrosion specimens are exposed to fire, then the connections will change from semirigid to hinged.

Effect of loading rate on mechanical properties of autoclaved aerated concrete having steel wool fibres, construction waste and alkaline solution by employing accelerated curing

This paper introduces a new method for developing Autoclaved Aerated Concrete (AAC) blocks, investigating the impact of different loading rates on compressive strength and failure behaviour. Alkaline solution and accelerated curing tank curing were explored as alternatives to conventional methods using aluminium powder and autoclave curing with fly ash. Construction and demolition waste was used as a substitute for fly ash, and chopped steel wool fibres were added to enhance block strength. The blocks were tested under various loading rates, and stress–strain graphs were generated to calculate Young’s modulus of elasticity values. ANSYS software was used for simulation and comparison, validating the accuracy of analytical models. The study shows a correlation between experimental and simulated values, confirming the successful incorporation of CDW and CSWF in AAC block development. Increasing the loading rate during testing leads to lower measured Young’s modulus, indicating strain rate dependency. However, including CSWF enhances Young’s modulus by redistributing stress and restraining crack propagation. The research contributes to understanding AAC's mechanical properties and performance, supporting its potential as a sustainable alternative for masonry materials in structural applications.