Steel Structures Research Articles

Influence of Soil Structure Interaction on Seismic Performance of Steel Structure Interaction with Different Types of Foundations and Soil

Influence of Soil Structure Interaction on Seismic Performance of Steel Structure Interaction with Different Types of Foundations and Soil

An Analytical Model for the Initial Stiffness of Bearing Connections with Slotted Holes

In steel structures, cover plate joints are mainly used with normal round holes, but slotted holes, where the slot is oriented perpendicular to the direction of the bearing force, make it possible to release displacements in selected directions and thus better control the complex state of stresses in the connected plates. This study investigates the initial stiffness of a cover plate with a single slotted hole. The aim of this paper is to propose an analytical model that predicts the initial stiffness of slotted holes with respect to experimental results obtained on a panel of different geometries. This approach makes it possible to evaluate the effects of the end distances on the bending of the plate compared to the bearing under the bolt. A large panel of geometries is tested to quantify the experimental value of initial stiffness using Digital Image Correlation (DIC) technique compared to Linear Variable Differential Transformer (LVDT) sensors. To evaluate the initial stiffness, a method of processing experimental data is developed that allows a reproducible determination of stiffnesses. An analytical model is then proposed based on the improvement of existing models available in the literature. It is validated for different specimen geometries considering the contribution to the initial stiffness due to bending, shearing and support of the steel plate under the bolt. The comparisons show that the proposed analytical model can predict the initial stiffness of different geometries of tested specimens with slotted holes.

Finite Element Analysis and Weight Optimization of Knuckle joint for different Materials by using CAE Tools

The current study involved the analysis of a knuckle joint using finite elements. A mechanical joint with two intersecting cylindrical rods whose axes are in the same plane is called a knuckle joint. Knuckle joint should be designed and manufactured in such a way that it can sustain more load without failure. The objective of the present study is to study knuckle joints made of different materials like aluminum, stainless steel, structural steel, magnesium, and gray cast iron using CAE tools. The CAD model of knuckle joint is made in CATIA V5 R20. The finite element analysis of this CAD model using ANSYS 15 has been carried out to investigate maximum stress and deformation. The CAE results compared with the analytical results using conventional approach. The CAE results have been found close to the analytical results, thus validating the model. The knuckle joint of aluminum is found to have highest factor of safety (1.641) at 50 KN load and is the most the most suitable material for knuckle joint. Weight of vehicle plays an important role in overall performance and fuel efficiency of vehicle. Knuckle joint is a part of vehicle. Hence weight optimization of knuckle joint made of aluminum has been performed using ANSYS 15 and it is observed that weight of knuckle joint made of aluminum can be reduced by 5.08% for 50 KN loading condition. Key Words: Knuckle joint, Finite element analysis, Mechanical joint, Load-bearing capacity, Material selection, CAE tools, Deformation analysis etc.

Study on the Anti-Progressive Collapse Behavior of Steel Frame Structures under Close-Range Blast Loading

The steel frame structure plays an important role in strategic deployments and is widely used in heavy machinery, metallurgy, military, and other important industries. To study the impact of explosive loads on the anti-progressive collapse performance of steel structures, this paper proposes to establish the vulnerability characteristics of steel frame structures and provides a method for calculating vulnerability characterization indicators. A finite element model is used to analyze the dynamic response of steel frame structures under the action of close-range explosive loads, and factors influencing the anti-progressive collapse of steel frame structures are proposed, including the number of stories and diagonal bracing. A comparison is made between the various column types of steel structures under explosive loads, such as corner columns, long-edge middle columns, short-edge middle columns, inner columns, also in various coupling conditions. The results show that the progressive collapse of steel frame structures is greatly influenced by the position of the explosion and less affected by the amount of explosive material. The simultaneous failure of corner columns and long-edge middle columns is more likely to cause overall structural failure. The addition of diagonal bracing significantly improves the anti-progressive collapse ability and prevents the lateral displacement of steel frame structures; increasing the number of stories provides more alternative load transfer paths for steel frame structures, thereby preventing their collapse.

Life cycle cost analysis comparison between structural steel and light gauge steel structures

Life cycle cost analysis comparison between structural steel and light gauge steel structures

Revealing the mechanism of crack initiation and propagation in CGHAZ of S690QL welded joints through low-temperature impact tests with gradient setting of pendulum angle

As the most brittle areas of welded S690QL high-strength steel structures, coarse-grained heat-affected zone (CGHAZ) was crucial for the structural integrity of components. This paper designed an innovative low-temperature impact testing method with a gradient setting of pendulum angle to investigate the micro-mechanism of crack initiation and propagation in the CGHAZ of S690QL welded joints. The results reveal that continuous blocky M−A constituents were distributed along prior austenite grain boundaries (PAGBs), leading to stress concentration and crack initiation. During low-temperature impact processes, cracks propagate in a transgranular mode along {100} or {110} crystal planes. Due to the interaction between compressive stress and the crack tip, regions with high kernel average misorientation (KAM) such as PAGBs can divert the crack. The coarsening of prior austenite grains in the CGHAZ leads to a diminished hindering effect of PAGBs on crack propagation. The findings elucidate the complex relationship between microstructure and impact toughness of CGHAZ, providing insights into crack behavior and mechanisms in CGHAZ.

Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding

Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.

Strain rate-temperature effects and constitutive models for Q690D QT steel

This paper investigates the mechanical properties of the high-strength structural steel Q690D QT (Quenched and Tempered) over a wide temperature range and a wide strain rate range. Firstly, a series of quasi-static and dynamic tests adopting the universal testing machine and Split Hopkinson Pressure Bar were carried out to investigate the mechanical properties at strain rates from 0.00025 s−1 to 5000 s−1 and temperatures from room temperature (20 °C) to 700 °C. Stress-strain curves and dynamic yield strength increase factors were extracted and investigated. Test results show that Q690D QT exhibits different strain rate effects at different temperatures, more significant at the temperatures of 600 and 700 °C, as well as the high-temperature softening effect. Dynamic strain aging effect is identified at temperatures between 300 − 600 °C for plastic strain rates of 800 s−1 and 2300 s−1, nevertheless, this effect is observed at a higher temperature range of 500–700 °C for higher plastic strain rates of 4000 s−1 and 6400 s−1. From the analysis, the adiabatic thermosoftening effect cannot be ignored when the plastic strain rates reach 4000 s−1. Finally, an improved form of the Johnson-Cook model is proposed for capturing the adiabatic temperature effects at different temperatures and validated by the test data. A parameter dynamic temperature factor is proposed to describe the comprehensive effect of strain rate, test temperature, and adiabatic thermosoftening.

Effect of U-Shaped Metallic Dampers on the Seismic Performance of Steel Structures based on Endurance-Time Analysis

Seismic performance of steel moment-resisting frames is investigated through the incorporation of U-shaped metallic dampers. The primary objective is to assess the effectiveness of these dampers in mitigating seismic responses by utilizing various analysis techniques. Two representative structural configurations (5 and 10-story) are studied in both damped and undamped states to reveal the impact of dampers on seismic response reduction. The study utilizes the endurance time analysis (ETA) method, known for its efficiency in evaluating structural seismic performance. To validate the analysis results, a benchmark comparison is made through nonlinear time history analysis (NTHA). Incremental dynamic analysis (IDA) is also conducted to assess structures’ intensity measures with respect to their damage intensity index. The findings demonstrate that U-shaped metallic dampers substantially reduce inter-story drift and story shear forces. Importantly, a close alignment between the results obtained from ETA and NTHA underscores the reliability of the former in assessing seismic performance with supplemental damping devices.

ADJUSTABLE NITROOXIDATION TECHNOLOGY FOR LOW ALLOY STEEL

The article discusses the production of a surface diffusion nitride-oxide layer on low-alloy structural steel with specified structures and properties. To develop a controlled technology for nitro-oxidation of low-alloy carbon steel, the dependences of the composition and structure of the nitrided and oxide layer on the chemical composition of the steel and the technological parameters of the process were studied. Technical iron was used as a model alloy and samples of industrial steel grades 40X, P6M5 and steel 45 were processed. Saturation temperatures were studied in the ranges above and below the eutectoid temperature for the “Fe-N” system and, accordingly, for the “Fe-O” system and it was found that the best structures are at saturation temperatures below the eutectoid

Finite Element Analysis and weight Optimization of Knuckle joint for different materials by using CAE Tools

The current study involved the analysis of a knuckle joint using finite elements. A mechanical joint with two intersecting cylindrical rods whose axes are in the same plane is called a knuckle joint. Knuckle joint should be designed and manufactured in such a way that it can sustain more load without failure. The objective of the present study is to study knuckle joints made of different materials like aluminum, stainless steel, structural steel, magnesium, and gray cast iron using CAE tools. The CAD model of knuckle joint is made in CATIA V5 R20. The finite element analysis of this CAD model using ANSYS 15 has been carried out to investigate maximum stress and deformation. The CAE results compared with the analytical results using conventional approach. The CAE results have been found close to the analytical results, thus validating the model. The knuckle joint of aluminum is found to have highest factor of safety (1.641) at 50 KN load and is the most the most suitable material for knuckle joint. Weight of vehicle plays an important role in overall performance and fuel efficiency of vehicle. Knuckle joint is a part of vehicle. Hence weight optimization of knuckle joint made of aluminum has been performed using ANSYS 15 and it is observed that weight of knuckle joint made of aluminum can be reduced by 5.08% for 50 KN loading condition. Key Words: Knuckle joint, Finite element analysis, Mechanical joint, Load-bearing capacity, Material selection, CAE tools, Deformation analysis etc.

Nanosilica from canary seed husk for corrosion protection of structural steel

AbstractAn alternative technique is presented for the corrosion protection of the A36 structural steel (A36SS) in acid medium (H2SO4) using silica obtained from canary seed husk (CSH). The silica was obtained in a solid amorphous state with a particle size of 10–22 nm. The anticorrosive properties of nanosilica (NS) were studied using potentiodynamic polarization (PDP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS). Before carrying out the corrosion tests, the A36SS was subjected to a treatment with NaOH solution without and with the presence of NS. The A36SS treated with NS presented the lowest current density values and the noblest corrosion potential values, indicating that the corrosion rate decreased. The surface morphological study of the tested systems using SEM/EDS showed that the NS‐treated A36SS had a more efficient physical barrier against corrosive species.

Innovative Brace Damper System for Mitigating Seismic Response in High-Rise Steel Structures

This study investigates the seismic response of a G+14 steel frame building with composite columns using fluid viscous dampers. The effectiveness of these dampers is assessed through analysis employing the Equivalent Static Method, Response Spectrum Method, and Time History Analysis in ETABS. Results indicate a significant 40–60% reduction in displacement and storey drift, underscoring the efficacy of fluid viscous dampers in enhancing structural resilience. This research underscores the importance of innovative damping systems in mitigating seismic risks in tall steel buildings.

Study on mechanical properties and bearing capacity calculation of eccentric compression of RC columns reinforced with prestressed lattice steel

The external steel structure and RC column under eccentric compression have a reduced ability to work together, and using prestressing technology can significantly improve their ability to work together. Therefore, the paper proposes a new prestressed column reinforcement technology by adopting a space profile steel structure instead of angle steel and combining prestressing technology with the bolted connection. By conducting eccentric compression test studies on 11 specimens with different reinforcement methods, prestressing and eccentricity, load-displacement curves, stress distribution laws, ultimate bearing capacity, damage modes and prestressing influence rules were obtained. The main conclusions are as follows: prestressing can significantly improve the ability of external reinforcement steel structure and core column to work together and inhibit the development of concrete cracks. Compared with the traditional angle steel reinforcement, the bearing capacity is increased by 17.5 %, the stiffness is increased by 26.6 %, and the ductility is increased by 12.3 %. However, the reinforcement effect will be reduced if the prestressing is too large. It is recommended that the prestressing should be applied according to the size of 0.09 fc of the unilateral area of the core column. According to the prestressed lattice steel constraint mechanism, a mechanical analysis model of the reinforced member was established. Finally, based on the cross-section equilibrium method, a calculation method of eccentric compressive ultimate bearing capacity was proposed, and the research results can provide a basis for the engineering application of the new reinforcement method.

Cost optimization of tall buildings having tube composite columns using social spider algorithm

SummaryThis study aims to develop an algorithmic approach to obtain optimum designs for tall buildings having composite columns and investigate the material cost advantages of these buildings over steel structures. The social spider optimization (SSO) algorithm, a new meta‐heuristic optimization method that has shown promising results in optimizing frame structures, was used to obtain the optimum designs. Concrete‐filled steel tube sections were chosen for composite columns. To define the optimization problem, we considered the material cost of the structure as the objective function, the size of columns (strength, deflection, drift, and geometric limitations) as the constraint functions, and ready steel sections as the design variables. We tested eight different frame structures of varying heights and irregularities to analyze how cost varied according to these parameters. Our results demonstrate that composite columns are a more cost‐effective option than steel structures, even for buildings that are not considered high rises. We found that the difference in cost between the two types of structures increases with building height and irregularity. Additionally, our optimization algorithm was unable to find feasible designs for steel structures taller than 180 m using ready steel profiles.

Detailed Design of Special-Shaped Steel Structures Based on DfMA: The BIM-FEM Model Conversion Method

(1) This paper, based on the characteristics of complex steel structures as well as difficult points in the process of their detailed design, introduces the product design concept of DfMA (Design for Manufacturing and Assembly) from the manufacturing industry and studies the detailed design method of BIM-FEM model conversion. The BIM software Revit (2020) is used as the basis for the BIM detailed design of the project, which achieves the purpose of rapid modeling and provides a detailed design model basis for finite element analysis. (2) Utilizing the Revit API and C# for secondary development as the technical means, this approach involves converting the geometric entity model described by CSG-Brep into an APDL stream. This creates an interface with the finite element analysis software ANSYS (12.0) to implement the detailed design of BIM-FEM model conversion, optimizing the algorithm for converting complex analysis models that require high precision for special-shaped steel structures. (3) This research addresses issues such as the disconnection between the design, manufacturing, and construction of special-shaped steel structures, providing support for design decisions. Moreover, it enhances the detailed design method by improving the standardization of special-shaped components under the condition of design diversity. (4) These studies provide sustainability for engineering design, manufacturing, and construction projects, enabling the maximization of benefits and product lifecycle management (PLM) through these projects. (5) Finally, a case study analysis was conducted on the Wuhan City New Generation Weather Radar Construction Project, designed by the Central South Architectural Design Institute (CSADI), to verify the detailed design of BIM-FEM model conversion. This proved the scientific validity, practicality, and necessity of this research.

Improved pass-through dimensionality reduction for point cloud contour extraction

Obtaining a point cloud model that considers the overall information of large steel components as well as the local information of bolt holes is an important approach for the virtual assembly of large steel structures. A point cloud extraction method to improve the uniformity of the dimensionality reduction distribution is presented. Firstly, point cloud data characterising the overall information of a large-size component and local information of the bolt-hole group are obtained by combining vertical three-dimensional (3D) laser scanning and handheld 3D laser scanning. The point cloud is then triaxially equidistant and reduced in dimension based on improved straight-pass filtering and the corner point cloud is extracted using a planar point cloud distribution uniformity algorithm. Finally, the point cloud is restored to the same space to complete the contour extraction of the point cloud. The accuracy of the contour extraction method was verified by conducting point cloud feature extraction tests using standard components. Compared with conventional feature extraction, the method provides targeted local feature extraction for bars with a certain regularity of geometric configuration, reducing the time required for feature extraction and providing a brief database for the virtual assembly of steel joist beams.

Resilience-based seismic design and cyclic behavior of assembled joints between self-compacting concrete-filled rectangular steel tube frame columns and H-shaped steel beams

The overall stability of prefabricated steel structures depends significantly on the strong seismic resilience exhibited by the connections between beams and columns. This paper introduces a novel beam–column connection approach, referred to as the welded upper and lower flanges and two diagonal web plates (WULF-TDWP). Unlike conventional methods, this approach replaces bolted connections with butt-welded joints between steel beams and employs short cantilever beams to achieve plastic hinge displacement. The steel-column cross-section was designed with a larger aspect ratio to better absorb and distribute energy. Six full-scale specimens were subjected to cyclic loading tests to investigate the seismic performance of the WULF-TDWP system. The main test parameters included the axial load ratio, welding configuration in the node region, and presence of reinforcement plates. The specimens exhibited two distinct failure modes: plate buckling deformation and beam–column end weld tearing. The experimental results included the hysteresis curves, skeleton curves, ductility coefficients, stiffness degradation curves, and strength degradation curves of the specimens. The experimental findings highlighted the favorable hysteresis performance, load-carrying capacity, and deformation capacity of all the nodes. Additionally, the plastic hinges were observed to shift, thereby delaying the premature failure of the node region. Notably, the omission of welding between the cantilever short beam flange and steel column significantly reduced the initial stiffness of the node. Through finite element analysis, the seismic performance of the beam-column joints with upper and lower flange welded connections and cantilever short beams was elucidated. The reliability of the finite element model for assessing the seismic performance of the nodes was confirmed through validation using experimental findings. Furthermore, this paper categorizes the nodes and introduces a simplified calculation model based on the moment–rotation method.

Experimental and numerical investigations of seismic performance of stepped beam-column joints with different connection forms

The seismic resilience of prefabricated steel structures significantly depends on the design and construction of beam-column joints. To address the challenges related to the installation of prefabricated wall panels and overall system assembly, this study introduces a novel stepped beam-column joint. The effectiveness of different connection configurations on the seismic behavior of the joints was investigated. A series of cyclic tests were conducted on four joint specimens with different configurations, and their failure mechanisms, hysteretic curves, skeleton curves, stiffness degradation, load-bearing capacity, and energy dissipation capacity, were revealed. The experimental results showed that the stepped joint configuration offers favourable seismic performance, with notable asymmetry observed in the response patterns under positive and negative loading directions. Reducing the height of the stepped segment or the thickness of the end plate adversely affected the seismic performance, leading to early bolt failure. Consequently, a detailed finite element model of the stepped joint was developed and the model demonstrated satisfactory agreement with the experimental results. Furthermore, a parametric analysis focusing on variations in stepped segment's height was conducted, providing insights into optimization of the load-bearing capacity of the stepped joint. The difference in the performance between the stepped joints and traditional flush end plate joints is also highlighted.

Imperfections for the calculation of steel structures by the finite element method. Part 1

It is well known that imperfections are always present in structural elements. Imperfections can significantly affect the behavior and bearing capacity of steel structures, especially in the case of stability-related tasks. Therefore, inconsistencies must be taken into account in the loadbearing capacity model and their correct application (setting the shape and value) is a key point in the numerical analysis process. In recent decades, much attention has been paid in the domestic scientific space to updating imperfection models for use in numerical models, including taking into account modern more accurate manufacturing and installation technologies for steel structures. The purpose of this study is an analytical review and analysis of scientific research and technical literature, followed by synthesis and elaboration of recommendations on imperfections in relation to the calculation of steel structures using computer modeling technology, including the finite element method. The results of the study contain instructions on how to set the shapes and values of imperfections for different groups of imperfections. The article consists of two parts. The first part is devoted to the study of geometric imperfections, residual stresses and rules for the combination of imperfections, the second part of the article is devoted to equivalent imperfections.