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Buckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and built-up steel sections are widely employed. These type of steel members are affected by torsional and flexural-torsional buckling, but the European (EN 1993-1-2) and the American (AISC 360-16) design norms do not explicitly treat these phenomena in fire situation. In this work, improved buckling curves based on the EN 1993-1-2 were extended by exploiting a previous work of the authors. Moreover, new buckling curves of AISC 360-16 were proposed.

The buckling curves provided in the norms and the proposed ones were compared with the results of numerical investigation. Compressed angles, tee and cruciform steel members at elevated temperature were studied. More than 41,000 GMNIA analyses were performed on profiles with different lengths with sections of class 1 to 3, and they were subjected to five uniform temperature distributions (400–800 C) and with three steel grades (S235, S275, S355).

It was observed that the actual buckling curves provide unconservative or overconservative predictions for various range of slenderness of practical interest. The proposed curves allow for safer and more accurate predictions, as confirmed by statistical investigation.

This paper provides new design buckling curves for torsional and flexural-torsional buckling at elevated temperature since there is a lack of studies in the field and the design standards do not appropriately consider these phenomena.

Steel shear walls have recently received exclusive remark. Respective of most building code requirements, design of shear wall vertical boundary elements (VBEs) and local boundary elements (LBEs) against web yielding triggers exaggerated stiffness. The extent of stiffness reduction effects in boundary elements thus calls for more exhaustive investigation. The paper aims to discuss these issues.

To this end, FEM-based push-over curves demonstrating base shear vs roof displacement, and von Mises plastic strains were scrutinized in half-scale and full-size models. Analyses were in perfect conformity with experimental data.

With reference to the AISC requirement, up to 35 percent decrease in the VBE moments of inertia could be imparted in higher levels without the ultimate load capacity nor displacement to failure being reduced. Also considered was open shear walls with reduced or minimum-design LBEs, the latter being used in continuous or abridged form. LBEs could be used with a moment of inertia 80 percent smaller than required if only used in a continuous form. The effect due to opening geometry was negligible on loading capacity but distinguished on the post-yielding buckling-induced softening.

Light-weight design of low- to medium-level steel structures against earthquake loads.

With respect to continuous walls, the results are more comprehensive than those existing in the literature in that they combine the effects due to scale and orientation (horizontal or vertical) of boundary elements. The results for open shear walls are not only comprehensive but also original in a sense that they account for the influences induced by the opening type (door or window), orientation (horizontal or vertical), and design (full-length or abridged) of boundary elements, in reduced form, on the lateral stiffness of the frame.

This study seeks to understand the connection of methodology by finding relevant papers and their full review using the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA).

Concrete-filled steel tubular (CFST) columns have gained popularity in construction in recent decades as they offer the benefit of constituent materials and cost-effectiveness. Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), Gene Expression Programming (GEP) and Decision Trees (DTs) are some of the approaches that have been widely used in recent decades in structural engineering to construct predictive models, resulting in effective and accurate decision making. Despite the fact that there are numerous research studies on the various parameters that influence the axial compression capacity (ACC) of CFST columns, there is no systematic review of these Machine Learning methods.

The implications of a variety of structural characteristics on machine learning performance parameters are addressed and reviewed. The comparison analysis of current design codes and machine learning tools to predict the performance of CFST columns is summarized. The discussion results indicate that machine learning tools better understand complex datasets and intricate testing designs.

This study examines machine learning techniques for forecasting the axial bearing capacity of concrete-filled steel tubular (CFST) columns. This paper also highlights the drawbacks of utilizing existing techniques to build CFST columns, and the benefits of Machine Learning approaches over them. This article attempts to introduce beginners and experienced professionals to various research trajectories.

Mild steel plates used in buildings and offshore platforms are prone to fire accidents. These plates being ductile are designed effectively for buckling and ultimate strength characteristics under static loads. These characteristics get drastically affected due to reduction in stiffness of the stress strain characteristics of mild steel with increase in temperatures. This paper presents a numerical study conducted on clamped plates at elevated constant temperature for the assessment of reduced buckling and ultimate strengths. Coupled Nonlinear static thermal analysis on clamped plates was performed using standard FE software ANSYS®. Both geometric and material nonlinearities are considered in the analysis. The study comprises of plates with varying aspect ratio (1 to 4) and breadth to thickness (28 to 128) at constant elevated temperatures of 0 °C, 200 °C, 400 °C, 600 °C and 800 °C. Nondimensional plate slenderness ratios based on AISC and Eurocode at elevated temperature was evaluated. Several charts showing normalised buckling stress vs temperature and normalised ultimate strength vs temperature for varied nondimensional plate slenderness ratio and plate aspect ratios are drawn. The buckling and ultimate strengths from this study are found to be underestimated in comparison to Eurocode and AISC calculations. The reduction in buckling and ultimate strength was found to be significant beyond 400 °C. It is observed that for all plate aspect ratios, the effect of plate breadth to thickness ratio is important for temperatures below 500°C and at 800°C ultimate strength of plate is only about 10% of that of at normal temperature.

Different approaches, originally developed for ambient conditions, exist in current codes and standards for incorporating the effect of moment–shear (M–V) interaction on the plastic-carrying capacity of wide-flanged (WF) steel sections. There is a lack of experimental and theoretical studies that address this issue under fire conditions.

The current paper presents a numerical study investigating the effect of fire exposure on the plastic M–V capacity curves of doubly symmetrical, WF, hot-rolled steel sections. Validated high-fidelity finite element (FE) models constructed via ANSYS are used to study the effect M–V interaction on the plastic capacity of WF sections. Also, a simplified plastic sectional analysis, intended to be used by engineering practitioners, is proposed for generating the plastic M–V interaction curves.

The study shows that the fire-induced non-uniform heating of the section plates affects the shape of the plastic M–V interaction capacity curves. Comparison of different methods against FE results shows that the method specified in the Eurocode is very conservative at room-temperature, but it turns out to be barely sufficiently conservative under fire conditions.

It is well noted that lack of fire tests on the M–V interaction, including the stability of the plates of steel sections under fire, make it difficult to reach a definite assessment on the effect of M–V interaction on the bearing capacity of steel beams.

This paper presents highlights of on-going research, which aims at developing analytical, computational and experimental predictions of the phenomenon of creep buckling in steel columns subjected to fire. Analytical solutions using the concept of time-dependent tangent modulus are developed to model time-dependent buckling behavior of steel columns at elevated temperatures. Results from computational creep buckling studies using Abaqus are also presented, and compared with analytical predictions. Material creep data on ASTM A992M steel is also presented and compared to existing creep models for structural steel. Both analytical and computational methods utilize material creep models for structural steel developed by Harmathy, by Fields and Fields, and by the authors. Predictions from this study are also compared against those from Eurocode 3 and the AISC Specification. Results of this work show that neglecting creep effects can lead to erroneous and potentially unsafe predictions of the strength of steel columns subjected to fire.

Top-seat angle connection is known as one of the usual uncomplicated beam-to-column joints used in steel structures. This article investigates the fire performance of welded top-seat angle connections.

A finite element (FE) model, including nonlinear contact interactions, high-temperature properties of steel, and material and geometric nonlinearities was created for accomplishing the fire performance analysis. The FE model was verified by comparing its simulation results with test data. Using the verified model, 24 steel-framed top-seat angle connection assemblies are modeled. Parametric studies were performed employing the verified FE model to study the influence of critical factors on the performance of steel beams and their welded angle joints.

The results obtained from the parametric studies illustrate that decreasing the gap size and the top angle size and increasing the top angles thickness affect fire behavior of top-seat angle joints and decrease the beam deflection by about 16% at temperatures beyond 570 °C. Also, the fire-resistance rating of the beam with seat angle stiffener increases about 15%, compared to those with and without the web stiffener. The failure of the beam happens when the deflections become more than span/30 at temperatures beyond 576 °C. Results also show that load type, load ratio and axial stiffness levels significantly control the fire performance of the beam with top-seat angle connections in semi-rigid steel frames.

Development of design methodologies for these joints and connected beam in fire conditions is delayed by current building codes due to the lack of adequate understanding of fire behavior of steel beams with welded top-seat angle connections.

Analysis of designing and controlling the failure of marine structures attached to the bottom of the sea under dynamic load obtained from the sea waves is one of the main engineering challenges in recent years. The circumstances of the onshore marine structures have their own complexity and the difficulty due to the effect of hydrodynamic factors and dynamic responses which are dominant in the marine environment. The paper aims to discuss these issues.

The structure elements are composed of the metal pipe with a length of 5 m, outside diameter of 20 cm and thickness of 1.5 mm. the failure control with a safety factor of 2 indicates the absence of the above marine structure failure. It has been diagnosed to be trustworthy and reliable.

In this study, the control of marine steel structure failure with the height of 60 m under the dynamic load of the sea water waves having sinusoidal shape in the Caspian Sea has been studied and analyzed.

In this paper, the minimum and maximum internal force and movement in six directions of freedom were obtained for each element. To analyze and control the failure, the combination of stresses caused by static and dynamic loads has been used. According to the regulation of 10-360-AISC, the control was conducted.

Brief introduction on the importance and the need for plastic analysis methods were presented in the beginning section of this review. The plastic method for analysis was considered to be the more advanced method of analysis because of its ability to represent the true behaviour of the steel structures. Then in the following section, a literature analysis has been carried out on the previous investigations done on steel plates, steel beams and steel frames by other authors. The behaviour of them under different types of loading were presented and are under the investigation of innovative new analysis methods.

Structure member connections also have the potential for plastic failure. In this study, the authors have highlighted a few topics to be discussed. The three topics in this study are T-end plate connections to a square hollow section, semi-rigid connections and cold-formed steel storage racks with spine bracings using speed-lock connections. Connection is one of the important parts of a structure that ensures the integrity of the structure. Finally, in this technical paper, the authors introduce some topics related to seismic action. Application of the Theory of Plastic Mechanism Control in seismic design is studied in the beginning. At the end, its in-depth application for moment resisting frames-eccentrically braced frames dual systems is investigated.

When this study involves the design of a plastic structure, the design criteria must involve the ultimate load rather than the yield stress. As the steel behaves in the plastic range, it means the capacity of the steel has reached the ultimate load. Ultimate load design and load factor design are the methods in the range of plastic analysis. After the steel capacity has reached beyond the yield stress, it fulfills the requirement in this method. The plastic analysis method offers a consistent and logical approach to structural analysis. It provides an economical solution in terms of steel weight, as the sections designed using this method are smaller compared with elastic design methods.

The plastic method is the primary approach used in the analysis and design of statically indeterminate frame structures.

In this study, the application of a novel combined steel curved damper (SCD) and steel plate shear wall (SPSW) system in the 5-, 10- and 15-storey steel moment-resisting frames (SMR) subjected to earthquake excitation has been investigated. The proposed system is called here as the SMR-WD (steel moment resisting–wall damper).

At the beginning of this research, an SMR-W and an SMR-D are separately modeled in ABAQUS software and verified against the available experimental data. After that, three different heights SMR-WD systems (5-, 10- and 15-storey) are designed and simulated. Then, their performances are examined and compared to the corresponding SMR-W under the effects of six actual earthquake records.

The obtained results show that the proposed system increases the mean values of the base shear for 5-, 10- and 15-storey SMR-WD equal to 27, 20.15 and 16.51%, respectively compared to the corresponding SMR-W. Moreover, this system reduces the drift of the floors so that the reduction in the average values of maximum drift for 5-, 10- and 15-storey SMR-WD is equal to 10, 7 and 29%, respectively with respect to the corresponding SMR-W. The results also reveal that the considered system dissipates more energy than SMR-W so that the increase in the mean values of the energy absorption for 5-, 10- and 15-storey SMR-WD is 30.8, 25.6 and 41.3%, respectively when compared to the SMR-W. Furthermore, it is observed that SMR-WD has a positive effect on the seismic performance of the link beams and panel zones of the frames. By increasing the height of the structure in the SMR-WD, the energy dissipation and base shear force increases and the drift of floors decreases. Hereupon, the proposed SMR-WD system is more useful for tall buildings than SMR-W frames.

For the first time, the application of a novel combined steel curved damper (SCD) and steel plate shear wall (SPSW) system in the 5-, 10- and 15-storey steel moment-resisting frames (SMR) subjected to earthquake excitation has been investigated.