Steel Frame Structure Research Articles

Load Identification in Steel Structural Systems Using Machine Learning Elements: Uniform Length Loads and Point Forces

Actual load identification is a most important task solved in the course of (1) engineering inspections of steel structures, (2) the design of systems rising or restoring the bearing capacity of damaged structural frames, and (3) structural health monitoring. Actual load values are used to determine the stress–strain state (SSS) of a structure and accomplish various engineering objectives. Load identification can involve some uncertainty and require soft computing techniques. Towards this end, the article presents an integrated method combining basic provisions of structural mechanics, machine learning, and artificial neural networks. This method involves decomposing structures into primitives, using machine learning data to make projections, and assembling structures to make final projections for steel frame structures subjected to elastic strain. Final projections serve to identify parameters of point forces and loads distributed along the length of rods. The process of identification means checking the difference between (1) weight coefficient matrices applied to unit loads and (2) actual loads standardized using maximum load values. Cases of neural network training and parameters identification are provided for simple beams. The aim of this research is to enhance the reliability and durability of steel structures by predicting consequences of unfavorable load, including emergency impacts. The novelty of this study lies in the co-use of artificial intelligence elements and structural mechanics methods to predict load parameters using actual displacement curves of structures. This novel approach will enable engineering inspection teams to predict unfavorable load peaks, prevent emergency situations, and identify actual causes of emergencies triggered by excessive loading.

A physics‐informed deep reinforcement learning framework for autonomous steel frame structure design

AbstractAs artificial intelligence technology advances, automated structural design has emerged as a new research focus in recent years. This paper combines finite element method (FEM) and deep reinforcement learning (DRL) to establish a physics‐informed framework, named FrameRL, for automated steel frame structure design. FrameRL models the design process of steel frames as a reinforcement learning (RL) process, enabling the agent to simulate a structural engineer's role, interacting with the environment to learn the methods and policies for structural design. Through computer experiments, it is demonstrated that FrameRL can design a safe and economical structure within 1 s, significantly faster than manual design processes. Furthermore, the design performance of FrameRL is compared with traditional optimization algorithms in three typical design cases and a high‐rise steel frame case, demonstrating that FrameRL can efficiently complete structural design based on learned design experiences and policies.

The impact of corrosion due to salinity levels in the eastern zone of krueng aceh on the service life of steel frame building structural elements

Abstract The use of profile steel as the main element in construction has gained significant popularity due to its mechanical strength and ease of workability. Corrosion is a problem that occurs within steel as a result of the chemical interaction between the steel and its surrounding environment. The purpose of this research is to assess the impact of corrosion rate on the service life of steel frame structures in the East Zone of Krueng Aceh based on varying levels of salinity. This study employs direct observation and an experimental method that carry out testing on-site for 30 days on test objects/items. The test specimens consist of steel plates measuring 50mm x 25mm x 5mm with BJ45 quality, which were cut and buried in soil excavated to a depth of approximately 1 to 2 meters for one month while submerged. Subsequently, calculations were made using the Weight Loss Method to obtain the corrosion rate value.The results obtained in Zone II, which has the highest salinity level of 6788 ppm, yielded a corrosion rate value of 0.145 mm/year. In this study, the structural element under consideration is the column. Remaining service life analysis is based on the reduction in the cross-sectional area of the column profile after corrosion, thus assessing the decrease in its strength while referring back to the requirements outlined in SNI 1729:2020. The remaining service life of the steel frame structure in Zone II after corrosion is 21 years. For the test specimens placed in Zone IV, which has the lowest salinity level of 941 ppm.

Structural acceleration response reconstruction based on BiLSTM network and multi-head attention mechanism

The effectiveness of structural health monitoring often relies on the precise analysis of structural response data, with data completeness directly impacting the performance of monitoring systems. Addressing the common issue of data loss in structural health monitoring systems, this study proposes a Bidirectional Long Short-Term Memory (BiLSTM) network based on a multi-head attention mechanism for the reconstruction of missing structural acceleration responses. Firstly, employing a two-layer BiLSTM network to establish an encoder-decoder framework for extracting spatio-temporal correlation features among sensor data. Subsequently, innovatively embedding a multi-head attention mechanism into the network framework enhances the modeling capability of long-distance input elements and establishes dependencies among different sensors, thereby enabling the network to better capture the global features of input information. The proposed method undergoes validation through a numerical example of a simply supported beam, practical monitoring data on the Hardanger Bridge from the Norwegian University of Science and Technology, and an experimental study of steel frame structure from our laboratory. These validations are compared with alternative response reconstruction models. The experimental results make obvious that the proposed method demonstrates superior accuracy in response reconstruction. Additionally, the suitability of this method for modal identification is validated. Through the utilization of reconstructed responses, the method effectively discerns the structural natural frequencies with accuracy.

Collapse analysis and robustness assessment of dropped-story steel frame structures based on structural vulnerability theory

ABSTRACT This paper proposes an improved analysis method based on the theory of structural vulnerability, which incorporates structural redundancy and comprehensively analyzes structural vulnerability and robustness by considering the changes in structural stiffness and redundancy after damage to structural members under conventional loading. The improved method takes into account the changes in the strain energy of the structure after the damage of the structural members, which can be more in line with the actual situation of continuity collapse, and solves the complex process of traditional structural vulnerability theory that requires clustering and unclustering, greatly reducing the workload as well as solving the problem of not being able to find the critical members of the structure. The improved method is used to analyze the vulnerability of a 5-story dropped-story steel frame structure, to find the critical members of the structure based on the test data simulated by ABAQUS, to evaluate the robustness, and to propose improvement measures. The results show that the improved vulnerability assessment method is more reasonable and effective and can be applied to different steel frame structures.

Study on uneven settlement and correction of steel frame structures based on numerical simulation method.

Lifting-correction is a technique to restore buildings experiencing uneven settlement, while ensuring the safety and integrity of the main structural system. This study was based on a real light-steel building structure and provided a detailed description of scenarios involving uneven settlement and the process of lifting and correction. Additionally, a sophisticated finite element (FE) model was established using the generic FE software ABAQUS, with refined material constitutive models to ensure the accuracy of simulation results. Firstly, the impact of uneven settlement on the structure was examined, including modal and stress field analyses. Different methods of breaking column (BC) and lifting column (LC) were compared and scrutinized to identify optimal approaches and minimize damage and disturbance to the building. Four methods have been proposed and compared, including simultaneously breaking columns, breaking columns with chessboard style, simultaneously lifting columns and lifting columns in multiple stages. The four methods were comprehensively evaluated from the perspectives of stress fields, displacement responses, damage and energy dissipation. The results indicated that after uneven settlement, the eigenvalues and frequencies of the structure decrease, the structure tended to be unstable. Simultaneously, as stress increases, some joints' materials enter the yielding stage, affecting the overall structural stability and safety. When damage occurs in some joints, the structural safety was compromised. The comparison between the two BC methods, including the chessboard style and simultaneously BC methods, it was revealed that the former causes less disturbance to structural initial stress field. The comparison between the two LC methods, including, simultaneously and LC in multiple stages, it was revealed that the latter performs slightly better in terms of stress fields, displacement fields, damage, energy dissipation and internal forces. Therefore, the methods of BC in chessboard style and LC in multiple stages were recommended to use in engineering practice to ensure less structural disturbance. The findings obtained from this study can provide guidance for structural engineers to solve the uneven settlement of buildings.

Study on the Damping Efficiency of a Structure with Additional Viscous Dampers Based on the Shaking Table Test

This study specifically focuses on the damping efficiency of a damped structure with additional viscous dampers. A two-layer steel frame structure with eight sets of viscous dampers is used to conduct a series of seismic simulation shaking table tests, including a non-damped structure without dampers and two damped structures with dampers placed at 1/2 and 1/6 of the beam span, respectively. By conducting these tests, the energy dissipation, force, and displacement of the damper, as well as the parameters of the structure such as floor displacement and acceleration, are obtained. The main damping efficiency indicators of the damped structure are calculated, including the additional damping ratio, inter-story displacement utilization rate, as well as the reduction rate of the vertex displacement and the base shear relative to the non-damped structure. The study shows that the viscous dampers exhibit full hysteresis loops and a strong energy dissipation capacity in the structure. The seismic response of the vertex displacement and base shear in the damped structure is significantly smaller than that in the non-damped structure. Under different seismic levels, including frequent earthquakes, occasional earthquakes, and rare earthquakes, the damping effect of the dampers placed at 1/2 of the beam span is significantly better than that placed at 1/6 of the beam span. For example, the additional damping ratio for the X-direction artificial wave REN is 19% and 11%, 20% and 13%, and 13% and 11%, respectively. The patterns for inter-story displacement utilization ratio, reduction rate of the vertex displacement, and reduction rate of the base shear are similar. The research findings strongly indicate that the damped structure with additional viscous dampers exhibits excellent damping efficiency. In future damping design, designers need to fully consider the placement of viscous dampers within the beam span.

Research on the anti-collapse performance of steel frame structures with infilled walls in the form of reduced beam sections connections

Steel has more deformation capacity and resistance to compression buckling than concrete materials, which providing steel frames a distinct edge in preventing collapse. This study examines the anti-collapse performance and mechanism of steel frame structures with infilled walls in the form of reduced beam section connections. It also examines the effects of wall thickness, frame aspect ratio, and connection control size on performance and addresses the applicability of current code formulas in the early deformation of the structure. The study discovered that steel frame structures with infilled walls in the form of reduced beam section connections can, during the failure stage, enhance the infilled wall's contribution to the collapse bearing capacity, thereby stimulating the structure's potential performance, in contrast to those with infilled walls in the form of non-reduced beam section connections. Due to the supporting effect of the double strut that forms inside the infilled wall during the failure stage, steel frame structures with infilled walls that have non-reduced beam section connections have higher deformation capacity than corresponding pure frames; however, this effect also decreases the deformation capacity of the structure with reduced beam section. Furthermore, the infilled walls cause the structure to collapse in a same way across a range of aspect ratios, yet their contribution to the structural bearing capacity differs across these same aspect ratios. It is noteworthy that altering the local connection control size can greatly enhance the structure anti-collapse performance, even in unfavorable aspect ratio scenarios. The study also discovered that the bearing capacity of the structure studied in this paper was overestimated by the FEMA356-2000 code and the MSJC code, which were used to predict the initial bearing capacity of infilled frames. The former's overestimation reaches a maximum of 39 %, while the latter's prediction is only accurate within a limited range of aspect ratios. Furthermore, the formula by Qian and Li, which has a maximum error of 9 % in bearing capacity prediction within the standard range of aspect ratios, is better appropriate for the failure mode of the structure described in this study.

Study of Panel Zone Behavior in Interior Beam–Column Joints with Reduced Beam Section (RBS)

Based on the post-earthquake investigation of the Beiling and Hanshen earthquakes, many welded rigid beam–column joints were found to exhibit brittle failure. The failure modes of the joint region and the overall steel frame structure under the action of the earthquake need to be studied. The seismic performance of different types of weakened beam-end interior joints was investigated. The finite element method was verified by high-strength steel beam–column joint tests conducted by our research team. Finite element modeling of weakened steel beam flanges and weakened steel beam web joints was carried out based on the validated finite element modeling method. The joints were studied and analyzed using seismic parameters such as joint stress clouds, equivalent story shear–inter-story displacement ratio curves, panel zone bending moment–shear ratio curves, ductility, stiffness, and energy dissipation. The results of this study showed that honeycomb open hole-type joints exhibit a better deformation and energy dissipation capacity compared to open circular web hole-type joints. However, their load carrying capacity is reduced, which is mainly due to the larger area of the web openings. Additionally, double reduced beam section (DRBS) joints exhibit superior seismic performance and plastic hinge outward movement characteristics compared to single reduced beam section (RBS) joints. It was also found that the deformation and energy dissipation of DRBS joints and steel beam honeycomb hole-type joints are mainly borne by the beams, with the panel zone’s participation in energy dissipation accounting for a smaller proportion of the energy.

Seismic vulnerability analysis of a high‐rise steel frame structure equipped with novel displacement‐amplified viscoelastic dampers

SummaryThe energy dissipation capacity of conventional viscoelastic dampers (VEDs) cannot be fully exerted due to the relatively small inter‐story displacement of building structures. Thus, a novel VED with a displacement amplification mechanism based on the lever principle is developed in this study to achieve small displacement but high energy dissipation ability. First, the structural layout of an amplified viscoelastic damper (AVED) system is briefly introduced, and then the displacement amplification effect is described in detail. According to the working principle of the AVED and the relationship of force and geometric displacement in an actual frame structure, the restoring force theoretical formula of the corresponding amplified damper is derived. Based on the restoring force of the AVED and in combination with the secondary development function of the ABAQUS unit, a VUEL subroutine suitable for the explicit algorithm is programmed with the FORTRAN language. Then, the correctness of the subroutine is verified through a comparative analysis of the ABAQUS simulation and theoretically calculated results. Consequently, the vulnerability analysis of a high‐rise steel frame structure is conducted by using the incremental dynamic analysis (IDA) method, and the influence of the AVED on the seismic performance of the steel frame structure is quantitatively analyzed from the perspective of probability statistics. The analysis results show that compared with the VED structure, the failure probability of the AVED‐2 and AVED‐3 structures reaching the ultimate failure state at all levels is reduced by approximately 43% and 57%, respectively, and the collapse margin ratio (CMR) of structures under large earthquakes is increased by approximately 35% and 68%, respectively. This indicates that the AVED structures with displacement‐amplified dampers have a better effect on the seismic stability of tall steel frame structures under random seismic excitations. This study aims to provide comprehensive information for the seismic‐resistant design of tall buildings in earthquake‐prone regions.

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.

GPU-based parallel programming for FEM analysis in the optimization of steel frames

ABSTRACT Optimization of large-scale frame structures consumes a vast amount of time since the analysis of such complex systems contains several iterative processes. Mitigating computational burden and reducing this time to a reasonable level is possible by running GPU (Graphical Processing Unit) processors, which can be found on standard computers. This study presents an algorithm for the acceleration of size optimization of steel frames by using the BBO (Biogeography-Based Optimization) method that is suitable for GPU architecture. The GPU-based parallel algorithm, designed for FEM (Finite Element Method) analysis, is applied to three hypothetical steel-frame case structures with different numbers of members and nodes; and processed on four different computers which are available on the market. The presented case studies revealed that the proposed solution’s efficiency increases as the number of members increases and confirmed the ability of the acceleration algorithm for optimization of large-scale frame structures and provided time efficiency.

A two-loop RBDO approach for steel frame structures using EVPS, GWO, and Monte Carlo simulation

This paper evaluates Enhanced Vibrating Particle System (EVPS) and Grey Wolf Optimizer (GWO) algorithms for Reliability-based Design Optimization (RBDO) of steel frames. The two-loop RBDO method minimizes frame weight while satisfying strength, drift, and reliability constraints, considering uncertainties in material properties and loads. Both EVPS and GWO effectively reduce structure weight and ensure required reliability levels, demonstrating their applicability in sustainable steel frame design.

Seismic performance of recentering energy dissipation bracing with pendulum in prefabricated steel frame structure systems

This research introduces the recentering energy dissipation bracing with a pendulum in prefabricated steel frame (REBP-PSF) structures. The primary objective of this study is to mitigate potential severe damage to steel frames during seismic events and to expedite postearthquake rehabilitation. This innovative system harnesses energy dissipation through friction between structural members and facilitates recentering through the cable pretensioning force. Consequently, this may make postearthquake repairs minimal or even unnecessary. Three REBP-PSF structures and a prefabricated steel frame with cantilever beam splices (PSF-CBS) were meticulously modeled using the ABAQUS finite element method to evaluate the seismic performance of this novel system. The study investigated the effects of pretensioning parameters and varied structural morphologies on seismic performance metrics, including failure modes, hysteresis performance, energy dissipation capacity, and residual displacements. This paper introduced a simplified method to simulate the restoring force model of REBP using the connection element method. Subsequently, a model for the REBP-RSF overall structure was established, enabling nonlinear dynamic time-history analysis, which was then compared with the rigid steel frame (RSF) structure. The results showed that the REBP-PSF structure outperformed the PSF-CBS in terms of initial stiffness, yield load, ultimate load, and energy dissipation capability. The bearing and energy dissipation capacities of the REBP-PSF structure were enhanced by augmenting the cable pretensioning force within this structure. The proposed connection element method could accurately simulate the hysteretic behavior of REBP. Compared with the RSF structure, the REBP-RSF demonstrated superior seismic performance, characterized by small story drift and residual displacements during seismic activities. Furthermore, a notable augmentation was observed in the lateral stiffness and torsional rigidity of the proposed structure.

Evaluation Method for Seismic Toughness of Steel Frame Buildings with Buckling Constraint Braces Based on the Whole Construction Process

As a common building structure, steel frame building is of great significance in seismic design and construction in earthquake areas. However, the traditional steel frame structure is brittle under earthquake, which is prone to buckling instability and serious damage. Therefore, taking the whole construction process as a parameter index, the buckling-restrained brace-steel frame structure is strengthened, and different seismic waves are selected as seismic input to analyze and study its seismic capacity under earthquake action. The research results show that: (1) The steel frame with buckling-restrained braces still has strong seismic toughness when there is a large stiffness loss in the earthquake; (2) The base shear curve of building buckling-restrained brace-steel frame in X direction increases exponentially; (3) Buckling-restrained brace-steel frame has high shear force shared by columns and axes in X direction under strong earthquake, which can effectively realize the function of secondary protection; (4) The short duration of strong earthquake has little influence on the hysteretic energy consumption ratio, while the damage of the long duration of strong earthquake to the building buckling restrained brace-steel frame increases with the increase of strong earthquake duration; (5) Buckling restrained brace-steel frame has good deformability and can adapt to earthquake load through plastic deformation

Multi-objective optimization method for steel frame with top-and-seat angles considering yield control

Based on the yield mechanism control principle of “strong columns and weak beams, strong joints and weak components” in steel frames connected by top-and-seat steel angles, this paper proposes a method to define the relationship between the bending capacity of various components through inequality iteration and deduction. A number of component parameters has been identified that enables control of the yielding sequence in structural components. The study also developed an objective function and used genetic algorithms to create a multi-objective optimization technique for semi-rigid steel frame structures. The method considers the non-dominated cost interval, resulting in a more comprehensive approach. From the optimization case studies against the published experimental results and finite element simulations, it demonstrates that the proposed approach efficiently manages the yielding sequence and minimizes the decision space. The optimization model provides the coordination optimization between structural cost and lateral base shear capacity.

Performance-based fire protection of clustered individual members within a steel frame structure

Fire resistance rating (FRR) in the existing codes and literature sets an overall criterion for buildings by different fire resistance levels with undifferentiated fire protection. However, the performance diversity of individual members within a building is not considered. Therefore, a performance-based fire protection method for clustered individual members within a steel frame structure is established. First, parametric models of a steel frame structure exposed to two typical fires are built for data acquisition. Three features considering the mechanical properties of steel members and their impact on the entire structure are selected. Then, K-means clustering is adopted for the classification and ranking of individual members to assign fire resistance ratings and conduct clustered fire protection design. A comparison between the undifferentiated fire protection strategy and the clustered fire protection strategy is conducted. The quantitative evaluation results indicate the feasibility of the proposed method for clustered fire protection design, with the consideration of the performance diversity of individual members within the steel structure.

Steel structure design and analysis of a modern extreme sports center

A modern extreme sports center consists of a three-story main structure and ancillary structures. The overall architectural shape is simple and elegant. In order to ensure that the center has the high strength, earthquake resistance, corrosion resistance and other characteristics required for extreme sports venues, while taking into account comfort and aesthetics, the building structure adopts a steel frame structure system. This article uses the PKPM2021-V2.1.1.1 version software to conduct an overall calculation and analysis of this steel structure project, and checks the floor displacement calculated by the elastic method under the action of wind load or frequent earthquake standard values. The results show that the vertical structure of this structure is The deformation of the axial members meets the requirements of the code; the displacement ratio and inter-story displacement ratio of the structure under the action of specified horizontal seismic forces considering the influence of accidental eccentricity are checked, and the results show that the structure does not belong to torsional irregularity; the overturning resistance of the structure is checked and The shear-to-weight ratio was calculated and the results showed that the stability of the structure met the specification requirements. It can be seen from the above calculation and analysis that this structure can meet the specification requirements under various working conditions, and the structural design is safe and reliable.

Numerical analysis of the behaviour of a concrete floor in a steel-framed structure subject to a traveling fire

This paper presents a finite element model for a multi-story structure subjected to traveling fire. The structure selected has been previously investigated in experimental studies. The study investigates the effect of the number and positions of the panels exposed to fire on the fire behavior of the composite floor in the structure. Parameter analyses were conducted, including floor thickness, reinforcement arrangement, loads, position and number of panels exposed to fire, and traveling fire. The study shows that there are three different patterns of membrane action: ring type, diagonal U type, and opposite side U type. The moment and axial force of the steel beam near the fire panel increase gradually, while the internal force change of the steel beam at a distance from the panel exposed to fire is relatively small. The axial force of the edge and corner columns changed more significantly compared to the axial force of the middle column. Furthermore, the displacement, fire resistance, failure mode, and membrane action of the floors depend primarily on the position of the panels exposed to fire, the traveling fire, and the interaction among members.

An inelastic beam-like model for nonlinear dynamic analyses of multi-storey buildings

This paper presents an equivalent non-uniform inelastic beam-like model for the evaluation of the nonlinear behaviour of multi-storey buildings subjected to earthquake loadings. The proposed beam can be used to model buildings with non-uniform mass and stiffness distribution. The model is characterised by a number of degrees of freedom corresponding to the number of floors of the building and is conceived to predict its nonlinear dynamic response after a proper calibration based on the results of pushover analyses performed on a nonlinear FEM model. In spite of its simplicity, the proposed equivalent model provides, with a very low computational effort, an accurate representation of the nonlinear dynamic behaviour of the building comparable to that obtained through the more demanding nonlinear 3D FEM models. The effectiveness of the proposed simplified modelling approach is here validated by means of nonlinear dynamic analyses firstly performed on a benchmark known in the literature as SAC9 building, modelled as a plane steel frame structure and secondly on a three-dimensional reinforced concrete structure, designed according to old standard structural design rules. The very good agreement with the results obtained through accurate 3D FEM frame modelling, for different earthquake loadings, on the considered benchmarks provides a first validation of the proposed inelastic equivalent beam-like model and suggests its potential use for the seismic assessment of building structures. The low computational cost related to the beam-like model could be particularly advantageous for all the seismic vulnerability approaches requiring several nonlinear dynamic analyses, as those related to large scale applications, or those expressed in terms of probability of failure generally expressed in terms of fragility curves.