Steel Beam-columns Research Articles

OPTIMIZATION OF STEEL PROFILE DIMENSIONS AND BOLT CONNECTIONS IN INTAKE STRUCTURES FOR ENHANCED STRUCTURAL INTEGRITY

Intake structures are facilities for clean water supply situated along riverbanks. These structures are reinforced concrete with pile foundations, and the intake structure comprises a profiled steel frame serving as the upper column-beam framework. The implementation of steel structures demands a high level of precision, particularly in designing connections between sectional steel beams and columns. This study, therefore, aims to determine the optimal dimensions for steel profiles by referring to the design of bolt connections as specified in SNI 1729-2020, particularly for steel beam columns subjected to pump loads and load combinations. The analysis concludes that all three material types meet the safety criteria, with a structural ratio value of ≤ 1 and structural deflection within the allowable limits. Additionally, after assessing the steel column and beam sections' capacity to bear pump loads, it was determined that the optimal bolt connection involved 8 bolts of 24 mm diameter. The ideal supplementary steel plate connection required a plate thickness of 13 mm.

Finite Element Analysis of Seismic Performance of RCS Hybrid Joints of Steel Hoop Structure

Reinforced concrete column-steel beam (RCS) composite structures are widely used in super highrise buildings due to their excellent performance. In this paper, the numerical simulation analysis of the RCS hybrid joints of “beam through” and “column through” RCS constructed with steel hoop structure are carried out, and the influence of five different parameters, i. e. , flange width-thickness ratio, steel yield strength, axial compression ratio, concrete strength and end plate thickness, on the seismic performance and failure mode of RCS hybrid joints is investigated. The results show that the ABAQUS finite element model can simulate the performance of RCS mixing under static load through reasonable parameter settings, which is in good agreement with the experimental results. Under the mechanism of “strong column and weak beam”, the combined node firstly undergoes beam-hinge damage, and the change of the axial compression ratio and the concrete strength parameter of the joint have little effect on the ultimate bearing capacity and deformation performance of the joint. Increasing the flange width-thickness ratio reduces the bearing capacity of the joint by up to 11%, and increases the yield strength of the steel, and increases the bearing capacity of the joint by 36. 4%. The thickness of the end plate of the column through specimen is increased, and the bearing capacity and deformation performance of the joint are improved to a certain extent. The changes of each parameter have no significant effect on the final plastic hinge failure mode of the joint. The research in this paper provides theoretical support for the design and research of this type of node in the future.

Numerical Investigation of the Beam Web Weakening Pattern Impact On the Seismic Behavior of the Steel Beam-Column Connection

Numerical Investigation of the Beam Web Weakening Pattern Impact On the Seismic Behavior of the Steel Beam-Column Connection

Shear mechanism of RCS joints with whole column-section diaphragm

The authors proposed a new precast RC column-steel beam (RCS) joint with whole column-section diaphragm, aiming to address the shortcomings including bearing failure and difficulty in prefabrication of the RCS joint details available in the existing literature. Due to its unique details, the proposed RCS joint may have a dissimilar force-transferring mechanism from the conventional beam-through type RCS joint. Moreover, the effect of various parameters on this novel joint was still unclear by limited test results. The objective of this study was to clarify the shear mechanism of the proposed joint and the impact of critical parameters. Specimens with different axial load ratios and thickness of parallel FBPs were tested under cyclic loading. The results showed that the increase in axial load ratio and thickness of parallel FBPs improved joint strength in this test. A detailed three-dimensional finite element (FE) model was developed and verified using the experimental results. The difference in the force transferring between the proposed joint and conventional beam-through RCS joints was explained in detail based on the numerical results. The dowel action of longitudinal column bars were evident in the proposed joint and the orthogonal FBPs were ineffective in activating the inner concrete strut. A parametric study was further conducted. The impacts of width of parallel FBPs, thickness of orthogonal FBPs, and axial load ratio were investigated. The joint strength linearly increased with the width of parallel FBPs. A parabolic distribution of shear stress in the parallel FBP section was obtained, while the yield zone was concentrated in the central area of the parallel FBP. The ductility could be improved with the thickness of orthogonal FBPs when the thickness was less than 10 mm. Further increasing the thickness of orthogonal FBP beyond 10 mm did not significantly affect the overall joint behavior. The joint may attain the optimal shear strength when the axial load ratio is between 0.3 and 0.4. The modeling approach in this study could be adopted as an effective tool to assess joint behavior. Moreover, the conclusions obtained by numerical study potentially promoted the application of the proposed joint.

The Performance of Cold-Formed Steel Beam-Column Connections with Screw Configuration

Cold-formed steel is being used as a viable substitute for traditional steel and building materials due to its performance, affordability, convenience, lightweight, and environmental friendliness. The major purpose of this current research is for a reaction to force-deformation at the connection level to be delivered, which is proper for typical cold-formed steel (CFS) screwed beam-column assembly CFS C-section, and to show the influence of the behavior of CFS under bending test. An inner plate, double angle plate, and self-drilling screws are used by a basic beam-column frame idealized CFS to join the beam-column. Fixed support was implemented at the column base, whereas the beam end had free support. A 0.75 mm cold-formed steel C-section with 80mm height and 30mm width was utilized in this study and assembled into an "I" and "box" configuration. 3d and 4d were used to compute screw spacing for self-drilling screws with 4 mm heads and 2 mm bodies. The first type was each angle plate (top and seat angle) screwed with eight screws, whereas the second involves four screws. The CFS section’s thinness led to the use of screw connections, which are essential to their ability to withstand connection failures, to anticipate the failure mode of the connection segment. Numerical simulation by ABAQUS Student Edition and analytical studies have been conducted by AS/NZS 4600:2018 to investigate the capacity of CFS under bending. Quantity and the arrangement of the screws determine the displacement ductility with tighter spacing enhancing performance and reinforcing global and local buckling resistance.

Behavior of steel beam section under warping using BIM program

AbstractWarping not only one of the most important phenomena in steel section it is also considered as the most complicated phenomena. Ductility, bearing capacity and serviceability of steel sections may affect by increasing stress concentration of the normal stresses due to warping. In the present work, simulation of steel beam section under effect of warping is studied. Two cantilevers connected to two columns in opposite sides with a middle steel beam-column connection to create different moments on the beam to investigate the behavior of steel section under warping using building information modeling. It is found that the stress strain relationship has four groups depending on the load intensity and the angle of rotation induced due to warping.

Design and seismic performance analysis of a novel special-shaped steel tube concrete column steel beam joint

In this study, a novel special-shaped steel tube concrete column steel beam joint is proposed. Bolt connections are used to connect the pre-welded steel beam and the special-shaped steel tube concrete column. Based on the finite element software ABAQUS, we established finite element models of the column-beam joints, and conducted a series of finite element analyses to investigate the influence of various parameters on the seismic performance of the joint. These parameters include the shape and size of the flange hole, the shape and size of the web hole, and thickness of the spliced plate on the flange. The results show that the difference between the finite element analysis and experimental results for bearing capacity and displacement is within 10%. This indicates that finite element analysis can be effectively utilized to study the seismic performance of the joint. Compared to joints with non-spliced beam, the rotational deformation capacity of the joint is reduced when using bolts and spliced plates designed by the equal-strength method. The energy dissipation capacity and ductility deformation capacity of the joints with spliced beams are significantly improved by using elliptical bolt holes in the flange, and plastic hinges are formed in the spliced region. The elliptical holes in the web with varying sizes have little effect on the seismic performance of the joint. The thicknesses of the spliced plate ranging from 6 mm to 8 mm has little effect on the seismic performance of the joint, and a thin spliced plate will reduce the seismic performance of the joint. The study presented in this paper can provide a reference for promoting the engineering application of special-shaped steel tube concrete structures.

Self-centering concrete-filled steel tubular column-steel beam joint: Experiment and numerical modeling

This paper studied the seismic behavior of a novel self-centering concrete-filled steel tubular column-steel beam (SCSTCSB) joint. The restoring force was provided by the post-tensioned tendons arranged in the CFST columns. Cyclic loading tests were performed on five 1/3 scaled specimens by varying the parameters of steel tendon type, concrete strength (fc), and axial compression ratio (n). The failure modes, hysteresis behavior, stiffness and strength degradation, energy dissipation, post-tensioned tendons response, residual deformation, and strain distribution were studied in detail. The finite element models were established to capture the stress distribution of the joints. In addition, parameter analysis was performed by expanding 17 finite element models. The results show that the ratio of residual deformation to beam rotation angle of the specimens ranged from 0.068 to 0.172. And the proposed joints demonstrated excellent self-centering ability. The self-centering (SC) performance of joints with ordinary steel tendons was better than that of joints with high-strength steel tendons. With the increase of n, the SC performance of the joints intensified at the lower ratio (n from 0.1 to 0.3) and weakened after n = 0.3. The flexural capacity of the joints improved with the increase of axial compression ratio (n), width-thickness ratio (D/t), diameter of steel tendons (d), and assembly part strength (fy,a).

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.

Effect of beam-column depth ratio on seismic behavior of precast RC column-steel beam joint

To achieve the simultaneous horizontal casting of the joint and column in the factory, the authors proposed a new precast RC column-steel beam (RCS) joint. The overall behavior of the proposed joint has been investigated. However, the effects of various design parameters were unclear. This paper focused on the impact of the beam-column depth ratio on the proposed RCS joints. Three 2/3 scale interior RCS joint specimens were designed and tested under cyclic loading. Experimental results showed that the joint shear strength and ductility of the specimen improved as the beam-column depth ratio decreased. A large beam-column depth ratio could modify the bond condition of column bars. Moreover, a numerical study was conducted to further investigate the influential mechanism of the beam-column depth ratio. According to the distribution of compressive stress, the concrete strut was activated in the joint. The angle between the strut and the horizontal increased with the beam-column depth ratio, leading to less horizontal component to resist the joint shear force. The joint shear strength tended to be overestimated as the beam-column depth ratio increased by using current design methods. Ignoring the effect of the beam-column depth ratio in the design methods may cause significant errors in predicting the joint shear strength.

Experimental study and numerical simulation analysis of RCS joint with asymmetric friction connection

Based on the seismic design principle of recoverable function and replaceable seismic design, a novel type of reinforced concrete column-steel beam (RCS) joint was proposed, incorporating an asymmetric friction connection in the lower flange of the steel beam. Subsequently, experimental tests, numerical simulations, and theoretical analyses were conducted to evaluate this joint. The test results indicate that the RCS joint with asymmetric friction connection can effectively exert friction slip energy dissipation characteristics, demonstrating good seismic performance in terms of bearing capacity and stiffness. The damage observed in the specimen is primarily focused on the spliced cover plate of the steel beam, with minimal deformation in the core area of the joint. Numerical simulation and parameter analysis were conducted using ABAQUS software. The results demonstrate that the finite element model accurately reproduces the observed phenomena in the test. The parameter analysis reveals that a 10 % increase in bolt preload or a 0.05 increase in friction coefficient can result in a 7 % or 13 % rise in joint bearing capacity, respectively. Finally, a calculation method for determining friction slip in RCS joints with asymmetric friction connection was developed, showing close agreement between the calculated results and finite element outcomes, indicating the accuracy of the formula.

Experimental research on H-section beam-square steel column joints connected by self-tapping screws

This paper proposes a novel thin-walled steel beam-column joint entirely using self-tapping screws. Compared to bolted and welded connections, its advantages of easy construction, low precision requirements, and fast construction are suitable for low-rise steel structures. Four full-scale H-section beam-square steel column joints connected by self-tapping screws were tested and the force transfer mechanism was investigated. Three of the specimens were loaded monotonically at the beam ends. The effects of the L-shaped connecting plate thickness and the arrangement of stiffening ribs on the bending performance of the joints are analyzed. Monotonic loading tests have demonstrated that the increased thickness and the arrangement of stiffening ribs enhance the common forces in the clusters of self-tapping screws, thereby increasing the bending stiffness of the joints. One of the specimens was tested with cyclic loads. The cyclic loading test revealed that the hysteretic curve of the self-tapping screws connection is relatively full, with high energy dissipation capacity and low degradation of strength and stiffness. Finally, the improved component method proposed the calculation method of bending resistance of self-tapping connection joints. The calculation accuracy is within 10 %, which can be used as a reference for the design of bending resistance.

Unified machine-learning-based design method for normal and high strength steel I-section beam–columns

High strength steel is regarded as a promising construction material due to its superior mechanical properties. However, the codified failure load predictions for high strength steel welded I-section beam–columns are not accurate in some cases owing to the lack of relevant design codes for high strength steel structures. In addition, current design codes ignore the interaction effect of the cross-section plate elements, leading to the inaccuracy of codified predictive ultimate resistances for both normal and high strength steel beam–columns. In this paper, a unified and accurate design method was proposed based on machine learning for both normal and high strength steel welded I-section beam–columns failing by different failure modes. Firstly, a total of 812 experimental and numerical data on welded I-section beam–columns with various steel grades, geometric dimensions, including cross-section dimensions and member lengths, and failure modes, including global buckling, local buckling and local–global interactive buckling were collected to establish a database. Seven machine learning algorithms, including Decision Tree, Random Forest, Support Vector Machine, K-Nearest Neighbour, Adaptive Boosting, Extreme Gradient Boosting and Categorical Boosting were applied to develop regression models to predict failure loads. Based on the established database, each machine learning model was then trained and key hyperparameters were optimised. The model performance was evaluated through a series of statistical indicators and the feature importance analysis, and the evaluated results indicated that the XG-trained regression model had the highest level of accuracy. Finally, the predictions given by the XG-trained regression model were compared with those of the existing codified design provisions, as given in Eurocode and American codes. The evaluation results indicated that the codified predictive bearing capacities of I-section beam–columns were scattered and inaccurate, while the XG-trained regression model provided substantially improved failure load predictions.

Mechanical property of bolted-assembled reinforced concrete column-steel composite joints

Herein, a new type of bolted-assembled reinforced-concrete column-steel (RCS) beam composite joint is proposed by analysing the force and force transmission process of RCS beam composite joints. The practicality and uniqueness of the structure apply to beam–column joints in large shopping malls, mid- to high-rise office buildings, factories, garages and other building structures. By the finite-element software modelling, a numerical simulation is established and used to analyse the variation of stress and equivalent plastic deformation, hysteresis curve, skeleton curve, stiffness degradation and energy dissipation coefficient under monotonic displacement–load and cyclic displacement–load. Results elaborate that the RCS composite connection has good ductility under monotonic displacement–load. Besides, under the cyclic displacement–load capacity, the hysteresis curve is full, the stiffness degradation is not obvious and the ductility and energy dissipation are good. This study is expected to promote the engineering application and guide follow-up research of the new nodes.

Experimental Study on Hysteretic Performance of Steel Moment Connection with Buckling-Restrained Dog-Bone Beam Sections

Steel beam–column connections with dog-bone beam sections have gained significant attention and have been extensively applied. This is attributed to their ability to effectively centralize and integrate plastic hinges, thereby diverting potential damage away from the beam ends during earthquake events. In order to achieve the enhancement of the ductility and energy dissipation of connections by inhibiting local buckling during an earthquake event, a novel steel moment connection with buckling-restrained dog-bone beam sections was proposed in this paper. There were three types of proposed connections according to the different arrangements of restrained steel plates, including arranging the restrained plates only on the flanges, only on the web, and on both the flanges and webs of the dog-bone beam sections. In this study, three specimens with buckling-restrained dog-bone beam sections and one control specimen with a dog-bone beam section were tested under cyclic loading. The failure modes, hysteretic curves, skeleton curves, stiffness degradation ductilities, displacement ductility ratios, and energy dissipation capacities of the specimens were analyzed based on the experimental results to evaluate the seismic behavior of the proposed connections. The results indicated that the local buckling of the proposed connections was significantly reduced compared with the traditional connection with a dog-bone beam section under the condition of keeping the plastic hinges away from the beam–column connection core. The arrangement of the restrained plates in the dog-bone beam section had little effect on the bearing capacity and the initial stiffness, with errors all being within 6%. It is worth mentioning that the connection with restrained plates only on the flanges in the dog-bone beam sections showed a more obvious improvement in the deformation capacity and energy dissipation capacity of the connection, which increased by 21% and 16%, respectively. Additionally, high-quality welding between the beam and column, smooth cutting shapes on the weakened flanges, and the high-quality drilling of long slots at the fixed point in the restrained plates and the dog-bone beam sections should be guaranteed to improve the hysteretic stabilities of the proposed connections.

Experimental and numerical investigation of the hysteretic behavior of reinforced concrete column-steel beam interior joints under low seismic intensity levels

For the composite frame structure of concrete column and steel beam, a connection structure based on ribbed angle steel connector (RASC) is proposed, and the hysteresis performance and force transmission mechanism of this new type of composite joint are studied. Through quasi-static experimental research, the influence of beam and column cross-sectional dimensions on the bearing capacity, energy dissipation capacity, stiffness degradation, ductility, and failure form of the frame structure was analyzed. The results of experimental and finite element analysis show that the failure forms of this joint under low-cycle repeated loading are mainly manifested as the shear failure of concrete in the core area of beams and columns and sliding failure between angle steel connectors and steel beams, and the hysteresis curves of the joints are similar to those of frame beams and columns, respectively.

Seismic behavior of an improved drilled flange connection for I-beam to CFST column

The use of cold-formed steel tubes in the concrete-filled steel tubular (CFST) columns makes the design of the moment connections between beams and CFST columns much more challenging. This is because setting the internal diaphragms in the CFST column to transfer the bending moment of the beam end becomes impossible, and thus new joints are needed. A novel joint was proposed in a previous study by the authors, where two end plates were used for the force transmission between CFST columns and beam flanges. Moreover, to satisfy the “weak member strong joint” requirement, the I-beams were reduced by drilling a series of circular holes in their flanges. However, most of the tested specimens failed by the unexpected rupture of the complete joint penetration (CJP) groove welds between the beam flanges and end plates. In this paper, three specimens are redesigned and tested, where modifications are made to improve their behaviors under the seismic load. In this test, the local buckling of beam flanges at the drilled sections was observed in all specimens, and two specimens failed due to the fracture at the drilled sections, while CJP weld fracture and significant bending of beam flanges both occurred at the failure of the rest specimen. The hysteresis curves of all specimens are fusiform, indicating their good energy dissipations (the maximum equivalent viscous damping coefficients between 0.35 and 0.40). The failure rotation angles are about 2.44–3.01, and the ductility coefficients are between 2.26 and 2.66. According to EC3, all specimens can be classified into the rigid and full-strength joints. Subsequently, the parametric analyses using the validated finite element model are carried out, where the effects of main parameters are investigated on the seismic behavior of the presented joint. This study brings insights into the moment connections between the steel beam and CFST column with the outer cold-formed section.

Three-dimensional analysis of steel beam-column bolted connections

Abstract The design of steel beam-column end-plate bolted connections is becoming increasingly popular owing to its simplicity of production. This requires knowledge of the full nonlinear resisting moment–rotation (M–Φ) behavior of the joint. To investigate the impact of various geometrical factors on the overall behavior of the connection, this work provides a three-dimensional finite element model (FEM) utilizing ABAQUS software. The suggested model accounts for the pretension force on the bolts, material and geometrical deviations from linearity, and the proximity of surfaces that are adjacent. The numerical model’s ability to simulate and process both the total and specific behavior of varieties of end-plate steel riveted connections is confirmed by calibrating the finite element findings with experimentally disclosed outcomes, which are reviewed in this study. The ultimate behavior was then investigated through a parametric study using the verified FEM with variations in the bolt pretension load, yield strength of the sections, and yield stress of the bolt considering the M–Φ curve. The results of the parametric study showed that as the bolt pretension load and yield stress of the column, beam, and plate materials increased, so did the connection’s moment ability. The yield tension of the bolts, however, had only a minor effect on the connection’s moment capacity.

New beam-based models for fire-induced buckling analysis of class 4 steel columns

Steel cross-sections with thin walls are vulnerable to fire-induced buckling instability, which reduces their load-bearing capacity. Eurocode 3 design provisions have been found inadequate, leading to alternative methods such as effective design strategies and advanced structural models built mostly with shell FE, which can be complex. For Class 4 steel beam-columns subjected to fire conditions, beam-type modelling to predict the Flexural-Torsional Buckling (FTB) strength has been proposed as an alternative approach, but it has not yielded satisfactory results for large compressive load eccentricities. This paper presents two new low computational cost modelling strategies based on Timoshenko's beam FE to address this issue: the Single beam-column Model (SbcM) and the Cruciform beam-column Model (CbcM). The first consists of a single line of beam FE, while the second uses a grid of beam FE for more flexibility. Both strategies effectively simulate the FTB behaviour in Class 4 steel beam-column during a fire, offering quicker computations compared to shell models. Still, the single-line model is favoured for its simplicity, making it more efficient in analysing complex fire engineering problems.

Simplified analytical model for prediction of collapse resistance of restrained steel beam-column substructure exposed to fire

This paper provides a simplified analytical model for the restrained steel beam-column substructure under a fire-induced progressive collapse scenario, which is applied to predict the collapse resistance of substructures under fire. The simplified model is formulated for axially and rotationally restrained two-span steel beam-column substructures under column-loss scenarios and involves rigid and semi-rigid connections. The response characteristics of restrained substructures exposed to fire under column-loss scenarios in each response stage are elaborately analyzed. A “negative” catenary stage, in consideration of the unique negative axial force effects induced by the temperature thermal expansion, was first introduced in the five-stage simplified model for restrained substructures exposed to fire against progressive collapse. Subsequently, the explicit calculation formulas for determining the vertical loads and deflection of both rigid and semi-rigid joint substructures exposed to fire were derived in a quantified way, based on rigid-plastic mechanisms and restraint coefficient methods. In addition, the corresponding numerical simulation analysis on a restrained two-span steel beam-column substructure with different end constraints and fire conditions was carried out to verify the applicability and reliability of established theoretical formulas. Comparisons of vertical load-deflection relationships between the calculation formulas and corresponding numerical simulation shows good accuracy. For more accurate prediction results, the error analysis was further conducted, and several theoretical formulas were modified, which were verified to be accurate and reliable after correction. With derived resistance functions, the resistance of steel beam-column substructures in fire-induced progressive collapse scenarios can be predicted.