Behavior Of Steel Beams Research Articles

The behavior of steel beams with triangular welded hollow flange

The behavior of steel beams with triangular welded hollow flange

Behavior of steel beams with different web profiles along the beam length

Previous research confirmed that a corrugated web beam (CWB) can sustain a higher shear stress than the conventional flat web beam (FWB), contrary to the case of pure bending. In this paper, a new steel beam (SB) is proposed using variable web geometry along the beam length to implement each web shape in a convenient zone along the beam length. Experimental, theoretical, and analytical investigations on the behavior of a SB with different web profiles along the beam length are presented. Accordingly, three specimens were fabricated, created, and tested (one specimen with a FW, one specimen with a CW, and the third with both web shapes). The effective width of the CWB compression flange was calculated theoretically, and the corresponding bending moment was determined using two standards and compared with the experimental results. Finally, a 3D-FEM was built using ANSYS software commercial program. By using the validated model, the flange and web thickness in both the M–V and M zones were analyzed in addition to the steel grade of the flange. This study's results revealed that the new beam model specimen with both CWB and FWB outperformed its FWB counterpart in terms of shear strength and ultimate capacity by 60%. The Eurocode design of steel structures recommends formulas that can safely predict the beam bending moment of the new model. The results of the parametric analysis showed that the most imperative parameters affecting the capacity and behavior of new beam model are the flange-to-web thickness ratio and flange steel grade.

Behaviour of steel beam subjected to the fire

Fire as one of the extraordinary load is essential to study in all its aspects. It evolve to study the fire development as well as the structural analysis of elements subjected to the fire. The present paper deals with steel beam fire resistance determination by these two approaches (analytical and numerical) and compares the results.

Strengthening of I-Section Steel Beams by Prestressing Strands

Six I-section steel beams had been fabricated and tested to understand the influence of prestressing strand on the load deflection behavior of steel beam. All tested beams are simply supported having the same gross sectional area with clear span (2850) mm, five beams strengthened by two low relaxation seven wire strands, while sixth beam is the reference one. The strengthening beams were subjected jacking stress equal to (1120MPa) and subdivided according to prestressing strand positions (eccentricity). From the experimental tests, it can be noted that, the load deflection curves for strengthened beams are stiffer as compared with reference beam and the percentage of ductility for strengthened beams were decreased when the eccentricity positions change form (0 to 96)mm respectively, on the other hand, the percentage of increasing in maximum applied load for strengthened beams were increased with increasing of strands eccentricity and the maximum applied load reaches to 61.74% as compared with reference, also, the percentage increasing in maximum deflection at middle span for strengthened beams decreases with increasing of strands eccentricity and the minimum percentage of decreasing at middle span of strengthened specimens reaches to 36.31% as compared with the reference beam.

Behaviour of steel beams with circular web openings under impact loading

This paper presents a 3D nonlinear finite element analysis on simply supported steel beams subjected to impact load. The modelling was developed to simulate the beams and the models developed were validated against the corresponding experimental results with good correlation. Parametric studies were achieved to study the steel beam with web openings and to investigate the effect of several parameters such as the number of openings, impact energy and impact location on the impact response of the steel beams. The numerical predictions show that the opening presence reduced the impact force and increased the displacement. In contrast, increase the number of openings has insignificant effect on the impact behaviour within the conditions of this study. Also, higher impact energy induces the beams to exhibit higher impact force and displacement.

Study on the flexural behavior of corroded built-up cold-formed thin-walled steel beams

Eight cold-formed thin-walled steel beams were performed to investigate the effect of corrosion damage on the flexural behavior of steel beams. The relationships between failure modes or load-displacement curves and corrosion degree of steel beams were investigated. A series of parametric analysis with more than forty finite element models were also performed with different corrosion degrees, types and locations. The results showed that the reduction of cross-section thickness as well as corrosion pits on the surface would lead to a decline in the stiffness and flexural capacity of steel beams, and gradually intensified with the corrosion degree. The yield load, ultimate load and critical buckling load of the corroded specimen IV-B46-4 decreased by 22.2%, 26% and 45%, respectively. The failure modes of steel beams changed from strength failure to stability failure or brittle fracture with the corrosion degree increasing. In addition, thickness damage and corrosion pits at different locations caused the degradation of flexural capacity, the worst of which was the thickness damage of compression zone. Finally, the method for calculating flexural capacity of corroded cold-formed thin-walled steel beams was also proposed based on experimental investigation and numerical analysis results.

Behavior of Castellated Steel Beams: State of the Art Review

The state of the art of behaviour of Steel Castellated Beams is explain in this paper. The present research status of behavior of castellated beams is not mature and need much through study compared to beams without openings in the web. The existence of various shapes of openings such as circular, hexagonal, rectan-gular, octagonal and oval etc. in beams web add some additional failure modes namely; lateral-torsional buck-ling of web posts, web post buckling due to shear force, formation of four plastic hinges around the corners of openings, rupture of welded of joints in the castellated beams over a conventional steel beams. A review of experimental and analytical work carried out on castellated steel beams has been presented. The paper also focuses on the influence of various parameters such as types of openings, size of openings, spacing of the openings, aspect ratio, various numbers of openings and strengthening on the behavior of steel beams with web openings

Parametric Study on Behavior of Steel Beam to Reinforced Concrete Column Connections in Moment Frames

The steel beam to concrete column connections in moment frames has been studied during recent years. This system has more advantages compared with steel and concrete systems. There are two kinds of joints, including “through-beam-type” and “through-column-type”. One of the most important parts of the composite structures is their connections. Recently, the various experiments have been performed on the steel beam-concrete column composite structures. In this research, one kind of the joints was modeled in the ABAQUS finite element program and its seismic performance was verified by the experimental results. A parametric study was conducted on the eccentric load, axial load in the center of column, the compressive strength of the concrete, the resistance of the steel and the steel cover plate height effects. The obtained results showed the effectiveness of these parameters on the behavior of connections.

Flexural behaviour of steel beams reinforced by carbon fibre reinforced polymer: Experimental and numerical study

The paper presents the results of an experimental and numerical programme to characterize the behaviour of steel beams reinforcement by composite plates. Important failure mode of such plated beams is the debonding of the composite plates from the steel beam due to high level of stress concentration in the adhesive at the ends of the composite plate. In this new research, an experimental and numerical finite element study is presented to calculate the stresses in the sika carbodur and sika wrap reinforced steel beam under mechanical loading. The main objective of the experimental program was the evaluation of the force transfer mechanism, the increase of the load capacity of the steel beam and the flexural stiffness. It also validated different analytical and numerical models for the analysis of sika carbodur and sika wrap reinforced steel beams. In particular, a finite element model validated with respect to the experimental data and in relation to the analytical approach is presented. Experimental and numerical results from the present analysis are presented in order to show the advantages of the present solution over existing ones and to reconcile debonding stresses with strengthening quality.

Parametric study on load ratio effect on the flexural bending behaviour of axially-restrained HSS steel beams subjected to fire

Purpose In fire condition, the limiting temperature of a restrained steel beam depends on a few parameters, e.g. temperature distributions along and across the beam, beam’s load ratio and span length. The purpose of this study is to investigate the structural fire behaviour of axially restrained steel beams under different beam’s load ratios, taking into consideration the effect of the beam’s end connections configuration. Design/methodology/approach A three-dimensional finite element (FE) computer model has been developed to simulate the structural fire behaviour of axially restrained steel beams and their end connections. After successfully validating the developed model against the outcomes of the available large-size fire resistance experiments, the FE model has been used in a parametric study to investigate the beam’s load ratio effect on the behaviour of the axially restrained steel beams and their end connections. Findings The parametric study showed that increasing the beam loading level significantly increased the beam deflections at elevated temperatures; where, increasing the beam’s load ratio from 0.5 to 0.9 reduced the beam fire resistance by about 100 s. In contrast, decreasing the beam’s load ratio from 0.5 to 0.3 allowed the beam to easily achieve a 30-min fire resistance rating with no fire protection applied. Originality/value Experimental parametric studies are difficult to control in a laboratory setting and are also expensive and time consuming. Therefore, the reasonable accuracy of the validated FE model in reproducing the experimental fire behaviour of steel beams and their end connections makes it a very useful tool for both numerical and analytical studies.

Experimental investigation for failure analysis of steel beams with web openings

This paper presents an experimental study on the behaviour of steel beams with different types of web openings. Steel beams with web openings became progressively more accepted as a well-organized structural form in steel construction since their existence. Their complicated design and profiling method provides better flexibility in beam proportioning for strength, depth, size and location of holes. The objective of this study is to carry out the experiments on steel beams with different types of web openings and performed non-linear finite element (FE) analysis of the beams that were considered in the experimental study in order to determine their ultimate load capacity and failure modes for comparison. Ten full scale models of steel beam with web openings have been tested in the experimental investigation. The finite element method has been used to predict their entire response to increasing values of external loading until they lose their load carrying capacity. FE model of each specimen that is utilized in the experimental studies is carried out. These models are used to simulate the experimental work to verify test results and to investigate the nonlinear behaviour of failure modes such as local buckling, lateral torsional buckling, web-post buckling, shear buckling and Vierendeel bending of beams.

Behaviour of restrained steel beam with reduced beam section exposed to fire

Reduced beam section (RBS) is one of the connection types, which is economical and popular for use in steel moment frames in seismic regions. By cutting some portions of the beam flanges near the column face, the RBS connections are designed to form plastic hinge within the RBS zone so that it could enhance the structural seismic performance. However, the steel beams with RBS connections have to provide robustness when exposed to fire. Although the responses of ordinary steel beams to elevated temperatures have been investigated over the last few decades, there has been very limited research on the behaviour of steel beams, with RBS connections in fire. This study includes a series of numerical analysis, to investigate the high-temperature performance of steel beams with RBS connections, compared to the responses of ordinary steel beams to fire. Various parameters have been considered, including the types of fire curves, the levels of beam-end restraints and the cutting profiles of the RBS connections. Overall, the deformation shape of RBS beams at high temperature is similar to that of ordinary steel beams, whereas the RBS beams could have longer period of fire resistance. The cut section actually provides both rotational and axial ductility/deformability to the connection, enhancing its fire resistance. Moreover, the cutting length, proposed by EC8, is also adequate for fire design. The minimum distance, between the RBS zone and the beam-end, proposed by FEMA-350 has been shown sufficient.

Linear buckling analysis of welded girder webs with variable thickness

Steel girder web panels have been subjected in recent decades, to a number of experimental and numerical studies but the mechanisms that regulate the behaviour of the panels composed by two subpanels with different thickness were not deeply studied. Furthermore specific design rules regarding the estimation of the buckling coefficient for panels with variable thickness are not included in the codes even if this is a common situation particularly for steel bridge girders with beams having significant height. In this framework,this work aims to investigate buckling behaviour of steel beams with webs composed of panels with different thicknesses subjected to both in-plane axial compression and bending moment and gives some simplified equations for the estimation of the buckling coefficient.

Effects of temperature change on elastic behavior of steel beams with semi-rigid connections

Based on the nonlinear displacement-strain relationship, the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change. Considering the non-uniform temperature distribution across the thickness of beams, the formulas for stresses and vertical displacements were presented. On the basis of a flowchart for analysis of the numerical example, the effect of temperature change on the elastic behavior of steel beams was investigated. It is found that the maximal stress is mainly influenced by axial temperature change, and the maximal vertical displacement is principally affected by temperature gradients. And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints. Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints. It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant. However, the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.

Dynamic Crushing Behaviour of Box Section Steel Beams

As a popular energy absorber, steel box-sectional beams are widely used in various engineering structures. In this paper, the dynamic crushing behaviours of steel beams with box cross sections are investigated and outlined. Systematic parametric studies were conducted in order to study the effect of material properties, including strain hardening ratio and strain rate effect, length of the beam, and initial impact velocity on the crushing behaviours of the steel beams. A series of numerical models were constructed with various sets of parameters and used for crashworthiness analyses. Maximum crushing force, mean force, and specific energy absorption were recorded after analyses and compared to reveal the influences of parameters. Empirical equations were also developed based on the analyses results using nonlinear regression method, which can predict the effects of the initial impact velocity on the peak crushing forces of steel beams with box sections.

An Inelastic Beam Element with Hysteretic Damping

In this work, an inelastic beam macro-element that incorporates hysteretic damping is presented. Based on classical theory of plasticity, a Bouc-Wen type model is utilized that simulates the hysteretic behavior of an inelastic spring element. Using this model, an inelastic nonlinear beam element is formulated based on the appropriate combination of two coupled nonlinear spring elements. The equations of motion are determined and are cast in a state-space form for the vector of the end displacements, velocities and hysteretic forces. The system is solved by employing a Runge-Kutta type of algorithm. The proposed inelastic beam model is then employed to simulate the experimental dynamic behavior of steel beams. The model parameters are estimated with the aid of a nonlinear system identification algorithm using existing experimental data. The proposed element approximates the inelastic behavior of steel beams adequately within plastic regions that do not undergo substantial stiffness degradation, or other relevant phenomena. Finally, the hysteretic damping features of the model are demonstrated.

Residual Stresses in TIG-Welded I-Beams. Experimental Test-Setup and Validation of Numerical Model

The presence of residual stresses is a determining factor in the buckling behaviour of steel beams. It is therefore necessary to know the magnitude and the distribution of residual stresses in welded beams. Experimental measurements of these residual stresses are expensive, timeconsuming and they give no insight in the evolution of the stresses during the welding process. For these reasons it is interesting to have a numerical model which allows a prediction of the residual stresses due to welding and which allows a study of the parameters that have an influence on the residual stresses (e.g. yield stress, heat-input, thermal expansion coefficient, …). Such a numerical model can result in a proposal for a welding process that leads to less detrimental residual stress distributions in welded I-beams. However, the results of the numerical model must always be checked with reality. This contribution contains the experimental verification of the finite element model for both single plates and I-beams with rather small dimensions. First, an overview of generally accepted influencing factors on the residual stresses is given. After this introduction, a setup which allows control of the parameters for making reproducible weld seams is presented. This setup is usable for both plates and I-beams. Next it is described how the residual stresses in a plate and a beam were measured. Finally the results obtained from different configurations in the experiments are compared with the results from the FE-model. It is shown that the FE-model gives reliable predictions for the residual stresses.

A simplified analysis of catenary action in steel beams in fire and implications on fire resistant design

This paper describes the results of a numerical investigation of the large deflection behaviour of steel beams under fire conditions, taking into consideration the effect of catenary action provided by the surrounding structures. The main focus is on the development, validation and application of a simplified calculation method that may be adopted in design calculations. Because no experimental result is available for validation of the simplified calculation method, the finite element program ABAQUS has been used to simulate the large deflection behaviour of a number of steel beams so as to provide alternative results for validation of the proposed method. Utilising catenary action has the potential of eliminating fire protection to all steel beams without causing structural failure in fire. However, practical application of catenary action will be restricted by concerns over large beam deflection causing integrity failure of the fire resistant compartment and additional cost of strengthening the connections and the surrounding structures to resist the catenary forces in the steel beams. This paper will provide a discussion on practical implications of utilising catenary action in steel beams as a means of eliminating fire protection. A number of examples will then be provided to illustrate the type of steel framed structure that could benefit the most from exploiting catenary action in fire resistant design.

Bolted end plate connections for steel reinforced concrete composite structures

In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.

FLANGE COMPACTNESS EFFECTS ON THE BEHAVIOR OF STEEL BEAMS WITH CORRUGATED WEBS

In this paper, the effects of the flange compactness on the behavior of steel beams with corrugated webs are experimentally and analytically studied. The experimental program consists of four simply supported beams with different web configurations (Flat or Corrugated) and different flange compactness (non-compact or compact). Nonlinear finite element technique was used to model the tested specimens and to carry out the parametric study. The variables of the parametric study were the thickness and the width of the flange transversal stiffeners (FTS), and the flange thickness (FT). The results obtained from the finite element were compared with the corresponding experimental ones that show a reasonable degree of accuracy. Finally, comparison between beams with corrugated webs and those with flat webs was carried to exhibit the advantages and disadvantages of using web corrugation. The results indicate that; the flange transversal stiffeners enhances the beam yield load by 21% and the flange thickness can increase the yield load by 56%, where if both of them are used (FTS and FT) the beam yield load can achieved 72% more than beam without these enhancement.