Beam Web Research Articles

Effect of Web Post Width on Strength Capacity of Steel Beams with Web Openings: Experimental and Analytical Investigation

Day by day, technology has been changing progressively because of the remarkable hastening of research and development activities. Perforated beams are one such example of advancement in construction technology. Steel beams with web openings are those that have regularly spaced web openings along the length of the beam. The web openings are created in various ways such as wire cutting and welding. Castellated and cellular beams differ in the creation of web openings. Studies addressing the effect of web post width of steel beams with web openings on the strength capacity of beams are rare. Therefore, the objective of the present work was to examine the influence of web post width on the strength capacity of beams with web openings. First, experimental tests were carried out on three full-scale specimens of a steel beam with oval-shaped web openings, cellular beam, and solid web beam. The same beam was modeled using finite-element software ANSYS and the behavior was compared in terms of load–displacement curve and failure modes. Later, a detailed parametric study was carried out to study the behavior of beams with web openings having variation in web post width using nonlinear finite-element analysis. The simply supported steel beams with web openings subjected to midspan concentrated load with varying web post width and shape of openings were modeled and analyzed. From the analysis results, it was found that the shape of web openings and the web post width play an important role in the strength capacity of the perforated beams. The maximum strength reduction capacity was found to be 51.78% for hexagonal openings of depth 150 mm and having a web post width of 50 mm. The minimum strength reduction capacity was found to be 8.93% for hexagonal openings of depth 100 mm having a web post width of 500 mm. Web post width plays a significant role in the ultimate strength capacity of beams. Web post buckling is a predominant failure mode in steel beams with web openings and it can be prevented by maintaining sufficient web post width.

Studying the web notch shape effect on shear load: Numerical analysis for steel beams

The connections made for steel beams are used quite often, in which a part of the beam cross-section needs to be cut at the connection joint. There are many shapes in which the location of the cutting part of the web is formed, but this is done in a manner where previous studies or calculations have not been made and may cause an adverse effect on the section's resistance to stresses. For this reason, a finite element (FE) analysis was conducted on 34 models in this research, among which many variables and notched shapes were selected that could be implemented in the web cutting process. Some specimens were first compared that were used for studying in the experiments of the previous research. Great agreement and high accuracy were obtained in the use of FE numerical analysis in the modeling of this type of steel structural elements. The maximum load capacity, the distribution of normal stresses as well as the shear stresses at the notched zone were measured. From the study of the different variables, it was observed that the use of a quarter-circle notch was the best shape for locating the beam web cutting, as the increase of the load ratio reached 1.14 when compared to the right angle. The use of a half-circle notch, either from one or both sides of the beam web, negatively affects the web's resistance to stress. A quarter-circle notched from both sides must also be used to increase the load capacity if the flange is cut from both sides.

Development of bent shear panel dampers for eccentrically braced composite frames

Traditional shear panel dampers (SPDs) can be vertically installed in eccentrically braced composite frames (EBCFs) to effectively increase the stiffness and strength of such frames. Moreover, SPDs can dissipate the input energy in such frames through their plastic deformation in seismic conditions. However, vertically installed dampers may impose an additional bending moment on the middle segment of the primary beam in the composite frame, resulting in significant damage to the concrete slab. To overcome this limitation, a novel type of SPDs with bent web panels (BSPDs) is developed, in which the end plate of the BSPD is connected to the web of the composite beam. In this configuration, the bending moment resulting from the SPDs can be minimized, thereby reducing the damage to the concrete slab. In this study, the characteristics of BSPDs and their configuration in EBCFs were examined. Subsequently, the key design parameters of the EBCFs with BSPDs, which could help alleviate the damage to the concrete slab, were identified. Moreover, different BSPDs were experimentally and numerically investigated to verify their seismic performance. The results indicated that BSPDs exhibit ductile behaviour after yielding and excellent energy dissipation capacities. Low-yield-point steel and link flanges can be used to increase the deformation capacity and energy dissipation efficiency of such dampers. Results of the experimental and numerical investigations were considered to specify design recommendations for the application of BSPDs.

Experimental and numerical study on bent shear panel damper made of BLY160 steel

Shear panel dampers (SPDs) are widely used in eccentrically braced composite frames (EBCFs) to effectively increase their stiffness and strength and dissipate input energy through plastic deformation in seismic conditions. However, these vertically installed SPDs could also impose an additional bending moment and axial forces on the composite beam in the frame, thus damaging the concrete slab of the frame. The SPDs used in this study were bent in the middle and connected to the web of the composite beam in the frame to overcome the drawbacks of traditional SPDs. Therefore, the resulted bending moment and axial force by the SPDs can be minimized, thus controlling the damage to the concrete slab. In this study, the cyclic behavior of the bent SPDs (BSPDs) made of low-yield-point steel is experimentally studied. Twelve specimens were designed and tested under quasi-static hysteretic loading to investigate the influence of web thickness, constrained flange, out-of-plane buckling restraint, and BSPD length ratio on the mechanical properties of BSPDs. Furthermore, the failure modes and hysteretic force–displacement curves of BSPDs made of low-yield-point steel are obtained through the tests. Finally, finite element models were established to simulate the cyclic behavior of BSPDs and analyze the key factors affecting the mechanical properties of BSPDs.

Analysis of the openings of aircraft composite laminated wing beam web under shear load

Abstract In this paper, experiments and finite element methods are used to study the openings of the composite wing spar web of a civil aircraft. First, according to the design principles of composite laminates, determine the layup sequence and layup ratio of the spar, and then lay the beam webs and the beam edge strips integrally; then, calculate the equivalent of the spar by using the classic laminate theory Material properties, the method to calculate the equivalent elastic modulus of composite laminates of different thicknesses is derived; then, the influence of opening shape and opening angle on the strength of composite wing spar web under shear load is analyzed. Finally, the reinforcement design is carried out on the opening position. This research method not only solves specific engineering design problems, but also proposes a set of practical, cost-effective and efficient design methods for composite material opening shapes, which has a certain generality. Its design ideas and methods provide technical support for civil aircraft structural design.

Parametric Analysis of Structural Noise of Steel-Concrete Composite Slab Beams

In this study, the vibration acceleration and radiation structure noise in specific points, 30 cm away from the center surface of each plate of the concrete deck, web, and flange of the steel beam, are measured via the hammering test. The test is conducted on the middle concrete deck of an 8.5 m steel-concrete composite slab beam. The accuracy of the numerical model is then carefully justified. The influence of the number of shear studs, spacing, and arrangement of ribs on the concerning results is methodically examined and discussed by employing the numerical model. In the center frequency of 10–1000 Hz, the total sound power level of the structure can be lessened by improving the concrete deck thickness as well as the number of shear studs. The reduction of the rib spacing can effectively lessen the sound power level as well. The noise reduction of the plate with rib arrangement in the midspan zone is more influential than the case with uniform layout in the whole span.

Coupling of NURBS and Meshfree RPIM for plane stress of web with openings

This study presents a novel approach for the coupling of the non-uniform rational B-spline (NURBS) with the radial basis functions (RBF) under the framework of the meshfree radial point interpolation method (RPIM). In this method, denoted as N-RPIM, the NURBS basis functions are employed to model the geometry of the problem domain exactly, whilst the RPIM is used for field variables interpolation. The formulation is applied to the web of a cellular beam under plane stress condition to highlight the advantages. The results show that the method works efficiently, and provides favourable performance against FEM. The solution of the former converges faster, thus highlighting the potential of N-RPIM for future development.

NUMERICAL INVESTIGATION OF AS-BUILT AND CARBON FIBER REINFORCED POLYMER RETROFITTED REINFORCED CONCRETE BEAM WITH WEB OPENINGS UNDER IMPACT LOADING

It is not uncommon to provide openings in beams due to utility needs such as mechanical, electrical and sewerage passages. However, no clear guidelines are available in code of practice to handle beam web openings and presence of openings in beams changes behavior of Reinforced Concrete beam into a more complicated one. This research work investigates response of RC beam with openings under impact loading and proposes application of carbon fiber reinforced polymer (CFRP) composites to restore lost beam performance due to the presence of web openings. 3D nonlinear finite element software LS-DYNA is used for model development, validation and parametric finite element analysis work. The accuracy of the nonlinear finite element models are verified using experimental results from literature. Further parametric studies are performed to optimize beam web openings on opening location, size and CFRP no. of layers and fiber orientation. Numerical results showed as compared to control, large opening cutouts in RC beam decreased impact resistance of a beam by 54%. Also, RC beam exhibited poor impact loading resistance close to loading point (mid span) and performed good near shear zone. As compared to control as-built RC beam, Carbon Fiber Reinforced Polymer (CFRP) composites strengthening reduced mid span deflection by 74% and improved beams brittle failure mode. Also, 900 fiber orientation complete wrapping resulted in reduction of shear cracking around opening however exhibited low overall impact resistance as compared with 0º fiber orientation.

Improvement of progressive collapse resistance for a steel frame system with beam–web opening

Various disasters may trigger a progressive collapse of frame structures, resulting in a high demand for new preventive structural strategies. Among the strategies adopted, increasing the joint rotation capacity to improve catenary action and forming a second path in the joint area are the most effective. In this study, a novel principle is proposed, in which the web opening is used to meet the rotation capacity, and kinked reinforced bars are installed in the beam–column joint to realize a second path. Experimental and numerical investigations were conducted on a frame substructure with kinked reinforced bars, considering their diameters, kinked heights, and lengths. The deformation capacity, vertical force vs. deformation response, failure mode, and contributions of the flexural and catenary actions on the reinforced bars were evaluated. The test results demonstrate that the kinked reinforced bars in the reduced-web-section connection (RRWS) specimens started to work after the plastic state. Although they had little influence on the flexural action, they were very important to the catenary action. When the kinked height a was less than 2d, the bearing capacity and ductility of the specimen increased with a, but further increasing the kinked height a beyond 2d would reduce both the bearing capacity and the ductility. In addition, the failure modes of the specimens were related to whether the plastic hinge was formed first or the reinforced bar had a major role first. Therefore, it is suggested to select the kinked height of the reinforced bar according to the deformation capacity of the beam, and the diameter of the bar as half of the kinked height.

Optimum Design of Fully Composite, Unstiffened, Built-Up, Hybrid Steel Girder Using GRG, NLR, and ANN Techniques

Composite steel beams are commonly used element in multistorey steel buildings to enhance floor economy and serviceability and provide more clear height. Due to the low level of stress in the webs of such beams, hybrid sections are used where the flanges have higher strength than the webs. A lot of earlier research was carried out to optimize the design of the hybrid and nonhybrid composite steel beams under both static loading and dynamic behavior. However, there is still a need to develop a more practical optimization method. The aim of this research is to develop simple and practical equations to determine the optimum cross section dimensions for both shored and unshored, simply supported, hybrid and nonhybrid, composite steel beam under static loads. To achieve that goal, a research program of two phases was carried out. The first phase was generating a database of 504 composite beams with different steel grades for flanges and webs, subjected to different values of bending moment. The cross section of each beam in the database was optimized using GRG technique to minimize the cost considering the unit price of each steel grade. In the second phase, the generated database was divided into training and validation subsets and used to develop two predictive models using Nonlinear Regression (NLR) technique and Artificial Neural Network (ANN) technique to predict the optimum cross section dimensions and hence the optimum weight and cost. The accuracies of the developed models were measured in terms of average error percent. NLR and ANN models showed average error percent of 16% and 11%, respectively.

Experimental study of bending resistance of pre-fabricated truss beams under eccentric loads

In order to study the flexural performance of pre-fabricated integrated floor truss beams under eccentric loads so as to improve the beam design for its application in actual projects. This paper proposes a new type of fabricating truss girder connected by high-strength bolts. And taking Yuyan Tower as an example, this paper conducted an elastic loading test for code compliance verification and a destructive test of ultimate bearing capacity for the pre-fabricated truss beams, with a focus on the mechanical performance of the truss beams, joint interface shear resistance, destructive mechanism, and deformation law of the truss beams. The results showed that under eccentric loads, buckling failure occurred at the diagonal webs and end vertical webs of the truss beams under compression, and no sliding and friction energy dissipation occurred at the connection joints, which was in accordance with the design principle of “strong joints and weak members” as stipulated in the design code. Compared with the designed load, the ultimate bearing capacity of the truss beams was increased by 80.5%, inhibiting sufficient safety reserve. Also, the truss beams showed good overall stability and safety. After the truss beams were unloaded, the tension displacement and vertical displacement from the middle part to the lower part of the span could recover up to 78% and 83% of the maximum displacement respectively, indicating that the truss beams had strong deformation resistance. Through theoretical derivation, the theoretical value of shear resistance at the splice joints was found to be higher than the experimental value, which implied that the performance of the shear bolts at the joints was not fully developed and the structure design was relatively safe. The results of the study can provide important experimental data and theoretical basis for the actual projects, which can offer scientific guidance on project design and construction and is of great significance to the sound development of pre-fabricated buildings.

Effect of a “Slight” Curvature of the Axis of a Thin-Walled Nonprismatic Beam on its Free Vibration

This paper presents an analysis of the effect of a “slight” curvature of the axis of a thin-walled beam on its eigenfrequencies and forms. By “slight” we understand such a beam curvature at which no theory of curved beams (arches, horizontally curved girders), but classical beam theory is applied. The subject of the analysis is the open nonprismatic thin-walled beams with any geometrical parameters, and prismatic beams. The thin-walled beam model used in the analysis was derived on the basis of the momentless theory of plates, using the Vlasov assumptions. The free vibrations of the beams were analysed. Calculations were performed for four groups of beams. Each of the groups comprised two beams with the same configuration of flanges and identical geometrical cross section characteristics, but differing in web geometry. One of the beams had a symmetrical web (a beam with a rectilinear axis in the web plane), whereas the web of the other beam was asymmetrical (a beam with its axis curved in the web plane). The algorithm based on Chebyshev polynomials was used to solve the variable coefficient equations describing the model’s vibration. According to this algorithm, solutions are sought in the form of Chebyshev series and the closed analytical recurrence formulas generated by the algorithm are used to calculate the coefficients of the equations. It has been shown that even a “slight” curvature of the beam’s axis has a significant effect on its eigenfrequencies and forms, as confirmed by a comparison of the results with the ones obtained using Finite Element Method (FEM).

Innovative self-centering systems using shape memory alloy bolts and energy dissipating devices

In conventional eccentrically braced frames (EBFs), earthquake input energy is mainly dissipated by plastic deformation of link beams. However, the plastic deformation of link beams can cause extensive structural damage during severe seismic events. The self-centering eccentrically braced frames (SEBFs) are one of the strategies that have been proposed to address this problem. This paper presents two new SEBF systems incorporating shape memory alloy (SMA) bolts and energy dissipation devices, consisting of shear tabs and web hourglass pins (WHPs). SMA bolts are employed in collector beams-to-link beam connections to dissipate energy and recenter the frame with negligible residual drift after an earthquake, while shear tabs and WHPs are utilized in both ends of the link beam web to enhance the seismic performance of the frame. Detailed finite element simulations are performed to assess the cyclic performance of the proposed self-centering systems using experimentally validated models. The results indicate the excellent efficiency of the proposed systems in terms of recentering and energy dissipation capacity. It is shown that the application of shear tabs and WHPs can improve the ultimate strength, equivalent damping and energy dissipation capacity of the system by up to 20%, 35% and 60%, respectively. The experimentally validated models are then used to investigate the effects of key design parameters such as initial prestress of SMA and shear tab bolts, friction coefficient, and the diameter and clear length of the hourglass pins. The results of this study should prove useful in the practical design of the SMA-based self-centering systems.

Experimental investigation of link beams with perforated web section in eccentrically braced frames

Eccentrically braced frame (EBF) system is one of the most effective lateral loads resisting systems for steel structures. In these systems, links are designed in such a way that they yield in shear not only to provide high ductility and rigidity but also to provide a high energy dissipation capacity. In particular, as the internal forces to be considered for the design of the members outside of the links must be calculated with the amplification factor based on the yielding of the links, the magnitude of the internal forces may become so large that they may not be met by the adjacent members. Therefore, it is challenging to develop an economic design for adjacent members and connections because of the high level of design loads obtained by the amplification factor. This paper studies the effect of the perforation arrangement in the web of shear link beams in eccentrically braced frames. Both experimental and numerical investigation were conducted to demonstrate the effectiveness of the link beam with slotted perforations in the web portion. Seven equivalent isolated link beam specimens with various slot-hole patterns were tested under quasi-static cyclic loading. The results of the study indicate that using slot-holes in the web portion reduces the link shear capacity significantly. The results also show that the failure mechanism of reduced link sections was controlled by fracture at end of the slot-holes and inelastic rotation capacities were varying between 0.025 rad and 0.065 rad depending on the slot-hole patterns.

Cold-formed steel beam-to-column bolted connections for seismic applications

Cold-formed steel (CFS) portal frames are gaining increased popularity around the world. The structural performance of these frames is to a large extent controlled by the CFS beam-to-column connections, which in most practical applications transfer the loads through the beam web using a gusset plate, while the flanges are left unconnected. This can lead to premature local buckling failure of either the CFS beam web in the connection zone or the gusset plate, leading to poor seismic performance. This paper aims to develop two new connection configurations which engage the flanges in the connection behaviour. In conjunction, practical seismic design recommendations are presented, which allow a balance between the load carrying capacity of the connections and their seismic performance to be reached. Detailed Finite Element connection models, taking into account material nonlinearity and initial geometric imperfections, are developed and validated against experimental data. The validated FE models are then used to conduct a comprehensive parametric study to investigate the effects of key design parameters, including the beam thickness and the gusset plate shape and thickness, on the moment–rotation behaviour of the connections. Based on the results, suitable connections, which balance strength with seismic performance, are introduced. Their seismic performance is evaluated in terms of ductility, energy dissipation and damping coefficient, leading to some practical design recommendations commensurate with different seismic performance levels.

Shear Strengthening of RC Deep Beams with Symmetrically or Asymmetrically Positioned Square Openings Using CFRP Composites and Steel Protective Frames

In most cases, openings are made in the Web of deep beams for installations to pass through. These members require to be strengthened since the openings reduce load‐bearing capacity. This study utilizes carbon fiber‐reinforced polymer (CFRP) composites and steel protective frames (SPF) as strengthening configurations in reinforced concrete (RC) deep beams to improve the strength lost due to the square openings. To this end, eleven specimens with 10 × 50 × 120 cm in size were subjected to the three‐point monotonic loading. In each beam, one or two square openings of 18 cm in each side are positioned either symmetrically or asymmetrically along the beam before it is strengthened with CFRP composites or SPFs. The strengthening composites were installed using externally bonded reinforcement (EBR) or externally bonded reinforcement on grooves (EBROG) techniques in two wrapped or inclined configurations. The obtained results indicate that specimens retrofitted by the SPF exhibited a superior performance as their loading capacity and energy absorption were enhanced by 115% and 337% in comparison with the reference beam, respectively, while these values for the specimens retrofitted by the EBROG technique were 58% and 182%, respectively, and 42% and 105% for those strengthened with the EBR technique.

Effects of Beam Cross-Sectional Size and Web Connection Type on Mechanical Properties of Beam-to-Column Connection

Effects of Beam Cross-Sectional Size and Web Connection Type on Mechanical Properties of Beam-to-Column Connection

Thermal Effects on the Bearing and Ductility of Tubular Reduced Beam Section Connection: Numerical Investigation

In the present paper, an innovative fire-earthquake resistant joint called high-performance tube (HP-T) connection is presented and numerically validated. This HP-T connection improves the axial and rotational ductility as well as prevents brittle failure. Two series of models were simulated in ABAQUS software. In the first set of models, which was designed for heat simulation, a sequentially coupled thermal-stress analysis was performed to investigate the effects of different parameters such as web and flange tube thickness and the ratio of the applied load. To simulate the fire damage, two probable scenarios were considered: bottom flange tube damage and beam web damage when exposed to combined initial loading and fire. In the second set of models for seismic simulation, the failure mode, hysteretic curves, and strain distribution were analyzed. According to the results, HP-T robust connection not only provides appropriate ductility enhancement in force-variable fire conditions but also withstands at least 8% inter-story drift without considerable strength reduction.

The Effect of Connections on The Global Response of Built-up Cold-formed Steel Beams with Corrugated Webs

The objective of this paper is to quantify the slippage and rotation in the connections of a double fixed corrugated web beam. Two types of connections between the component parts of the built-up beam were used, i.e. MIG brazing and spot welding, which offer different rigidities and bearing capacities for the built-up beams. Experimental tests were conducted on three MIG brazed and two spot welded specimens, respectively. The test setup consisted of a six-point bending configuration which is equivalent to a uniform distributed load applied to the beam. The load was applied from a 500kN actuator through a leverage system that allowed the distribution of the force. An out-of-plane structure prevented the beam from lateral torsional buckling. The testing exhibited relatively large slippage and deformation in the bolted connections and in the supporting device, respectively. However, the high rigidity of the beam maintained the mid-span deflection in the serviceability limit state limits. The built-up corrugated web beams made of cold-formed steel profiles represent an efficient and suitable structural solution for buildings. Nevertheless, experimental research due to inevitable slippage and the endplate deformation must be performed to characterize the connection.

Parametric study of trapezoidally corrugated web beam

In this paper, the behaviour of cold-formed steel beam having trapezoidal corrugation profile of web has been studied by finite element method using ANSYS APDL V12.0. In this investigation, the considered parameters are corrugation angle, and the thickness of web plate. The corrugation angle has been varied from 30˚, 33˚, 36˚ 39˚, 42˚ and 45˚. The thickness of the web is taken as 3 mm. From the study, it is concluded that a rise in corrugation angle leads to an increase in the strength capacity of beams. The average increase in strength capacity of a corrugated web beam is 22% over a plain web beam. The 45˚ angle of web corrugation is found to be excellent amongst all angles of web corrugation. The height to thickness (h/tw) ratio is the main variable responsible for the buckling of the beam. As the ultimate load behaviour of trapezoidal corrugated web beams with stiffeners was found to be better than beams without stiffeners, therefore its importance cannot be neglected in the analysis and design.