Steel Webs Research Articles

Fragility Assessment of a Long-Unit Prestressed Concrete Composite Continuous Girder Bridge with Corrugated Steel Webs Subjected to Near-Fault Pulse-like Ground Motions Considering Spatial Variability Effects

Prestressed concrete composite girder bridges with corrugated steel webs (PCCGBCSWs) are extensively employed in bridge construction because of their low dead weight, fast construction, and high prestressing efficiency. Moreover, PCCGBCSWs will experience deformation and failure of the corrugated steel webs, including steel fatigue and fracture, during earthquakes. These changes will introduce safety hazards, which can be addressed via bridge disaster prevention and mitigation. Because near-fault pulse-like ground motions (NFPLGMs) have high peak accelerations, these motions can easily cause damage to a bridge. Therefore, in this study, a seismic fragility assessment is performed for long-unit PCCGBCSWs subjected to NFPLGMs considering spatial variability effects, and a sensitivity evaluation of the seismic fragility is conducted considering girder type, bearing type, ground motion type, and apparent wave velocity to offer a point of reference for seismic design. The results show that PCCGBCSWs are less vulnerable than concrete bridges. The shock absorption effect of the friction pendulum bearing is better than that of the viscous damper. The impact of NFPLGMs on bridges is greater than that of near-fault non-pulse-like ground motions (NFNPLMs) and far-fault ground motions (FFGMs). The seismic fragility under nonuniform excitation conditions is greater than that under uniform excitation conditions, showing an increasing trend with decreasing apparent wave velocity.

Calculation method for flexural capacity of composite girders with corrugated steel webs

Experimental and numerical simulation studies were conducted to investigate the differences in bending performance between steel I-girder composite girders with corrugated steel webs (CSWs) and traditional steel I-girder composite girders with flat steel webs (FSWs). The flexural capacity calculation method specified in Eurocode 4 is applied to steel I-girder composite girders with FSWs. However, using the method of steel I-girder composite girders with CSWs revealed an error of approximately 25% between the calculated results and the experimental results. This paper employed the continuous strength method to conduct an elastic–plastic analysis of steel I-girder composite girders with CSWs, considering both the bending contribution of CSWs and the strengthening effect of the steel girder. A calculation method for the flexural capacity suitable for composite girders with CSWs was also introduced. Remarkably, the research outcomes indicated that under ultimate loads, the webs of the steel I-girder composite girder with FSWs underwent buckling deformation. In contrast, the webs of the steel I-girder composite girder with CSWs remained intact, showcasing excellent buckling stability. Compared to the calculation results of the formula specified in Eurocode 4, the accuracy of the proposed calculation method in this paper is improved by 17%. This method can effectively predict the flexural capacity of composite girders with CSWs and is suitable for practical engineering applications.

Optimization of open web steel beams using the finite element method and genetic algorithms

Studies on structural optimization have gained prominence recently, and the search to consume resources in a more conscious and effective way encourages the use of such techniques in all fields. In this respect, this study aims to use computational optimization techniques to determine the maximum load-bearing capacity of hollow-core steel beams for two groups of different shear lines, one generating beams with opening in the shape of hexagons and the other having the shape of ellipses. The second group includes beams with circular openings as a particular case. A three-node triangular finite element for the analysis of structures in plane stress is used for the structural analysis of the beams. The design variables define the shape and number of opening in the beam, and a computational formulation using a genetic algorithm is presented to find the cut line that maximizes the load capacity of the beam considering different ultimate and service limit states. Numerical and experimental models in the literature are used to validate the implementations presented in this article, and the results of optimized hollow core beams are presented, demonstrating the efficiency of the formulations used.

Structural Health Monitoring System for a Complicated Long‐Span Continuous Girder Bridge: Implementation and Demonstration

The Dongbao River Xin’an Bridge is the first hybrid continuous girder bridge with corrugated steel webs in China. To assess its service conditions and guarantee its safe operation, a continuous structural health monitoring (SHM) system is designed in this paper. The SHM system consists of a sensor system, a data acquisition and transmission system, and a data processing and control system. The measurement parameters, including vehicle loads, temperature, deformation, strain, and acceleration, are determined, and a detailed sensor layout is given based on the mechanical characteristics of the bridge. The SHM system adopts a bus gateway and an IP modem to collect and transmit sensor data. Monitoring data from October 9, 2022, to March 16, 2023, were analyzed. The probability distributions of the daily maximum temperature differences and vehicle loads are reconstructed. The correlation of girder deflection and strain with ambient temperature has been demonstrated. The identification and tracking of modal parameters are implemented. The results show that the maximum deflection is within the threshold range and that the modal parameters are basically stable. All the results demonstrate the healthy structural condition of the bridge and the excellent working performance of the SHM system. The collected data provide scientific guidance for the performance evaluation of the Dongbao River Xin’an Bridge and the optimized design of similar bridges.

Experimental Study on Fatigue Performance of Composite Box Girder With Steel Bottom Plate and Corrugated Steel Webs

In order to study the fatigue performance and fatigue failure mode of the composite box girder with steel bottom plate and corrugated webs (SBCSWs), the model beam was made and the constant and variable amplitude fatigue experiment were performed. Combined with ABAQUS finite element software, the strain, deflection, and fatigue failure mode of the composite box girder with SBCSWs were analyzed. The results showed that the slope of the load–deflection curve, the slope of the load–strain curve, and the neutral axis height of the model beam did not change during the constant amplitude fatigue test. In the variable amplitude fatigue test, as the fatigue loading time and fatigue load amplitude increased, the slope of the load–deflection curve and the slope of the load–strain curve of the model beam decreased significantly, while the neutral axis height increased significantly. The section strain of the composite box girder with SBCSWs was consistent with the quasi‐plane section assumption. The fatigue failure of the composite box girder with SBCSWs began at the stress concentration at the junction of the steel bottom plate and the corrugated webs. The fatigue fracture section has typical fatigue fracture characteristics.

Dynamic Response Impact of Vehicle Braking on Simply Supported Beam Bridges with Corrugated Steel Webs Based on Vehicle-Bridge Coupled Vibration Analysis

Dynamic Response Impact of Vehicle Braking on Simply Supported Beam Bridges with Corrugated Steel Webs Based on Vehicle-Bridge Coupled Vibration Analysis

Analysis the torsional vibration of PC Box Girder Bridge with Corrugated Steel Webs

In this study, in order to accurately calculate the torsional vibration frequency of a simply supported corrugated steel web composite box girder, the element stiffness matrix of the torsional vibration of the simply supported corrugated steel web composite box girder was derived using the principle of constant dynamic potential energy, taking into account the shear deformation of the corrugated steel web. Analyzed the influence of waveform steel web plate type and shear deformation on torsional vibration frequency. The results show that the torsional vibration frequencies of the four commonly used types of simply supported corrugated steel web composite box girders in engineering are relatively close, and the influence of corrugated steel web types on torsional vibration frequencies can be ignored in practical calculations; The influence of shear deformation on the torsional vibration frequency of simply supported corrugated steel web composite box girder is significant, and exceeds the influence on its bending vibration frequency. Therefore, the influence of shear deformation must be considered in practical engineering calculations

Shear force distribution mechanism of perfobond leiste connectors in joint between corrugated steel web and concrete top slab

Compared to composite bridges with flat steel webs (FSWs), the corrugation shape and significant shear deformation of the steel web in composite bridges with corrugated steel webs (CSWs) will influence the distribution and magnitude of the shear force of connectors in the joint between the steel web and concrete slab. However, these effects have not been considered in current design specifications, which may lead to unsafe designs. This paper investigates the shear force distribution mechanism of perfobond leiste (PBL) connectors in the joint between the CSW and concrete top slab in composite bridges with CSWs. The theoretical solution for the shear force of the joint per unit length is firstly derived based on the elastic bending theory considering the shear deformation of the CSW. Then, finite element simulations using hybrid models of solid and spring elements are conducted to further investigate the shear force distribution of PBL connectors and influencing parameters. The results show that the shear deformation of the CSW has a negligible effect on the shear force of the joint per unit length. In contrast to composite bridges with FSWs, the CSW induces sinusoidal variations in the shear force of PBL connectors, which leads to an increase in the shear force of partial PBL connectors. The amplification factor for the shear force increases with the wavelength of the CSW and the shear stiffness of the PBL connector, while it decreases with the increasing dimensions of the steel upper flange, perforated ribs, and hole spacing. Finally, a calculation formula and corresponding procedure are proposed for predicting the shear force of PBL connectors in the joint between the CSW and concrete top slab for composite bridges with CSWs.

Improved softened truss model for prestressed concrete composite box girders with corrugated steel webs under pure torsion

This paper aimed at developing a theoretical model for prestressed composite box girders with corrugated steel webs (CSW) under pure torsion, based on the combined action softened truss model (CA-STM). The equilibrium equations and materials' constitutive laws were modified, considering the relationship between the initial stress and strain generated by prestressing. According to the yield state of the CSW, proper shear flow conditions were also introduced to describe the deformation coordination relationship between the CSW and concrete slabs. The effect of the width of cantilever slabs on the torsional performance of composite box girders was investigated. An optimized algorithm was employed to solve the CA-STM, resulting in a more efficient and stable solution procedure. The validity of the model was confirmed through the available experimental data. Results showed that the prediction accuracy of the improved CA-STM for depicting entire torsional behavior is great, when considering the reasonable shear strain relationship and modified initial torque calculation formula.

Shear Bearing Capacity of Steel-Fiber-Reinforced Concrete Shear Wall under Low-Cycle Repeated Loading Based on the Softened Strut-and-Tie Model

In this paper, the loading mechanism of steel-fiber-reinforced concrete (SFRC) shear wall (SW) under low-cycle repeated loading is analyzed, and the softened strut-and-tie model (SSTM) of SFRC SW composed of horizontal and vertical resistant members and diagonal strut is proposed, in which the contributions of distributed web reinforcement, concrete, and steel fiber (SF) to the shear bearing capacity (SBC) of SFRC SW is identified. Furthermore, a new algorithm to obtain the SBC of SFRC SW is established, and then it is validated by using the test results of steel-fiber-reinforced high-strength concrete (SFHSC) SW and SFRC SW under low-cycle repeated loading. The results show that the calculated values are in good agreement with the experimental values for the 11 SFRC SWs, and the average strength ratio between calculated and experimental values (Vjh,t/Vjh,c) is 0.958. Therefore, the proposed calculation method is scientific and accurate for analyzing and predicting the SBC of SFRC SW. In addition, the proposed calculation method can scientifically and accurately analyze and predict the SBC of SFRC SW.

Study on seismic performance of prestressed composite joint with CESA columns

Several issues persist in the design and construction of conventional prestressed concrete encased steel (CES) frame structures. This includes the need to strengthen the steel flanges and webs during the passage of prestressed tendons and longitudinal reinforcements through the joint, and insufficient compaction of the concrete cast in the joint core. Therefore, a novel type of prestressed CES frame structure was developed using concrete-encased steel angle (CESA) columns to replace the conventional CES columns. To investigate the seismic shear performance of this new type of prestressed composite joints to propose a method for predicting the shear capacity of joint cores, this study performed tests and nonlinear analysis on three prestressed joints and one non-prestressed joint under low cyclic loading. The failure patterns, energy dissipation, stiffness degradation, deformation recovery performance, and ductility properties were examined for these joints. The effects of prestress level, axial compression ratio, web thickness, stirrup ratio, and steel angle ratio are also discussed. Two formulas are proposed to predict the shear capacity of joint cores based on the fitting of tests and finite element analysis. The results revealed that the oblique crushing of concrete occurred in the joint core at the peak load, resulting in shear failure. Increasing the thickness of the steel web effectively enhanced the horizontal peak load to increase the shear capacity in the joint core. However, an increase in the axial compression ratio may reduce ductility. The formulas developed to predict the shear capacity of the joint core exhibited much higher accuracy, where the simplified practical formula can facilitate convenient design implementation. Overall, these findings demonstrate excellent seismic shear behavior for prestressed composite joints while providing technical support for applications in such types of prestressed frame structures.

Analytical theory of composite beams with CSWs using the state space method

Based on the zig-zag theoretical model of corrugated steel web beam (CSW), the governing equations in the form of state equations are derived and their analytical solutions are obtained for different loads, variable cross-sections and boundary conditions. Through numerical examples, it is verified that the bending moment, deflection and stresses predicted by the present analytical method have a good agreement with the results of the three-dimensional finite element model. The applicability of the present method for non-prismatic continuous beams with CSWs under different loads is also demonstrated. Meanwhile, it is found that the quasi-plane assumption is still valid in non-prismatic continuous beams with CSWs. Through quantitative analysis of the flexural stresses in the top and bottom slabs, it is confirmed that the zig-zag theory in this study can well reflect the accordion effect of CSWs. Because of the inclined bottom slabs in the non-prismatic beams with CSWs, the Resal effect on the shear stresses in the CSWs and bottom slabs, which is caused by the vertical component of the axial force in the bottom slab, is discussed. A refined shear formulation is developed for more accurate shear stresses in the CSWs and bottom slabs, which provides fundamental theoretical support for the strength prediction of the non-prismatic beam with CSWs.

Behavior of Composite Box-Girder Bridges with Corrugated Steel Webs under Eccentric Loading

Behavior of Composite Box-Girder Bridges with Corrugated Steel Webs under Eccentric Loading

Experimental and numerical study on seismic performance of L-shaped multi-cellular CFST frames

Steel-concrete composite frames have been widely used in high-rise buildings. To improve the utilization efficiency of the indoor area, irregular-shaped concrete-filled steel tubular (CFST) columns were proposed for an alternative of the traditional rectangular CFST columns. In this paper, the L-shaped multi-cellular CFST (LM-CFST) frame was proposed, consisting of LM-CFST columns and H-shaped steel beams. Firstly, four LM-CFST frames were tested under combined axial compression and cyclic lateral loads. The local buckling was observed at both the top and bottom ends of the column, and fracture of steel occurred when the drift ratio was large. The hysteresis curves were spindle-shaped with the ductility indexes of 2.61–3.24. Then, a refined finite element model was established and validated against the test results. A parametric analysis was conducted to study the effect of axial compression ratio, web cell length, concrete strength and steel tube thickness on the seismic performance of LM-CFST frames. It was found that the axial compression ratio could affect the seismic performance of LM-CFST frames significantly, while the concrete strength had little effect. Finally, the compression-bending capacities obtained from the sectional analysis method specified in EC4 were compared with those obtained from tests. It was found that this method could predict the compression-bending capacity of the LM-CFST frame under combined axial compression and cyclic lateral loads with reasonable discrepancies.

Corrugated steel web I-girder welding deformation and residual stress research

The distribution law of residual stresses in the welding of corrugated steel web I-girders is still unclear. It is investigated by a combination of experiments and numerical simulations. The three-dimensional thermoelastic finite-element model of corrugated steel web and conventional flat web I-girders were established. Use the resistance strain gauge method to measure the residual stress in the welded corrugated steel web I-girders to verify the correctness of the established finite element model. Analysis of welding residual stress distribution and deformation of two types of I-girders through experimental data and numerical simulation data. The results show that the established finite-element model is correct, and the experimental residual stress values are matched with the simulated values. Two different web I-girders have significant differences in their welding residual stress distribution. At the same time by the two deformation curve can be seen, welding deformation and web shape related.

Synergistic effects of web reinforcement and hybrid fibres on shear performance of continuous deep beams with unsymmetrical web openings

Application of fibre-reinforced concrete or novel web reinforcement detailing could be an effective way to enhance structural behaviour of continuous deep beams with web openings. However, there are very few experimental works studying the synergistic effects of these two methods. Therefore, an experimental programme is introduced in this paper to study synergistic effects of shear reinforcement and hybrid fibres on shear strength of nine double-span deep beams with unsymmetrical web openings (denoted as pierced span). The test specimens were designed to consist of a pierced beam span with a web opening and an adjacent solid beam span. The spans with openings were designed with different shear reinforcement configurations. It was experimentally shown that provision of sufficient web steels above and below web openings has the most important and beneficial effect on ultimate shear strength of the pierced spans. Besides, a tailored steel reinforcing method was also proposed that is capable of improving strut capacity near the web opening. In addition, adoption of hybrid fibre reinforcement led to enhanced crack-opening resistance, ultimate shear strength and shear deformation. Based on the research outcomes, it was recommended to adopt the proposed detailing method or fibre reinforcement dosage for shear strength enhancement of continuous deep beams with web openings. Furthermore, an analytical model was adopted to the shear strength of continuous deep beams accounting for web openings, steel stirrups, and hybrid fibres, which yielded safe predictions.

Sectional strength design of a double-skin truss-reinforced composite shear wall

The double-skin truss-reinforced composite shear wall is an innovative element which comprises two steel plates, core concrete, concrete-filled steel tubes (CFSTs), which act as boundary members, and steel truss connectors. Truss connectors decrease the out-of-plane deformation that affects the steel plates, and due to the resultant connection and constraint effects, the truss connectors enhance the bearing capacity of the wall. This paper briefly introduces the quasi-static test of five full-scale rectangular double-skin truss-reinforced composite shear wall specimens. The specimen exhibited shear compression failure with an aspect ratio of 2.0, and flexure shear failure occurred when the aspect ratio exceeded 2.0. Based on the analysis of actual stress state of the steel web and actual working performance of the infilled concrete, the shear strength and flexure strength design formulas of double-skin truss-reinforced composite shear wall were established. Comparison results with 26 specimens demonstrate that the design formulas exhibit remarkable accuracy, as most errors are within 20 % and 25 %, respectively. Which provide a preliminary sectional strength design proposal for the double-skin truss-reinforced composite shear wall.

Seismic performance and bearing capacity calculation of cross shaped concrete columns with built-in T-shaped steel and steel tubes.

Incorporating T-shaped steel and square steel tubes into a cross shaped concrete column can significantly improve the seismic performance of the cross shaped column. However, the experimental samples are limited, so ABAQUS finite element (FE) analysis method was adopted in this paper to study the seismic performance of this cross shaped column, calculate and verify three specimens in the existing reference. Based on the reliable model, parameter analysis was carried out (25 specimens in total). The results show that the established model has a high degree of coincidence in the hysteretic curve, skeleton curve and failure mode, and the error of ultimate bearing capacity and ductility is within 10%. The configuration of T-shaped steel and square steel tubes inside the cross column can meet the ductility requirements specified in the standard under high axial compression ratio. The ultimate bearing capacity of the cross shaped column increases with the increase of the thickness of the square steel tube, but the ductility deteriorates. The increase in steel tube size increases the strength of the concrete in the core area, and the seismic performance of the cross shaped column was improved. Increasing the thickness of the T-shaped steel flange can better improve the seismic performance of the cross shaped column compared to increasing the thickness of the T-shaped steel web plate. Increasing the height of the specimen will significantly reduce its seismic performance. When the shear span ratio is not greater than 4.1, the ductility can meet the standard requirements. The error of the formula for calculating the compression-bending bearing capacity proposed based on existing calculation methods is less than 5%.

Flexural study on U-shaped steel–concrete composite beam cross joints with L-shaped connection longitudinal transition components

The paper focuses on the U-shaped steel–concrete composite bottom beam cross joints of U-shaped Steel-concrete Composite Open-web Sandwich Plate (USCOSP), presenting a new type of cross joints transmitting the internal force of steel web by L-shaped connection Longitudinal Transition Component (LLTC). LLTC consists of sleeves, L-shaped connection plates and threaded rebars installed on the steel web using sleeves and L-shaped connection plates. Compared with the conventional cross joints which transmit internal force of steel web by Welded Longitudinal Transition Rebar (WLTR), the LLTC cross joints transfer eccentric internal force within the steel web. Through simple-point loading experiments with simply-supported at four ends, the research experimentally investigated the flexural behavior of the WLTR cross joints and the LLTC cross joints. The five specimens were varied to differ in the type of longitudinal transition components, the diameter of WLTR, the number of threaded rebars of LLTC and the strength grades of threaded rebars of LLTC. Experimental results showed that the failure mode of U-shaped steel–concrete cross joint was the buckling of steel web, the buckling of top longitudinal rebar and crush on the concrete under compression near the central region. The LLTC cross joints experienced higher load capacity and better ductility than WLTR cross joints because of little steel web buckling. The ultimate load capacity calculated according to JGJ 138–2016 and the deflection in the elastic stage calculated according to the displacement method agree well with the experiment results.

Experimental study on seismic behavior of RC column-steel beam joints with whole column-section diaphragm

RC column–steel beam (RCS) frame is one of the most popular hybrid structural systems. Multiple types of RCS joints have been proposed in the last few decades. To avoid undesirable bearing failure, complicated strengthening details were required in RCS joints, which caused difficulties in construction. This study proposed a whole column-section diaphragm type RCS joint with simple details. Compared to most RCS joints, the steel web was cut off at the beam-column interface in the proposed joint, which facilitated the arrangement of stirrups and concrete casting. Moreover, the bearing failure could be avoided since the bearing area of concrete was enlarged and the local bearing stress decreased, requiring no additional strengthening details. To investigate the seismic performance of the proposed RCS joint and the impacts of strengthening configurations, four interior joint specimens were designed, fabricated, and tested under cyclic loading. In addition, joint strengths were calculated using the existing methods. The test results showed that joint shear failure occurred in all specimens. The concrete within the hole in the diaphragm has limited influence on joint behavior. The force in flanges could be fully transferred to concrete through the dowel action of longitudinal reinforcements and friction between the diaphragm and concrete. The ductility of joints was significantly improved due to the confinement provided by face bearing plates (FBPs). The orthogonal FBPs could greatly increase the shear resistance of the joint. The predictions for joint shear strengths following the current calculation methods were significantly conservative. It confirmed that adequate shear capacity could be obtained although the simplified details were used. The conclusions of this research can provide a reference for the engineering application of the RCS hybrid frame.