Steel Girder Research Articles

Experimental study on fatigue behavior of UHPC joint in negative moment region of π-shaped steel–concrete composite beams

To improve the crack resistance of concrete bridge decks in the negative moment region of π-shaped steel–concrete composite beam, a novel ultra-high performance concrete (UHPC) joint was first proposed. Based on an actual bridge, a 1:2 scale model was then designed as the specimen. A fatigue test was conducted to investigate the variation of its structural properties during fatigue loading, and a static test was performed to evaluate its residual bearing capacity. The test results show that the new UHPC joint has good crack resistance under fatigue loading and can meet the engineering requirements. The stiffness of the specimen significantly decreases after 3 million fatigue cycles. However, without significant fatigue damage on the surface of specimen, plenty of stiffness is reserved. It is found that there is no significant slip between the concrete deck and steel girder, and between the UHPC and normal concrete in the static test after fatigue, indicating that the studs inside the π-shaped steel–concrete composite beam are arranged reasonably and the interaction of the overall structure is reliable. Furthermore, the ultimate bearing capacity of the specimen decreased by only 9.4% from its design value after being subjected to 3 million fatigue cycles. It is revealed that the application of UHPC in the composite beam effectively improves its crack resistance, resulting in a smaller reduction in bearing capacity. This paper can provide theoretical foundation for the preparation and application of the π-shaped steel–concrete composite beams with UHPC joints.

Theoretical and Numerical Analyses of Steel-timber Composite Beams with LVL Slabs

Recently conducted studies have shown that significant benefits are to be gained by joining steel beams and timber slabs. Steel-timber composite beams present a sustainable solution for the construction industry because of their high strength and stiffness, and lower carbon footprint and self-weight than steel-concrete composite beams. The behaviour of steel-timber composite beams is still being investigated to reduce knowledge gaps. This paper presents theoretical and numerical analyses of steel-timber composite beams consisting of steel girders and laminated veneer lumber slabs. The elastic and plastic resistance to bending were estimated analytically based on the elastic analysis and the rigid-plastic theory. The impact of the composite action, the LVL slab thickness, the cross-section of a steel girder and the steel grade on resistance to bending was evaluated. The load-deflection curve of the composite beam was obtained using a 2D finite element model, in which timber failure was captured using the Hashin damage model. The results of the numerical simulation were in good agreement with the ones of the theoretical analyses.

Mechanical behaviour of steel-concrete joint in hybrid girder cable-stayed bridge

A steel-concrete joint section test model was constructed based on a mixed-scale ratio of the Lancang River hybrid girder cable-stayed bridge in Jinghong City, Yunnan Province. The internal forces and test loading values during normal operations were determined using finite element analysis. The performance was analysed by determining the mechanical indicators at key positions during the loading process. A finite element model of the test girder section was established to analyse the force transmission mechanism of the studied steel-concrete joint section. The test results showed that the centroid of the section moved upward during force transfer from the concrete to the steel girder. The relative slippage at the steel-concrete interface resulted in local unloading and an uneven distribution of longitudinal stresses in the crosswise direction. In addition, the cooperative bearing of the steel-concrete joint girder was transformed to a single bearing of the concrete girder, leading to a monotonic variation of stresses in the web plate. The simulation results showed that the surface plate force-sharing ratio of the composite bridge was the highest. In addition, the force-sharing ratios under the axial force and bending moment scenarios were 57.65% and 78.91%, respectively, indicating that the investigated steel-concrete joint demonstrated good stiffness transition stability. Furthermore, four force transfer types were identified in the steel-concrete joints. The research outcomes provide a fundamental basis for the rational design of joint components applied in hybrid girder cable-stayed bridges.

Damping and tuning of inerter-based dampers for cable vibration mitigation considering girder vibrations

As the spans of cable-stayed bridges increase, and with the use of steel towers and girders, bridge stiffness decreases, the bridge frequencies approach the frequencies of the cables. The effect of girder–cable coupling vibrations cannot be ignored in cable vibration control. This study focuses on the performance of inerter-based dampers (IBDs) in cable vibration control when considering girder vibrations. Two types of IBD, a viscous inerter damper (VID) and a tuned inerter damper (TID), are studied. The system dynamics are formulated through complex modal analysis. Damping effects of the VID and TID are evaluated and optimized based on the complex frequency loci of the damped system. The results indicate that the control performance of the VID and TID for the target cable mode is drastically reduced when the ratio between the girder and target cable frequencies is approximately 1. The effects of the girder–cable coupling vibration on the optimal parameters and control performance of the VID and TID for the target cable mode are found to be significant even when the girder-cable frequency ratio is not close to 1, and the effect can be increased for a smaller girder–cable mass ratio. The different evolution characteristics of the girder–cable coupling effect are revealed by comparing the designs and performances of the VID and TID. The effectiveness of the VID and TID to control the system model considering dynamic cable force and cable sag is verified using a numerical model.

Rehabilitation of Corroded Steel Bridge Girder Ends using Partial-Height Ultra-High-Performance Concrete Encasement

Beam end corrosion is one of the most prominent types of deterioration on simple-span steel bridges. To address this concern, the Connecticut Department of Transportation and the University of Connecticut have jointly developed a repair method for corroded steel girder ends using ultra-high-performance concrete (UHPC) encasement. In this repair, shear studs are welded to the undamaged portion of the web and encased in UHPC to create an alternate load path for bearing and shear forces. This novel repair method has been implemented in multiple states. The widespread promotion of steel girder end repair with UHPC demonstrates the need for literature on field implementations and alternative designs. This paper advances the findings from a field implementation completed in Connecticut in October 2021, which was the first instance of a partial-height repair in the country, the first application of the repair to a weathering steel bridge, and the first use of flange studs to restore shear capacity at the junction of the web and bottom flange. Two of the girder ends were fully instrumented to collect data on the performance of the repaired locations. The paper presents an overview of the bridge, discusses the design and implementation of the repair, provides short-term monitoring data showing its successful activation, and discusses lessons learned throughout the process. It is anticipated that the findings put forward provide support for the use of UHPC encasement as a promising method for the repair of corroded steel girder ends.

Study on The Mechanical and Economic Performance of Super Long-Span Cable-Stayed Bridges with UHPC-Girder

This paper introduces the mechanical and economic performance of cable-stayed bridges with ultra-high-performance concrete (UHPC) girders. Based on the determined general layout and structure system, aiming at minimizing material consumption and considering multiple constraints, the parametric analysis and optimization process of the UHPC girder were discussed. Subsequently, full-scale models of a 1,200 m cable-stayed bridge with UHPC girders and those with steel girders were established and analyzed under load combinations to evaluate their static mechanical performance. Additionally, the material consumption estimation equation was established to evaluate the economic performance of cable-stayed bridges. The economic performance of cable-stayed bridges with UHPC-girder scheme and that of steel-girder scheme were investigated and compared by theoretical calculation and finite element modelling. The results indicated that UHPC-girder cable-stayed bridges are highly competitive for super long-span cable-stayed bridges and represent a promising alternative for the design of large-span bridges in the future. This study provides valuable insights into the feasibility and potential of UHPC-girder cable-stayed bridges.

Prediction of tapered steel plate girders shear strength using multigene genetic programming

Tapered steel plate girders have been widely used in the construction of bridges and heavy industry structures. However, predicting their structural behavior, particularly in shear, is challenging due to their non-prismatic sections and ill-understood influencing factors. Therefore, simplified analytical and classic regression techniques may not be able to capture the underlying nonlinear relationships controlling the shear behavior of tapered plate girders. In this study, multigene genetic programming (MGGP) was utilized to explore such complex relationships, and subsequently develop robust predictive expressions for the tapered steel plate girders shear strength. Attributed to the lack of a large experimental dataset, a nonlinear finite element model (FEM) was first developed and validated against available experimental results in literature. The FEM was subsequently employed to generate a matrix of 211 numerical results to augment 200 more FEM results compiled from previous studies, to cover a wider range of design parameters. The entire dataset was then used in the training and testing of the MGGP predictive expressions. The prediction accuracy of the developed expressions was evaluated against that of other existing expressions. The results showed that the adopted MGGP approach, guided be mechanics understanding, produced elegant predictive expressions with high level of accuracy and generalizability compared to other existing ones examined herein. As such, the developed expressions present an efficient prediction tool that can be adopted by design standards for estimating the ultimate shear strength of tapered steel girders. Finally, reliability analysis is performed on the developed expressions to introduce strength reduction factors in order to satisfy target design conservatism.

Live load and long-term response of steel bridges with high skew

High skew in bridges alters live load distribution and creates performance issues such as deck cracking, superstructure in-plane (horizontal) displacements and bearing distress. In-plane superstructure displacements, also called racking, are particularly important as they cause misalignments of superstructure and approach slabs, stress bearings and expansion joints. This study had two objectives: to evaluate live load distribution in skewed bridges and to understand how skew influences in-plane superstructure displacements. The effect of bridge design details on live load distribution and in-plane superstructure displacements was assessed through parametric studies on highly skewed bridges.A three-span, steel girder-concrete deck bridge with a 47-degree skew was load tested. Load test results were employed to validate finite element analyses that were used to understand the impact of varying skew angle, bridge features and bearing fixity on live load distribution and in-plane superstructure displacements. The ability of the American Association of Highway and Transportation Officials Load and Resistance Factor Design Bridge Design Specifications (AASHTO LRFD BDS) to accurately capture live load distribution for steel girder bridges was evaluated.Field test results, consisting of girder bending and vertical shear strains measured through strain gages strategically located on one of the exterior spans, and parametric studies showed that AASHTO LRFD BDS predicted shear and moment distribution very conservatively and closely, respectively. Seasonal temperature changes were sufficient to create in-plane (horizontal) superstructure displacements. These displacements caused the superstructure to rotate towards obtuse and acute corners for negative and positive temperature changes, respectively. Larger skew angles led to greater transverse (i.e., perpendicular to bridge longitudinal axis) displacements at girder bearings. Longitudinal (i.e., parallel to bridge longitudinal axis) displacements were consistently smaller than transverse displacements and were not affected by skew. Mixed bearing fixity arrangements, with both fixed and expansion bearings over the same pier, limited superstructure transverse in-plane displacements.

Conflation of modal strain energy, spectral finite element, and machine learning techniques for damage detection in multi-span steel girder bridges with variable sections

A new approach is proposed to detect micro and small damages in multi-span bridges constructed with variable sections by combining modal strain energy and spectral finite element through the use of machine learning techniques. The traditional finite element methods are inefficient in detecting and estimating structures' micro-damages. Therefore, wave propagation-based methods must be applied. Micro-damages can be modeled through the spectral finite element method, widely adopted in wave propagation simulation. Among the frequency-based methods used in damage identification, the modal strain energy is more sensitive, especially in complicated structures. However, this method is difficult to apply to steel girders with variable sections and different support conditions. By combining the modal strain energy and the spectral finite element and applying the support vector regression method, the location and severity of damage in steel girders could be accurately identified to overcome the difficulties of detection in complicated elements. To improve the ability of the support vector regression method, in the damage severity estimation, it was combined with feature selection. To evaluate the proposed method's ability, first, an element of the beam- type, with the characteristics of a spectral finite element, is defined in the OpenSees software. To assess the accuracy of the defined element in detecting micro-damages, a tested numerical model was adopted to measure the accuracy of the provided element. Next, to detect small damages, the model of the steel girder bridge with the defined element was prepared, and the modal properties of the structure were extracted. Due to the change in cross-section along each girder, the modified modal strain energy-based damage index (β) equation was used in the subject model. By applying the damages of different severities in steel girders in single and multiple damage scenarios, the modified damage index β was calculated. With the damage indexes calculated in the different scenarios and applying the machine learning method, the severity of damage was estimated. The obtained results indicate that this proposed method is accurate and satisfactory for detecting and estimating micro and small damages with high accuracy in bridges with variable section girders.

Recycled CFRP Plate Retrofitting using Adhesive and TRS for Steel Girders

AbstractThe retrofitting method using CFRP (Carbon Fiber Reinforced Plastic) plates was applied to a steel highway bridge in 2002 for the first time in Japan, where some of CFRP plates have been detected to be peeled from their ends, recently. CFRP plates are light‐weight and anti‐corrosive comparing with steel plates, while they have problems in the durability of adhesives bonding CFRP plates to steel plates. Currently, recycled CFRP plates have been developed for the environmental load reducing. Additionally, long sized CFRP plates are required to retrofit bridge members. In this study, the effectiveness of TRS (Thread Rolling Screw) used to connect the long‐size recycled CFRP plate end to the steel girder bottom flange with adhesives is investigated through static and fatigue loading tests using large size steel girder specimens. As a result, TRS can prevent long‐size recycled CFRP plates from peeling off under allowable stress static loadings, while the long‐size recycled CFRP plates connected by only adhesives without TRS peeled off from their ends. In fatigue loading tests, TRS can also prevent long‐size recycled CFRP plates from peeling, though fatigue cracks were developed from TRS holes under higher stress range.

Lateral trusses between I‐girders introducing torsional stiffness to a composite bridge in Guatemala

AbstractThe ways of designing and building steel girder bridges with a composite concrete deck vary much between different parts of the world. A bridge system with twin steel I‐girders or a concept with multiple (more than two) girders can be used. The design and use of details and secondary systems also vary a lot. In order to give horizontal stabilization and distribute horizontal loads, bracing between the I‐girders bracings are often used. Although not so common, the bracing can also be used to distribute vertical loads between the main girders. To describe and to analyze the possible impact from using a lateral bracing, this paper describes the design of a curved bridge in Guatemala City and its challenges. The new Bridge over the Pinula River is designed as a steel‐concrete composite bridge with multiple steel girders with a concrete deck on top and has lateral bracing between the girders. The bridge is used as a case study to analyze the impact from a lateral bracing system on the vertical load distribution between the longitudinal girders. The bridge was designed with lateral bracing between the top flanges along the whole bridge and with bracing between the lower flanges near the supports. The case study shows that the distribution of eccentric vertical loads between the longitudinal girders can be improved by using lateral bracing between the lower flanges for multiple girders. In some cases, it may not be beneficial to use lateral bracings along the whole bridge length, like for example this bridge. In this case due to the governing design cases in the construction stages where these bracings influenced the torsional stiffness of the bridge in such way that an unfavorable distribution of the support reactions between the six girders at some supports was achieved.

Investigations of the shear connectors and the load‐bearing behaviour of steel cross‐laminated timber composite beams

AbstractA strengthening of cross laminated timber (CLT) by a composite effect with steel girders can act as a sustainable option to replace concrete or composite slabs for spans of more than 7 m. The efficiency of a composite structure is strongly influenced by the stiffness of the shear connectors. Therefore, fully threaded screws and shear studs were investigated in double push‐out tests. The screws are inclined to increase their stiffness and are rotated within the drilled hole towards the web, so that a multidimensional load situation with both axial and shear loads results. The shear studs are placed in openings of the CLT and cast in with mortar. The shear tests confirmed that their load bearing behaviour can basically be described with existing analytical calculation approaches. The findings were extended in large‐scale 4‐point bending tests to investigate the bending behaviour of the composite beam.

Numerical validation on steel and stainless-steel girders under transverse monotonic loading

Numerical validation on steel and stainless-steel girders under transverse monotonic loading

Lateral–Torsional and Distortional Buckling of I-Shaped Welded Steel Girders

Lateral–Torsional and Distortional Buckling of I-Shaped Welded Steel Girders

Bearing capacity of headed studs under combined tension and shear loading in composite beams with large web openings

AbstractThe use of steel‐concrete composite structures with a high installation grade is becoming increasingly popular in building and industrial construction. To reduce construction height building services are routed through web openings in the girders. However, these openings represent local points of interference where, in the case of composite girders, parts of the acting shear forces are transferred from the web of the steel profile into the concrete slab. This results in additional, local stresses in the remaining steel girder and in the concrete chord, which must be considered in the design of the floor girders and shear connectors. Web openings in composite girders are not addressed in the current European design standard for steel‐concrete composite construction (EC 4). Only with the introduction of the second generation of Eurocodes in the coming years this case will be normatively regulated. During the preparation of the standard further questions about the load‐bearing behaviour arose, as the existing design approaches usually only consider a selection of possible failure scenarios or neglect essential verification steps. A joint research project between the University of Kaiserslautern‐Landau and RWTH Aachen University aims to develop a suitable design concept for composite girders with web openings. Model and beam tests accompanied by numerical simulations will provide further information on the complex local and global load‐bearing behaviour of the composite girders.This paper presents the results of experimental investigations and numerical simulations on the influence of large web openings on the global load‐bearing behaviour of the shear connectors in the composite joint. Based on 60 pull‐out tests and numerical simulations, the load‐bearing behavior of head bolt anchors under combined shear and tensile loading was researched and evaluated.

Fatigue behavior of girder with flange thickness transitions and cope holes ‐ tests and simulations

AbstractThe fatigue behavior of steel girders with flange thickness transition and cope hole has been experimentally analyzed with two large‐scale cyclic tests. Special attention is paid to the arising and interacting local effects. The fatigue tests have been conducted in a four‐point bending setup. Both girders have shown fatigue‐induced failure at the flange butt welds at the thickness transition. The experimental results are presented in terms of fatigue life, differentiating the initiation and propagation life, as well as observed crack position and shape. Moreover, an advanced fatigue life prediction using the Two‐Stage‐Model is applied to the tested girders. The Two‐Stage‐Model applies the Strain‐Life and the Crack Propagation Approach to assess the total fatigue life. Thereby, the number of cycles as well as the crack shape show a good agreement with the experimental results and proves the applicability of the Two‐Stage Model for an advanced fatigue assessment.

Memory‐Steel for Smart Steel Structures: A Review on Recent Developments and Applications

AbstractThis study reviews the recent works on the development and application of iron‐based shape memory alloy (Fe‐SMA), the so‐called memory‐steel, for steel structures. First, the studies on the material properties of Fe‐SMA in terms of shape memory effect and superelasticity are discussed. Next, the use of Fe‐SMA in prestressed strengthening of steel structures is explained, including the applications in strengthening of steel girders, connections, and fatigue crack repairs. Various strengthening solutions such as using mechanically anchored or adhesively‐bonded Fe‐SMA, as well as the studies on the behavior of the Fe‐SMA‐to‐steel bonded joints, are discussed. The use and application of Fe‐SMA for strengthening of a 113‐years steel bridge has been explained. In addition, studies on the innovative application of the Fe‐SMA as pipe couplers are presented. At the end, innovative ongoing research on the additive manufacturing of architected Fe‐SMA (4D‐printing) are discussed.

Urban Viaducts at Section 1 of the “Tren Maya” railway

AbstractThe new Urban Viaducts at the Section 1 of the “Tren Maya” railway are located in southern Mexico, at the municipalities of Tenosique (State of Tabasco) and Candelaria and Escárcega (State of Campeche).The structural solution for the urban viaducts' deck is made of a reinforced concrete slab with a pair of “I” main steel girders. The girders have vertical bracing trusses, in order to reduce the distortion of the cross‐section, and a lower horizontal bracing truss, to close the torsional circuit. Steel diaphragms are located at the supports to transfer vertical and horizontals forces to the column.Viaducts consist of a succession of simply supported 40 m spans. The lengths of the viaducts are: 2920 m Tenosique, 990 m Candelaria and 1080 m Escárcega.The viaducts are located in a zone of high seismicity hazard, so the columns' design has been developed by a displacement‐capacity analysis. As a result, they consist of a single shaft on which rests a pier cap, both of reinforced concrete.This typology has been chosen because of the benefits of its construction process, which allows the execution of the spans to be independent. The steel structure of the deck also allows to reduce its mass, what helps to reduce the dimensions of the substructure.

COMPARATIVE STUDY ON THE GIRDER ERECTION SCHEME FOR THE CHIBI YANGTZE RIVER HIGHWAY BRIDGE

The construction process of composite cable-stayed bridges varies, and it closely affects the finished bridge. This study takes the Chibi Yangtze River Highway Bridge, which is the world's largest-span composite cable-stayed bridge, as an example in determining the optimal scheme of girder erection during the construction of the composite cable-stayed bridge. Six girder construction schemes were proposed for comparison and analysis. On the basis of satisfying the objective principles of the finished bridge, the stress safety principle, and the economic principle, qualitative and quantitative methods were used to analyze the girder erection schemes. The refined model of the composite girder segment was established by the finite element software ABAQUS to examine the local stress of the bridge. Subsequently, the optimal scheme of girder erection was determined. Then, the key calculation results of the optimal scheme of girder erection during the construction stages and for the finished bridge were given, which proved the feasibility, safety, economy, and controllability of the proposed optimal scheme. Results show that the measured data of the girder line shapes and the cable forces of the finished bridge agree well with the theoretical values. This agreement verifies the correctness of the determination and demonstration of the proposed optimal scheme. This study provides a certain reference for the determination of the girder erection scheme of composite cable-stayed bridges. Keywords: Composite girder; cable-stayed bridge; steel girder erection; single segment one cycle; two segments one cycle; construction process;

Design Methodology of U-Shaped Infilled Composite Beams with Angled Shear Connectors Using Finite Element Analysis

A composite beam is a structural member that behaves as a single unit by using shear connectors between a concrete slab and an I-shaped steel girder. The composite ratio is crucial and is determined by the shear connectors’ ability to withstand the horizontal shear forces between the concrete and steel girder. In this study, a U-shaped composite beam was designed, which differs from conventional composite beams as it allows the use of a steel girder as a formwork. Moreover, angle-type shear connectors, instead of stud-type connectors, were employed. Based on this design, large-scale U-shaped composite beams with angle-type shear connectors were fabricated, and load tests were conducted to analyze the behavior after composite action and the influence of shear connector spacing. Additionally, the strength of the angle-type shear connectors used in this paper was evaluated through finite element analysis. Finally, a strength evaluation method for composite beams of this configuration is proposed.