Stress Of Girder Research Articles

Calculation of Shear Stress in New-Type Composite Box Girder with Corrugated Steel Webs under Restrained Torsion

The objective of this paper is to outline a method for the systematic analysis and calculation of the constrained torsional shear stress in corrugated steel web composite box girders. Initially, leveraging Umansky’s secondary theory, the calculation formula for the constrained torsional shear stress within the composite girder is derived from the conditions of cross-sectional torque equilibrium and continuity in warping displacement. Subsequently, a torsion test is conducted using a scaled model of an actual girder. Finally, the constrained torsional shear stress of the corrugated steel web composite girder is examined based on theoretical analyses and the results of torsion testing. The influence of wing plate length and web thickness on the torsional shear stress of the composite girder is also investigated. The findings reveal a strong agreement between the experimental results obtained from model testing and the theoretical calculations. Notably, under torsional constraint, it is observed that the shear stress in the web is maximal and evenly distributed, followed by the bottom plate and then the top plate, with no discernible shear stress observed at the free end of the cantilever plate. Numerical analysis indicates that an increase in the relative width of the cantilever plate initially leads to an increase in shear stress for both the cantilever plate and roof plate, followed by a decrease until reaching a relative width value around 0.6, where the changes tend to stabilize. Moreover, an increase in web thickness results in a monotonic decrease in web shear stress. Additionally, the shear stress of the roof and bottom plate decreases initially before subsequently increasing.

Numerical Modeling and Dynamic Response Analysis of an End-Anchored Floating Bridge With a Damaged Pontoon Under Repair Operation

Abstract Floating bridges face potential hazards due to ship collisions throughout their operational lifetime. In a situation where a pontoon is significantly damaged from an accident, a floating drydock may be used to compensate for the lost buoyancy and provide a dry atmosphere for operations. As the repair might take months, a primary concern is whether the repair can be in-site conducted without shutting down the road traffic. This study aims to investigate the feasibility of using a drydock for the repair. The numerical model of the in-operation damaged bridge is established for a comparative dynamic analysis with the intact end-anchored bridge. Eigenvalue analysis is conducted, and pendulum modes of oscillation are found with an eigen-period of around 15 s. The dynamic responses are analyzed through a series of fully coupled time-domain simulations under various environmental conditions. The results indicate that the standard deviation of the moment about the girder weak axis increases significantly at the damaged pontoon axis due to the excitation of low-frequency resonant response. Swell wave loads might induce dynamic amplification to the damaged bridge, even with a relatively small wave height. In addition, the internal stress of the bridge girder is investigated and found to be larger, especially, at the lower locations of the cross section. It is suggested that the responses can be managed by limiting the excitation of pendulum modes or providing special damping devices in practical engineering.

A tensioning control method for stay cables with super large tonnage cable force

PurposeEffectively solving the large tonnage cable in the construction process due to the tensioning method of the inclined cable often appears in the overall cable force and the design value of the deviation is large, cable internal strand force is not uniform, the main girder stress exceeds the limit of the problem affecting the safety of the structure.Design/methodology/approachIn this study, the finite element method and theoretical analysis method are utilized to propose a construction control method of tensioning the whole bunch of diagonal cables in two parts according to the deformation coordination relationship between the main girder and the diagonal cables. This methodology was implemented during the actual construction of the PAIRA Bridge in Bangladesh.FindingsTests conducted on cable-stayed bridges using this controlled tensioning method demonstrate that the measured cable strength of a single strand exhibits an error of less than 0.15% compared to the design target cable strength. The deviation between the measured and designed cable forces ranges from 0.16% to 0.27%. Furthermore, no tensile stress is observed in both the top plate and bottom plate of the root section of the main girder, indicating a state of full-section compression throughout the entire construction process.Originality/valueThrough the comparison with the test value, it can be proved that the whole bunch of diagonal cable tensioned in two parts of the construction control method proposed in this paper can make the internal strand force more uniform, to meet the precision requirements of the site construction, to protect the safety of the bridge construction process. The method proposed in this paper is highly accurate, easy to calculate, and has a high value of popularization and application.

A Two-Stage Optimisation of Ship Hull Structure Combining Fractional Factorial Design Technique and NSGA-II Algorithm

The intricate nature of ships and floating structures presents a significant challenge for ship designers when determining suitable structural dimensions for maritime applications. This study addresses a critical research gap by focusing on a three-cargo hold model for a multipurpose cargo ship. The complex composition of these structures, including stiffening plates, deck plates, bottom plates, frames, and bulkheads, necessitates thorough structural analysis to facilitate effective and cost-efficient design evaluation. To address this challenge, the research utilises FEMAP-integrated NX NASTRAN software (2021.2) to assess hull girder stress. Furthermore, a novel approach is introduced, integrating the Design of Experiments (DOE) principles within Minitab 21.4.1 software to identify critical parameters affecting hull girder stress and production costs. This method determined the top five key parameters influencing hull girder stress: Hatch coaming plate, Hatch coaming top plate, Main deck plate, Shear strake plate, and Bottom plate, while also highlighting key parameters that impact production costs: the inner bottom plate, Inner side shell plate, Bottom plate, Web frame spacing, and Side shell plate. Ship design optimisation is then carried out by incorporating regression equations from Minitab software into the Non-dominated Sorting Genetic Algorithm II (NSGA-II), which is managed using Python software (PyCharm Community Editon 2020.3.1). This optimisation process yields a significant 10% reduction in both ship weight and production costs compared to the previous design, achieved through prudent adjustments in plate thickness, web frame positioning, and stiffener arrangement. The optimally designed midship section undergoes rigorous validation to ensure conformity with industry standards and classification society regulations. Necessary adjustments to inner bottom plates and double bottom side girders are made to meet these stringent requirements. This research offers a comprehensive framework for the structural optimisation of ship hulls, potentially enhancing safety, sustainability, and competitiveness within the maritime engineering industry.

Finite-Element Performance Degradation Behavior of a Suspension Prestressed Concrete Arch Bridge with Grouting Defects

In response to the difficulty in effectively dealing with grouting defects in corrugated pipes within a suspension prestressed concrete arch bridge, a method for assessing the deterioration in the performance of prestressed concrete girders afflicted with grouting defects was established in the present study. Specifically, a time-varying model of steel strand corrosion within grouting defects was constructed by investigating the corrosion theory of steel strands. In addition, a full-scale numerical simulation model of the long-span prestressed concrete bridge was established based on a practical project. Through the described means, the long-term impact of steel strand corrosion at various locations, lengths, and quantities on the vertical displacement and axial stress of girders was elucidated. The results reveal that in the presence of corrosion affecting 16 steel strands located in the midspan bottom plate, a vertical displacement alteration of 17.55 mm was observed in the midpoint region of the girder over a 30-year period following the bridge’s construction. Further, when considering the combined effects of concrete shrinkage, creep, and the corrosion of 16 steel strands in the midspan bottom plate, the axial compressive stress within the midpoint region of the girder decreased from an initial 6.30 MPa to 0.79 MPa over the same 30-year timeframe post-construction. It was observed that two indicators of vertical displacement and axial stress can be employed to evaluate the performance degradation of prestressed concrete bridge girders with grouting defects. The present findings may provide a reference for the operation and management of bridges with grouting defects.

Конструктивно-технологический аспект возведения сталежелезобетонного пролетного строения автодорожного моста через реку Ветлугу

Purpose: To consider structural and technological aspects of construction of steel reinforced concrete span of road bridge over the Vetluga River. To consider the issues of creating a computational model in the Midas Civil program complex with regard to the presented requirements to meet the requirements of GOST and SP. To give a detailed analysis of the stress-strain state of the model on the basis of calculation of the created model. Methods: Analysis of the design and allocation of the main parameters; comparison of the calculation models obtained taking into account the stage of concreting of the monolithic reinforced concrete slab of the roadway and without taking into account the stage of work. Results: The stress-strain state has been analyzed, and the structural and technological features of the erection of a road bridge over the Vetluga River have been considered. It is established that stresses in metal main girders increase significantly in comparison with the model that does not take into account the stages of erection. The combined operation of steel and reinforced concrete section starts only after the monolithic reinforced concrete slab of the roadway has gained strength. It is established that the development of cracks in concrete in the support zones caused by negative moments can be accounted for by reducing the elastic modulus of concrete in the support zones by 8 times. The change of stresses and strains in the structure by stages has been analyzed. The stresses and deformations arising in the structure during its erection are "inherited" from one stage to another when calculating by stages. Practical signifacance: The methods of creating a reliable calculation model of steel-reinforced concrete spans, reflecting the actual nature of the work of the structure both at the stage of construction and at the stage of operation, are shown. The methods described in the article can be recommended for creating a calculation model in the Midas Civil software package with consideration of the presented requirements to meet the requirements of GOST and SP, as well as to avoid accidents at all stages of the life cycle of the structure.

Application and Experimental Validation of Seven-Degree-of-Freedom Beam Element for Girder Bridges during Deck Construction

During bridge deck construction, the deck finishing machine and the fresh concrete often produce large vertical loads and torsional moments acting on the bridge girder system. In some cases, these loads can cause excessive vertical deflection and transverse rotation in the bridge girders, leading to many maintenance and safety problems, such as changes in deck thickness and local and global instabilities during construction. To minimize the potential problems caused by deck construction, the AASHOTO LRFD Bridge Design Specification requires consideration of these torsional moments during the design procedure, and a detailed three-dimensional finite element analysis may be conducted. However, for bridge girders with open-section thin-walled sections, only the solid or shell element can be used to recognize the warping of the girder since the torsional warping effect is not included in the classical beam element. In this research, a warping degree of freedom was added to a beam element, and a three-dimensional beam element with seven degrees of freedom (7-DOF) at each node was derived as an alternative method for analyzing girder bridges during deck construction. A computer program based on the 7-DOF beam element was also developed in MATLAB. To assess the 7-DOF beam element, one bridge was selected to measure the transverse rotation, vertical deflection, and stress of the exterior girder and the first interior girder during deck construction. Also, three full-scale numerical models using solid elements, classical three-dimensional beam elements, and 7-DOF beam elements were created based on the geometries and loads of the experimental bridge. A comparative study was conducted by comparing the results from the numerical models and experimental monitoring data to evaluate the 7-DOF beam element. The results showed that the 7-DOF beam element had excellent behavior in analyzing the girder bridges under construction load, especially in the torsional analysis of bridge girders. Also, unlike the solid element model, which also provided reasonable results, the 7-DOF beam element model can compute the internal forces of the cross-sections along the bridge, which allows the 7-DOF beam element to be an alternative approach for design and research requiring less modeling effort and computational complexity.

Investigation on the Through-Thickness Temperature Gradient and Thermal Stress of Concrete Box Girders

Bridges are generally affected by thermal loads which include the daily cycle, seasonal cycle and annual cycle. Thermal loads mode and thermal effects on bridges, especially for concrete girders, are quite essential but complicated. To investigate the temperature field and thermal stress in the thickness direction of a concrete box girder, the temperature field of a prestressed concrete continuous box girder bridge is monitored, and the temperature distribution in the thickness direction of the concrete box girder is analyzed. Finite element simulation, utilizing air elements specifically designed for concrete box girders, is employed to analyze the temperature field and thermal stress profiles along the thickness of the slab. The findings indicate a variation in temperature along the thickness of the concrete box girder slab. The most significant temperature differential, reaching up to 10.7 °C, is observed along the thickness of the top slab, followed by the bottom plate, with the web exhibiting relatively smaller differentials. Temperature in the full thickness range has a significant impact on the top plate, while the web plate and bottom plate are greatly influenced by temperature ranging from the outer surface to the center of the plate thickness. The temperature difference between the center of the plate thickness and the inner surface is approximately 0. The variation in temperature due to the variation in thickness direction is a temporal factor, wherein the outer layer of the roof is primarily compressed, while the inner layer is subjected to tension. The external surface of the web is mainly compressed. The stress exerted by the internal surface temperature is minimal. The internal and external surface effects of the floor are similar, and as time passes, tensile and compressive stresses appear.

Stress increases in crane runway girders due to rail joints

AbstractVertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce two types of stresses in crane runway girders: i) global stresses due to bi‐axial bending and torsion and ii) local stresses which mainly affect the girder's web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically connected to the top flange with rail clips. These clips maintain the position of the rail in vertical and horizontal transverse direction, but they generally allow for longitudinal movement of the rail. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as finite element calculations. The aim of the investigations is to develop a better understanding of the mechanical behaviour in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.

Research on Reasonable Construction Plan for Cast-in-Place UHPC Bridge Deck Plate of Cable-Stayed Bridge

This article takes a single-tower cable-stayed bridge with a steel-UHPC composite deck steel box girder as the research object and develops different casting plans for the UHPC layer on the bridge deck. It analyzes the influence of factors such as the block casting sequence of the UHPC layer on the bridge deck, whether or not to set up a post-casting section, whether or not to set up bridge deck counterweights and the range of it on the additional deformation and stress of the formed UHPC bridge deck during the construction stage, exploring the impact of various factors on the structural target bridge’s completion status (cable force, bridge completion linearity, bridge deck and steel box girder stress) under different pouring schemes. Research has shown that under the constant initial tension of stay cables, adjusting the pouring sequence of UHPC bridge decks and setting post-pouring sections is not significant in reducing the tensile stress of UHPC bridge decks. The more effective technical measure is to use bridge deck counterweight pouring during construction; the closer the counterweight is to the later stage constant load loading value, the more significant the decrease in UHPC tensile stress is. When factors such as on-site construction conditions, construction period, and labor costs are limited, local weight balancing on the bridge deck can be used.

Impact of rail joints on the local stresses in crane runway girders

Vertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce global stresses due to bi-axial bending and torsion and local stresses in crane runway girders which mainly affect the girder’s web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically used for moderate to high wheel loads. They are usually connected to the top flange with rail clips. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as numerical parametric studies based on finite element calculations, both for rails with and without elastomeric bearing pads. The aim of the investigations is to develop a better understanding of the mechanical behaviour and to quantify the increase factor for maximum local stresses in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.

Relationship between stress and magnetic signal of steel box girder based on magnetic memory method

Metal magnetic memory testing (MMMT) is a nondestructive testing technique that can detect early signs of damage in components. Many scholars have studied the effect of uniform stress on the self-leakage magnetic field (SLMF) strength of ferromagnetic materials. However, there is still insufficient research on the stress concentration caused by uneven stress, under the combined action of bending and shear. In this study, we studied the law of distribution of the magnetic signal, HP(y) and magnetic gradient, K, on a part of the surface of a steel box girder damaged by buckling, using a four-point bending pattern. The results showed that combining the three peak positions, namely, the magnetic signal, its newly added comparing initial magnetic signal, and magnetic gradient distribution curves, could accurately determine all stress concentration positions on the flange of the steel box girder, and reduce the interference of the initial complex residual magnetic field. Furthermore, we studied the quantitative relationship between normal stress, shear stress, and a magnetic signal. It was found that the stress-magnetic relationship conformed to the Jiles–Atherton model. The peak value of HP(y) – 𝜎, |HP(y)|a – 𝜎, and Kmax – 𝜎 relationship curves could be used as the characteristic point of the critical yield stress at the action of normal and shear stress. The degree of stress concentration of the flange and web could be quantitatively evaluated by fitting the Kmax – 𝜎 relationship. This study can provide an experimental reference for the application of MMMT in the evaluation and early warning of the state of damage to a steel box girder.

Static Response of Self-anchored Suspension Bridge under Vehicle Load Considering Time-varying Effects

In order to study the structural state of the bridge under the influence of time-varying effect, the response of the concrete self-anchored suspension bridge under vehicle load and temperature load during the 30-year operation period is studied, through field load test and finite element analysis based on ANSYS refined spatial solid model. The results show that with the increase of the service life of the bridge, the bottom plate of the box chamber of the main girder gradually tends to be tensioned in the longitudinal direction of the bridge, and the horizontal preload stress of the main girder gradually loses when the bridge is completed; The transverse bridge stress at the junction of the outermost bottom of the box chamber and the web tends to be tensile, while the transverse bridge stress at the measuring point of the inner bottom plate gradually increases. The change value of the cable force of the hanger is obviously affected by the restraint mode of the support. Affected by the main tower support, the cable force of the hanger adjacent to the main tower decreases greatly. During the operation of the bridge, the working conditions of the mid span and east span hangers shall be monitored.

Experimental study and analysis for the long-term behavior of the steel–concrete composite girder bridge

Due to the influence of the meteorological factors, the long-term behaviors of steel–concrete composite girders of the real bridge is different from that of indoor laboratory models. In order to address this issue, a long-term field test of 4 years was performed on the simply-supported steel–concrete composite girder bridge to study the temperature, shrinkage and creep effects. The temperature field models (TFM) and mechanical behavior models (MBM) were built in sequence and verified by the test results of the concrete deck and steel girders of 2018 and 2019 since the temperature and strain changed greatly during this period. The temperature calculated by the TFM agreed well with the test results. Although the stress of composite girders obtained by the test is different from that of the MBM, the difference in the whole service stage is small. The test results of the steel cross beam, the steel–concrete interface, the wet joint and the concrete continuous layer were also discussed, and the former three were all under compressive state, while the concrete continuous layer is under tensile state in some time period with the maximum tensile stress 3.12 MPa. Then, the verified models were used to separate the temperature strain from the long-term tested strain, and the remaining tested strain is the shrinkage and creep strain. In summer and winter, the shrinkage and creep stress calculated by the age-adjusted effective modulus method (AEMM) was different from the tested values due to the influence of air humidity, initial load age, stress level and inherent error of the prediction model. Much attention should be paid to the influence of the meteorological factors on the long-term behaviors of steel–concrete composite girder bridges.

Thermal load models for the static design of steel-concrete composite girders

Although the recommended temperature gradient models of composite girders are considered in current specifications for classifying temperature effects in various countries, they are not appropriate enough for static design. Moreover, existing national standards cannot explain the mechanism of the thermal effect on the bridge. To further investigate thermal load models of composite girders, this work proposed a decomposing method for vertical nonlinear temperature gradients based on thermal effects and a calculating method for the thermal stress of composite girders. Equivalent temperature (equivalent uniform temperature, equivalent linear temperature, and equivalent nonlinear temperature), temperature difference, and cyclic equivalent uniform temperature are analyzed to reflect the characteristics of thermal effect in composite girders. The stand values of temperature differences and equivalent temperature with a 50-year return period were investigated via probabilistic statistical analysis. Additionally, two vertical thermal load models (VTLM Ⅰ and VTLM Ⅱ) were set up to facilitate the design and applied to stress analysis. The result demonstrates that the proposed thermal load model is more suitable than the Chinese Specification for calculating the thermal effects of composite girders.

Process monitoring and terminal verification of π–section girder cable-stayed bridge

PurposeIn this paper, taking a p-section girder cable-stayed bridge as an example, the construction monitoring and load test of the bridge are implemented.Design/methodology/approachIn order to ensure the safety of cable-stayed bridge structure in construction and achieve the internal force state of the completed bridge, the construction process is monitored for liner and stress of the p-section girder, construction error and safety state during construction. At the same time, to verify whether the bridge can meet the design requirements, the static and dynamic load tests are done.FindingsThe results of construction monitoring show that the stress state of the structure during construction is basically consistent with the theoretical calculation and design requirements. The final measured stress state of the structure is within the allowable range of the cable-stayed bridge, and the structural stress state is normal and meets the specification requirements. The load tests results show that the measured deflection of the midspan section of the main girder is less than the theoretical calculation value. The maximum deflection of the main girder is 48.03 mm, which is less than 54.25 mm of the theoretical value, indicating that the main girder has sufficient structural stiffness. Under the dynamic load test, the natural frequency of the three spans of the bridge is less than the theoretical frequency.Originality/valueThis study can provide important reference value for the construction and maintenance of similar p-section girder cable-stayed bridges.

Structural Response of an Extra-Wide Concrete Self-Anchored Suspension Bridge under Static Vehicle Loads: Testing and Numerical Simulations

The finite element (FE) analysis by ANSYS software based on field test was used to study the structural performance of an extra-wide concrete self-anchored suspension bridge under static vehicle loads. The longitudinal, transverse and vertical stresses of the extra-wide girder were analyzed, and the changing criteria of girder stresses induced by vehicle loads were presented. Additionally, the effects of the shear lag on extra-wide box girders were investigated. The results showed that the maximum shear lag coefficient was 1.89 at the junction of bottom plate and outer web at the middle of midspan. Moreover, the non-uniformity of cable force is perceptible under eccentric load. Furthermore, an optimization measure for comparable bridges and essential health monitoring locations were outlined.

Simplified Analytical Model for Predicting the Transverse Stress of Steel Box Girder with Large Cantilevers in Cable-Stayed Bridges

Simplified Analytical Model for Predicting the Transverse Stress of Steel Box Girder with Large Cantilevers in Cable-Stayed Bridges

Construction verification of a cable-stayed arch cooperative bridge in China

The mechanical properties of cooperative system bridges are complex. This paper describes the construction monitoring and load tests of a cable-stayed and arch cooperative bridge. The cable force, girder stress and arch alignment were monitored during construction to ensure the safety of the bridge structure and attain the intended internal force state in the completed bridge. Static and dynamic load tests were performed after completing the bridge to test its bearing capacity. The construction monitoring observations indicated that the cable force and suspender force change of the bridge during construction were generally consistent with theoretical calculations. The measured cable force of cable C01 was between 2155 and 3085 kN, and the measured value of suspender LS15 was between 980 and 1250 kN; these values conform to the laws of mechanics. The load test results demonstrated that the maximum deflection of the mid-span section of the girder was 5.8 mm, which was less than the theoretical value (6.3 mm). The measured impact coefficients of the bridge under four sets of working conditions based on dynamic load testing were similar to the computed results. These results confirm that the girder has sufficient structural stiffness.

Study of the Mechanical Behavior of Steel-Hybrid Composite Beams Constructed by Suspension Bracing Method

The construction process of steel–concrete composite girders was simulated using a 3D finite-element model and suspension-bracing method. The influences of multiple factors such as self-weight of suspension bracket, wind load, longitudinal spacing of suspension points, concrete deck slab thickness, concrete casting process, and suspension bracket removal on the mechanical properties of the main steel girder and the composite girder were analyzed. The mechanical behavior of the steel–concrete composite girders during the construction process using the suspension-bracing method was revealed. The results show that (1) the normal stress and displacement of the steel girder increases with the increase of the weight of the suspension bracket, and they have a relatively large impact on the increase. (2) The wind load during the construction process will produce large transverse displacement of the main steel girder, the transverse wind load should be considered in the load combination analysis, and necessary measures should be taken to limit the transverse displacement of the main steel girder during the deck casting process. (3) The displacement and stress of the main steel girder will show a parabolic change with the change of the longitudinal spacing of the suspension points, so the optimal value of the longitudinal spacing of the suspension points is recommended to be 4 m. (4) The maximum midspan displacement and stress of the main steel girder increase with the increase of the deck slab thickness, and the weight of the deck slab occupies the main position in the whole system force. (5) In the process of casting deck slabs with the suspension-bracing method, the stress and deformation of the main steel girder increase with the concrete construction stage of the deck slabs. To ensure that the geometric shape of the bridge at each stage is consistent with the theory result, the design elevation of each section should be preraised during the construction process according to the vertical displacement and deformation of the main steel girder caused by the construction of each casting stage. In addition, the upward rebound of the main steel girder caused by the removal of the suspension bracket must be fully considered when setting the prearch of the steel–concrete composite girder.