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Steel Construction Published the List of Highly Influential Articles of 2020
2024 Vol. 39, No. 9
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2024, 39(9): 1-14.
doi: 10.13206/j.gjgS24022001
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Abstract:
With the development of novel engineering materials, the rational application of high-performance materials in the field of civil engineering, alongside the evolution of structural forms, has become a significant pathway for innovations in steel-concrete composite beams. Steel-UHPC composite beams exhibit exceptional mechanical and durability properties, offering a promising pathway and solution for the innovative development of civil engineering structures in our country. In order to promote the transformation and upgrading of Chinese bridge engineering towards lightweight, high-performance, prefabricated, sustainable, and intelligent directions, this paper analyses the main research progress and future development directions of steel-UHPC composite beams. This is done by examining the current state of engineering applications, mechanical performance, and the mechanical behaviour of shear connectors from both domestic and international research and applications. Firstly, the paper reviews the current state of engineering applications of steel-UHPC composite beams in the field of bridge construction both domestically and internationally. These applications span from small and medium-span simply supported and continuous beam bridges to suspension and cable-stayed bridges with spans exceeding a thousand meters, showcasing the presence of steel-UHPC composite beams in various types of bridge structures. It indicates that with the rise of low-carbon construction globally and the introduction of China's "Transportation Powerhouse" strategy, steel-UHPC composite beam bridges are poised to encounter significant development opportunities. Secondly, the paper summarises the research progress on the mechanical performance of steel-UHPC composite beams under positive and negative bending moments, including the calculation theories for bending performance and finite element simulation methods. It indicates that the application of steel-UHPC composite beams can significantly enhance the structural crack resistance, flexural capacity, and flexural stiffness. This is beneficial for reducing the self-weight of the structure, facilitating prefabricated construction, and promoting the further development of high-performance engineering structures. Subsequently, the current state of research on various shear connectors was discussed, including conventional stud shear connectors, short stud shear connectors, large diameter shear connectors, grouped stud shear connectors, perforated steel plate shear connectors, and bolt shear connectors. It indicates that the rational selection and design of shear connectors can simultaneously address the dual requirements of interface connection reliability and the efficient utilisation of UHPC materials in steel-UHPC composite beams across various engineering contexts. Although the research on the force transmission mechanism and mechanical performance of steel-UHPC composite beam has been gradually developed, the systematic research is insufficient, and indepth systematic research should still be carried out around the basic theory and design method, so as to meet the needs of a large number of engineering applications. Finally, an outlook is provided on the key issues, main challenges, and future development trends related to the study of the load-bearing performance and design theory of steel-UHPC composite beams, research on high-strength steel-UHPC composite beams, the load-bearing performance of novel shear connectors, and the intelligent design of steel-UHPC composite beams. This is intended to offer innovative insights into the academic research and engineering applications of bridge engineering in China.
With the development of novel engineering materials, the rational application of high-performance materials in the field of civil engineering, alongside the evolution of structural forms, has become a significant pathway for innovations in steel-concrete composite beams. Steel-UHPC composite beams exhibit exceptional mechanical and durability properties, offering a promising pathway and solution for the innovative development of civil engineering structures in our country. In order to promote the transformation and upgrading of Chinese bridge engineering towards lightweight, high-performance, prefabricated, sustainable, and intelligent directions, this paper analyses the main research progress and future development directions of steel-UHPC composite beams. This is done by examining the current state of engineering applications, mechanical performance, and the mechanical behaviour of shear connectors from both domestic and international research and applications. Firstly, the paper reviews the current state of engineering applications of steel-UHPC composite beams in the field of bridge construction both domestically and internationally. These applications span from small and medium-span simply supported and continuous beam bridges to suspension and cable-stayed bridges with spans exceeding a thousand meters, showcasing the presence of steel-UHPC composite beams in various types of bridge structures. It indicates that with the rise of low-carbon construction globally and the introduction of China's "Transportation Powerhouse" strategy, steel-UHPC composite beam bridges are poised to encounter significant development opportunities. Secondly, the paper summarises the research progress on the mechanical performance of steel-UHPC composite beams under positive and negative bending moments, including the calculation theories for bending performance and finite element simulation methods. It indicates that the application of steel-UHPC composite beams can significantly enhance the structural crack resistance, flexural capacity, and flexural stiffness. This is beneficial for reducing the self-weight of the structure, facilitating prefabricated construction, and promoting the further development of high-performance engineering structures. Subsequently, the current state of research on various shear connectors was discussed, including conventional stud shear connectors, short stud shear connectors, large diameter shear connectors, grouped stud shear connectors, perforated steel plate shear connectors, and bolt shear connectors. It indicates that the rational selection and design of shear connectors can simultaneously address the dual requirements of interface connection reliability and the efficient utilisation of UHPC materials in steel-UHPC composite beams across various engineering contexts. Although the research on the force transmission mechanism and mechanical performance of steel-UHPC composite beam has been gradually developed, the systematic research is insufficient, and indepth systematic research should still be carried out around the basic theory and design method, so as to meet the needs of a large number of engineering applications. Finally, an outlook is provided on the key issues, main challenges, and future development trends related to the study of the load-bearing performance and design theory of steel-UHPC composite beams, research on high-strength steel-UHPC composite beams, the load-bearing performance of novel shear connectors, and the intelligent design of steel-UHPC composite beams. This is intended to offer innovative insights into the academic research and engineering applications of bridge engineering in China.
2024, 39(9): 15-23.
doi: 10.13206/j.gjgS23090802
Abstract:
In this paper, the wind-resistant performance and wind-damaging wind speed of a large-span double-cylinder mesh shell structure of a dry coal shed in Henan Province are investigated by means of large-vortex simulation and structural response calculation. As a flexible system, the large-span space structure is sensitive to the wind load, and it is easily affected by the unsteady strong wind and vibration, which leads to the damage or even collapse of the structure. Therefore, it is necessary to analyze the wind vibration response of the large-span space structure by simulating the generation of unsteady pulsating wind to provide a basis for the study of structural wind-resistant measures. Firstly, the structure is modeled by ANSYS ICEM CFD and SAP 2000 software based on the actual engineering parameters of the dry coal shed, and the unstructured mesh is used for mesh delineation, while the inlet surface is divided into 9 regions to ensure the simulation accuracy. MATLAB software combined with harmonic superposition method and Fast Fourier Transform (FFT) simulation to get the non-stationary pulsating wind, superimposed with the time-varying mean wind will get the non-stationary strong wind in the inlet surface area. Secondly, FLUENT is used to simulate the wind pressure distribution of the structure at five different wind angles under the mean wind pressure and to obtain the wind pressure values on the building surface, so as to determine the most unfavorable wind angle that will cause damage to the structure. The deformation of the structure is analyzed by nonlinear static elastic-plastic analysis (Pushover method) in SAP 2000 and the wind pressure distribution is combined to determine the critical areas of the structure. Finally, the LES vortex simulation method is used to simulate the unsteady strong wind acting on the structure under the most unfavorable wind angle, and the node wind load times are further calculated by obtaining the wind pressure times in the key nodes in the key area. The wind vibration response and other data are analyzed to determine the damage of the structure, and the ultimate wind load capacity is studied to obtain the ultimate wind speed that will damage the structure. Comparison of the simulation results with the actual damage of the structure reveals that the damage is the same, and the model simulation in this paper is considered to be reliable. After the simulation results, it is determined that the 90° angle is the most unfavorable wind angle for the large-span double-cylinder mesh shell structure, and the central region of the structure is the most unfavorable location, and it is determined that the horizontal displacement in the y-direction of the structure is the key to the damage of the structure through the analysis of the displacement time course. The structure reaches the ultimate wind load bearing capacity under the condition of 80 m/s instantaneous wind speed.
In this paper, the wind-resistant performance and wind-damaging wind speed of a large-span double-cylinder mesh shell structure of a dry coal shed in Henan Province are investigated by means of large-vortex simulation and structural response calculation. As a flexible system, the large-span space structure is sensitive to the wind load, and it is easily affected by the unsteady strong wind and vibration, which leads to the damage or even collapse of the structure. Therefore, it is necessary to analyze the wind vibration response of the large-span space structure by simulating the generation of unsteady pulsating wind to provide a basis for the study of structural wind-resistant measures. Firstly, the structure is modeled by ANSYS ICEM CFD and SAP 2000 software based on the actual engineering parameters of the dry coal shed, and the unstructured mesh is used for mesh delineation, while the inlet surface is divided into 9 regions to ensure the simulation accuracy. MATLAB software combined with harmonic superposition method and Fast Fourier Transform (FFT) simulation to get the non-stationary pulsating wind, superimposed with the time-varying mean wind will get the non-stationary strong wind in the inlet surface area. Secondly, FLUENT is used to simulate the wind pressure distribution of the structure at five different wind angles under the mean wind pressure and to obtain the wind pressure values on the building surface, so as to determine the most unfavorable wind angle that will cause damage to the structure. The deformation of the structure is analyzed by nonlinear static elastic-plastic analysis (Pushover method) in SAP 2000 and the wind pressure distribution is combined to determine the critical areas of the structure. Finally, the LES vortex simulation method is used to simulate the unsteady strong wind acting on the structure under the most unfavorable wind angle, and the node wind load times are further calculated by obtaining the wind pressure times in the key nodes in the key area. The wind vibration response and other data are analyzed to determine the damage of the structure, and the ultimate wind load capacity is studied to obtain the ultimate wind speed that will damage the structure. Comparison of the simulation results with the actual damage of the structure reveals that the damage is the same, and the model simulation in this paper is considered to be reliable. After the simulation results, it is determined that the 90° angle is the most unfavorable wind angle for the large-span double-cylinder mesh shell structure, and the central region of the structure is the most unfavorable location, and it is determined that the horizontal displacement in the y-direction of the structure is the key to the damage of the structure through the analysis of the displacement time course. The structure reaches the ultimate wind load bearing capacity under the condition of 80 m/s instantaneous wind speed.
2024, 39(9): 24-33.
doi: 10.13206/j.gjgS23072702
Abstract:
This study investigates the seismic performance of steel columns with different heights of concrete core fill under the combined action of axial compression and low-cycle reversed loading. The comparison between finite element modeling and experimental results is employed to validate the seismic performanceaccuracy of finite element modeling method. The fundamental parameters studied in the finite element model include the height of the core concrete, core concrete strength, steel material strength of the outer steel tube, axial load ratio, and the diameter-to-thickness ratio of the members, among others, all of which have a significant impact on the seismic performance of steel columns. The finite element analysis primarily focuses on hysteresis loops, skeleton curves, initial stiffness, stiffness degradation curves, and energy dissipation capacity. The following findings were obtained: Firstly, the height of the core concrete significantly influences the seismic performance of steel columns. Steel columns with lower concrete fill heights exhibit lower peak loads and failure displacements due to the smaller volume of concrete fill. As the concrete height increases from 0.25 times the column height to 0.5 times the column height, both peak loads and failure displacements increase significantly, along with a notable increase in the total number of cyclic loading cycles. This underscores the importance of considering concrete filling height in the design of steel columns to ensure adequate seismic performance. Secondly, the influence of the strength of the core concrete and steel material on seismic performance is relatively minor. High-strength concrete and steel do not significantly increase the initial stiffness of steel columns. This suggests that within a certain range, different concrete and steel materials can be chosen without a substantial impact on seismic performance. However, practical engineering still requires the selection of appropriate materials based on specific strength and stiffness requirements. Finally, an increase in the axial load ratio and the diameter-to-thickness ratio of members can enhance seismic performance to some extent, particularly in terms of energy dissipation capacity. Increasing the axial load ratio improves the load-carrying capacity of steel columns, while increasing the diameter-to-thickness ratio enhances their stiffness, thereby improving their seismic performance. Therefore, practical design considerations should comprehensively account for take these two parameters into account to optimize the seismic performance of steel columns. In summary, this study, through a detailed parameter analysis, elucidates the significant impact of core concrete height on the seismic performance of steel columns and provides a robust basis for the design and optimization of steel column structures.
This study investigates the seismic performance of steel columns with different heights of concrete core fill under the combined action of axial compression and low-cycle reversed loading. The comparison between finite element modeling and experimental results is employed to validate the seismic performanceaccuracy of finite element modeling method. The fundamental parameters studied in the finite element model include the height of the core concrete, core concrete strength, steel material strength of the outer steel tube, axial load ratio, and the diameter-to-thickness ratio of the members, among others, all of which have a significant impact on the seismic performance of steel columns. The finite element analysis primarily focuses on hysteresis loops, skeleton curves, initial stiffness, stiffness degradation curves, and energy dissipation capacity. The following findings were obtained: Firstly, the height of the core concrete significantly influences the seismic performance of steel columns. Steel columns with lower concrete fill heights exhibit lower peak loads and failure displacements due to the smaller volume of concrete fill. As the concrete height increases from 0.25 times the column height to 0.5 times the column height, both peak loads and failure displacements increase significantly, along with a notable increase in the total number of cyclic loading cycles. This underscores the importance of considering concrete filling height in the design of steel columns to ensure adequate seismic performance. Secondly, the influence of the strength of the core concrete and steel material on seismic performance is relatively minor. High-strength concrete and steel do not significantly increase the initial stiffness of steel columns. This suggests that within a certain range, different concrete and steel materials can be chosen without a substantial impact on seismic performance. However, practical engineering still requires the selection of appropriate materials based on specific strength and stiffness requirements. Finally, an increase in the axial load ratio and the diameter-to-thickness ratio of members can enhance seismic performance to some extent, particularly in terms of energy dissipation capacity. Increasing the axial load ratio improves the load-carrying capacity of steel columns, while increasing the diameter-to-thickness ratio enhances their stiffness, thereby improving their seismic performance. Therefore, practical design considerations should comprehensively account for take these two parameters into account to optimize the seismic performance of steel columns. In summary, this study, through a detailed parameter analysis, elucidates the significant impact of core concrete height on the seismic performance of steel columns and provides a robust basis for the design and optimization of steel column structures.
2024, 39(9): 34-42.
doi: 10.13206/j.gjgS24012901
Abstract:
In order to study the axial compression of H-shaped bending-torsion aluminum alloy members, an axial compression test was carried out on an H-shaped flexural-torsional aluminum alloy member, which was obtained by sweeping and twisting the H-shaped section around a section of arc. The cross section design size is H350×200×10×12, the bending arc radius is 2 850 mm, the span is 2 936 mm, the torsion angle is 26°, the material is 6061-T6 aluminum alloy profile, and the boundary condition is hinged at both ends. Firstly, in order to obtain the accurate geometric model of H-type bending and torsion aluminum alloy member, the whole component is scanned in three dimensions, and the cloud point data of the outer surface of the component are obtained. By comparing the cloud point data with the ideal geometric model, it is found that most of the overall geometric deviation is controlled within 3 mm, and the thickness and width of the upper flange of the component are less than the ideal geometric model to varying degrees. Then, the load-displacement curve, load-strain curve and failure mode of the component are obtained through the axial compression test. The ultimate bearing capacity of the H-type bending-torsion aluminum alloy member is 313 kN, and finally the lower flange of the member and the web near the lower flange appear serious buckling deformation. Finally, the accurate geometric model of the component is obtained according to the inverse processing of the three-dimensional scanning data. On this basis, the finite element model is established by ABAQUS. The stress development and failure mechanism of the component are obtained by numerical analysis. The failure mode, load-displacement curve and load-strain curve of the aluminum alloy component are in good agreement with the test, which verifies the reliability of the finite element simulation. Before reaching the ultimate bearing capacity, the lower flange and web of the component are subjected to large-scale compression and yield into plasticity, and the failure mode of the component is flexural-torsional buckling failure.
In order to study the axial compression of H-shaped bending-torsion aluminum alloy members, an axial compression test was carried out on an H-shaped flexural-torsional aluminum alloy member, which was obtained by sweeping and twisting the H-shaped section around a section of arc. The cross section design size is H350×200×10×12, the bending arc radius is 2 850 mm, the span is 2 936 mm, the torsion angle is 26°, the material is 6061-T6 aluminum alloy profile, and the boundary condition is hinged at both ends. Firstly, in order to obtain the accurate geometric model of H-type bending and torsion aluminum alloy member, the whole component is scanned in three dimensions, and the cloud point data of the outer surface of the component are obtained. By comparing the cloud point data with the ideal geometric model, it is found that most of the overall geometric deviation is controlled within 3 mm, and the thickness and width of the upper flange of the component are less than the ideal geometric model to varying degrees. Then, the load-displacement curve, load-strain curve and failure mode of the component are obtained through the axial compression test. The ultimate bearing capacity of the H-type bending-torsion aluminum alloy member is 313 kN, and finally the lower flange of the member and the web near the lower flange appear serious buckling deformation. Finally, the accurate geometric model of the component is obtained according to the inverse processing of the three-dimensional scanning data. On this basis, the finite element model is established by ABAQUS. The stress development and failure mechanism of the component are obtained by numerical analysis. The failure mode, load-displacement curve and load-strain curve of the aluminum alloy component are in good agreement with the test, which verifies the reliability of the finite element simulation. Before reaching the ultimate bearing capacity, the lower flange and web of the component are subjected to large-scale compression and yield into plasticity, and the failure mode of the component is flexural-torsional buckling failure.
2024, 39(9): 43-51.
doi: 10.13206/j.gjgS24011501
Abstract:
Membrane structure has the advantages of green environmental protection and sustainable development, and is an important research direction for China to achieve energy conservation and emission reduction in the field of buildings. There are no studies on carbon trace tracking, carbon emission accounting, and carbon emission factor statistics of building membrane structures at home and abroad. Based on the above background, this study aims to propose a calculation strategy for the carbon emissions of the whole life cycle of building membrane structures and analyze the key factors affecting emissions. By adopting a comprehensive carbon emission assessment method, combined with Life Cycle Assessment (LCA) and carbon source tracking calculation, the whole life cycle of a typical building membrane structure was studied in detail, and carbon emission calculation models at different stages were established to calculate the carbon emissions at each stage. The results show that the carbon emissions generated in the production stage of the membrane structure project are 8 621.61 kgCO2e, accounting for 79.75%, which is the main source of carbon emissions in the whole life cycle of the structure, followed by the construction stage, accounting for 16.53%, and the transportation stage and service dismantling stage accounted for a small proportion; It is suggested that the membrane structure should further optimize the production process in the production stage, adopt energy-saving technology and equipment, and renewable energy to reduce carbon emissions in the production process of materials. This study provides an important data reference for the carbon accounting of membrane structures, and provides important support for the high-quality and sustainable development of membrane structures.
Membrane structure has the advantages of green environmental protection and sustainable development, and is an important research direction for China to achieve energy conservation and emission reduction in the field of buildings. There are no studies on carbon trace tracking, carbon emission accounting, and carbon emission factor statistics of building membrane structures at home and abroad. Based on the above background, this study aims to propose a calculation strategy for the carbon emissions of the whole life cycle of building membrane structures and analyze the key factors affecting emissions. By adopting a comprehensive carbon emission assessment method, combined with Life Cycle Assessment (LCA) and carbon source tracking calculation, the whole life cycle of a typical building membrane structure was studied in detail, and carbon emission calculation models at different stages were established to calculate the carbon emissions at each stage. The results show that the carbon emissions generated in the production stage of the membrane structure project are 8 621.61 kgCO2e, accounting for 79.75%, which is the main source of carbon emissions in the whole life cycle of the structure, followed by the construction stage, accounting for 16.53%, and the transportation stage and service dismantling stage accounted for a small proportion; It is suggested that the membrane structure should further optimize the production process in the production stage, adopt energy-saving technology and equipment, and renewable energy to reduce carbon emissions in the production process of materials. This study provides an important data reference for the carbon accounting of membrane structures, and provides important support for the high-quality and sustainable development of membrane structures.
2024, 39(9): 52-59.
doi: 10.13206/j.gjgS23083001
Abstract:
The transfer floor of super high-rise tower in Hangzhou West Railway Station TOD project adopts the reinforced steel-concrete structure with large steel truss prefabricated, and the construction quality of the steel truss is crucial for the long-term performance of the structure.To ensure precise control of steel truss construction, three key technologies for steel truss construction are carried out. Firstly, based on the basic parameters of steel structure segmented weight, lifting arm length, lifting capability, the suitable tower crane model is selected through comparative analysis of lifting weight. Theoretical analysis and load bearing capacity verification of the basement roof is conducted. With the consideration of load distribution on simply-supported two-way slabs, the bearing capacity of the basement roof at the most unfavorable state during the driving conditions is analyzed. The site load deployment is clarified and the steel structure lifting capacity meets the requirements. Secondly, a three-dimensional model of the steel structure is built and information are integrated. Based on visualized complex steel structure model, the difficulty of pouring construction is judged by checking the enclosed compartments. In the original plan, two closed compartments are formed due to the interlacing of multiple web plates and transverse partitions; and a secondary pouring construction method was designed by grouting the closed compartments first and then uniformly pouring other steel reinforced concrete structures. Based on three-dimensional model and the principle of improving pouring quality, the concept to enlarge pouring holes on the top surface of the steel column diaphragm, remain flow holes on the inner cabin web, and change the outer sealed plate to several battens is proposed and discussed carefully, thereby greatly reducing the enclosed space. At the same time, the diaphragm holes enlarged, one-time-concreting shaping plan is proposed by changing the concrete flow direction from top to bottom, as an alternative method of secondary pouring plan from bottom to top, optimizing the steel structure structure to ensure pouring molding. Finally, with consideration of the lifting capacity of tower crane, the construction and installation process of the steel truss structures is designed. Based on the truss installation process, analyze the components that affect mid span deformation is analyzed and calculate the key parameter of mid span camber in the process is calculated. The initial preset height of the bed frame should be composed of three parts of displacement, those are, the mid span deflection caused by the self weight of the half truss when supported by the bed frame, deflection caused by the self weight of the overall truss after welding and dismantling the bed frame, and displacement designed at the mid span for the pre-arch structure when reinforced concrete is considered in the structural design. A three-dimensional solid nonlinear finite element model is established by ABAQUS, and the deflection of 16.2 m span truss structure under the construction state considering the support stiffness for the aforementioned key construction processes.The results show that when installing the half truss, the maximum mid span deflection of the structure is 6.41 mm; after removing the jig frame, the structure undergoes a further downward deflection of 1.53 mm in the span. Therefore, based on the finite element calculation results, the pre arch value is determined to be 24.1 mm, which is approximately 1.5/1 000 of the span. This article determines the tower crane model through numerical analysis, optimizes the steel structure layout through three-dimensional models, and clarifies key construction parameters through numerical simulation, ensuring the accuracy and quality of truss layer construction. The relevant experience can be used as a reference for similar projects.
The transfer floor of super high-rise tower in Hangzhou West Railway Station TOD project adopts the reinforced steel-concrete structure with large steel truss prefabricated, and the construction quality of the steel truss is crucial for the long-term performance of the structure.To ensure precise control of steel truss construction, three key technologies for steel truss construction are carried out. Firstly, based on the basic parameters of steel structure segmented weight, lifting arm length, lifting capability, the suitable tower crane model is selected through comparative analysis of lifting weight. Theoretical analysis and load bearing capacity verification of the basement roof is conducted. With the consideration of load distribution on simply-supported two-way slabs, the bearing capacity of the basement roof at the most unfavorable state during the driving conditions is analyzed. The site load deployment is clarified and the steel structure lifting capacity meets the requirements. Secondly, a three-dimensional model of the steel structure is built and information are integrated. Based on visualized complex steel structure model, the difficulty of pouring construction is judged by checking the enclosed compartments. In the original plan, two closed compartments are formed due to the interlacing of multiple web plates and transverse partitions; and a secondary pouring construction method was designed by grouting the closed compartments first and then uniformly pouring other steel reinforced concrete structures. Based on three-dimensional model and the principle of improving pouring quality, the concept to enlarge pouring holes on the top surface of the steel column diaphragm, remain flow holes on the inner cabin web, and change the outer sealed plate to several battens is proposed and discussed carefully, thereby greatly reducing the enclosed space. At the same time, the diaphragm holes enlarged, one-time-concreting shaping plan is proposed by changing the concrete flow direction from top to bottom, as an alternative method of secondary pouring plan from bottom to top, optimizing the steel structure structure to ensure pouring molding. Finally, with consideration of the lifting capacity of tower crane, the construction and installation process of the steel truss structures is designed. Based on the truss installation process, analyze the components that affect mid span deformation is analyzed and calculate the key parameter of mid span camber in the process is calculated. The initial preset height of the bed frame should be composed of three parts of displacement, those are, the mid span deflection caused by the self weight of the half truss when supported by the bed frame, deflection caused by the self weight of the overall truss after welding and dismantling the bed frame, and displacement designed at the mid span for the pre-arch structure when reinforced concrete is considered in the structural design. A three-dimensional solid nonlinear finite element model is established by ABAQUS, and the deflection of 16.2 m span truss structure under the construction state considering the support stiffness for the aforementioned key construction processes.The results show that when installing the half truss, the maximum mid span deflection of the structure is 6.41 mm; after removing the jig frame, the structure undergoes a further downward deflection of 1.53 mm in the span. Therefore, based on the finite element calculation results, the pre arch value is determined to be 24.1 mm, which is approximately 1.5/1 000 of the span. This article determines the tower crane model through numerical analysis, optimizes the steel structure layout through three-dimensional models, and clarifies key construction parameters through numerical simulation, ensuring the accuracy and quality of truss layer construction. The relevant experience can be used as a reference for similar projects.
2024, 39(9): 60-64.
doi: 10.13206/j.gjgS23081401
Abstract:
With the improvement of people's living standards, and the concept of park city, the demand for architectural landscape is increasing, more and more urban landscape bridges are also appearing, the spatial shape of steel bridges presents a trend of complexity, affected by its complex force situation, often accompanied by manufacturing problems such as ultra-thick plate （more than 60 mm thickness） pressing, and the production process of steel bridges with solid space distortion structure is worth exploring in depth.
The west line span Jiangxi River Bridge is located on the Jiangxi River in Chengdu, the bridge adopts a three-span continuous downward bearing beam and arch combination system steel bridge, the span diameter is (55+175+55)m, the width is 51 m, the plane is located in the radius R=400 m circular curve, the side longitudinal beam and arch rib are in a spatial distortion form, extremely irregular, the spatial configuration is completely determined by the architectural landscape, and there is no arch axis in the conventional sense, the arch rib and the side longitudinal beam are seamlessly integrated. The vault at the center pile is 30 m from the bridge deck, and the inverted angle of the north side arch rib is about 47.69°. The angle of inversion of the rib on the south side is about 24.85°, and the two arches meet in the middle of the span, the length of the joint section is 14 m, and there is no other transverse connection between the arches. The south and north arch ribs adopt a single-box single-chamber steel box structure, bounded by the vault joint section, the two arches are quadrangular sections on the small mileage side, and the large mileage side is a pentagonal section, and the space shape of the arch ribs is very complex. Except for the wall plate of the vault joint section, the rest are twisted hyperboloid versions. In the most complex area of the arch beam joint section, the thickest part of the steel plate is 80 mm, and the angle between the two steel plates is 22°, as a steel structure landscape bridge, the spatial distortion structure of this project has obvious characteristics, the thickness of the steel plate is large, and it is of reference significance to study based on this project.
At the beginning of the project, the main pressing methods of thick steel plate are hot pressing and cold pressing. Because the cost of making molds is too high and the impact of heating on the performance of steel plates, finally the project adopts the trend analysis method+fire correction molding process to achieve the design modeling. The specific process is as follows: firstly, the three-dimensional software is used to analyze the curvature trend of the profiled steel plate and divide the profiled segmentation area, and then the profiled segmentation area is divided into equal parts according to the 50~100 mm spacing to draw the profiled control line, and mark the profiled direction, press the profiled line with a large-tonnage press, and check whether the curvature of the steel plate is satisfied with the inspection sample. After qualifying, the steel plate will be transferred to the vertical tire frame, and after the fire adjustment is fine-tuned, it will be transferred to the assembly area. Before assembly, the tire frame should be made according to the linear shape of the steel bridge, and the tire frame foundation should have enough bearing capacity to prevent the tire frame from settling in the process of assembly, and the tire frame should have enough rigidity to support the steel bridge. The support density of the tire frame is the same as the spacing of the partition, and the tire frame needs to be made continuously. Because it is an irregular shape, the wall plate rib should be assembled after the wall plate and the partition plate are assembled. At the same time, steel beam needs to be welded on the tire frame after the completion of the appropriate trimming according to its ring mouth matching situation to ensure the continuity of its modeling.
According to this process, the west line across the Jiangxi River bridge manufactured avoids the mold making, and the pressing process can form a systematic flow construction, which greatly saves the mold production cost and construction period. The linear shape is beautiful after the bridge is completed, and can be used as a certain reference for the construction of similar steel structure engineering.
With the improvement of people's living standards, and the concept of park city, the demand for architectural landscape is increasing, more and more urban landscape bridges are also appearing, the spatial shape of steel bridges presents a trend of complexity, affected by its complex force situation, often accompanied by manufacturing problems such as ultra-thick plate （more than 60 mm thickness） pressing, and the production process of steel bridges with solid space distortion structure is worth exploring in depth.
The west line span Jiangxi River Bridge is located on the Jiangxi River in Chengdu, the bridge adopts a three-span continuous downward bearing beam and arch combination system steel bridge, the span diameter is (55+175+55)m, the width is 51 m, the plane is located in the radius R=400 m circular curve, the side longitudinal beam and arch rib are in a spatial distortion form, extremely irregular, the spatial configuration is completely determined by the architectural landscape, and there is no arch axis in the conventional sense, the arch rib and the side longitudinal beam are seamlessly integrated. The vault at the center pile is 30 m from the bridge deck, and the inverted angle of the north side arch rib is about 47.69°. The angle of inversion of the rib on the south side is about 24.85°, and the two arches meet in the middle of the span, the length of the joint section is 14 m, and there is no other transverse connection between the arches. The south and north arch ribs adopt a single-box single-chamber steel box structure, bounded by the vault joint section, the two arches are quadrangular sections on the small mileage side, and the large mileage side is a pentagonal section, and the space shape of the arch ribs is very complex. Except for the wall plate of the vault joint section, the rest are twisted hyperboloid versions. In the most complex area of the arch beam joint section, the thickest part of the steel plate is 80 mm, and the angle between the two steel plates is 22°, as a steel structure landscape bridge, the spatial distortion structure of this project has obvious characteristics, the thickness of the steel plate is large, and it is of reference significance to study based on this project.
At the beginning of the project, the main pressing methods of thick steel plate are hot pressing and cold pressing. Because the cost of making molds is too high and the impact of heating on the performance of steel plates, finally the project adopts the trend analysis method+fire correction molding process to achieve the design modeling. The specific process is as follows: firstly, the three-dimensional software is used to analyze the curvature trend of the profiled steel plate and divide the profiled segmentation area, and then the profiled segmentation area is divided into equal parts according to the 50~100 mm spacing to draw the profiled control line, and mark the profiled direction, press the profiled line with a large-tonnage press, and check whether the curvature of the steel plate is satisfied with the inspection sample. After qualifying, the steel plate will be transferred to the vertical tire frame, and after the fire adjustment is fine-tuned, it will be transferred to the assembly area. Before assembly, the tire frame should be made according to the linear shape of the steel bridge, and the tire frame foundation should have enough bearing capacity to prevent the tire frame from settling in the process of assembly, and the tire frame should have enough rigidity to support the steel bridge. The support density of the tire frame is the same as the spacing of the partition, and the tire frame needs to be made continuously. Because it is an irregular shape, the wall plate rib should be assembled after the wall plate and the partition plate are assembled. At the same time, steel beam needs to be welded on the tire frame after the completion of the appropriate trimming according to its ring mouth matching situation to ensure the continuity of its modeling.
According to this process, the west line across the Jiangxi River bridge manufactured avoids the mold making, and the pressing process can form a systematic flow construction, which greatly saves the mold production cost and construction period. The linear shape is beautiful after the bridge is completed, and can be used as a certain reference for the construction of similar steel structure engineering.
2024, 39(9): 65-67.
doi: 10.13206/j.gjgS24031920
Abstract:
GB 50017—2017 Standard for Design of Steel Structures put a special demand on steel plate wall ( SPW ) avoiding carryinggravitational load. Because of the difficulty of realizing this demand, this clause prohibited application of SPW. Unloading ofgravitational loads occurring in SPW, chevron and cross braces and buckling-restrained braces during the plastic response underearthquake are pointed out in this article, and therefore, requiring the SPW carrying no gravitational load in the design stage has theresults that the boundary columns and beams are prepared to receive such unloading. Such an explanation provides an additional designrequirement of SPW, and increases the confidence of using SPW.
