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Steel Construction Published the List of Highly Influential Articles of 2020
2025 Vol. 40, No. 6
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2025, 40(6): 1-9.
doi: 10.13206/j.gjgS24062601
Abstract
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Abstract:
Steel structure link corridors are frequently used to connect two separate buildings， achieving maximized utilization of building functions. However， their construction poses significant challenges in project management. For the construction of high-altitude long-span steel structure link corridors in particular， the construction environment is the most complex， requiring consideration of various construction phases and conditions， thus typically presenting a higher risk level. The No.1 Industry Park Project of the Zhengzhou Research Institute of Harbin Institute of Technology adopted the structural form of a high-altitude long-span steel structure link corridor. The steel structure link corridor has a maximum span of 50.400 meters， a height of 49.500 meters， and a width（measured along the main beam axis） of 20.5 meters， with an approximate mass of 1200 tons. Based on the structural form of the steel structure link corridor and the on-site construction conditions， three construction schemes were proposed using existing domestic and international steel structure lifting techniques. Scheme 1 involves the high-altitude assembly method， utilizing on-site tower cranes and mobile cranes to erect numerous supporting structures and complete the high-altitude assembly work in accordance with the construction sequence. Scheme 2 adopts a sectional lifting method， where the steel structure link corridor is first disassembled into modular lifting units based on the performance of lifting equipment. A limited number of supporting structures are erected on-site， and the sections are lifted in a logical sequence to form an overall corridor structure. Scheme 3 employs hydraulic overall lifting technology， where no supporting structures are erected on-site. The entire steel corridor is assembled on the ground within the projection area of the steel structure link corridor， inspected， and then lifted to the designed elevation using hydraulic lifting devices. Considering the overall schedule， measure costs， quality requirements， safety performance， and the impact on other main construction activities， it was decided to adopt Scheme 3， the hydraulic overall lifting scheme.By calculating the measure costs， Scheme 3 incurred the least cost as it does not require the erection of supporting structures. Finite element analysis with MIDAS/Gen confirmed that during the installation process， both the vertical displacement and component stress of the steel structure link corridor under Scheme 3 remained within the permissible range as per regulations， meeting the overall stability and precision control requirements of the corridor under on-site construction conditions. ANSYS simulation analysis of the hydraulic lifting fixture nodes showed that the stress on the lifting fixtures was below the yield strength of the material， meeting the lifting requirements. In addition， to meet the construction requirements of the hazardous major project involving steel structures， the visualization capabilities of BIM technology were utilized to simulate and rehearse construction scenarios， identify key elements for risk control during installation， and focuse on critical construction management points. This multi-angle verification demonstratesd the economic viability and safety of Scheme 3. To ensure safety during the construction of the steel structure link corridor， multiple measures were implemented， including temporary reinforcement in high-stress areas. Real-time monitoring of high-altitude operations was conducted using drones during hydraulic lifting， and wind speed measurement instruments were used to monitor wind speeds. By integrating finite element simulation analysis with BIM technology for construction scenarios， a rapid construction speed， high installation accuracy， and low safety risks were achieved.
Steel structure link corridors are frequently used to connect two separate buildings， achieving maximized utilization of building functions. However， their construction poses significant challenges in project management. For the construction of high-altitude long-span steel structure link corridors in particular， the construction environment is the most complex， requiring consideration of various construction phases and conditions， thus typically presenting a higher risk level. The No.1 Industry Park Project of the Zhengzhou Research Institute of Harbin Institute of Technology adopted the structural form of a high-altitude long-span steel structure link corridor. The steel structure link corridor has a maximum span of 50.400 meters， a height of 49.500 meters， and a width（measured along the main beam axis） of 20.5 meters， with an approximate mass of 1200 tons. Based on the structural form of the steel structure link corridor and the on-site construction conditions， three construction schemes were proposed using existing domestic and international steel structure lifting techniques. Scheme 1 involves the high-altitude assembly method， utilizing on-site tower cranes and mobile cranes to erect numerous supporting structures and complete the high-altitude assembly work in accordance with the construction sequence. Scheme 2 adopts a sectional lifting method， where the steel structure link corridor is first disassembled into modular lifting units based on the performance of lifting equipment. A limited number of supporting structures are erected on-site， and the sections are lifted in a logical sequence to form an overall corridor structure. Scheme 3 employs hydraulic overall lifting technology， where no supporting structures are erected on-site. The entire steel corridor is assembled on the ground within the projection area of the steel structure link corridor， inspected， and then lifted to the designed elevation using hydraulic lifting devices. Considering the overall schedule， measure costs， quality requirements， safety performance， and the impact on other main construction activities， it was decided to adopt Scheme 3， the hydraulic overall lifting scheme.By calculating the measure costs， Scheme 3 incurred the least cost as it does not require the erection of supporting structures. Finite element analysis with MIDAS/Gen confirmed that during the installation process， both the vertical displacement and component stress of the steel structure link corridor under Scheme 3 remained within the permissible range as per regulations， meeting the overall stability and precision control requirements of the corridor under on-site construction conditions. ANSYS simulation analysis of the hydraulic lifting fixture nodes showed that the stress on the lifting fixtures was below the yield strength of the material， meeting the lifting requirements. In addition， to meet the construction requirements of the hazardous major project involving steel structures， the visualization capabilities of BIM technology were utilized to simulate and rehearse construction scenarios， identify key elements for risk control during installation， and focuse on critical construction management points. This multi-angle verification demonstratesd the economic viability and safety of Scheme 3. To ensure safety during the construction of the steel structure link corridor， multiple measures were implemented， including temporary reinforcement in high-stress areas. Real-time monitoring of high-altitude operations was conducted using drones during hydraulic lifting， and wind speed measurement instruments were used to monitor wind speeds. By integrating finite element simulation analysis with BIM technology for construction scenarios， a rapid construction speed， high installation accuracy， and low safety risks were achieved.
2025, 40(6): 10-15.
doi: 10.13206/j.gjgS24072001
Abstract:
The unloading schemes of steel roof structures vary significantly due to factors such as the complexity of the structural system， the scale of the structure， and the boundaries of the construction process. The quality of unloading schemes is often qualitatively analyzed by comparing the deformations at local key joints and the additional stress ratios of members in the completed roof structure. However， changes in local joints and members cannot fully and accurately reflect the overall structural changes. To address the shortcomings in the effectiveness and accuracy of conventional data representation methods， this paper proposed a design principle based on feasibility， economy， and technical rationality. It adopted the comprehensive minimum residual sum of squares of deformations and stress ratios of all joints in the completed and designed steel roof structure as a quantitative evaluation index to assess the quality of unloading schemes. Furthermore， the criteria and calculation formulas for different deformation and stress ratio indications were provided. Taking the steel grid roof of the T5 Terminal at Xi’an Xianyang International Airport as an example， a comparison of batch-by-batch and level-by-level unloading schemes was conducted. Through a comparative analysis of the deformations and stress states of all members throughout the unloading process corresponding to different schemes， the unloading sequence from the middle to the east and west was selected as the initial scheme for construction planning. The comparison results showed that while the unloading sequence had a relatively minor impact on the completed structure after closure， the different force transmission paths during the unloading process significantly affected the stability of small-section members， making them prone to compressive instability during construction. A comparison between the unloading scheme adopted during the implementation phase and the preferred initial scheme verified the reliability of the proposed technical rationality evaluation method for unloading schemes. To address safety concerns throughout the unloading process， this paper proposed quality and safety control techniques that incorporate internal force control， deformation control， and synchronization control of unloading operations for all structural members. The unloading scheme design principles were simple and easy to implement， while the analysis method exhibited strong data representation and high accuracy. It comprehensively considered the effects of different unloading schemes on the deformations and stresses of all members throughout the unloading process. Additionally， the quality and safety control techniques were highly targeted and operable.
The unloading schemes of steel roof structures vary significantly due to factors such as the complexity of the structural system， the scale of the structure， and the boundaries of the construction process. The quality of unloading schemes is often qualitatively analyzed by comparing the deformations at local key joints and the additional stress ratios of members in the completed roof structure. However， changes in local joints and members cannot fully and accurately reflect the overall structural changes. To address the shortcomings in the effectiveness and accuracy of conventional data representation methods， this paper proposed a design principle based on feasibility， economy， and technical rationality. It adopted the comprehensive minimum residual sum of squares of deformations and stress ratios of all joints in the completed and designed steel roof structure as a quantitative evaluation index to assess the quality of unloading schemes. Furthermore， the criteria and calculation formulas for different deformation and stress ratio indications were provided. Taking the steel grid roof of the T5 Terminal at Xi’an Xianyang International Airport as an example， a comparison of batch-by-batch and level-by-level unloading schemes was conducted. Through a comparative analysis of the deformations and stress states of all members throughout the unloading process corresponding to different schemes， the unloading sequence from the middle to the east and west was selected as the initial scheme for construction planning. The comparison results showed that while the unloading sequence had a relatively minor impact on the completed structure after closure， the different force transmission paths during the unloading process significantly affected the stability of small-section members， making them prone to compressive instability during construction. A comparison between the unloading scheme adopted during the implementation phase and the preferred initial scheme verified the reliability of the proposed technical rationality evaluation method for unloading schemes. To address safety concerns throughout the unloading process， this paper proposed quality and safety control techniques that incorporate internal force control， deformation control， and synchronization control of unloading operations for all structural members. The unloading scheme design principles were simple and easy to implement， while the analysis method exhibited strong data representation and high accuracy. It comprehensively considered the effects of different unloading schemes on the deformations and stresses of all members throughout the unloading process. Additionally， the quality and safety control techniques were highly targeted and operable.
2025, 40(6): 16-24.
doi: 10.13206/j.gjgS23122902
Abstract:
The three towers of an R&D project all adopt four-side suspension structural system. The suspended structure system is composed of core tube， cantilever truss， and suspended outer frame （davit， steel beam）. The top elevation of the tower structure is 59.9 meters， and each building is upside down with eight layers of frame structure. The external suspended steel columns transmit the force to the cantilever trusses at the top of the tower from the bottom up， and finally from the top trusses to the core structure. Compared with the traditional structure system， the four-side suspended structure system requires higher installation accuracy， more complex force transmission path and higher construction difficulty. The two construction methods determined based on project characteristics and force transfer route are reversed construction method and following construction method. The main control and checking analysis points of reverse construction method are： the design and calculation of the temporary support system of the lower part of the suspended outer frame， the 4th floor and the following floors mixed concrete checking， roof truss construction sequence， steel column pressure-tension force conversion， and steel column axial force calculation of the various stages， construction feasibility analysis and summary. The main control and checking analysis points of the following construction methods are as follows： the design and calculation of the temporary support system under the suspended outer frame， the 4th floor and below mixed concrete floor checking， roof truss construction sequence， steel column pressure-tension force conversion and steel column axial force calculation of the various stages， construction feasibility analysis and summary. Comprehensively comparing different schemes of the construction on convenience， safety， final forming state and other major factors. Whole process simulation and verification are conducted on the construction process， to further contrast the feasibility of different programs，and provide reference for similar projects.
The three towers of an R&D project all adopt four-side suspension structural system. The suspended structure system is composed of core tube， cantilever truss， and suspended outer frame （davit， steel beam）. The top elevation of the tower structure is 59.9 meters， and each building is upside down with eight layers of frame structure. The external suspended steel columns transmit the force to the cantilever trusses at the top of the tower from the bottom up， and finally from the top trusses to the core structure. Compared with the traditional structure system， the four-side suspended structure system requires higher installation accuracy， more complex force transmission path and higher construction difficulty. The two construction methods determined based on project characteristics and force transfer route are reversed construction method and following construction method. The main control and checking analysis points of reverse construction method are： the design and calculation of the temporary support system of the lower part of the suspended outer frame， the 4th floor and the following floors mixed concrete checking， roof truss construction sequence， steel column pressure-tension force conversion， and steel column axial force calculation of the various stages， construction feasibility analysis and summary. The main control and checking analysis points of the following construction methods are as follows： the design and calculation of the temporary support system under the suspended outer frame， the 4th floor and below mixed concrete floor checking， roof truss construction sequence， steel column pressure-tension force conversion and steel column axial force calculation of the various stages， construction feasibility analysis and summary. Comprehensively comparing different schemes of the construction on convenience， safety， final forming state and other major factors. Whole process simulation and verification are conducted on the construction process， to further contrast the feasibility of different programs，and provide reference for similar projects.
2025, 40(6): 25-32.
doi: 10.13206/j.gjgS24030301
Abstract:
This article conducted numerical simulation research on the entire construction process of the steel structure dome project in a new campus of a college. The stress situation of the grid structure during the construction process was analyzed， and the stress and deformation at key positions were monitored， in order to provide a theoretical basis for the construction of open steel structure glass domes and ensures construction safety. This article used the life and death element method to numerically simulate the installation and unloading process of fish belly support， circular truss， and temporary support in dome structures， and devided the entire process into three parts： fish belly support installation， circumferential truss installation， and construction unloading. By comparing and analyzing the different installation methods of fish belly support， it was found that if sequential installation was used， there will be significant lateral displacement in the structure， which is prone to instability and damage. Therefore， in construction and installation， a central symmetric method should be adopted， with minimal deformation of the top pressure ring and overall lateral deformation of the structure， showing good stability. The main manifestation of structural deformation is vertical displacement， with a maximum vertical displacement of the top pressure ring reaching 24.5 mm， and the maximum vertical displacement of the circular truss reaching 28.65 mm. The maximum lateral displacement of the dome structure was only 15 mm， and after the installation of the sixth group of fish belly support， the maximum lateral displacement began to decrease. After the installation of the three sets of fish belly support， the maximum bending stress and combined stress appeared at the top pressure ring， and the stress value increased rapidly. The bending moment at the welding point between the temporary support and the top pressure ring also increased sharply. After the installation of all fish belly support and circumferential truss， the maximum combined stress was 141.4 MPa， which is far from reaching the yield stress of the steel. The maximum lateral displacement of the dome structure was only 9 mm， less than 1/400 of the temporary support height. The construction unloading adopted a graded unloading mode， with each level unloading 3mm downward.During the unloading process， the deformation of the members in the dome structure showed a linear trend. Therefore， the unloading method selected in this article was reasonable. After the temporary support removal was completed， the structure transformed from the stress state of the temporary support system to the free stress state of the structure. The dome structure showed good stability throughout the whole construction process.
This article conducted numerical simulation research on the entire construction process of the steel structure dome project in a new campus of a college. The stress situation of the grid structure during the construction process was analyzed， and the stress and deformation at key positions were monitored， in order to provide a theoretical basis for the construction of open steel structure glass domes and ensures construction safety. This article used the life and death element method to numerically simulate the installation and unloading process of fish belly support， circular truss， and temporary support in dome structures， and devided the entire process into three parts： fish belly support installation， circumferential truss installation， and construction unloading. By comparing and analyzing the different installation methods of fish belly support， it was found that if sequential installation was used， there will be significant lateral displacement in the structure， which is prone to instability and damage. Therefore， in construction and installation， a central symmetric method should be adopted， with minimal deformation of the top pressure ring and overall lateral deformation of the structure， showing good stability. The main manifestation of structural deformation is vertical displacement， with a maximum vertical displacement of the top pressure ring reaching 24.5 mm， and the maximum vertical displacement of the circular truss reaching 28.65 mm. The maximum lateral displacement of the dome structure was only 15 mm， and after the installation of the sixth group of fish belly support， the maximum lateral displacement began to decrease. After the installation of the three sets of fish belly support， the maximum bending stress and combined stress appeared at the top pressure ring， and the stress value increased rapidly. The bending moment at the welding point between the temporary support and the top pressure ring also increased sharply. After the installation of all fish belly support and circumferential truss， the maximum combined stress was 141.4 MPa， which is far from reaching the yield stress of the steel. The maximum lateral displacement of the dome structure was only 9 mm， less than 1/400 of the temporary support height. The construction unloading adopted a graded unloading mode， with each level unloading 3mm downward.During the unloading process， the deformation of the members in the dome structure showed a linear trend. Therefore， the unloading method selected in this article was reasonable. After the temporary support removal was completed， the structure transformed from the stress state of the temporary support system to the free stress state of the structure. The dome structure showed good stability throughout the whole construction process.
2025, 40(6): 33-40.
doi: 10.13206/j.gjgS23120401
Abstract:
For the integral lifting construction of irregular grid structures with "sharp corners" at the ends， the method of adding lifter in the "sharp corners" area is generally adopted to control its deflection. Although this method can effectively control the deflection in the "sharp corner" area at the end of the grid， the lifting reverse force of the lifter at that location is often small， resulting in a low contribution of the overall grid lifting process and a waste of construction costs.Therefore， based on a segmented lifting project in Central Zone C of Xianyang Airport， this study investigated control methods for end deflection during the lifting construction of irregular grid structures.Two methods for controlling the end "sharp corner" deflection of irregular grid structures have been proposed， including after lifting in place and during the lifting process. The former method uses machinery such as car cranes and chain hoists to apply vertical loads to the "sharp corners" area with large deflection， after the grid is lifted into the target place， causing the structure in that area to arch upwards， thereby reducing the deflection of that area. This method is convenient for construction but requires high construction site conditions. The latter method involves setting up a support frame on the upper part of the structure in high-stiffness areas and using steel wire ropes to secure the "sharp angle" area， thereby reducing its deflection during the lifting process. This method can compensate for the shortcomings of the deflection control method， which is highly limited by on-site construction conditions after the lifting process.This paper analyzed the effects of two deflection control methods through construction simulations， and also analyzed the influence of factors such as the pretension force of the steel wire rope， the height of the support frame， and the position of the tensioning node on effectiveness of the deflection control methods during the lifting process. The results showed that： 1） the difference between the structural deflection and component stress by the deflection control method after lifting in place， and by the lifters was very small， indicating that the deflection control method after lifting in place had a small impact on the structure； 2） when using the deflection control method during the lifting process， the pretension force of the steel wire rope was positively correlated with the control effect， indicating that the control effect could be improved by increasing the pretension force of the steel wire rope； the height of the support frame was positively correlated with the control effect within a certain height range， after exceeding a certain height， the impact of the support frame height on the control effect gradually decreased and then even exhibited a negative correlation； when the steel wire rope tensioning node was set in an area with high structural stiffness and stringent deflection control requirements， the control effectiveness was optimized， and increasing the number of tensioning nodes and evenly arranging them within the node area could improve the control effectiveness； 3） the two deflection control methods proposed in this paper for post-lifting and during-lifting stages was proved to be feasible and cost-reducing.
For the integral lifting construction of irregular grid structures with "sharp corners" at the ends， the method of adding lifter in the "sharp corners" area is generally adopted to control its deflection. Although this method can effectively control the deflection in the "sharp corner" area at the end of the grid， the lifting reverse force of the lifter at that location is often small， resulting in a low contribution of the overall grid lifting process and a waste of construction costs.Therefore， based on a segmented lifting project in Central Zone C of Xianyang Airport， this study investigated control methods for end deflection during the lifting construction of irregular grid structures.Two methods for controlling the end "sharp corner" deflection of irregular grid structures have been proposed， including after lifting in place and during the lifting process. The former method uses machinery such as car cranes and chain hoists to apply vertical loads to the "sharp corners" area with large deflection， after the grid is lifted into the target place， causing the structure in that area to arch upwards， thereby reducing the deflection of that area. This method is convenient for construction but requires high construction site conditions. The latter method involves setting up a support frame on the upper part of the structure in high-stiffness areas and using steel wire ropes to secure the "sharp angle" area， thereby reducing its deflection during the lifting process. This method can compensate for the shortcomings of the deflection control method， which is highly limited by on-site construction conditions after the lifting process.This paper analyzed the effects of two deflection control methods through construction simulations， and also analyzed the influence of factors such as the pretension force of the steel wire rope， the height of the support frame， and the position of the tensioning node on effectiveness of the deflection control methods during the lifting process. The results showed that： 1） the difference between the structural deflection and component stress by the deflection control method after lifting in place， and by the lifters was very small， indicating that the deflection control method after lifting in place had a small impact on the structure； 2） when using the deflection control method during the lifting process， the pretension force of the steel wire rope was positively correlated with the control effect， indicating that the control effect could be improved by increasing the pretension force of the steel wire rope； the height of the support frame was positively correlated with the control effect within a certain height range， after exceeding a certain height， the impact of the support frame height on the control effect gradually decreased and then even exhibited a negative correlation； when the steel wire rope tensioning node was set in an area with high structural stiffness and stringent deflection control requirements， the control effectiveness was optimized， and increasing the number of tensioning nodes and evenly arranging them within the node area could improve the control effectiveness； 3） the two deflection control methods proposed in this paper for post-lifting and during-lifting stages was proved to be feasible and cost-reducing.
2025, 40(6): 41-48.
doi: 10.13206/j.gjgS24052802
Abstract:
According to the specifications of American and Chinese design for structural steel， a detailed introduction is provided on the methods for structural steel stability design. There are some design methods in the two specifacations， with similarities and differences between them. In order to deepen understanding of the direct analysis method and promote its further application in practical engineering， this study focused on a comprehensive comparison of the direct analysis method between the two specifications. The comparison showed significant differences in the methods used to address the P-Δ and P-δ effects. The American. specification offers more practical convenience in application but lacks sufficient theoretical basis in some aspects. Although the Chinese specification has strong theoretical support， its practical application is sometimes cumbersome， and some details are not yet clear. Meanwhile， a simple comparison was conducted between the direct analysis methods of the two specifications through a calculation example. The results showed little difference in internal force calculations between the two methods. However， in terms of horizontal drift， the results obtained using the American specification were greater than those from the Chinese specification.
According to the specifications of American and Chinese design for structural steel， a detailed introduction is provided on the methods for structural steel stability design. There are some design methods in the two specifacations， with similarities and differences between them. In order to deepen understanding of the direct analysis method and promote its further application in practical engineering， this study focused on a comprehensive comparison of the direct analysis method between the two specifications. The comparison showed significant differences in the methods used to address the P-Δ and P-δ effects. The American. specification offers more practical convenience in application but lacks sufficient theoretical basis in some aspects. Although the Chinese specification has strong theoretical support， its practical application is sometimes cumbersome， and some details are not yet clear. Meanwhile， a simple comparison was conducted between the direct analysis methods of the two specifications through a calculation example. The results showed little difference in internal force calculations between the two methods. However， in terms of horizontal drift， the results obtained using the American specification were greater than those from the Chinese specification.
2025, 40(6): 49-54.
doi: 10.13206/j.gjgS24041702
Abstract:
In the design of steel structures， the rigidity classification of joints in the calculation model is necessary before conducting global analysis and member design. Therefore， determining the rigidity classification of joints is a fundamental and critical task in steel structure design. Through a comparative analysis of the definitions， classification requirements， and judgment methods for the rigidity classification of steel joints under elastic design in China， the United States， and the European Union， it was found that the design standards of all three regions classify joint rigidity according to the mechanical characteristics of the connections， categorizing them into three types： rigid， semi-rigid， and pinned joints. The requirements of joint rotational stiffness in Chinese， American and European standards are defined by the moment-angle （M-φ） curve of the joint. The joint rigidity classification in Chinese standards is based only on the conceptual description of the M-φ curve， and neither the rotational stiffness of joints nor the rotational stiffness limit of joint rigidity classification can be defined quantitatively. Although the limit of rotational stiffness for the rigidity classification of beam-column joints is defined in American standards， there is no calculation method for the tangential stiffness of the joints. The calculation formula of rotational stiffness of common beam-column and column-base joints， as well as the requirements for the rotational stiffness limit in joint rigidity classification are given in EN standards. In terms of the detail requirements for joint rigidity classification， both American and European standards require that pinned joints must possess a certain rotational capacity， so the bolts and plates connected by end plates must meet flexibility and ductility requirements in detail， and ensure rotation capacity in the structure of the single-plate connection. Since rigid joint bear large bending moments， the flanges and webs of H-shaped steel columns often need to be strengthened， and the corresponding strengthening methods are provided in Chinese， American， and European standards. Therefore， both Chinese and American standards can only "qualitatively" determine joint rigidity classification through details. The European standards can "quantitatively" determine whether a joint is rigid， based on the calculation formula for the rotational stiffness of common joints and the rotational stiffness limit requirements for joint rigidity classification. Of course， for complex joins， it is still necessary to determine the M-φ curve of through tests or finite element analysis. In the design of steel joints， attention should be paid to the detailing requirements and factors influencing the determination of joint rigidity classification. In structural analysis， the influence of joint rigidity classification which simplifies the application of the calculation model must be considered.
In the design of steel structures， the rigidity classification of joints in the calculation model is necessary before conducting global analysis and member design. Therefore， determining the rigidity classification of joints is a fundamental and critical task in steel structure design. Through a comparative analysis of the definitions， classification requirements， and judgment methods for the rigidity classification of steel joints under elastic design in China， the United States， and the European Union， it was found that the design standards of all three regions classify joint rigidity according to the mechanical characteristics of the connections， categorizing them into three types： rigid， semi-rigid， and pinned joints. The requirements of joint rotational stiffness in Chinese， American and European standards are defined by the moment-angle （M-φ） curve of the joint. The joint rigidity classification in Chinese standards is based only on the conceptual description of the M-φ curve， and neither the rotational stiffness of joints nor the rotational stiffness limit of joint rigidity classification can be defined quantitatively. Although the limit of rotational stiffness for the rigidity classification of beam-column joints is defined in American standards， there is no calculation method for the tangential stiffness of the joints. The calculation formula of rotational stiffness of common beam-column and column-base joints， as well as the requirements for the rotational stiffness limit in joint rigidity classification are given in EN standards. In terms of the detail requirements for joint rigidity classification， both American and European standards require that pinned joints must possess a certain rotational capacity， so the bolts and plates connected by end plates must meet flexibility and ductility requirements in detail， and ensure rotation capacity in the structure of the single-plate connection. Since rigid joint bear large bending moments， the flanges and webs of H-shaped steel columns often need to be strengthened， and the corresponding strengthening methods are provided in Chinese， American， and European standards. Therefore， both Chinese and American standards can only "qualitatively" determine joint rigidity classification through details. The European standards can "quantitatively" determine whether a joint is rigid， based on the calculation formula for the rotational stiffness of common joints and the rotational stiffness limit requirements for joint rigidity classification. Of course， for complex joins， it is still necessary to determine the M-φ curve of through tests or finite element analysis. In the design of steel joints， attention should be paid to the detailing requirements and factors influencing the determination of joint rigidity classification. In structural analysis， the influence of joint rigidity classification which simplifies the application of the calculation model must be considered.
2025, 40(6): 55-68.
doi: 10.13206/j.gjgS25051301
Abstract:
This paper systematically elaborated on the structure and composition of the European civil engineering construction standard system， the development process of the first and second generations of Eurocodes， their main characteristics， and their innovative content. Since the launch of the first generation of Eurocodes in 1975， after nearly 40 years of development， it has become the authoritative civil engineering construction design standard adopted by the EU and several non-EU countries. Relying on its systematic， universal， and diverse features， the standards meet the technical requirements and market demands of different countries and regions. The second generation of Eurocodes， building on the previous standard， has expanded its scope of application， incorporating more high-performance materials and design methods. The innovative framework and content updates of the standard system not only reflect the latest technological advancements and market demands but also enhance user-friendliness and strengthen the consistency across standards. In addition， the second generation of Eurocodes includes content related to the appraisal and retrofitting of existing structures， the impact of climate change， and structural robustness， demonstrating the up-to-date nature of the new generation of standards. Drawing on the experience of the European engineering construction standard system is of great significance for reforming and improving China’s engineering construction standards， enhancing their internationalization， supporting enterprises in "going global"， and strengthening their core competitiveness in the global market.
This paper systematically elaborated on the structure and composition of the European civil engineering construction standard system， the development process of the first and second generations of Eurocodes， their main characteristics， and their innovative content. Since the launch of the first generation of Eurocodes in 1975， after nearly 40 years of development， it has become the authoritative civil engineering construction design standard adopted by the EU and several non-EU countries. Relying on its systematic， universal， and diverse features， the standards meet the technical requirements and market demands of different countries and regions. The second generation of Eurocodes， building on the previous standard， has expanded its scope of application， incorporating more high-performance materials and design methods. The innovative framework and content updates of the standard system not only reflect the latest technological advancements and market demands but also enhance user-friendliness and strengthen the consistency across standards. In addition， the second generation of Eurocodes includes content related to the appraisal and retrofitting of existing structures， the impact of climate change， and structural robustness， demonstrating the up-to-date nature of the new generation of standards. Drawing on the experience of the European engineering construction standard system is of great significance for reforming and improving China’s engineering construction standards， enhancing their internationalization， supporting enterprises in "going global"， and strengthening their core competitiveness in the global market.
2025, 40(6): 69-73.
doi: 10.13206/j.gjgS24071030
Abstract:
In the analysis of frame steel beams（designed as steel beams） in multi-story and high-rise buildings， the stiffness of the steel beams is usually amplified to consider the composite effect between the steel sections and the concrete slabs. This paper studied this amplification factor. In calculating the stiffness of the composite beam， interfacial slip at the steel-concrete interface was taken into account. The studs were determined by the demand of full composite action between steel and concrete. The analysis considered the following parameters： slab thickness ranging from 100 mm to 120 mm， beam spans of 5-10 m， steel beam section heights varying between 350 mm and 900 mm， and concrete grades C30 and C40.The main conclusions are as follows： for residential buildings， the stiffness amplification factor can be taken as 1.4 for interior beams and 1.35 for edge beams； for office buildings and other structures， the factor may be adopted as 1.3 for interior beams and 1.25 for edge beams， while for super high-rise office buildings exceeding 100 m in height， these values may be further reduced by 0.05 （resulting in 1.25 for interior beams and 1.20 for edge beams， respectively）.
In the analysis of frame steel beams（designed as steel beams） in multi-story and high-rise buildings， the stiffness of the steel beams is usually amplified to consider the composite effect between the steel sections and the concrete slabs. This paper studied this amplification factor. In calculating the stiffness of the composite beam， interfacial slip at the steel-concrete interface was taken into account. The studs were determined by the demand of full composite action between steel and concrete. The analysis considered the following parameters： slab thickness ranging from 100 mm to 120 mm， beam spans of 5-10 m， steel beam section heights varying between 350 mm and 900 mm， and concrete grades C30 and C40.The main conclusions are as follows： for residential buildings， the stiffness amplification factor can be taken as 1.4 for interior beams and 1.35 for edge beams； for office buildings and other structures， the factor may be adopted as 1.3 for interior beams and 1.25 for edge beams， while for super high-rise office buildings exceeding 100 m in height， these values may be further reduced by 0.05 （resulting in 1.25 for interior beams and 1.20 for edge beams， respectively）.
