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Steel Construction Published the List of Highly Influential Articles of 2020
2020 Vol. 35, No. 7
Display Method:
2020, 35(7): 1-16.
doi: 10.13206/j.gjgSE20041904
Abstract
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Abstract:
With the rapid development of Chinese economy, the demand for building large span spatial structures has been increasing in past few years to satisfy various requirements of culture, sports, transportation and other social events. Lots of spatial structures have been successfully constructed and great progress has been made on innovation and application of spatial structures in China. To describe the accomplishments and to promote further developments of spatial structures in China, this paper presents a summary and review on recent development and engineering practice of spatial structures in China in following aspects:1)application of spatial grid structures in airport terminals; 2)development of aluminum alloy spatial structures; 3)innovation of cable supported structures; 4)practice of membrane structures. Practical applications of spatial structures in engineering projects are introduced. The development review, application summary, structural design consideration, structural details of projects, and innovation of spatial structures are presented. This gives a good reference for further research and engineering practice of spatial structures.
With the rapid development of Chinese economy, the demand for building large span spatial structures has been increasing in past few years to satisfy various requirements of culture, sports, transportation and other social events. Lots of spatial structures have been successfully constructed and great progress has been made on innovation and application of spatial structures in China. To describe the accomplishments and to promote further developments of spatial structures in China, this paper presents a summary and review on recent development and engineering practice of spatial structures in China in following aspects:1)application of spatial grid structures in airport terminals; 2)development of aluminum alloy spatial structures; 3)innovation of cable supported structures; 4)practice of membrane structures. Practical applications of spatial structures in engineering projects are introduced. The development review, application summary, structural design consideration, structural details of projects, and innovation of spatial structures are presented. This gives a good reference for further research and engineering practice of spatial structures.
2020, 35(7): 17-28.
doi: 10.13206/j.gjgSE20041901
Abstract:
Structural vibration control technology is one of the hotspots in the research field of civil engineering against undesirable earthquake or strong wind. In this paper, the research progress of the seismic isolation and vibration reduction system of large-span spatial structures are systematically summarized in terms of the design concept, mechanical properties, isolation mechanism, and engineering application. These applications have provided meaningful experience for the development of seismic isolation and vibration reduction system for large-span spatial structures. A series of potential future research directions on the vibration control device and vibration control mechanism are suggested for the promotion of the application of seismic isolation and vibration reduction system in large-span spatial structures.
Structural vibration control technology is one of the hotspots in the research field of civil engineering against undesirable earthquake or strong wind. In this paper, the research progress of the seismic isolation and vibration reduction system of large-span spatial structures are systematically summarized in terms of the design concept, mechanical properties, isolation mechanism, and engineering application. These applications have provided meaningful experience for the development of seismic isolation and vibration reduction system for large-span spatial structures. A series of potential future research directions on the vibration control device and vibration control mechanism are suggested for the promotion of the application of seismic isolation and vibration reduction system in large-span spatial structures.
2020, 35(7): 29-42.
doi: 10.13206/j.gjgSE20041902
Abstract:
ETFE (Ethylene-Tetra-Fluoro-Ethylene) cushions are popularly used in large-span steel structures such as National Swimming Center, etc. Due to flexibility and wind-sensitivity, ETFE cushions under wind often suffer large deformation and vibration, which, however, further changes the surrounding wind field and therefore its action on the enveloping membrane, causing a significant fluid-structure interaction. The fluid-structure interaction can be characterized by the effects of change in the structural shape, added mass, aerodynamic damping and pneumatic stiffness. So far, the literature only focused on the fluid-structure interaction of tensioned membrane structures under uniform flow and the research on inflated membranes such as ETFE cushions still remains untouched. In view of this, this paper aims to numerically explore the fluid-structure interaction of ETFE cushions under uniform flow and its effect on the dynamic responses by comparing the results from the CFD/CSD (computational fluid dynamics/computational structure dynamics) analysis and the FSI (fluid-structure interaction) analysis. Since aerodynamic damping is not included in the analysis and pneumatic stiffness can be considered with the potential flow element in the CSD module of ADINA, attention is only paid in the paper to the influences of the change in the structural shape and added mass. The results indicate that the effect of FSI has a slight effect on the wind pressure but plays a significant role in the dynamic responses of ETFE cushions.
ETFE (Ethylene-Tetra-Fluoro-Ethylene) cushions are popularly used in large-span steel structures such as National Swimming Center, etc. Due to flexibility and wind-sensitivity, ETFE cushions under wind often suffer large deformation and vibration, which, however, further changes the surrounding wind field and therefore its action on the enveloping membrane, causing a significant fluid-structure interaction. The fluid-structure interaction can be characterized by the effects of change in the structural shape, added mass, aerodynamic damping and pneumatic stiffness. So far, the literature only focused on the fluid-structure interaction of tensioned membrane structures under uniform flow and the research on inflated membranes such as ETFE cushions still remains untouched. In view of this, this paper aims to numerically explore the fluid-structure interaction of ETFE cushions under uniform flow and its effect on the dynamic responses by comparing the results from the CFD/CSD (computational fluid dynamics/computational structure dynamics) analysis and the FSI (fluid-structure interaction) analysis. Since aerodynamic damping is not included in the analysis and pneumatic stiffness can be considered with the potential flow element in the CSD module of ADINA, attention is only paid in the paper to the influences of the change in the structural shape and added mass. The results indicate that the effect of FSI has a slight effect on the wind pressure but plays a significant role in the dynamic responses of ETFE cushions.
2020, 35(7): 43-53.
doi: 10.13206/j.gjgSE20041903
Abstract:
Combining the peak change of the total strain energy of the reticulated shell and standard deviation of the strain energy change rates of all reticulated shell members, an improved strain energy method for evaluating the importance of the cables in the loop-free suspen-dome is proposed. Taking two 100 m-span loop-free suspen-domes as examples, the central difference method is employed to calculate the dynamic response and obtain the time history of internal forces and displacements in seven cable-rupture schemes in each model. The peak change of the total strain energy of the reticulated shell and standard deviation of the strain energy change rates of all the reticulated shell members are calculated according to the dynamic response. The results show that the importance ranking results by current strain energy method varies with magnitudes of cross-sectional areas and pre-tension levels of the cable-strut system. The importance ranking results by improved strain energy method is stable and only determined by the location of the cable. It is concluded that the improved strain energy method is reasonable in evaluating the cable importance of the loop-free suspen-dome. It is also found that an outer cable layer is more important than an inner cable layer, and cables in a layer share approximate the same importance. The reticulated shell members with increased strain energy are mostly distributed near the ruptured cable, and members that are far away from the ruptured cable are less affected.
Combining the peak change of the total strain energy of the reticulated shell and standard deviation of the strain energy change rates of all reticulated shell members, an improved strain energy method for evaluating the importance of the cables in the loop-free suspen-dome is proposed. Taking two 100 m-span loop-free suspen-domes as examples, the central difference method is employed to calculate the dynamic response and obtain the time history of internal forces and displacements in seven cable-rupture schemes in each model. The peak change of the total strain energy of the reticulated shell and standard deviation of the strain energy change rates of all the reticulated shell members are calculated according to the dynamic response. The results show that the importance ranking results by current strain energy method varies with magnitudes of cross-sectional areas and pre-tension levels of the cable-strut system. The importance ranking results by improved strain energy method is stable and only determined by the location of the cable. It is concluded that the improved strain energy method is reasonable in evaluating the cable importance of the loop-free suspen-dome. It is also found that an outer cable layer is more important than an inner cable layer, and cables in a layer share approximate the same importance. The reticulated shell members with increased strain energy are mostly distributed near the ruptured cable, and members that are far away from the ruptured cable are less affected.
2020, 35(7): 54-61.
doi: 10.13206/j.gjgSE20051502
Abstract:
This paper teases apart the key issues in the cable net form-finding of the National Speed Skating Oval (NSSO) of China which will serve the 2022 Beijing Winter Olympics. The topics include the geometry optimization, the form-finding under fixed boundary condition and the form control considering supporting structure flexibility.
The determination of the key parameter that dominates the geometry of the cable net is set forth in the part of geometry optimization. Firstly, a hyperbolic paraboloid formula is employed to mathematically describe the geometry of the cable net. The four corners of each spatial quadrilateral grid of the cable net with a square projection prove to be coplanar. This feature enables the roof modules to be designed and manufactured as a plane, significantly reducing the level of difficulty in the fabrication of the roofing system and raising the necessity of maintaining the roof cable net in its target geometry after erection. Then the key parameter that dominates the geometry is extracted according to the geometrical constraint condition and a parametric analysis is conducted to determine the target geometry considering the recommendation in the national technical specification of China, the performance of the truss ring, the pretension level, the structural rigidity as well as the cable consumption. The sag of the suspending cable and the rise of the stabilizing cable are finally determined as 8.25 m and 7 m, respectively.
The form control of the cable net is preliminarily realized in the part of form-finding under fixed boundary condition. The form-finding, in which the cooperative influence of the boundary shape, the topology, the cable tensioning and the distribution of the roof weight is taken into consideration, limits the maximum deviation of the cable net geometry in the initial state within 5 mm from the theoretical hyperbolic paraboloid. Meanwhile, the orthogonality of the projection of the cable net in the initial state is realized, guaranteeing that the four corners of each grid are coplanar. The form-finding also enables the adjustment of the pretension level without varying the target geometry, making it possible to modify the percentages of the pretension in the cable envelope force and the geometrical stiffness in the global stiffness, by which the optimal comprehensive structural performance can be achieved.
The form control of the cable net considering the supporting structure flexibility sets the final goal of the form-finding. The impact of the supporting structure deflection due to cable tensioning on the form of the cable net is firstly analyzed, in which the maximum deviations from the results under fixed boundary condition are found to be 502 mm for the geometry and 11.1% and 7.3% for the cable pretensions of the suspending cables and stabilizing cables, respectively. Afterwards, the form control of the cable net considering the supporting structure flexibility is realized using a calibrating algorithm involving pre-deformation of the truss ring and modification of the initial strains from the fixed-boundary form-finding. In the initial state of the primary steel structure, not only the form of the cable net is identical to that under fixed boundary condition, but also the geometry of the truss ring and the forces of the stay cables reach their targets.
This paper teases apart the key issues in the cable net form-finding of the National Speed Skating Oval (NSSO) of China which will serve the 2022 Beijing Winter Olympics. The topics include the geometry optimization, the form-finding under fixed boundary condition and the form control considering supporting structure flexibility.
The determination of the key parameter that dominates the geometry of the cable net is set forth in the part of geometry optimization. Firstly, a hyperbolic paraboloid formula is employed to mathematically describe the geometry of the cable net. The four corners of each spatial quadrilateral grid of the cable net with a square projection prove to be coplanar. This feature enables the roof modules to be designed and manufactured as a plane, significantly reducing the level of difficulty in the fabrication of the roofing system and raising the necessity of maintaining the roof cable net in its target geometry after erection. Then the key parameter that dominates the geometry is extracted according to the geometrical constraint condition and a parametric analysis is conducted to determine the target geometry considering the recommendation in the national technical specification of China, the performance of the truss ring, the pretension level, the structural rigidity as well as the cable consumption. The sag of the suspending cable and the rise of the stabilizing cable are finally determined as 8.25 m and 7 m, respectively.
The form control of the cable net is preliminarily realized in the part of form-finding under fixed boundary condition. The form-finding, in which the cooperative influence of the boundary shape, the topology, the cable tensioning and the distribution of the roof weight is taken into consideration, limits the maximum deviation of the cable net geometry in the initial state within 5 mm from the theoretical hyperbolic paraboloid. Meanwhile, the orthogonality of the projection of the cable net in the initial state is realized, guaranteeing that the four corners of each grid are coplanar. The form-finding also enables the adjustment of the pretension level without varying the target geometry, making it possible to modify the percentages of the pretension in the cable envelope force and the geometrical stiffness in the global stiffness, by which the optimal comprehensive structural performance can be achieved.
The form control of the cable net considering the supporting structure flexibility sets the final goal of the form-finding. The impact of the supporting structure deflection due to cable tensioning on the form of the cable net is firstly analyzed, in which the maximum deviations from the results under fixed boundary condition are found to be 502 mm for the geometry and 11.1% and 7.3% for the cable pretensions of the suspending cables and stabilizing cables, respectively. Afterwards, the form control of the cable net considering the supporting structure flexibility is realized using a calibrating algorithm involving pre-deformation of the truss ring and modification of the initial strains from the fixed-boundary form-finding. In the initial state of the primary steel structure, not only the form of the cable net is identical to that under fixed boundary condition, but also the geometry of the truss ring and the forces of the stay cables reach their targets.
