2024 Vol. 39, No. 6

Research
Study on the Connection Performance of Aluminum Alloy Honeycomb Plate Composite Structure with Lock Riveting Connection
Liangjian Yuan, Tengteng Zheng, Caiqi Zhao, Ye Gu
2024, 39(6): 1-6. doi: 10.13206/j.gjgS23052701
Abstract:
In order to study the mechanical properties of aluminum alloy honeycomb panel rod combination structures with lock riveting connections, this paper conducted static test analysis on three sets of aluminum alloy honeycomb panel rod combination structures with lock riveting connections, and explored the influence of honeycomb panels, lock riveting connection spacing, etc. on the mechanical characteristics and deformation performance of the combination structure. Experiments have shown that the participation of aluminum alloy honeycomb panels in the joint work of grid shell structures fully utilizes the advantages of lightweight and high-strength honeycomb panels and aluminum alloy members, significantly improving the mechanical and deformation properties of the composite structure. The effective connection between aluminum alloy honeycomb panels and aluminum alloy rods is the key to unleashing the performance of aluminum alloy honeycomb panels and rods. The ultimate failure mode of non-plate composite structures is brittle failure at the connection nodes of aluminum alloy rods, while the ultimate failure mode of aluminum alloy honeycomb panel rod composite structures is ductile failure that can continue to bear the load even after the aluminum alloy rod fractures while ensuring the connection performance of locking and riveting connectors. At the same time, different connection methods have a significant impact on the composite structure. Compared to traditional core pulling rivet connections, plate to rod locking rivet connections can effectively improve the overall integrity of the composite structure, and there is no locking rivet node failure when the structure is damaged. There is only local buckling in plate, which has good connection performance. In addition, the spacing between locking and riveting connections has a significant impact on the bearing capacity and deformation performance of aluminum alloy honeycomb panel rod composite structures. With the same diameter, connection process, and honeycomb panel thickness, the smaller the connection spacing, the greater the bearing capacity of the composite structure.
Structure Optimization and Performance Analysis of Box-Type Support Joint of L-Shaped Partially Coated Steel-Concrete Composite Column
Zuowei Qin, Hui Li, Dong Han, Haiqiang Jiang
2024, 39(6): 7-13. doi: 10.13206/j.gjgS22082301
Abstract:
Partially encased steel-concrete composite columns (PEC columns) have broad application prospects in the field of prefabricated buildings. In recent years, rectangular PEC columns have been widely used in the residential field, but L-shaped PEC columns, especially in frame-support structures, are less used. L-shaped PEC column is a new type of composite structural member. Because its limb thickness is the same as that of the wall, it avoids indoor convex columns, so it has better application prospects in prefabricated steel structure residential buildings. However, the structure of box steel support joints is more complicated. Usually in the project design, the connection structure is determined by referring to the steel structure joint structure in the 16G519 Multi-High-Rise Civil Building Steel Structure Joint Structure Detail Map. Therefore, the research on the connection structure and performance of L-type PEC column and support needs to be improved. Based on the background of Dongshenghefu 10# building residential project, according to the seismic design requirements of “strong joint and weak component”, the internal force of YJK model is extracted according to the requirements of elastic analysis under moderate earthquake: under the condition combination of 1. 3(D+0. 5L) +0. 3W+1. 4Eh, the maximum axial pressure of the support is obtained, and the maximum axial tension of the support is obtained under the condition combination of 1. 0(D+0. 5L) +0. 3W+1. 4Eh. According to the internal force of the relevant members under the combination, the finite element analysis of the traditional scheme and the optimization scheme of the box steel support joint is carried out. Based on the results of the finite element analysis, the stress distribution and stress value of the concrete and the main steel parts under tension and compression are analyzed. It is concluded that the pressure from the abdomen of the box support can be resisted by the concrete filled in the L-shaped PEC column, and the tension can be effectively transmitted through the horizontal stiffening plate. In addition, the stress distribution and stress peak of the optimization scheme are basically the same as those of the traditional scheme under the combination of medium earthquake elastic conditions, and the safety margin of the connection is good, which meets the performance requirements of the “medium earthquake elastic”combination conditions. The performance of the box-type support node structure of the optimized L-shaped PEC column has not decreased significantly, but it brings convenience to the processing and improves the quality controllability.
Research on Seismic Performance of a Steel Frame Structure with Flat Steel Tubular Column and X-Type Brace
Jun Zou, Bing Shao, Zunsheng Xing, Qixiao Yu, Jiahui Cui, Huajiao Xu
2024, 39(6): 14-21. doi: 10.13206/j.gjgS23071902
Abstract:
With the features of light weight, high strength, good seismic performance and easy assembly, steel structure is one of the most ideal residences, and it has made great development in recent years under the advocacy of national and local policies. Traditional steel structure residential mainly adopts steel frame structure, steel frame support structure, steel frame shear wall structure, etc. However, these structural systems generally have the problem of “convex beams and columns”, which affects the use of building space and living experience. For this reason, this paper proposes a kind of a steel frame ftructure with flat steel tubular column and X-type brace on the basis of traditional steel frame structure, which adopts flat steel tube columns with cross-section width of 200 mm or less and narrow flange steel beams, and increases the lateral stiffness of the structure through the setting of X-type support, which can solve the problem of “convex beams and columns” better. For this new structural system, the following work is carried out in this paper: 1) PKPM structural design software is used to analyze the structural mechanical performance and overall index of a student dormitory building which adopts flat steel tubular column X-type supported steel frame structure and traditional steel frame structure respectively under multiple earthquakes, including the structural period, the maximum interstory displacement angle and the minimum stiffness ratio of the structure under earthquake action, and the steel amount used in the two structural systems is compared. 2) Elastic-plastic analysis of the structural system under rare earthquakes was carried out by selecting two natural seismic waves and one artificial seismic wave using SAUSAGE software, and the elastic-plastic interlayer displacement angle and member performance level of the structure under each seismic condition were statistically analyzed. 3) the static pushover analysis of the basic structural units of the system was carried out by using MIDAS FEA finite element software, and its failure mode and ductility performance were analyzed. The research results show that: 1) Through the reasonable arrangement of flat steel tubular column X-type support unit, the structure meets the requirements of the Code for Seismic Design of Building (GB 50011—2010) under the action of multiple earthquakes, and has a certain economy, and the steel consumption is saved about 3% compared with the traditional steel frame structure. 2) The structure shows good seismic performance under rare earthquakes, and most of the components are not damaged above moderate level, and the maximum elasticplastic interlayer displacement angle of the structure under each working condition is less than 1/ 50, which meets the code GB 50011— 2010. 3) Through the static finite element pushover analysis, the calculation of the structural displacement ductility coefficient is 8. 5, which indicates that the structure has good ductility and pushover resistance, at the same time, it can be seen that the column has more obvious damage in the part connected with the support, so the subsequent strengthening construction measures can be carried out for this part.
Optimization of Axial Buckling Capacity of Desulfurization Tower Based on Ideal Point Method
Ping Wang, Xingyu Hu, Fangming Zhou, Zhao Mei, Jinchi Wu
2024, 39(6): 22-30. doi: 10.13206/j.gjgS23032501
Abstract:
For the structural design problem of the core device of flue gas desulfurization in mining and chemical industries, taking the minimum weight and maximum buckling resistance as the optimization objectives, the multi-objective optimization problem is transformed into a single-objective optimization problem based on the ideal point method, combined with the stress distribution characteristics under different parameters. A buckling resistance optimization model for the desulfurization tower is established. Based on the APDL language, a parameterized modeling and optimization analysis method for the desulfurization tower′s buckling resistance is designed for a specific flue gas desulfurization project as the engineering background. The main conclusions of the axial compression buckling resistance optimization are as follows: 1) The ring and longitudinal reinforcing bars have good strengthening effects on the structural stability of the desulfurization tower under axial compression load, but the strengthening effect of the longitudinal reinforcing bar is significantly better than that of the ring reinforcing bar; Although the combined strengthening effect is lower than that of the longitudinal reinforcing bar alone, the engineering actual complex working conditions determine that the ring reinforcing bar is indispensable; 2) The combined strengthening structure has a significant increase in strength, the maximum allowable stress is raised by more than one and a half times, the strengthening effect is obvious; Although the degree of deformation of the structure has a slight increase, the distribution is more uniform, and the material bearing capacity can be used more fully to ensure the overall stability of the structure. 3) The optimized tower structure weight increased from 417 810 kg to 429 160 kg, an increase of 2.715%, and the structural buckling capacity increased from 22 077.435 N to 47 536.231 N, an increase of 115%. Through this optimized analysis method, a more reasonable reinforcement scheme can be obtained, the operation process is simple, and the optimization effect is obvious.
Design
Structural Design of Domestic Low-Mo Fire-Resistant Steel in Fire-Resistant Design of Tall Space Buildings Canopy
Hai Gong, Le Liu, Jianhao Guo, Peijun Wang, Qiang Cui
2024, 39(6): 31-41. doi: 10.3724/j.gjgS23122901
Abstract:
Fire is one of the critical safety threats to steel structures. The main conventional fire-resistant measures include painting fireresistant coating, forming composite structures by combining steel with concrete and setting fire-resistant plates, among which the fireresistant coating is the most widely used. However, the fire-resistant coating painted outdoors performs poor durability, owning the hidden danger that the coating may fall and hurt people. In addition, the extremely thick coating is required for steel structures with strict demand on fire resistance, which will especially affect the architectural rending of landmark buildings. In recent years, fireresistant steel has been paid more attention for its ability to effectively avoid the above drawbacks, as a novel fire-resistant approach. However, the cost usually becomes higher due to the massively added high-price alloy Mo. As a result, the novel fire-resistant steel proposed by the Institute of Nanjing Iron & Steel Co. Ltd gained widespread attention owing to the much lower cost by reducing the additive quantity of alloy Mo while maintaining excellent fire-resistant properties. This paper investigates the feasibility of applying low-Mo fire-resistant steel in the fire-resistant design, based on the carrying capacity method and relying on a large steel canopy with a tall space. The large canopy should meet the 3 h fire-resistant requirement as a landmarking building. First of all, the material properties of domestic fire-resistant steel are investigated under high temperatures. It is found that the novel fire-resistant steel meets the requirements of general fire-resistant steel by comparing with the current specification and the reduction of material properties can be accurately predicted according to corresponding equations in the specification. Subsequently, a total of 11 fire scenes located at the side-span and the middle-span are identified according to the structural design criterion, which is thought to include all the possible fire scenes of the large canopy during service. Furthermore, it is analyzed that the heating laws of the large canopy under various fire scenes. The results show that the highest temperatures of air and steel beam are close to 750 ℃ and 730 ℃, respectively, when the canopy is in the side-span fire scene, and those for the canopy in the mid-span fire scene are 600 ℃ and 570 ℃, respectively. All of them are much lower than the temperature in a standard fire specified in ISO 834, which demonstrates that the tall space structure could be the main application scene of fire-resistant steel. Finally, the bearing capacity and stability of the structural members are analyzed and validated using the general structural steel Q355 and the domestic fire-resistant steel Q345FR. It is indicated that the steel beams GL3, GL3a and GL4 fail to meet the load-carrying requirements when using the general structural steel Q355, while the strength and overall stability requirements can be achieved when applying the fire-resistant steel Q345FR.
Comparative Study on Fireproofing Design of Steel Structures in Petrochemical Industry Between Chinese and American Standards
Xianshun Li, Kai Zhang
2024, 39(6): 42-47. doi: 10.13206/j.gjgS23041001
Abstract:
Steel structure has advantages of high strength, light weight, easy processing and simple installation, and has been widely used in petrochemical enterprises. The fireproofing design is significant to the safety and economy of steel structures, and it is necessary for the designers to familiarize the differences between different standards in foreign projects. Through the comparative study on the fireproofing design of steel structures in petrochemical industry between Chinese and American standards, it is found that there are significant differences in the division of fire hazard zones, fireproofing scope, and fire-resistant time between Chinese and American standards. For the fireproofing scope of Chinese standard is mainly based on the explosion hazard zone, while the American standard is based on the fire hazard zone. And both the standards are highly related to the classification of fire hazards of the equipment. The explosion hazard zone in the Chinese standard is divided by electrical engineers, while the fire hazard zone in the American standard is divided by pipeline engineers. In addition, the fire-resistant time of the Chinese standard is stricter than that of the American standard. The fire resistance coating is generally used in the Chinese standard, while the external lightweight concrete is used in the American standard. For fire-resistant layer, domestic petrochemical steel structure devices generally use fire-resistant coatings for fire prevention, and overseas petrochemical steel structure devices generally use outsourced lightweight concrete for fire prevention. 1) The comparison of permeable steel grating, enclosed floor slabs, supporting medium and high hazard equipment indicates that the fireproofing scope of steel structures in both Chinese and American standards considers factors such as fire hazard zone, floor form, and air cooler layout. However, the Chinese standard fire protection height is specific to a certain elevation point, the American standard fire protection height is specific to a certain layer, and the American standard fire protection range should be the support layer of medium and highrisk equipment. 2) The comparison of steel pipe racks indicates that when the height of the first floor is lower than 4. 5 m, the fireproofing height of the Chinese standard is greater than that of the American standard, while the fireproofing height are the same when the height of the first floor is not lower than 4. 5 m. 3) Comparing the fireproofing scope of steel pipe racks with combustible liquid pumps in the lower floor, it is shown that the fireproofing height is specific to a certain point according to the Chinese standard, while fireproofing height is specific to a certain floor according to the American standard. 4) The following parts of load-bearing steel structures, supports and pipe racks in Chinese and American standards may not be covered with fire resistance layer:a. secondary beams that not directly bearing or transferring vertical load of equipment and pipelines; b. beams that only used to support floor slabs and steel grating; c. non-load-bearing supports that only used to resist wind loads and earthquake action; and d. the saddles of horizontal and heat-exchanger equipment. Finally, the fireproofing scope of the steel structure floors with set-back, and the fire protection requirements for column bracing are given. The fire resistance requirements of brace and column should be the same for the steel frame-braced structures. The fireproofing scope should be suitable to use the factors of floor format and the air cooler arrangement in the plane projection.
Design Discussion
Buckling of Bolt-Supported Plates and Its Application
Genshu Tong
2024, 39(6): 48-51. doi: 10.13206/j.gjgS23032920
Abstract:
Plates supported by bolts find application in bolted connections and in composite walls whose two face plated are interconnected by tie bolts and concrete is filled in between. This article presents the formula of the buckling stresses of this type of plate when plate-like and column-like buckling occur respectively. The bolt-bolt distances both in line and in row were determined by requiring their capacity be the yielding strength. The difference between the composite wall with double face-plate and tie-bolts and the multicellular concretefilled tube wall is discussed and the design requirement on tie-bolts are provided
Hot Spot Analysis of Steel Structures
2024, 39(6): 52-52.
Abstract: