2021 Vol. 36, No. 5

Display Method:
Steel Structure Design of Nantong International Conference Center
Longgui Bu, Zhongyi Zhu, Juehui Xing, Yiqiao Tang, Kai Qin, Zhaodong Li, Xuemin Wang
2021, 36(5): 1-6. doi: 10.13206/j.gjgS20071401
Nantong International Convention and Exhibition Center is located in Chongchuan District of Nantong City, on the northeast shore of Purple Lang Lake, with a total building area of about 80 000 square meters. Along the long direction of the building plan, the multi-function hall and the banquet hall and the conference hall were respectively arranged into two major functional divisions, which were connected by the entrance hall in the middle. The total length of the building is 280 meters, the width is 84 meters, and the maximum height of the functional structure roof is 23 meters. 1 underground floor used concrete structure for the garage and civil air defense function. The floors above the ground are 1 to 3, and the height is 9 meters, 6 meters and 4.5 meters respectively from bottom to top. The main body adopted the steel frame structure system, and the long-span space roof adopted the steel truss structure, with the maximum span of 54 meters. The top molding roof was free-form surface with a maximum height of about 30 meters and adopted cross pipe truss structure.
Combined with the architectural function, the main structure of the conference center adopted steel frame and long-span steel truss structure system, spatial grid structure was used to form the skeleton of the roof. The overall structure has the characteristics of multi-high-rise structure and spatial structure. Due to the super length of the structure and two structural units with different functional distinction, the overall structure was connected by the entrance hall roof and local roof. The structural design has many design difficulties, such as weak linkage, obvious torsion effect, and the design of peripheral supporting columns. In order to solve the above difficulties, the analysis and research were carried out from the aspects of conceptual design, computational analysis and construction measures. Buckling restrained braces were introduced to avoid overload of the supporting frame due to absorbing too much seismic actions, while maintained sufficient torsion resistance of the entire structure. Considering the unfavourable integration of over length plane and weak connective of the roof, an envelope bearing capacity design was conducted to cover difference from structural components designed as single structures to structural components designed as one connected structure. The weak connective position was locally strengthened. In order to realize the architectural effect of ultra-thin columns along the perimeter, the constraint conditions of the perimeter columns and the corresponding roof structural arrangement were optimized based on the seismic design concept. The column was designed to not participate in system of horizontal lateral swing column. The bottom of the pillars and columns released the bending constraints and only provided vertical and not participate in the overall lateral. At this point, the supporting column did not belong to frame column and construction measures slenderness ratio could be greatly reduced. The transformation joints of box-shape to I-shape of truss chord were analyzed from the aspects of force transmission mechanism and manufacturing difficulty, and finally a new joint form with simple structure and reliable force transmission was adopted, which reduced the difficulty of processing, manufacturing and field construction. Combined with the functional characteristics of the building, the local use of the latest research and development of high strength refractory corrosion resistant steel has played a good demonstration role.
Structural Design of Qinghe Station
Huimin Fu, Bin Ma, Longgui Bu, Yong Wang, Qing Zuo, Duomin Wang, Zhenyong Guo, Wenping Wu, Jianhua Li
2021, 36(5): 7-15. doi: 10.13206/j.gjgS20072302
Qinghe Station has a novel shape. Its west elevation is tilted upward, and the roof is high in the west and low in the east. In order to realize the design concept of "displaying the natural beauty of the structure", the main station building adopted the integrated structure system of bridge construction according to the requirements of building facade and interior decoration effect. The structure system of "A-column+Y-column+straight column supporting catenary steel truss roof" was designed. Among them, the inclination angle of the west leg of type A-column coincided with the building elevation angle, skillfully integrated the structural components into the building facade, and provided effective lateral force resistance support and vertical support for the structural system; Y-column strived for more spacious and comfortable use space for the waiting hall, enriched the indoor visual effect, and reduced the structural span of the two span main truss on the roof, which improved the roof structure for vertical support; vertical column achieved the effect of the east side of the building, while provided vertical support for the roof structure system; catenary type main truss beam avoided the cost increase and construction difficulty caused by the secondary structure finding.
This structural system has the advantages of integration of bridge construction, unique system. Which are concrete structure below the rail bearing layer and steel structure above the rail bearing layer. The damping ratio of these two structural materials was different. There was a sudden change in the lateral stiffness of the lower two parts. There was a large overhanging area in the entrance hall of the main station building area, and the floor slab of the waiting floor was discontinuous. The commercial interlayer was a transfer structure, and the vertical components were discontinuous. The maximum span of the steel roof was 84 m. The maximum roof overhanging was 18 m. The maximum height of the building was 43 m. This project was a complex composite structure. Based on the performance-based design, the dynamic elastic-plastic analysis of the structure was carried out by ABAQUS, and the vehicle-induced vibration comfort was analyzed by ANSYS. At the same time, the joint finite element analysis of key joints was carried out. The safety and economy of the structure was provided reliable theoretical support.
Structural Design of Xumi Mountain in the Second Phase Project of Zhejiang Buddhist College
Yansheng Liu, Zhigang Ma, Qingxiang Li, Guanghai Cui
2021, 36(5): 16-23. doi: 10.13206/j.gjgS20061001
The second phase project of Zhejiang Buddhist College is a large religious building constructed with modern architectural language. Xumi Mountain and Doushutian Palace are the core parts of the project. Xumi Mountain is a concrete shear wall structure with a cylindrical shape and a height of 56.85 m. A large platform is set on the top of Xumi Mountain, which is composed of 24 plane cantilever trusses. The maximum cantilever size of the truss is 22.5 m. The root of the cantilever truss is supported on 24 steel reinforced concrete columns arranged in a circular direction. Doushutian Palace is a steel frame structure with a height of 33 m. Its outermost steel column is vertically transformed by concrete ring beam, the middle steel column is connected with Xumi Mountain concrete cylinder through concrete corbel, and the innermost steel column falls on the long-span steel beam. The lower part of the project adopts concrete shear wall structure, while the upper part adopts steel frame structure. The stiffness difference between the upper and lower parts is large. It is a complex mixed structure, and has the characteristics of cantilever, conversion, floor opening and so on.
The project seismic acceleration is taken as 7 degree (0.1g), damping ratio is 0.05 for concrete, 0.03 for steel structure. The site characteristic period is 0.20 s, the maximum value of horizontal seismic influence coefficient is 0.08, and the vertical earthquake is selected as 0.65 of horizontal seismic influence coefficient. The seismic grade of concrete shear wall is grade 3, and that of steel structure is grade 3.
The whole model of Xumi Mountain and Doushutian Palace and the sub model only considering Xumi Mountain were calculated. The analysis results showed that the calculation results of the sub model were quite different from the overall model, and it was difficult to consider the interaction between steel structure and concrete structure in the sub model calculation. In order to ensure the safety and reliability of the design, the whole model and the sub model should be used to calculate and design according to the envelope force.
The Xumi Mountain platform is composed of 24 plane cantilever steel trusses. The calculation results showed that the cantilever truss had large stiffness and high comfort. The first-order out of plane elastic buckling load coefficient of the cantilever steel truss could reach 19.1. According to the installation requirements of curtain wall, three rigid tie bars were added, and the overall stability of the cantilever steel truss met the requirements. In order to ensure the safety and reliability of stress under strong earthquake, the method of adding concrete ring beam to the root of cantilever steel truss was adopted to strengthen the structure.
The small earthquake time-history analysis, fortification intensity earthquake and rare earthquake analysis were carried out. It showed that the seismic performance of the structure met the elastic requirements of fortification intensity earthquake, and the displacement angle between the lower layers of the structure met the requirements of the code. Only part of the members yield under the strong earthquake. The section of some yield members was increased, and the concrete beam with the transfer part bearing Doushutian Palace was strengthened by increasing the section and reinforcing bars.
Steel Structure Selection and Design of Zhuhai New Air Show Hall
Jinyu Chen, Tong Ou, Silin Huang
2021, 36(5): 24-32. doi: 10.13206/j.gjgS20061201
As the main exhibition hall of Zhuhai Air Show, the roof of the exhibition hall is of novel shape, regular column position and exposed roof structure. The structure form of beautiful and reasonable stress was selected:the space quadrangle cone truss and entrance mega truss combination system; according to the different opening modes of hangar door, four different working conditions were designed for wind tunnel test and later design to ensure the structural safety in complex wind environment. According to the structural characteristics, the technology and economy condition of the roof structure form, the split joint method, the height of the grid and the practice of ball joint were compared.
According to the building function, three-layer three-dimensional truss system was set above the hangar door for the first time. The upper two floors were connected with the network frame and the lower chord layer was used as the building floor of VIP Hall. The vertical traffic space on both sides of the hangar door was used to set up the three-dimensional truss column, which formed the overall structural rigidity with the truss beam above the hangar door. The aircraft did not need to be overhauled. Two structural joints were set for roof considering the stress. The load path of roof was analyzed, and the entrance truss born 85% of the total roof load. Due to the relationship between structural split, the stress of the grid frame should be transmitted to the direction of the hangar door as far as possible. The artificial interference force flow concept was adopted to make local evacuation for the transverse chord of the grid near the hangar door. The stiffness effect was used to make the force flow of roof transmit priority to the mega truss structure, so as to meet the needs of force flow control. In order to meet the comfort requirements, the comfort analysis of VIP Hall under different walking paths was carried out. In order to meet the strict site conditions of the project without stopping the navigation, it was determined that the "super large component hydraulic synchronous lifting technology" was adopted to upgrade the whole structure twice. On the premise of safety, economy and aesthetics, the reasonable structure scheme and connection nodes were designed. The steel quantity of the project was moderate. The expected target of construction period and cost has been successfully completed, and remarkable social and economic benefits have been achieved.
Structural Modeling and Design of BISTU Library Trumpet-Shaped Reticulated Shell Building
Zhanwei Li, Yong Yang, Yang Jiang, Tang Li, Haixia Geng
2021, 36(5): 33-39. doi: 10.13206/j.gjgS20071201
The atrium of the BISTU library is 25 m high, with both ends thick and thin in the middle, shaped like a trumpet. The structural form is a single-layer reticulated steel structure, and the structural components are rectangular steel pipes. The single-layer reticulated shell structure is very thin, and needs to focus on its stable design.
Taking the stability problem of a steel reticulated shell structure as the theme, and taking the whole process design as the main line. Discussed from several main aspects that affect the stability of the structure, mainly including structural form, modle, the application of second-order direct analysis method and boundary conditions. 1) By changing the number of circumferential components, the atrium structure was divided into three models for comparison, and the optimal structural model was selected. 2) The structural model of the rectangular pipe reticulated shell required one of the two main axes of the component to be perpendicular to the surface of the reticulated shell. The conventional solution was parametric modeling. From a practical point of view, the paper presented a simplified method of realizing accurate models with MIDAS software combined with RHINO Software. 3) The application of the second-order direct analysis method for structural design requires the model to include P0 and P-δ0P0 can adopt the method of adjusting the structure shape according to the first-order buckling mode, which can be done by general finite element software. Component defects can be simulated by half a sine wave, and the defects of rectangular tube component needs to be a specified direction. At present, general software cannot automatically consider the shape and direction of component defects. This is one of the difficulties in applying the second-order direct analysis method. To solve this problem, the paper used EXCEL to process MIDAS data files. 4) The single-layer reticulated shell structure has higher requirements for the support. A new type of structural support has been introduced, which has obtained the national patent authorization. This support achieved the effect of restraining the horizontal displacement and flexibly releasing the vertical displacement.
After analysis, we got:1) Due to the existence of the hoop, the triangle mesh model has the best integrity. 2) The precise modeling method of rectangular tube introduced was simple and practical, which was convenient for designers to operate. 3) The component defect P-δ0 modeling method introduced in this paper solved the difficulty that the software cannot automatically realize the component defect modeling at this stage. 4) The new patented support satisfied the model's requirements for the release and restriction of degrees of freedom.
Steel Structure Design of Wenzhou Culture and Art Building
Jiaxing Shen
2021, 36(5): 40-46. doi: 10.13206/j.gjgS20180626
Wenzhou Culture and Art Building is about 48 m high, with a total construction area of 20 543 m2, with 8 floors above ground and 1 floor underground. The whole structure adopts steel frame and central support structure system. The space layout inside the building is very complex which contains Xinhua bookstore, theater and rehearsal room of Wenzhou Yue Opera Troupe. There is a small theater in the center of the building on the third floor. The large span over the theater is 22.8 m, and there is a large floor splice in this floor. Due to the building's atrium, multiple elevators and staircases, there are many openings on each floor, and the width of the floor slabs on the fourth floor reaches about 60% of the total floor width. There are some problems in the building structure, such as discontinuous floor, uneven mass distribution of each floor and irregular torsion.
The measures taken were as follows:1) on the premise of satisfying the use function of the building, the support between columns were reasonably arranged to solve the torsion and irregularity of the structure; 2) the thickness of the fifth floor was thickened to 150 mm and rebar distribution rate was improved appropriately. Closed horizontal supports were set around the large-scale slab hole and the section of steel beams around the slab hole were strengthened to enhance the plane stiffness. The additional oblique rebar was set in the corner of the slab hole; 3) in the theater on the third floor, steel beams were set along the inclination of the stands. In the music pool, the elevation of the floor changes greatly so that slabs were set on the both flanges of the steel beam. The oblique steel plate was fixed in the joint between griders with different altitude, where griders on the both sides of the column. On the roof of the theater, H-section steel griders with large-size welded were set up.
The results showed that the lateral stiffness of the building and the in-plane stiffness of the floor slab could be guaranteed by such measures as the arrangement of staggered columns, the arrangement of horizontal struts around the large opening of the floor slab, the arrangement of axels and vertical trusses, and the structure arrangement could meet the functional requirements and achieve a better architectural effect.
Study on the Design of Main Girder of Wide Steel Box Girder Cable-Stayed Bridge with Single-Column Pylon
Ji Zhou, Xinguo Wang, Cheng Li, Xianyi Cheng
2021, 36(5): 47-54. doi: 10.13206/j.gjgS20062801
With the increasingly strict requirements of railway safety, the span of municipal engineering bridge over the railway is gradually increasing. In order to solve the construction problems of crossing high-speed railway and large-scale railway marshalling station, a long-span single column central cable-stayed bridge was taken as the research object, and the main beam design was studied in detail. The cross railway channel is generally a scarce channel resource, with many traffic functions and wide bridge deck. If the concrete section is used, its transverse stress is difficult to effectively control and the construction quality is difficult to guarantee. The process of steel-concrete composite beam is complex and needs to be pointed out to the Railway Administration for a long construction time. Considering that it is convenient to cross the railway and minimize the impact on the railway, and at the same time reduce the weight of swivel as far as possible, steel box girder was recommended as the main beam structure form of railway crossing bridge. According to the layout of stay cables and the types of integral and split steel box girder, three kinds of transverse arrangement of steel girder were compared and selected. Due to the low height of pylon and pylon of single column bridge, the stay cables arranged on both sides of steel box girder would incline into the traffic lane clearance. Meanwhile, there is still the risk of vehicles or foreign matters falling into the railway under the bridge in the separation of steel box girder central guardrail area. The whole steel box girder structure with central cable plane was recommended form. On the basis of determining that the main beam structure of cable-stayed bridge was the whole steel box girder, the height of steel box girder was further optimized. Taking the stress state of cable-stayed bridge structure and steel consumption as the optimization objectives, three kinds of steel box girder beam height schemes were preliminarily selected, with the section height of 3.0, 3.3, 3.5 m respectively.
Considering the stress state of the structure and the engineering economy, the 3.3 m beam height scheme was the best configuration for the stress of main beam and pylon and the saving of engineering materials. In order to study the mechanical performance of wide steel box girder, the design and research of wide steel box girder cable-stayed bridge with single column pylon was carried out. Based on the limit state method, the static load calculation and fatigue analysis of steel box girder were carried out. The static load analysis included the determination of loading mode, stiffness condition of steel box girder bridge deck and other indicators. Based on ANSYS, the spatial local stress analysis of standard steel box girder and steel box girder in ballast area was carried out. The fatigue calculation was carried out by selecting a reasonable fatigue load model and considering different loading positions of fatigue load comprehensively. The results of static load calculation and fatigue check showed that the static load deformation of steel box girder of bridge and the stress met the requirements of the code, the fatigue stress amplitude of each component and connection was less than the standard limit value, and there was appropriate safety margin, and the fatigue performance was good. In this paper, a hybrid finite element model was established by using the mixed finite element method of member system and plate shell. The shear lag effects of the mid span section, the intersection area of pylon and beam and the auxiliary pier area of side span in the control area of single column wide steel box girder cable-stayed bridge were analyzed, and the parameter indexes were extracted, which played an important guiding role in the design. The main girder of single column pylon wide steel box cable-stayed bridge has good economy and aesthetics, which could provide reference for long-span and wide bridge deck structure.
Hot Spot Analysis of Steel Structures
2021, 36(5): 55-56.