Structural design of a wet gas storage tank for building structure Zuo Xiaoming\Zhang Tongyi\ Gong Zheng 2 (1 China Zhongyuan International Engineering Co., Ltd., Beijing 100089; 2 Beijing Zhongji First Hospital Engineering Design Co., Ltd., Beijing 100044) Based on the analysis of the original structure of the 000m3 wet gas storage tank, a structural transformation plan was proposed to meet the functional requirements of the exhibition center, the performing arts center and the film museum. Further details on the support structure, the original vertical members, and the roof structure are introduced. According to the requirements of the specification, the structure is analyzed and calculated, and the corresponding calculation results are given.
Wet gas storage tank; transformation; support; lattice column; length to fine ratio; truss 1 wet gas storage tank original structure introduction The gas storage tank of this project is a four-tower structure, see the profile in the inflated state, the diameter is about 46m, the largest top The height is about 49.68m. The one to four tower columns and the upper and lower ring beams of each tower form the steel skeleton structure of each tower, and the outer periphery is a 3mm thick steel plate. The water tank is filled with water to insulate the gas in the inflated state, and the outer ring is composed of 18~6mm variable thickness spliced ​​welded steel plate, which is also reinforced by the top annular beam, and the lower part is directly welded to the bottom steel plate; the bottom steel plate is spliced ​​by 6mm thick steel plate. Round bottom plate with a diameter of 48,500 mm. The top of the gas tank is a single-layer grid beam structure. See the plane layout diagram. Among them, the 1 and 2 rods are I22a, the 3 rods are 22a, and the support system rods are L90x8. 2 gas tank structure transformation scheme and implementation measures are based on The existing conditions of the gas storage tanks have determined that the three gas storage tanks will be transformed into exhibition centers, performing arts centers and film museums. The heights of the three buildings are all around 20m. The internal space is high, large and rich, and the number of floors is 34. . Take the exhibition center as an example.
According to the above requirements, the following structural scheme is proposed: the three towers and the four towers are overlapped and raised, so that a building space of about 20 m height can be formed, see. This program is mainly based on the following aspects: (1) the requirements of the force system. Since the original gas storage tank is a tension system under the pressure of the gas outside, the structural members are very slender; and after the transformation, the whole structure becomes a compression system under the action of dead load and live load, and has resistance. Side force requirements. The three towers and four towers are raised in an overlapping manner, and the space between the two towers can be utilized to reinforce and reconstruct the original vertical structure, Zuo Xiaoming, and the like. The structural design of a wet gas storage tank is designed to support the structural joints to support the cross-section of the column, so that it meets the requirements of the long-to-fine ratio of the pressurized system.
(2) Building space requirements. The three towers and the four towers are overlapped and raised, and the lower support structure can be constructed at the center of the three towers and the four towers. Compared with the single layer rise, the interior space of the reconstructed building can be made larger (3) insulation requirements. In the case of adopting the above scheme, the insulation material can be filled in the space between the three towers and the four towers to solve the heat insulation problem of the pure steel outer sheath structure.
See the overall effect after the transformation.
Four tower members supporting ring beam three towers I component support column gas storage tank reconstruction structure scheme Overall effect after gas tank reconstruction 2.1 Supporting structure design Supporting structure After considering structural stress and combining construction requirements, determine 18 The steel column serves as a lower support vertical member. Since the 18 steel columns are separated by 20°, and the original columns of the third and fourth towers cannot be aligned, the steel ring beams are connected to the entire circumference of the steel column to support the loads from the upper three towers, four towers and the roof. .
The section selection of the column is determined by the planar shape of the building. The circular building plane is fully symmetrical in the Cartesian coordinate system, so the stiffness of the column is required to be substantially the same in both directions; in the cylindrical coordinate system, the circumferential stiffness of the column can be slightly smaller than the radial stiffness. According to the above analysis, a box-shaped steel column is used as a vertical member of the supporting structure.
Ring beam selection considers the force requirements. The upper structure has a torque effect on the ring beam under the action of the lateral force and the vertical load. Therefore, the ring beam is determined to adopt a box section. See the steel column and ring beam section ~7, see the three-dimensional diagram of the supporting structure.
2.2 Reconstruction of three-tower and four-tower vertical members The four-column column is I2a hot-rolled I-beam, and the three-column column is a 100-angle steel combination trough section. The slenderness ratio is much smaller than the vertical section of the supporting ring beam. The inter-column support arrangement scheme requires the column slenderness ratio. There are a total of 48 four-column columns along the circumference, and a total of 32 three-column columns along the circumference. There is no corresponding relationship between the two. See. According to the above situation, the following schemes are adopted: 1) A new column is placed inside the three towers, and the position corresponds to the original column of the four towers, which is 48 along the circumference, the section adopts hot-rolled narrow-edge H-shaped steel HN200b; 2) the original column of the four towers and Adding the webs between the three towers and adding the columns to form a lattice column. For details of the structural arrangement, see 10.3. Four-column column corresponding structure. 2.3 Reconstruction of gas tank roof structure. Single-layer grid beam structure. Under the original working condition, it is also a tension system under the action of gas external pressure. The main beam section is I22a hot-rolled I-shaped steel, and a horizontal support system is set every 90°. Similarly, after the gas storage tank was transformed into an exhibition center, a performing arts center, and a film museum, the single-story beam-type dome structure of the three- or four-tower column structure could not withstand the roofing renovation plan layer, snow, roof hanging, etc. Load. In summary, the original roof structure is added with a lower string, and the original beam and the lower string are connected by a web to form a truss-type roof truss structure. The lower string section is a welded H-shaped section with a section height of 220 mm and a width of 100 mm. See the specific structural arrangement. 2.4 Implementation of Internal Functional Structure after Gas Tank Reconstruction The internal functional structure is integrated with the envelope structure formed by the entire gas storage tank to withstand various loads. In this way, the overall stiffness and integrity are better, and the performance requirements of the structure can be better met.
2.5 oblique support setting 2.5.1 vertical inter-column support to strengthen the overall structure hoop stiffness, between the lower support columns set 4 vertical support between columns, 80 °, 100 ° interval arrangement; the same in the upper lattice Vertical support between the columns is also provided between the columns, one at every 90°. See the vertical column support arrangement.
The lower chord support of the roof structure is to ensure the stability and hoop stiffness of the lower chord plane of the roof truss, and the lower chord support is set according to the chord support position of the roof truss. The support is made of steel pipe cross section to ensure the aesthetic appearance of the support.
3 Computational analysis In the modeling, steel frame columns, steel frame beams and roof trusses are all simulated by rod elements; the supporting ring beams in the main structural members are constructed by shell elements, which also achieves the upper part. The transit node of the lattice column corresponds. The calculation analysis considers the working conditions such as modal, dead load, live load, wind load and earthquake action. The calculation results and analysis of the exhibition center are now explained.
3.1 Modal Analysis The modal analysis of the exhibition center calculates the vibration mode as 12 steps. 1 lists the first 4 modes and the period. The effective mass participation coefficient of the first 4 modes is 93%. It can also be seen from the figure. The first and second modes are two translational vibrations in the vertical direction, the third mode is the torsion around the z axis, and the fourth mode is the vertical vibration of the roof frame.
The distribution of the above modes conforms to the specification requirements and conceptual design principles.
At the beginning of the layout of the scheme, it was considered to separate the peripheral structure and the internal functional structure after the gas tank transformation from each other. Corresponding calculations were also made during the calculation process. 2 The first 3 modes of the external structure were listed. Compared with the calculation results of the overall model above, it can be concluded that: 1) each mode period is much longer than the overall scheme, and the structural stiffness is relatively poor; 2) from the various modes, it can be seen that the local structure has large local deformation. The position of the support ring beam is obviously deformed, and the circular shape can no longer be maintained, and the local vibration accounts for a large proportion. Therefore, such a scheme was abandoned, and finally the internal functional structure and the peripheral structure were integrated as a whole.
Modal 1 exhibition center final overall model front 4th mode mode 2 peripheral structure model 3rd mode shape Zuo Xiaoming, and so on. The layout of the vertical column-to-column support of the design of a wet gas storage tank is also based on the results of the modal analysis. 3 is the first-order mode shape without the oblique support between the vertical columns, which can be clearly seen as a torsional vibration mode.
4 is the third-order mode shape when the truss is not supported by the truss, and is the torsional vibration mode of the lower chord. The distribution of the above two modes is to be avoided in the design, so the diagonal support is added, and the final calculation results meet the corresponding requirements.
3 No vertical column inclination 4 No truss chord support When the first mode is supported, the third mode is 3.2. The wind load and seismic action are 55kN/m2, and the ground roughness is B. According to the calculated basic natural vibration period=0. 0.25s, the wind vibration effect of the pulsating wind pressure is considered in the analysis. In addition to the two orthogonal directions, the direction of action of the wind load also considers the wind load in the plane of 45°. The seismic fortification intensity of the project is 7 degrees, and the basic seismic acceleration is designed to be 0.15g. The horizontal seismic action is calculated by the mode decomposition reaction spectrum method. Since the internal structure is non-axisymmetric, the seismic action in the 45° plane is considered. The vertical seismic action of the roof is taken as 6% of the representative value of the gravity load.
3.3 Deformation analysis Through the calculation of the overall structure of the exhibition center, the deformation analysis was carried out. Under the action of the dead load + live load standard value, the vertical deformation of the truss span is 24.99mm, and the ratio to the span is 1/1 720, which meets the requirements of the specification. The vertical deformation of the ring beam is 1.86mm, and the ratio of the straight-line span is 1/4392. At the same time, the torsional deformation of the ring beam is also small under the action of the bending moment of the upper part of the column. The maximum inter-layer displacement angle is 3.4 stress under earthquake action. The maximum stress ratio of some components calculated by the exhibition center is analyzed: the support column is 0.787, the truss chord is 0.876, and the upper lattice leg is 0.575; the maximum stress: the support ring beam flange is 40. The support ring web is 42.77N/ Mm2. In recent years, the renovation projects for industrial sites have gradually increased, but the transformation of wet gas storage tanks is still rare, which deserves further consideration and research. This paper introduces the structural design of gas storage tank reconstruction in an industrial site renovation project, and puts forward some of the detailed processing methods, and gives the results of calculation and analysis, aiming at providing reference for the design of similar projects.
Car Wash Brush,Car Wash Brush With Handle,Professional Car Wash Brush,Car Wash Scrub Brush
Ningbo Longyang Auto Products Co., Ltd. , https://www.nblongyang-manufacturer.com