Construction technology of super-span steel dome building

 1. General situation of steel dome building structure and construction difficulties

The glass dome structure is a three-dimensional space shape, which has three-dimensional force characteristics under the action of load. Compared with the plane structure, it has the advantages of reasonable force, light weight, low cost, and can be used for large spans. It is widely used in storage bins. , Large-span factory area. Under the same span, compared with the portal steel frame or steel truss structure, the space frame dome structure can save about half of the steel consumption. However, due to the influence of the traditional design and construction concept, the use of the super-span space frame dome with a diameter of more than 100 meters is difficult. The amount of steel is generally still as high as about 120kg/m2, which not only directly affects the manufacturing cost, but also affects the construction safety of the space frame dome under such a large self-weight. Therefore, how to reduce the amount of steel used under the premise of ensuring safety is a The key to reducing the cost and improving the market competitiveness, in view of the shortcomings of the existing design and construction technology, this paper proposes a super-span double-layer space frame dome construction method

2. Construction plan

First, determine the architectural dimensions of the dome, including height and diameter, according to the needs of use.

Secondly, according to the building size, the space frame number of the entire dome is calculated according to the side length of 3-5 meters, and then the number of nodes is calculated.

Third, input the local meteorological parameters of the glass dome building to be built plus the calculated space frame number and node number of the entire dome into the wind tunnel test part of the finite element analysis software (such as MIDASAN, ANSYS, SFCAD), and get the average number of each space frame. Wind load distribution value. Fourth, input the wind load distribution value of each space frame calculated in the previous step plus the dead load, snow load and seismic action load into the finite element design software to obtain the maximum load of the entire dome and its components. .

Fifth, according to the maximum load of each member, select the member size that meets the conditions from the member library. In the specific implementation, the same parameters can be input into different software for verification, that is, repeat the first to fifth steps 1-3 times, and take the calculated rod with the largest size as the design basis;

Sixth, recalculate the construction drawing according to the selected member size.

Seventh, according to the construction drawing, first complete the masonry of the concrete foundation, and then adopt the following measures to complete the construction of the entire dome: 1. Adopt the construction plan of sealing circle by circle along the diameter and installing layer by layer from bottom to top, using small ground units, After forming 2 to 3 triangles, high-altitude installation is required to reduce high-altitude operations; during the installation of the first circle in the circle-by-circle closure, the bearing elevation and the roundness after closing should be controlled. The frame is adjusted by adding a jack; after the installation error has been repeatedly adjusted to meet the specification requirements, the support is initially welded and fixed; after the circle is closed, it should be reviewed in time to ensure the overall rigidity of the dome and reduce the accumulation of errors. After the second and third circles of the space frame are installed , the roundness and closing error of the overall installation should be checked and adjusted in time. After each index meets the requirements, the support is finally welded and fixed. After that, it should be installed and closed circle by circle, and the roundness of the structure should be checked and adjusted every three circles. , at this time, the ground anchor is used to adjust the wire rope tension.

2. Use the adjustable small bar spreader to hoist the small unit; each unit is composed of two bolt balls and eight rods;

3. Set up safety cable piles around the steel dome roof to be built, and use the cables to offset the influence of wind. The number and position of the safety cables should change with the height of the structure installation. When the construction height reaches 3/4 of the entire design height, it should be Increase the tension of the safety cable on the windward side; 4. Weld the "L" iron on the purlin support plate of the space frame frame, and install the "L" iron welding and drilling on the ground in advance, so that the purlins are directly connected with bolts at high altitude to speed up the construction speed;