Construction technology of curved spherical space frame (Part 2)

2 Construction technology requirements of curved spherical space frame

In terms of comprehensive analysis, the construction process requirements of curved spherical space frame mainly include the following aspects:

(1)The position deviation of the position of the top plate and anchor bolt. Before the construction of curved spherical grid, it is generally necessary to determine the position of the roof and anchor bolt of the supporting surface with the aid of the calibrator, steel ruler and theodolite. In this process, the position deviation of the top plate of the supporting surface and the anchor bolt of the support should be controlled within a reasonable range, as shown in Table 1.

Table 1 Position deviation range of supporting surface roof and supporting anchor bolt

（2）Supporting block design and installation requirements. The requirements for the construction and installation of supporting pads for the construction process of curved spherical space frame are mainly reflected in three aspects. That is, the types and specifications requirements of supporting cushion design and installation, the supporting point of the supporting cushion design and installation of the design and installation of the block design and installation, the position requirements of the position, and the form of the space frame support. Taking the space frame support as an example, it is required that it is required not to change or substitute the space frame support at will during the construction process. For example, the spherical rubber bearing is arbitrarily changed, it will directly lead to the change of boundary constraints, and then have a greater impact on the overall stability of curved spherical space frame structure.

(3) Requirements for overall structural stability. In order to ensure the construction quality of curved spherical space frame, it is necessary to improve the understanding of the stability requirements of the overall structure. During the period, the structure characteristics of the curved spherical space frame are comprehensively considered. For the assembly and combinations in the construction of the space frame, the corresponding operating specifications need to be followed. For example: During the assembly of the space frame, the center deviation of the node should be controlled at the range of ≤ 2.0mm; the deviation between the bolt ball nodes and the steel pipe center group must be controlled within the range of ≤2.0mm); The bending vector height of the bar is generally controlled at L/1000; String length error is required to be controlled within the range of ± 2.0mm; The error of cone height should be controlled within ± 2.0mm and so on.

3 Construction technology of curved spherical space frame

3.1 Preparation stage before construction

During the construction of the curved spherical space frame, in order to ensure the smooth development of relevant construction work and improve the overall quality of construction, the implementation of the preparation of the work in the early stage of construction is critical. The preparatory work content in the pre -construction mainly includes the following points:

①Measurement of related locations. Taking the positioning axis, horizontal degree, and elevation position of the space frame structure as an example, the corresponding measurement work is required to use tools such as the level instrument, steel ruler, and theodolite and other tools. Only after the original support structure inspection meets the relevant regulations, can we start the follow -up installation work;

②Considering that the internal force and node deformation of the rod are calculated under a specific restraint condition of the branch node, the specifications, types and places of the relevant supporting pads are required to meet the design standards. For example: the location of the support point and the distribution of the area with the surrounding support, point support, and the opening of both sides of the support on both sides. Assuming that the position of the branch point is changed with the orientation Conditions are stable.

3.2 Bolt connection of space frame

During the construction process of curved spherical space frame, bolt connection of the space frame is generally divided into ordinary bolt connection and high strength bolt connection two ways:

(1) Ordinary bolt connection. Before the implementation of the connection process of the space frame, it is required to determine which method of the use of crude bolts or refined bolts in combination with the actual situation. Under normal circumstances, crude bolts are suitable for two -type holes, while refined bolts are suitable for one type of holes.

(2) High strength bolt connection. In contrast, this method of high -strength bolt connection has significant installation convenience and simple process operation, so it has a wide range of applications during the construction of the space frame. However, because the bolt connection will be weakened due to the openings of the component, and the connected components need to be overlapped or added with other connectors such as stitching boards, corner steel, etc., the consumables increase, and its structure is also more complicated. Before the specific installation is installed, the anti -slip coefficient of the attached test components is required to be re -inspected. After the passing is determined, the installation can be started. For example: fully remove flying edges, burrs and welding spatter, ensure that the friction surface is dry and clean, prohibit rain operation. Secondly, the clearance of the overlapping contact surface is completed. For the clearance exceeding 3mm, the backing plate is required to be added. Finally, high strength large hexagon head bolt connection pair should be factory batch number recheck torque coefficient, so as to ensure the quality of connection construction.

3.3 Handling of quality problems in bolted connection of space frame

In the concrete construction process of bolt connection of space frame, it is easy to be affected by external factors and corresponding quality problems appear. In this regard, in order to ensure that the construction quality of bolt link can meet the requirements to the maximum extent, this paper analyzes the common construction quality problems of bolt link and their treatment methods.

First, the problem of space frame installation error. During the installation and construction of the space frame, the steel plate at the connection of the friction surface is required to be kept flat and straight, and there is no burr at the position of the plate edge and the hole edge, so as to ensure the close effect of the friction surface.

Second, the bolt fixed quality problem. It is required that high-strength bolts should be tightened gradually from the joint center to both ends in strict accordance with the construction sequence in the process of initial, rescrewing and final screwing.

The appearance and wide application of the construction technology of curved spherical space frame structure have remarkable advantages of high economic and technical benefits. In the specific construction work, in order to effectively ensure the construction quality and effect of curved spherical space frame, we should fully grasp the requirements of curved spherical space frame construction technology, combined with the actual construction technology optimization and innovation, so as to achieve the maximum value of its technology application.