Four key points of high-altitude loose fight on space frame

The space frame structure is a load-bearing roof structure with light weight, high spatial rigidity and good seismic performance, and belongs to the multi-time hyperstatically indeterminate spatial structure system. The installation and construction methods are generally divided into the overall installation method and the high-altitude bulk method. Although the overall installation method of the space frame has a faster construction speed and does not require turnover materials and scaffolding, it requires a large enough assembly site and mechanical hoisting site. At the same time, the weight of the space frame cannot If it is too large, it will be easily deformed during hoisting. The high-altitude bulk method only needs to use small units of the reference space frame for construction, which is suitable for projects that do not have large-scale assembly sites . So what are the points for attention in high-altitude bulk installation?

1 Processing plant management

Most space frame construction projects choose the high-altitude loose assembly method due to the limitations of the site and large-scale hoisting machinery. Therefore, in the limited construction area, the project management personnel must request the processing plant to deliver the space frame components in the order of loose assembly. However, in the early stage of many projects, in order to catch up with the construction period or lack of management personnel, no personnel were arranged to go to the processing factory to report the details, resulting in the processing factory directly processing according to the order of the component numbers in the space frame deepening drawing, and disorderly delivery, which eventually led to the accumulation of on-site components and the space frame structure. The secondary transfer of the cones on the ground is inefficient, which makes the originally limited construction area “worse”, as shown in Figure 1.

Therefore, in the pre-construction management of space frame structures, it is necessary for the project to arrange personnel to go to the processing plant to report on the site, and require the processing plant to deliver goods in an orderly manner according to the construction plan to avoid the accumulation and secondary transfer of components on site. At the same time, each bundle of space frame components should be equipped with Corresponding component number list (waterproof), so that the later assembly can quickly find the corresponding components and improve efficiency.

2 professional interface management

Interface management with civil works is the focus of space frame construction management. The positioning of the space frame support column and the verticality of the surface have high requirements. On-site management should strengthen the management of the space frame support column. Minor deviations will cause the space frame support to fail to sit, or lack of welds and other consequences, resulting in structural safety hazards, as shown in the figure Two shown. In addition, if the network frame is supported by the upper chord, the elevation of the top of the supporting column is different, and the elevation of the top of the column should be strictly controlled. The case in Figure 3 is that the elevation of the top of the column does not match the elevation of the support.

Figure II

Figure three

3 Installation efficiency management

The temporary support tire frame for the high-altitude scattered assembly of the space frame should use the finished support tire frame or the standard section of the tower crane, as shown in Figure 4. For the installation of the main and secondary purlins of the space frame, it is not recommended to install a single purlin at high altitude. The main and secondary purlins are assembled on the ground in different areas and then hoisted as a whole.

Figure 4 Finished supporting tire frame

4 On-site safety management

The high-altitude scattered construction of the space frame needs to assemble the pyramid in advance on the ground, as shown in Figure 5, which will easily lead to other uncivilized construction behaviors of cross operations (such as: high-altitude parabolic when the scaffold is dismantled) to destroy the space frame structure cone, as shown in Figure 6 A case where the lower chord bolts of the network frame of a project were damaged by high-altitude parabolic shear damage (the network frame members are two-force rods, which are not designed to be sheared).

Figure 5 space frame fight cone

Figure 6 Bolts damaged by shear

In order to prevent the above problems from happening, before the space frame components enter the site, the processing plant must be required to send the factory qualification certificate and material report of the component materials to the project technology department. At the construction site, a cordon is set up within the range of the ground frame of the space frame, and special security personnel stand by, and high-altitude throwing is strictly prohibited.