Steel structure takes you to analyze steel structure translation installation technology

With the vigorous development of steel structure, the overall translation installation technology of building steel structure has also been rapidly developed and applied in China. Steel structure translation installation is generally used for large-span large steel structure buildings such as airports, large convention and exhibition centers, large-span workshops, etc., although our Xirong steel structure construction now only involves a variety of medium-sized steel structure buildings of steel structure, but for such a large steel structure technology should also have some understanding and learning.

Steel structure translation installation technology is the experience of several generations of steel structure people, technology

has been the crystallization of wisdom, its technical content is very high, in addition to the steel structure knowledge and technology we are familiar with, but also need to combine hydraulic power system, electrical control system, computer control system, reaction system, personnel command system and emergency treatment system. Therefore, this is not a simple technical problem, it involves the precise cooperation of various departments and systems, and the unified cooperation can complete the huge project. Today we take the Guangzhou International Convention and Exhibition Center as an example to see how the translational installation of such a behemoth is achieved.

The steel structure of Guangzhou International Convention and Exhibition Center is composed of steel roof of the exhibition hall, steel roof of the

Pearl River promenade, steel frame of the east entrance, steel roof of truck passage, etc., and the total weight of the steel structure is about 17,000 tons. Among them, the steel roof of the exhibition hall is composed of 126.6m span tension string steel trusses (Figure 7-5), the spacing of the tension string trusses is 15m, and every 6 string trusses form a section, a total of five sections. The upper part of the tension string truss is an inverted triangular steel pipe truss, the lower part is a single cable tension string, and there is a web bar top brace between the truss and the tension string. The lifting weight of the single tension string truss is 150t, and the total weight of the steel structure in each section is about 1400t. One end of the tension string steel truss is a fixed hinge support, and the other end is a movable hinge support, and the support is connected to the truss by a pin shaft.

The installation of the steel roof of the exhibition hall was one of the most difficult parts of the project, considering that the indoor concrete structure had been fully completed, and large machinery could not enter the span for hoisting, the construction method of "main truss ground assembly, internode span assembly, and overall synchronous traction translation of the section was chosen". That is, on the east and west sides of the exhibition hall, truss group tire frames are erected; The tension string truss assembles the segmented group into a whole on the tire frame, and completes the steel cable tension, so that the tension string truss forms a load-bearing member; Four dedicated tower cranes then lift the entire string-string truss onto a slipway support flush with the concrete structure's roof; Then the purlin support system between the two trusses is installed by the 300t crawler crane to form a complete intersection; Then pan the installation process one by one to form a section; Finally, the computer-controlled hydraulic synchronous traction system uses the assembled steel structure section (130m×90m, weighing 1300t) to the design position through the slide preset on the concrete structure (average translation distance 135m, maximum translation distance 270m); The installation of the entire section steel structure is completed by support conversion and fine-tuning. The whole roof is divided into five sections A, B, C, D and E by expansion joints, and two operating lines are arranged to be constructed at the same time. The construction process of the steel roof of the exhibition hall is as follows (Figure 7-6):

(1) The first string truss in the east-west operation area is hoisted to the slide.

(2) The first chord truss in the east-west operation area pulls an internode (15m) distance inward.

(3) The second tension string truss is hoisted onto the slipway, and is supported by a 300t crawler crane to install an internode to become an internode.

(4) The whole internode is moved 15m inward, the end is continuously assembled, and the roof between D and C is completed in a cyclical operation.

(5) The two sections of C and D are translated to the required position as a whole.

(6) Repeat the process of the above (D~a) steps to complete the assembly of the BE interval.

(7) Repeat the process of step (5) above to translate the roof of sections B and E as a whole to the required position.

(8) Complete the assembly and translation of the A-section roof.

The skid steer system mainly includes two subsystems: the slide trolley system and the traction system.

The slide trolley

system is composed of two parts, the slide and the trolley, which play a load-bearing guiding role. The trolley adopts a shaped load roller trolley. The slide is composed of embedded parts, fixed channel steel and slide channel steel. At the end of the roof, the trolley (Fig. 7-7) of the constructed reinforced concrete structure (Figure 7-7) is extended by the high-altitude slide and crosses the truck passage, and the flanges on both sides of the channel steel are used as transverse limits.

The traction system

consists of two subsystems: hydraulic traction system and computer control system.

After the tension string truss roof slides into place, the support conversion (that is, from the trolley to the design support) is replaced by using the jack on both sides of the design support of the tension string

truss to transfer the load to the jack, and then unload the trolley, install the design supports at both ends of the tension string truss, and after the support is installed, relax the jack to complete the replacement.

Figure 7-9 shows the actual installation of traction slip of the tense string truss roof.

The top push translation of the steel structure is

automatically carried out by computer control, and the attitude of the steel structure in the translation is also detected and adjusted by the computer through sensors. Although the control accuracy of the computer is very high, but the sensor as an electrical device, can not fail to consider its failure rate, interference and environmental factors, as well as the construction site by accidental collision damage, therefore, arrange the existing measurement force of the project to monitor the attitude of the steel structure, and each ejector point operator in the stroke to observe the slide "edge" situation, at the end of the trip to measure the translation distance, to provide multiple insurance.

Through the above cases, we can see that the translation installation project of large-scale buildings is very complex, requiring the precise cooperation of multiple systems and the use of various large-scale equipment. At the same time, the most important thing is that the cooperation of various systems must be accurate, the volume and weight of the steel structure are very large, if the final positioning once pushed overhead, it is difficult to correct; If most of the positioning is in place, and there is still a gap in a few points, then it is very difficult to correct, especially those jacking points with large loads, and the correction alone may not be pushed, and may cause large structural deformation, so it is necessary to achieve high-precision positioning, and strive to achieve all points in place at the same time. Looking at such a large steel structure building such a complex and precise project, we can't help but think of our steel structure engineering, steel structure workshop, although our construction project is relatively small, the process is relatively simple, but the cooperation of all links and processes can not be less. Our buildings also need high-precision accuracy, and all points are in place at the same time, so that our steel structure buildings will not be deformed and will have safety guarantees. Attention to detail, success for the future!