In the transfer construction project of section cb02 of steel box girder of Hong Kong Zhuhai Macao Bridge, it is necessary to complete the transfer, splicing and storage of steel box girder in small sections by self-propelled modular vehicle SPMT hard parallel.
During the transportation of steel box girder section of Hong Kong Zhuhai Macao Bridge, due to the limitation of storage pier and trolley track, the transverse center distance of SPMT is 3630mm, and the length of corresponding transverse connecting rod assembly is 2990mm. Since the current specification of the pull rod can not meet the requirements of horizontal hard parallel operation during the transportation, splicing and storage of small sections, it is necessary to transform the pull rod. Effectively ensure the stability of SPMT lateral hard parallel operation; Improve construction efficiency; Effectively solve the problem of SPMT soft parallel running deviation; The use of tie rod can reduce the number of PPU and obtain economic benefits.
The pull rod assembly of SPMT is mainly composed of connecting rod 1, connecting rod 2, rod end bearing, lock nut, bolt and connecting seat. The length specifications of the assembled pull rod assembly mainly include 4185mm, 5160mm, 6135mm and 7110mm.
Technical scheme and effect of transformation
a. Transformation technology
According to the actual demand, the SPMT transverse tie rod can be modified as follows:
1. According to the actual construction requirements, cut the connecting rod 1 and connecting rod 2 to reach the required pull rod length: the length of the pull rod assembly transported by the steel structure of Zhongshan section is 2990mm, and the length of the pull rod assembly transported by the 45 t Gantry Crane of China Shipbuilding Longxue island is 5920mm;
2. Drill the connecting rod so that the pin holes of connecting rod 1 and connecting rod 2 fit;
3. Cut the connecting base web to meet the installation of tie rods at different angles.
b. Expected effect
1. The horizontal hard parallel operation of SPMT with pull rod can achieve SPMT walking synchronization and avoid the non synchronization of SPMT soft parallel operation.
2. The use of tie rod for horizontal hard parallel operation of SPMT equipment can make the economic benefit of PPU good.
Project case implementation
Case 1: steel box girder transfer in section cb02 of Hong Kong Zhuhai Macao sea crossing bridge
Bid section cb02 of Hong Kong Zhuhai Macao sea crossing bridge consists of 645 steel box girders. After welding in the workshop section, each section needs to be transported out of the span to the storage site for unloading and storage (the loading and unloading vehicles are completed through the self loading and unloading performance of SPMT, and the sections are supported and stored by buttresses). Among them, 543 are equal width segments and 102 are variable width segments.
The heaviest part in the section weighs about 423.011t and the overall dimension is 16.35 M × 38.8 m × 4.5 m； The smallest piece weighs about 123 T and the overall dimension is 6 m × 33.1 m × 4.5 m。 1ppu + 10 is adopted according to the length of subsection and the restriction of buttress × 4 axis SPMT horizontal hard parallel operation.
Case 2: transportation and relocation of 45t portal crane in CSSC Longxuedao shipbuilding base
The 45 t Gantry Crane needs to be moved from #1 repair dock to #5 wharf, about 200 m away; The dead weight of the gantry crane is about 800 t, the total height is 110 m (at the minimum amplitude), and the height of the center of gravity is about 30.1 M. The relocation scheme of the gantry crane adopts 1ppu + 16 × 4 (use tie rod for horizontal hard parallel operation, the width of the train set is 10670 mm, and the length of the modified tie rod assembly is 5920 mm) SPMT train set to load the gantry crane, then transport it to the predetermined position along the planned road in the plant, and cooperate to complete the unloading and installation of the gantry crane.
According to the above case from the article "Application of SPMT transverse tie rod transformation technology", at present, SPMT transverse hard shunting has been successfully applied in two construction projects: the steel box girder transfer construction project of section cb02 of Hong Kong Zhuhai Macao sea crossing bridge and the transportation and relocation of 45 t portal crane of CSSC Longxuedao shipbuilding base.
Because the stability of SPMT lateral hard parallel is better than that of soft parallel, the deviation of SPMT soft parallel is effectively solved; The use of pull rod can reduce the number of PPU and obtain economic benefits; Through the transformation of the pull rod, the function of SPMT connecting transverse splicing through the pull rod is expanded. The use of transverse tie rod improves the stability between SPMT, enhances the synchronization of SPMT travel, improves the rapid positioning of SPMT, improves the construction efficiency and saves the economic cost。