Supervisory Construction Quality Control of Entrance Canopies and Space Frame (Part 1)

An international leather leather goods raw materials logistics area of the second phase of the project monomer construction area of 385,000 square meters, 6 floors above ground, 2 floors underground. Mainly adopt frame structure, indoor store mezzanine and equipment mezzanine corridor using steel structure. The roof of the roc spreading wings modeling using overhanging space frame, mainly using bolted ball and support welded hollow ball connection of the space frame structure, four sides were overhanging out of the building facade 7.5 meters and 4.7 meters, the amount of steel 1340 tons. The upper surface of the space frame, the front facade, the lower eaves were wrapped with color plates, aluminum plates, aluminum composite panels. The two main entrance canopies are 22m cantilevered, 47.9m wide light steel structure, using 860 tons of steel. The main girder is a variable section box girder, the tie beams are steel tubes, the tie rods are steel tubes with two variable diameters at both ends, and the connection of the main girder with the tie rods and the main body is articulated. The steel structure is covered with aluminum plate, and tempered glass is installed on the beam.

Engineering characterization

This project has a large amount of steel structure and space frame works, and accordingly, there is a large amount of workload of pre-buried parts in the construction of main structure. Therefore, the quality control of embedded parts is an important guarantee for the construction quality of subsequent steel structure and space frame. The entrance canopy is a wave-type cantilevered steel structure, with the main beams weighing about 14 tons each and a total of 6 bays of main beams for each canopy. Since the ground is the basement roof in the range of 19 meters beyond the east-west wall and 30 meters beyond the north-south wall, the roof is not load-bearing enough to realize the automobile crane, which makes the lifting work very difficult. In addition, it is more than 40 meters high altitude installation work, construction safety and quality assurance is also very difficult. The project steel space frame for hyperbolic suspension structure, space frame along the long direction of the building is 304 meters, width direction is 159.4 meters, due to its purely decorative space frame, only in the roof around the formation of 21.476 meters wide hyperbolic space frame belt, space frame installation height of about 50-60 meters. Because the space frame is super long, three expansion joints are set up in the direction of the long side of the building, and one expansion joint is set up in the direction of the short side, so that the whole space frame is divided into eight big pieces, but the overall appearance of the space frame seems to be continuous. Due to the space frame overhead bulk using different methods, in the secondary design of the space frame, the secondary design unit should be required, according to the construction method approved by the supervisor, set aside a good amount of settlement to ensure that the settlement value after the work to meet the requirements of the building modeling. In the construction, to ensure that the elevation of each ball node of the space frame can meet the design requirements, the control of process accuracy is demanding and difficult. In addition, the space frame has a peculiar shape, and there are tens of thousands of specification varieties of space frame rods, and it is very easy to use wrong rods or find rods when assembling on site, so it is more difficult to put together than the general space frame project. Space frame lifting and entrance canopies are high-altitude work, its support system, safety protection system, work method, whether the slope can meet the design requirements, as well as the vertical transportation of materials is also a problem.

Due to the tight schedule, the volume is super-long and super-wide, so a single body is divided into two sections, contracted by two construction units, the space frame, entrance canopy are constructed by two steel structure subcontracting construction units, the space frame is bounded by expansion joints, and the two construction units are each responsible for half of the work (A, B standard). Canopies were located in the east and west, a unit to do a (A standard to do the west, B standard to do the east). The resulting problem is that the two construction methods, construction technology and management level of different, will result in differences in the finished product effect. Therefore, how to unify the construction process and standards, to eliminate the differences brought about by the quality deviation is a problem that the supervisor needs to think about and solve.