Application of Steel Space Frame Structure in Water Conservancy Projects

Angol Hydropower Station is a low dam (no regulation) water diversion type, mainly for power generation, with a total installed capacity of 25.20MW (12.63MW×2 units), and annual utilization hours of 3763h. The estimated total investment of the project is 148 million yuan. The ground power plant is composed of main plant, auxiliary plant and tailwater canal and other buildings. The main workshop is 49.87m long, 20m wide and 36.123m high.

Advantages of steel space frame structure

In the preliminary design, the roof of the main factory building is planned to adopt reinforced concrete thin-web beams and channel slabs. According to the actual progress of the project, the concrete pouring of the upper bent columns of the main factory building was completed on November 20, 2006. According to the measured temperature, the lowest temperature at that time was lower than – 5°C, has entered winter construction, the construction is difficult, the quality of concrete is not easy to guarantee, and the prefabricated beams and slabs require a site of nearly 2000m2, difficult to lift, low safety, long construction period, great interference to mechanical and electrical installation, cannot guarantee 2007 On April 10, 2019, the first unit will generate electricity on schedule. In order to solve the above problems, it was decided to adopt a steel space frame structure on the roof of the main factory building according to the actual situation. The construction speed is fast (taking 15 days), the installation and maintenance are easy, and the safety factor is high. It can also solve the urgent need for thermal insulation in electromechanical installation and ensure power generation on schedule.

Economically, the steel space frame structure actually covers an area of 1011m2 of the main factory building, and the price is quoted at 338 yuan/m2 (including construction, installation, decoration fees, etc.), a total of 341,718 yuan. Concrete beam and slab structure costs a total of 529,165.32 yuan for construction, installation, and decoration according to the preliminary design.

The degree of construction difficulty, the steel pipes, high-strength bolts, bolt balls, cone heads, sleeves, plates, purlins and other components used in the steel space frame structure are all processed and manufactured by the manufacturer according to the design requirements, and then transported to the construction site as parts after passing the inspection. According to the construction drawings, the technicians will assemble the space frame in five parts (each part weighs 3.20t). After derusting and painting, the existing 5t tower crane in the factory will directly hoist it into place, and after correction, it will be welded and fixed as a whole. . Then install, weld and fix the purlins and plates, and finally pour the fine stone concrete gutter. Reinforced concrete beam and slab structures are adopted. According to the design layout of the factory building and the actual conditions of the component dimensions and roads, beams and slabs must be prefabricated in the prefabrication yard and then hoisted with cables. The prefabricated components include 9 roof beams and 132 roof panels. The prefabricated site must be leveled, compacted and hardened to ensure no subsidence and prevent deformation of prefabricated components. After the prefabricated site is hardened, steel bar production, formwork installation, concrete pouring, curing, demoulding and component inspection are carried out. If the cable hoisting scheme is adopted, the cable design must be carried out in advance, and relevant parameters such as the minimum span of the cable, the number and diameter of the main cable and the wind rope steel wire rope of the rear cable, the specification and size of the main ground anchor, and the buried depth must be determined, and the force calculation should be carried out. On the basis of trial lifting, ground anchor pit test pulling and various work inspections, they can be hoisted one by one, put in place, corrected, fixed, and finally poured foam concrete. Compared with the steel space frame structure, the process is more complicated, more materials are consumed, and the construction interference is greater. It is difficult to guarantee the quality of the concrete during winter construction, and the preparation work is heavy, and there are many unforeseen factors. In contrast, the steel space frame structure is easy to construct, easy and safe to hoist, the amount of concrete is small, the quality is easy to control, and it is less affected by external factors such as electromechanical installation and harsh weather.

In terms of labor input and progress, a total of 8 people on the steel space frame structure need 15 calendar days to complete all the work, and a total of 120 man-days are required. When the reinforced concrete beam and slab structure is adopted, the prefabrication and hoisting of the concrete components will take 80 days in total. Calculated on the basis of 15 people/day for normal work, a total of 1,200 man-days will be required. It can be seen that the steel space frame structure has a short construction period and less labor input.