China Steel Structure Association "Technology Innovation Award" award-winning series reports

Basic situation

Award-winning project name: ETFE membrane sewage treatment tank insulation capping engineering technology innovation

Main completion unit: Ningbo Wanhao Spatial Structure Engineering Co., LTD

Main accomplices: Zhang Wei, CAI Rukai, Zhi Yongxin, Zhu Chengjiang, CAI Minfei

Award number: 2022-JC-06

Project background

Golmud Industrial Park Kunlun Industrial Park Industrial sewage treatment plant (the first phase) sewage treatment pool insulation project construction project is located in the Haixi Tibetan Autonomous Prefecture of Qinghai Province, Golmud industrial Park industrial sewage treatment plant. The total construction area of the project is about 2620 square meters, the height of the ground floor is 11.50 meters, the span is 55 meters, and the main steel structure adopts the tube truss structure, which is assembled by 16 main truss columns, 16 main truss beams and 1 strand node. The construction content of the project is 25,000 cubic meters/day engineering secondary sedimentation tank, hydrolysis acidification tank and pre-sedimentation tank thermal insulation surface covered with ETFE transparent film. This project is the first ETFE membrane structure sewage tank insulation capping project in China.

Innovation achievement

01

Winter construction technology of steel structure in cold region

1) When steel components are installed at negative temperature, the shrinkage of components should be considered according to the difference in ambient temperature, and the deviation should be adjusted in construction.

2) In order to slow down the cooling rate of welds after welding and prevent cold cracks. When the temperature is lower than 0℃, preheating before welding and slow cooling after welding should be used to reduce the deformation of welding residual stress. Preheat in the range of 80-100MM on both sides of the groove of the component to be welded, and the welding preheating temperature is controlled at about 30℃. After welding, wrap and keep warm with fireproof asbestos cloth to cool the components slowly.

3) Prepare for the welding of the steel structure: welding rod baking, groove inspection, arc introduction, extraction plate and steel pad and spot welding fixed, remove the anti-rust paint and debris around the welding groove, and preheat the welding mouth. Two persons are used for simultaneous symmetric welding to reduce welding deformation and residual stress.

4) When the steel structure is welded in the open air at a negative temperature, a temporary insulation protective shed is set up. Rain and snow should not fall on the hot weld.

5) Welders who participate in the construction of negative temperature steel structures should undergo negative temperature welding process training, pass the exam, and obtain the corresponding certificate.

6) When assembling components, remove rust, burrs, soil, oil, snow and other debris remaining in the joint 50mm, and keep the joint dry without residual moisture.

7) Multi-layer welding should be used when welding the steel plate above 9mm at negative temperature, and the weld should be surfacing layer by layer from the bottom to the top. Each weld should be welded once. If the welding is interrupted, the welding defects should be removed before welding again and then reheated. It is strictly forbidden to initiate arc on the welded base material.

8) When welding steel structure on site, in case of snow, windy weather and low temperature, insulation protection shed must be set up. Remove and re-weld unqualified welds.

9) When the ambient temperature is below 0 ° C, the coating process test is carried out before the coating of anti-corrosion coating. The rust, oil, burr and other things on the surface of the component must be cleaned up when the coating is done, and the surface should be kept dry. Do not paint on snowy days or when there is thin ice on the structure.

10) Anti-slip measures should be taken when transporting and stacking steel structures in winter. The stacking site of components should be flat and solid without puddles, and the ground should be ice-free. When the same type of component is stacked, the component should be kept level, the pad iron is placed on the same vertical line, and the component is prevented from slipping.

11) When using steel cables to lift steel components, anti-slip spacers should be added, and the node plate that is lifted at the same time as the component, and the fixtures required by the installation personnel should be tied firmly with ropes.

12) Steel structure installation welding process, both ends of a component shall not be welded at the same time.

13) Remove ice, snow and frost from the surface of the component before installation, but do not damage the coating.

14) The negative temperature installation truss shall be corrected immediately, the position correction shall be correct and permanently fixed immediately, and the components installed on the same day shall form a stable space system.

02

ETFE membrane is applied in the field of environmental protection sewage inverted hanging structure

This project more shows that ETFE membrane has its own many performance advantages over traditional glass and other building materials. It is the first environmental protection sewage field in China to choose ETFE membrane as the covering material of the inverted hanging anti-hanging structure canopy, which can not only meet the sealing effect of the sewage pool, but also meet the needs of the lighting and insulation function of the project. At the same time, it also reduces the damage and maintenance costs of traditional buildings such as glass in harsh environmental climates.

Popularization and application

This project is a large-span space pipe truss upside down ETFE membrane building structure system, the overall building system is novel, beautiful shape, full of innovation, a landmark building quality project. The overall shape of the structure is like a spring in the desert, and the facade resembles a continuous waterfall, which is a ray of sunshine and warms the heart, fully reflecting the charm of the building and the beauty that the building brings to mankind. The 16 trusses suspended in the middle increase the steel support for the ETFE membrane canopy, making the overall structure more stable and strong, the structural form of steel with soft, perseverance and stability. The establishment of the project has opened up a new direction and new ideas for ETFE membrane in the field of environmental protection sewage construction. As a new landmark in the high altitude, low temperature and desert area of Golmud City, Qinghai Province, it effectively interprets the advantages of the new building material - ETFE membrane material, which has a wide range of applications, diversified structural modeling and beautiful appearance.

This article is reprinted from: China Steel Structure Association Spatial structure Branch