Steel structure gas station canopy analysis in design, construction and use

According to the fact that most of the gas station canopies in China are designed and constructed with steel space frame structure, this paper mainly observes 20 gas station canopies in a certain place, of which 16 gas station canopies use space frame structure. Therefore, the following is a simple analysis and research of these observed gas stations as examples, mainly to analyze the problems existing in the design, construction, and application of the space frame structure of the gas station canopy, and then put forward some countermeasures.

1. The design of the space frame of the gas station canopy is not in place

Compared with other steel buildings, the span of the space frame structure of the fuel station canopy is relatively small. Through the inspection of the above 20 gas stations, it is found that the maximum span of the space frame structure of the gas station canopy does not exceed 33.2m. The span of the space frame structure of a gas station canopy is only 10.5m. The structural forms of the canopies of these gas stations are all square pyramids. This structural form is relatively scientific in design. The surrounding design of the space frame structure may not be taken seriously. During the inspection, the surrounding design of the space frame structure of the fuel s station canopy is relatively sloppy, leaving a major safety hazard. This is mainly due to the consideration of the facade shape in the design, and the space frame structure is usually closed around the height of the space frame, and at least three sides need to be closed. After the space frame is hoisted, it will be The vertical web bar and the lower chord are added to serve as the baffles of the supporting surface. The side baffles are completed synchronously from time to time during the design and construction. In addition, the implementation methods or methods are sometimes different. The form is the same as that of the baffles supporting the surrounding, so the angle steel section is basically selected during construction, and the connection is made by welding. There are often some problems in the above-mentioned process. The main reasons for these problems are as follows: because the section selection is usually small, the angle steel section selection is unreasonable, so the selected angle steel is not suitable as a compression member; in the space frame structure The welding is usually carried out at high altitude, and the quality of the welding is not high; the thickness of the coating does not meet the relevant specifications, which makes the corrosion of the space frame structure of the gas station canopy more serious.

2 The coating thickness of the canopy gas station steel frame structure is insufficient

From the perspective of the structure of many gas stations, there is a big problem with the hood enclosure system of the gas station. Because the roof of the gas station is mainly composed of bending components, the purlins of the roof are single-angle steel. The cross-sectional area is relatively small, so there is a big problem in this design, so it cannot meet the requirements of bearing capacity when calculating the deflection angle, so the purlins are mostly cold-formed thin-walled rectangular tubes. In addition, the top surface of the canopy is mostly made of profiled steel plates, but the size of the space frame structure is usually between 2 and 3m. Therefore, during the on-site inspection, it is necessary to ensure that the entire purlin structure cannot be deformed, and it is also necessary to ensure that The grid size of the grid is the same, so when designing, it is necessary to ensure that the distance between the purlins decreases, and the purlins are set as primary and secondary purlins. On the other hand, appropriate profiled steel plates can be selected to meet the strength and stiffness of the space frame structure. The wave height is increased during this design process.

3 The design of the enclosure system is unreasonable

When the space frame structure of the filling station is enclosed, due to the unreasonable situation and the incomplete construction of the entire enclosure system, it is urgent to investigate and analyze the space frame structure members of the filling station and summarize the method of the enclosure. To solve the corresponding design unreasonable situation. According to some regulations in the steel structure construction quality standard, the establishment of an effective enclosure system should start with the base layer being smeared, and the thickness of the smear should be practically satisfied. If the thickness is greater than 125um, the maximum allowable range for the deviation of the coating thickness is 25um. If the thickness of the coating is not enough, it is very easy to cause corrosion. Because the gas station is often in the open air, it is very easy to cause corrosion of the canopy. Especially in places with higher humidity, the corrosion is more obvious. In addition, the span between gas stations is relatively small, and the wall thickness of the space frame structure and the diameter of the steel pipe are very small. The diameter of the steel frame structure usually used is 42 to 151 mm, and the wall thickness of the steel pipe is 2.8 to 4 mm. 3mm. Therefore, due to its thin wall and small cross-sectional area, the space frame structure of the gas station has caused design defects in the enclosure system. The resulting corrosion cross-sectional area is very large, and it is very easy to cause the rods of the space frame structure to corrode. Therefore, the cross-sectional area of ​​the enclosure system around the grid is mostly made of angle steel, so it is more likely to rust or even individual rods are broken and corroded. In the enclosure system of the space frame structure, due to the more serious corrosion of the rods, it is necessary to apply better quality to the rods in the enclosure system, and the quality is better than that of the rods of the main body of the grid. At the same time, the rod area of ​​the steel structure in the enclosure system is thinner than the cross-sectional area of ​​the grid rod, and the corrosion degree is more serious. For example, when the purlin adopts a rectangular tube, the thickness of the tube wall is only 2mm, and the surrounding of the grid is only 2mm. The enclosure system is more directly impacted by rainwater, so it is easier to rust.

4 Countermeasures

In view of the above problems, this paper mainly proposes the following countermeasures: For gas stations that use angle steel sections as maintenance components, it is recommended to replace them with straight pipes or round pipes; for gas stations that use angle steel sections as roof purlins, it is recommended to use C The purlin should be replaced; the rusted rod should be inspected in time, and if it can continue to be used, it should be repainted and reinforced. If it can not be used, it should be replaced immediately.