C-shaped steel is widely used in the purlins and wall beams of other buildings, and can also be individually combined into light roof trusses, brackets and other components. In addition, the utility model can also be used for columns, beams, arms, etc. in the manufacture of mechanical light industry.

　Steel structure C-shaped purlin lap joint: Use 3 thick steel plates to make a C-shaped joint, add a 3 mm thick steel plate to the main purlin, and connect it with bolts. The above mentioned is a T-shaped connection. The purlin overlap, as long as the length of the overlap is not less than 1.5 times the height of the C-shaped steel, and it is fixed with bolts. The purlin is a force-bearing member, 2.5 mm thick. According to the specification, welding is not allowed.

The steel purlin is processed by hot-coiled and cold-bent, with thin wall, light weight, excellent section performance, and high strength. The material is Q195-345. Common steel purlins include Z-shaped steel purlins and C-shaped steel purlins. The steel purlin is a secondary load-bearing component in the roof structure system, which transmits the roof load to the steel frame.

The purlin members of the light portal frame can be C-shaped cold-formed steel channel steel and Z-shaped cold-formed thin-wall steel with oblique or straight curled edges. The height of the component is generally 140-250mm, and the thickness is 1.4-2.5mm. Cold-formed thin-walled steel components generally use Q235 or Q345, most of the purlin surface coating uses anti-rust primer, and there are also anti-corrosion measures using aluminum or zinc plating.

1. The arrangement of the purlin spacing and span

The design of the purlin should first consider the influence of skylights, ventilated roof ridges, lighting belts, roofing materials, and purlin supply specifications to determine the purlin spacing, and determine the span of the purlin according to the spacing of the main frame. Determining the optimal purlin span and spacing is a complex problem. As the span increases, the amount of main frames and purlins is bound to increase. However, the reduction in the number of main frames can reduce the amount of steel used, and the increase in the spacing of the purlins can also reduce the amount of purlins. Thicker purlins can also reduce the price per unit of steel. However, as the span of the purlin increases, the amount of support also increases accordingly. All these factors need to be considered comprehensively. There are relatively few studies in this area in my country. The United Kingdom has conducted a systematic study on 90-meter-long buildings. The results show that for frames with a span of more than 20 meters, a frame spacing of 7.5 meters is the best; for those with a span of less than 20 meters Frame, the frame of 4.5 meters is optimal. This result can only be used as a reference in our country.

2. The structure of simple support purlin and continuous purlin

The purlin member can be designed as a simply supported member or as a continuous member. Simple-supported purlins and continuous purlins are generally realized by different overlapping methods. Simple supported purlins do not need lap length. Figure 1 shows the simple lap method of Z-type purlins. The lap length is very small. For C-type purlins, they can be connected to the purlins separately. The use of continuous components can withstand greater loads and deformations, so it is more economical. The continuous structure of the purlin is also relatively simple, which can be realized by overlapping and tightening. Z-shaped purlins with oblique crimping can be overlapped, and crimping grooved purlins can be overlapped with different types of crimping groove cold-formed steel sleeves. Figure 2 shows the lap method of continuous purlins. Note that the overlap of the purlins at the end span is slightly different from the overlap of the middle span, mainly because the end span frame needs to be connected to the gable wall frame. The lap length of the purlin designed as a continuous component has certain requirements. The working performance of the continuous purlin is obtained by consuming the lap length of the component, so the continuous purlin generally has a span of more than 6 meters, otherwise it may not be able to achieve economic goals.

The square tube is a hollow square cross-section light thin-walled steel tube, also known as steel refrigerated bending section. It is a section steel with a square cross-section shape and size made of Q235 hot-rolled or cold-rolled strip or coil as the base material, which is formed by cold bending and then is welded by high-frequency welding. Except for the increase in wall thickness, the corner size and edge flatness of the hot-rolled extra-thick-walled square tube reach or exceed the level of the resistance welded cold-formed square tube.

The uses of square pipes include construction, machinery manufacturing, steel construction projects, shipbuilding, solar power generation brackets, steel structure engineering, power engineering, power plants, agricultural and chemical machinery, glass curtain walls, automobile chassis, airports, boiler construction, highway railings, and houses Building, etc.

The extension pipe of the square tube fixed rail bracket is used to connect the upper and lower square tube fixed rail brackets. The length is selected according to the height of the room. The longest length is 3 meters. The material is cast steel with a thickness of 0.5mm and has a strong load-bearing capacity. Features of the square tube bracket: 1. Used to support aluminum alloy track 2. High-density cast steel material 3. Strong and durable, strong load-bearing capacity.

Metal brackets play a very wide role in the display of goods or household storage. The existing brackets have a single structure. Most of them use a straight tube or a square tube to be fixed on the shelf or wall. The available positions of the bracket are limited, which is not conducive to more placement. There are many items, and the bracket is fixed by direct welding, which is not conducive to disassembly. Therefore, it is necessary to propose a metal bracket with a flexible structure and easy installation and disassembly.