Flat Space Frame Design For Rubber Manufacturing Factory /Plant

A flat steel space frame is a better structural type of space steel structure. It has the advantages of space stress characteristics, steel saving, large space rigidity, highly flexible building, large coverage area, good seismic performance, convenient factorization, stereotypes, and beautiful architectural appearance. At present, it has been widely used in China, especially in the large-span roof, showing its superiority. Therefore, it is increasingly used in rubber industrial plants, such as large-span radial tire workshops and roof structures of main buildings of 20~35t/h boiler rooms.

1. Advantages of flat space frames

The flat space frame can withstand concentrated loads and asymmetric loads, which is beneficial to local overloading and foundation subsidence, especially the seismic effect is more prominent. Because the space frame has many nodes and is evenly arranged, it is more flexible to set up various pipes, ceilings, maintenance channels, etc. without having to set up too many rods. For the radial tire workshop with a large span and large column net, it is convenient to set up suspension cranes in both vertical and horizontal directions. In particular, loads of air ducts, cable trays, suspended ceilings, and cranes in the radial tire workshop are complex, and some loads are relatively concentrated. It is more convenient to use the space frame structure for the roof structure

2. The use of a flat plate space frame

(1)Structural type

When the span of the workshop is large, three-way flat space frames are often used, in the medium or small span, the use of diagonal quadrangle and two orthogonal diagonal flat space frame, in the rubber factory room, the use of positive quadrangle flat space frame.

(2)Type of rod and node

Most of the steel pipes and hollow ball joints are used. Hollow balls are divided into welding balls (two round steel plates are hot-pressed or cold-pressed into two hemispherical shells butt-welded) and bolt balls (hollow cast steel balls). There are also steel ring nodes, circular simple nodes and so on. The bolt ball joint is light in weight, beautiful in appearance, convenient in transportation and installation, and easy to disassemble. Steel pipes and bolt ball joints are mostly used in rubber workshops.

3. Materials

Most of them are made of 16 manganese steel and 3 steel. The space frame members in the rubber workshop are made of 3# steel, and the bolt balls are made of 45 # steel or 40 Ming steel.

4. space frame support

Peripheral support, four-point support, multi-point support. The rubber workshops are mostly supported by the periphery, and the upper string ball nodes are supported on the top of the column or on the joist at a distance of 3 meters or 6 meters.

5.Anti-corrosion and fire prevention
Including steel rust removal, and intermediate rust removal, rust removal methods usually include pickling, sandblasting, etc., but avoid rust removal with steel wire brush. Anticorrosion mostly uses red Dan two degrees, two degrees of finish paint or anticorrosive paint, with vinylidene gas primer corrosion resistance, good adhesion. Fire retardant can reach 1 fire retardant grade above the fire retardant coating.

6. Find the slope for space frame drainage

 The space frame itself can not afford to arch, and the roof plate support is set on the upper chord node to find a slope of 1%~3%, and the roof plate is installed on the support (welding).

7. election of roof panels

Use light roofs as much as possible. At present, the roofs of rubber factories are mostly made of reinforced concrete slabs, and rubber membranes are waterproof. At the same time, polyurethane insulation, polystyrene insulation profiled steel roofing, and lightweight composite panels are also being tested.

8. Calculation of internal force of space frame members

Using the general program of the space space frame and the calculation of the electronic computer, the plane numbering diagram of the member and the internal force diagram of the member can be directly drawn. The poles of the space frame should be made of steel pipes as much as possible. The steel pipes have high bearing capacity, no directionality, and are light and beautiful. Although the price of steel pipe is more expensive than that of general section steel, the overall cost is cheap. For example, for a pressure rod 4 meters long and loaded with 4 tons, the angle steel is 2.4 times the weight of the steel pipe, and the bending member is 1.4 times. The thickness of the steel pipe used for the space frame of the rubber workshop shall not be less than 3mm. In the case of a crane and a skylight, the diameter of the steel pipe should not be less than 60mm.

9. The space frame construction

(1)Generally, segmented installation (the space frame is divided into several sections for segmental installation) and integral installation (all the space frames are assembled on the ground and then installed as a whole).

(2)Hoisting of roof field plate: It should be pointed out that after calculating the internal force of the space frame members, the load effect of the plate during installation cannot be ignored. The following is an example of a rubber plant we designed to illustrate the installation procedure: the plant width is 24m+24m+21m in three spans, the length is 14X6m, (the side column distance is 6m, and the center column distance is 12m). Since the load applied to the space frame by the hoisting of the plate is different from that in normal use, the first step of the space frame is to install 12 meters from one end of the workshop (installation of three spans at the same time), and then hoist the 6-meter plate near the end ( Leave 6 meters), at this time install the Tianzi board at both ends first, and then install the Tianzi board in the middle. The second step is to move the installation steel platform with the movable track and then install the second 12 meters, and then follow the same steps as the first step to hoist the roof square plate, which is carried out in sequence, and the skylight is hoisted together.

10. The safety of the space frame

During the installation process in a vulcanizing machine workshop, it was found that the installed space frame had a bent on the top chord. At this time, the board had been hoisted for 24 meters, and then two rods were replaced, and the roof structure was safe and undamaged. Even if the rod is broken after installation, it can be removed and replaced without being affected. During the installation of the space frame, due to the incomplete type of steel pipes, it is often necessary to replace the rods. It is not foolproof to replace the large size with the small one. After the rod is replaced with a large model, the stress of the rod also changes, causing the stress of the rod to be concentrated. An unsafe factor occurs.

11. Comparison of technology and economy

The following will compare the different practices of the roof structure of the rubber manufacturing factory /Plant. Check Table 1.