Detailed introduction of portal steel frame structure building

In the building steel structure system, the portal frame building steel structure is the most widely used. Such as single-storey industrial workshop, warehouses, trading markets, public buildings, etc. When customers choose this kind of steel structure building, they must first determine its main structural form, and set the framework for the whole building. The structural forms of the steel structure of portal frame buildings include single-span, multi-span, single-slope, double-slope, whether there is a crane, etc. Different structural forms mainly meet the needs of building functions, the magnitude of the applied load and the operating conditions. And to meet the treatment of problems such as drainage and snow accumulation during use.

Nowadays, the most common portal-type rigid structure buildings are made of H-beam as the main component material. Under the action of vertical uniform load, the portal steel frame has large bending moments at the joints between beams and columns and at the mid-span of beams. Under the action of horizontal load, the bending moment at the corner of the portal steel frame is relatively large, and the bending moment at other parts is small. Therefore, H-beam with large and small cross-sections can be used, which saves materials compared with steel with equal cross-sections.

In this structure, the force is mainly borne by the main structure, and the supporting system components complete the force transmission and support the role of the beam-column structure. They are very important, they are related to the safety of the installation process and the safety of the entire structure.

The components of the support system include tie rods, corner braces, braces, horizontal (longitudinal) supports, and inter-column supports, which together form the overall rigidity of the structure. The support system bears and transmits the horizontal wind load of the gable wall, the earthquake action, the longitudinal horizontal braking force of the vehicle, and the temperature stress, and transmits the horizontal load to the foundation, and the portal steel frame columns and beams are reliably supported outside the plane.

The position of the support between the columns determines the direction of the longitudinal deformation of the steel structure and the magnitude of the temperature stress. It is generally set in the middle of the bay direction, at the third point of the longer direction, and less than 60 meters. There is no support between the columns at the end of the crane to reduce the temperature stress. Corresponding to the horizontal support of the roof in the bay, it forms a geometrically invariant system. The purlin system attached to the main structure is a structure to support and fix the roof and wall enclosure.

The purlin system is usually composed of C, Z-shaped steel, braces, corner braces, support tubes, etc. These components are made of cold-formed thin-walled section steel, angle steel, round steel and steel pipe. Mounting connections are usually grade C bolts or welds. According to the location of use, it is divided into roof system and wall system. The roof needs to consider the weight of the maintenance board, self-weight, hanging weight, wind and snow load and construction load. The wall considers whether to hang wall panels and wind loads. The specifications and spacing of the purlins are determined by combining the doors, windows and the position of the sink.

The components of the purlin system are trivial, and the construction is often not tight and the bolts are loose, which is useless. Cause purlin system unstable quality hidden danger. Only when the steel section is reasonable and the support connection is reasonable can the maintenance part really play a role.