Connection Between Columns And Beams in Steel Structure
When dealing with connected nodes, the following basic principles are required:
Safe and reliable. The force analysis should be as close as possible to the actual working condition, and the calculation sketch should be consistent with or close to the actual connection condition of the component; the joint should have a clear force transmission route and reliable construction guarantee.
Easy to make, transport and install. Reduce the type of nodes; the size of the splicing should leave room for adjustment; try to facilitate the operation during construction, such as: avoiding the overhead welding of the site weld, setting the installation support.
Economical and reasonable. The most economical method is determined after comprehensive consideration of materials, production, construction, etc., not be simply understood as the savings in steel consumption.
Beam-column connections can be divided into three types: flexible connection (hinged), rigid joint, and semi-rigid according to the different rotational stiffness.
1.The flexible connection of the beam and column (the connection between the axial column and the beam is generally hinged)
A. Beam supported on the top of the column
Figure a: The bearing reaction force of the beam is transmitted directly to the flange of the column. A gap is left between adjacent beams so that there is room for adjustment during installation. The transmission force is clear, the structure is simple, and the construction is convenient. However, when the reaction forces of two adjacent beams are different, the eccentric compression of the column is caused. When the reaction force transmitted by one side beam is large, local buckling of the column flange may be caused.
Figure b: Even if the reaction forces of the two adjacent beams are not equal, the column is still close to the axis. The bottom of the flange stiffener should be flattened to the top of the column; the column web is the main force part, and its thickness should not be too thin; under the top of the column, stiffeners should be provided, and the stiffener should have sufficient length to meet Weld length requirements and uniform stress spread requirements.
B. The Beam is supported on the column side
Figure a: When the reaction force of the beam is small, the beam can be placed without any supporting stiffeners. It is placed directly on the ox leg of the column and connected by ordinary bolts. The structure is simple and the construction is convenient.
Figure b: Used when the beam reaction force is large. The reaction force of the beam is transmitted to the support by the end stiffener; the support is made of thick steel plate (the thickness of which should be greater than the thickness of the stiffener) or the angled steel after the stiffening and is connected with the weld on the column side.
Figure c: When the difference between the reaction forces of the two adjacent beams is large. The reaction force of the beam is transmitted through the web of the column so that the column is still close to the axial stress state.