1. Design of beam column joint points
There are three types of end plate connections between beams and columns: vertical end plate placement, oblique end plate placement, and flat end plate placement. Although oblique end plate placement has a larger force arm, it is difficult to construct and is generally not used. When using internal gutter drainage, if the end plate is placed vertically, the node stiffeners will affect the placement of the gutter, and the end plate can be placed flat. The flat placement of end plates can reduce the design shear force of nodes and fully utilize the beneficial effect of column pressure on nodes, making it a reasonable form of node. Due to the difference between the end plate connection and the assumed steel nodes in the calculation, it is necessary to ensure that the steel properties of the nodes are consistent with the calculation assumptions. End plate connection is a semi rigid connection form, and its ability to transmit bending moment is related to the thickness of the end plate, bolt diameter, and arrangement.
2. Supporting design
The factory structure should have a complete support system to form an effective force transmission path. Firstly, horizontal roof supports should be installed to enhance the rigidity of the roof and ensure the lateral stability of the roof beams. The wind load acting on the roof beams by the wind resistant columns should be transmitted to the top of the columns through the supports. Steel compression bars should be installed between the transverse cross supports to form a geometrically invariant system for transmitting horizontal forces.
Secondly, full-length tie bars should be installed at the top of columns, ridges, and steel frame turning points. Steel compression bars are installed at the end spans where the corresponding wind resistant columns are connected to the steel frame beams to transmit the forces transmitted by the wind resistant columns. The horizontal support of the roof should be coordinated with the support between columns, generally located in the same span, forming a geometrically invariant support system. The longitudinal support of the roof should form a closed support system as much as possible with the transverse support to enhance the rigidity of the entire factory building.
3. Strip design
The force of the brace generally needs to be transmitted to the steel frame. Diagonal braces and braces are installed at the ridge, and the force of the brace is transmitted from the diagonal braces and braces to the end of the purlin at the ridge, near the node between the purlin and the steel frame, which is equivalent to transmitting to the steel frame. The strut must be set simultaneously with the diagonal brace to form a geometrically invariant force transmission system.
Similarly, when opening skylight windows on the roof, diagonal braces and support bars should also be installed on the lower side of the skylight opening. Otherwise, the force of the braces will be transmitted to the purlin at the opening. If this purlin is not reinforced, it is likely to cause insufficient strength and damage. When opening windows on the wall, diagonal braces and braces should be placed under the window openings to transfer the force from the lower side of the window to the steel frame. Sometimes, when the wall is very high, setting diagonal braces and braces only at the top of the wall may not meet the requirements. Instead, braces and diagonal braces should be added at a certain height on the wall to transfer some of the force to adjacent steel frame columns.
For wall panels, especially those with single-sided hanging panels, double tension bars should be installed. The outer tension bar serves as a support point for the wall beam under vertical self weight, while the inner tension bar can serve as a lateral fulcrum for the compression flange of the wall beam under horizontal wind load, in order to improve the overall stability of the wall beam under wind load. For roof purlins, due to the fact that the roof panels are generally buckle type, there may be slight misalignment between the roof panels and the purlins, which cannot constrain the upper flange of the purlins. Therefore, tension bars are set at the three-point of their height.
4. Design of column base
When the tonnage of the crane is large, the column base should be fixed. In the seismic zone, it is advisable to use buried or inserted column bases. At 6 and 7 degrees, exposed column bases can also be used. For inserted column bases at the steel column root section, it is easy to meet the requirements of plastic hinges. When the burial depth reaches twice the height of the column section, it can be considered that the restoring force characteristics of the column base are basically spindle shaped.