Steel columns of steel structure factory buildings are generally axial compression members or bending members. Combined with their stress characteristics, the following reinforcement methods should be selected for the columns of steel structure factory buildings.
1. Steel structure pillar unloading method
When it is necessary to reinforce or replace a new column under the unloading situation, adopt the method of "column replacement for joist". When only the upper column needs to be reinforced, the crane beam bridge can be used to support the roof truss and unload the column. When the lower column needs to be reinforced or the lower column needs to be cut off by process requirements, a permanent joist can be placed under the crane beam to share the load of the upper column on the adjacent column.
This method should be taken into account that after the joist is used to replace the lower column, the joist will have a certain deflection, forcing the original roof truss to sink, which may damage the connection nodes of the components connected to the roof truss. To this end, a temporary load can be added to the joist in advance, so that the joist has a pre-deflection.
2. Steel structure steel column reinforcement method
Use steel plate or section steel to reinforce the column section, select welding or high-strength bolts to connect with the original column as a whole; add support. Supports are added to reduce the free length of the column, reduce the external load or internal force of the column, and reinforce the concrete around the steel column for reinforcement, which can obviously increase the bearing capacity.
3. Steel structure column foot reinforcement method
Add stiffeners at the base of the column to achieve the intention of reducing the calculation of the bending moment of the bottom plate. Pour concrete between the column base steel to make the bottom plate of the column base a rigid block. In order to increase the adhesion, the surface paint and rust on the column base should be cleaned.
4. Steel structure column reinforcement bearing capacity inspection algorithm
In the case of reinforcement calculation under load, the important question is whether the stress can be redistributed after reinforcement, that is, whether the original section can be distributed to the newly reinforced member cross-section after reinforcement if it can be redistributed, the sum of the new and old loads. Can be evenly distributed to the new and old sections, otherwise, the original load will still be borne by the original section, and the newly added load will be evenly shared by the new and old sections. In the case of unloading, the cross-section check calculation is based on the total section after reinforcement, taking into account the reinforcement reduction factor, and is calculated according to the current standard. That is, the calculation is based on the check formula for the static load of the reinforced section effect under load, and the same is true for the rods and beams. The reinforcement of columns in steel-structured factory buildings is a complex task, with many factors to consider. The reinforcement method should be selected from the aspects of convenient construction, no impact on production, reasonable economy and good effect.