The tolerance of steel column installation verticality I
The deviation of the verticality of the steel column exceeds the value allowed by the design or specification. The reasons are as follows:
Steel column is not made to take control deformation measures, or there is bending deformation without straightening.
Or because the hoisting process and the hoisting roof panel program are unreasonable, the bending and deformation is caused by the action of temperature, wind and external force.
Or the span of the truss has a deviation, and the external force is forcibly connected during installation, which causes the verticality of the steel column to be excessively biased.
As a result, the steel column is biased when subjected to force, which affects bearing capacity and stability.
(1) In the assembly and welding of steel column production, anti-deformation measures shall be taken, and the deformation generated during production shall be corrected in time. Steel column transportation and stacking, the support points should be appropriate to prevent bending deformation under self-weight. The long column has a poor outer plane stiffness, and the lifting point during lifting should be selected at 2/3 of the total length of the column to prevent deformation. The span of the steel roof truss is over-biased and should be corrected and installed to prevent forced connection and bend the column.
(2) When the steel column is hoisted to the base plane, the vertical and horizontal axes above the column base plate should be aligned with the foundation line to prevent deviations in the span size, resulting in horizontal tension or when the column head is attached to the roof truss. Thrust, and the column is bent and deformed for proper control.
(3) When the steel column and the tailstock are connected and installed, and then the roof panel is hoisted, the two slope edges of the upper center should be symmetrically synchronized with each other to prevent lateral concentrated pressure from being caused by one slope, resulting in bending deformation of the steel column. The steel column and other connected components shall not be used without the design permission, and the components and equipment that are horizontally hauled or vertically hoisted shall be prevented from bending or deforming or damaging the joint structure.
(4) Correction of the bent steel column with fixed verticality is installed. If it is elastic deformation, it can be restored to its original state after the external pressure is removed. It can be corrected without external force. If it is plastic deformation, it can be used in steel before correction. Temporary support is added above or at the top of the curved part of the column to reduce the gravity carried by it. Then, the side is fixed to the reaction frame at the bend, and the jack is used for correction. If the rigidity of the steel column is large, it needs to be supplemented by the curved convex surface. After heating with an oxyacetylene flame, a top force can be applied to obtain the correction.