According to the boundary conditions of structural internal forces, column bases can be divided into two categories: hinged column bases and rigid fixed column bases.The hinged column base only transfers the vertical and horizontal loads, while the rigid fixed column base transfers not only the vertical and horizontal loads, but also the bending moment.The rigid fixed column base can be divided into three types: exposed column base, embedded or inserted column base, and external column base.According to the structural form of column base, it can be divided into integral column base and separated column base.

           Generally, there are three methods for the installation of steel column, namely, steel plate, grouting plate and leveling nut and steel plate

1) . steel column assembly

           Large steel columns are usually transported in sections at variable section or upper part of shoulder beam.After assembling at the construction site, the whole column is connected by welding or high-strength bolts to form a whole column for hoisting.

Firstly, an assembly bench is set up on an axis, the lower section of the steel column is hoisted on the bench, leveled and determined the center line, and then the upper section of the column is hoisted to the connection, so that the plug-in ends of the two columns are aligned and spliced in place. After carefully calibrating the central axis and length of the column, the welding or high-strength bolt connection and fixation can be carried out according to the drawing requirements.

          In general, the horizontal assembly method is used, that is, the block components lie horizontally on the assembly platform.If the crane performance permits, the skylight truss and roof truss can be assembled into one.When assembling steel truss, the span error and distortion should be strictly controlled to make it not exceed the allowable value.In order to prevent deformation, reasonable lifting points should be determined and temporary reinforcement should be carried out if necessary.

For large-span roof truss with skylight or truss with large height, vertical assembly method should be used, because it is very difficult to overturn the truss.

          The structure of the roof system can be lifted after the expanded combination assembly, and the expanded combined assembly unit should be self-made or reinforced to form a structural system with spatial stiffness.

The principle of “first in the middle, then in the outside, first in the column and then in the beam, first in the bottom and then in the upper” is adopted in the hoisting of the steel structure grid.In the middle part of the workshop, a stable frame system is first formed, and then the remaining steel columns and beams are symmetrically installed.

         The joint plate bolt connection and welding connection are adopted for the inter column support and steel column. The manufacturing and installation deviation of steel column may have a great influence on its installation. The inter column support is transported to the site for installation after the whole frame is assembled in the factory.The weight of the support between columns is light, and it can be hoisted with a 25t truck crane.