(1) Pay-off:
a. Elevation control:
In this project, according to the depth of the concrete cup mouth and the elevation of the bottom of the steel column, during the construction of the concrete foundation, the elevation control iron parts and "medium reinforcement" (φ30 steel bars) are embedded in the middle of the bottom of the cup mouth. The elevation error of iron parts is controlled within ±1mm.
In order to ensure that the steel column is accurately and firmly placed on the pre-embedded φ30 "medium bar" in the foundation, a steel plate with a thickness of 20 is added to the bottom of the H-shaped steel column, as shown in the figure below.

To

When installing the steel column in the steel structure, clean the foundation cup first, and check the actual height of the embedded elevation control "medium reinforcement" (φ30 steel bar) in the foundation. Because the embedded elevation during the foundation construction controls the elevation of the "medium reinforcement" Precise control has been carried out, no need to add shim. With this method, the treatment of the steel column foot is simple, fast and efficient. The construction is fast, the force is reasonable, and the column can be adjusted freely in several directions when the elevation is unchanged.
b. Before installation, use a woodworking ink fountain to place the vertical and horizontal axis reference lines of the foundation plane on the top of the cup as the steel column installation positioning line.

(2) Column binding and hoisting
a After the steel column enters the site, place the steel column according to the position of the hoisting plan, and check whether the model and number are correct. The plane position of the steel column after entering the arena is shown in the figure below.

b Before lifting the column, draw a horizontal line with red paint at a point 2300mm upward from the bottom of the column, so that it can be used as a reference for reviewing the plane elevation before and after installation.
c. Column installation belongs to vertical vertical hoisting. In order to keep the hoisted column hanging down and facilitating its positioning, make sure that the lashing point is under the corbel. In order to prevent the sharp edges and corners of the column edges from damaging the sling during hoisting, separate them with rubber belts from old cars and set them around the corners of the sling. Note that the binding is firm and easy to remove.
d The temporary steel ladder and high-strength bolt installation work platform fixtures should be tied up on the steel column.
e In order to prevent the lifted column from swinging freely, the upper part of the column base should be tied with hemp rope as a restraining rope to adjust the direction.
f According to site conditions, hoisting adopts the rotation method:
After the preparations before hoisting are ready, first carry out a test hoist. When the height of the steel column hoisting is 200mm above the ground, the hoisting should be stopped to check whether the rigging is firm and the crane is stable. After confirming that there is no problem, the crane can be instructed to slowly rise, rotate to the top of the cup, and then slowly descend. When the column bottom is 40-100mm from the design position, adjust the two reference lines of the column and the foundation to reach an accurate position, and command the crane to descend Put it in place, and use steel wedges (or wooden wedges) and wind ropes to temporarily fix the pillars, and then remove the hooks when they are safe.
·Key points of rotation method: The method in which the crane rotates while lifting the hook to rotate the column around the column foot and hoisting the column is called the rotation method, as shown in Figure A below. When hoisting the column by the rotation method, in order to improve the efficiency of hoisting, when the steel column enters the site, the binding point of the column, the center of the column foot and the center of the cup-shaped foundation should be set at three points. The distance (that is, the radius of gyration of the hanging column) is the radius of the arc (referred to as the three-point one arc), as shown in Figure B below.

The steel column hoisting is shown in the following figure:

(3) Preliminary column calibration: The column calibration should first calibrate the side with large deviation, and then calibrate the side with small deviation.
a. The correction of the column generally includes the three contents of plane position, elevation and verticality.
b. When the steel column is hoisted in place, it is a one-time alignment, and generally does not require plane re-calibration. As for the elevation of the column, since the φ30 pre-embedded "medium rib" has been used to accurately control the elevation before hoisting, it generally only needs to be checked and no correction is required. Therefore, steel column correction is mainly to correct the verticality and review the elevation.
c. Column correction needs to be carried out at the same time with measuring tools. In this project, the verticality of the column is observed, and two theodolites are used to measure and correct.
·First, put the theodolite on the side of the column, align the longitudinal center wire with the base line of the column base, and then fix the screws of the horizontal plate.
·Measure the center line of the column, observe from bottom to top. If the vertical center line is aligned, the column is vertical, and the column should be adjusted until it is aligned with the longitudinal center wire of the theodolite.
·Measure the horizontal line in the same way so that the center line of the other side of the column is perpendicular to the horizontal axis of the baseline. After the column is accurately positioned, the column can be fixed.
·Steel column verticality correction: Adjustable pitch screw and steel wedge are used. Because the long side of the column has a small contact surface, a backing plate is set during the construction. The detailed drawing is as follows.

The dimensions of the steel wedge are as follows

(4) Final correction and fixation of steel column in steel building:
After the steel column is hoisted in place, the correction of the column is mainly to adjust the elevation and correct the verticality; the correction method can choose tools such as wind rope, jack, crowbar, and steel wedges (or wooden wedges). Apply vertical force and lateral force of pulling, topping, supporting and prying.
Adjust the verticality, positioning axis and elevation of the column. After confirming that it is correct, the gap between the steel column and the foundation cup should be compacted with C40 fine stone concrete. Expansive high-strength grout is preferred.