Steel Column Correction (Construction Method Of Steel Structure-Part 3)

To correct a steel column, three things must be done: plinth elevation adjustment, plinth axis adjustment, and column verticality correction.

A. Plinth elevation adjustment

Install the steel column, and control the elevation of the steel column using the nut or elevation adjusting block under the column base plate, precision can be controlled within the specification, and the clearance obligated under the column base plate can be filled with mortar of high strength, micro expansion, and non-shrinkage by grouting method. When adjusting the column bottom elevation with a nut, the strength and stiffness of the anchor bolts must be calculated.
B. Adjustment for the bottom column axis of the first section

In the event that the crane does not lose its hook, align the four points on the column base plate with the control axis of the steel column and gradually lower to the design elevation position.

C. Correction for the column verticality of the first section

Use the cable wind rope correction technique. Look for vertical by intersecting two theodolites at 90o. During the correction process, constantly fine-tune the nut under the column base plate, until the correction is complete, screw the two nuts on the column base plate, loosen the cable wind rope, and make it without force, the column body is in the free state, and then review by the theodolite, if there is a small deviation, repeat the above process, until there is no error, screw up the upper nut.

Anchor bolt nuts are typically double nuts, and the nuts and screw may be solidly welded after the nuts are screwed up.
D. Adjustment of the top elevation and control of other frame steel column elevation

Use the relative elevation installation method. After hoisting the column into position, secure the ear plate that connects the upper and lower steel columns with large six-angle-head high-strength bolts, but not too tightly. Hoist by crane, the crowbar can fine-tune the column space. Measure the elevation value at the top of the upper and lower columns, knock the steel wedge, and spot weld the limit in after meeting the requirements.