After forming the spatial stiffness unit, secondary grouting such as fine aggregate concrete and grouting materials should be carried out in a timely manner for the gaps between the column bottom plate and the foundation top surface. When placing shims, thick shims should be placed at the bottom, thin shims should be placed at the top, and the thinnest shims should be placed in the middle; But try to minimize or avoid using thin shims as they may affect the stability under stress and the quality of welding (spot welding). When determining the thickness of the flat pad iron, some inclined pad iron should also be forged and processed at the same time, with a slope of generally. The inclined pad iron should be used in pairs, and eccentric suspension should be prevented during placement.
In order to smoothly transmit force from the pad iron group to the foundation, the pad iron surface should be tightly adhered to the foundation surface. Therefore, before placing the pad iron, the uneven surface needs to be chiseled flat with tools. The main requirement for placing shims is that, without affecting grouting, the distance between adjacent shims should be as close as possible, so that the base plate, shims, and foundation can have a common and uniform force distribution, avoiding local bias, concentrated force, or deformation of the bottom plate when the anchor bolts are tightened.
Suspension objects and fixtures shall not be welded to the tension flanges of crane beams or beams directly subjected to dynamic loads, or to the tension chords of crane trusses or trusses directly subjected to dynamic loads. The positioning axis of the previous column can only be measured from the ground after all components of each column have been installed, welded, and bolted, and have been accepted as qualified.