Commercial Site Visit - Bank Site: Structural Columns and Steel Base Plates

          After applying the spray on tar and vinyl sheathing to the foundation wall and backfilling the site over the past few days, it came time to level the base plates.  As I mentioned in one of my earlier posts, the steel baseplates being used on this job are 1'-4" and 1'-2" sized plates with 10" anchor bolts with a 4" thread embedded into the concrete foundation wall.  The large 4" threaded area of the anchor bolt allows for the baseplates to be adjusted easily to ensure that they are perfectly level.  Back about two weeks ago when the concrete was first poured, the baseplates were not level.  Instead they were simply attached to the four anchor bolts and left unleveled until the concrete had cured and the anchor bolts had set into the concrete properly.

Shows baseplate after forms were removed.  Plate has not been leveled.

         Now that the concrete has had a substantial amount of time to cure, it came time to level the baseplate's and seal them.  The baseplates are leveled by adjusting the nuts along the threaded anchor bolts.  You may look at the baseplate above and say to yourself, "Won't there be a gap underneath the plate, meaning that an entire column is resting on only four bolts?" and the answer to this question is no.  After the baseplate has been properly leveled using the bolts, the gap under the plate is then sealed with grout.

Photo of leveled baseplate with a small gap underneath.

Baseplate which has been leveled and sealed with grout.

          I did some research about the grout used when sealing a baseplate and realized one very important thing about the grout used, as water evaporates out of concrete or grout, the concrete/grout will shrink.  For this reason it is important to use a non-shrink grout.