I have a situation where 4 box plate girders need to anchored to a concrete
bearing wall. The walls are adequate for the loads. The girders support a
large automotive manufacturing machine and are subject to dynamic loads from
impact from the machinery. Typically, anchors are provided with the wall,
but for whatever reason, the anchors were to be installed with the girders,
therefore the need to drill anchors.
Our current design involves drilling a 6" diameter hole and a 1 1/4"x 24"
long anchor bolt and filling the holes with mortar. The contractor wants to
core the hole due to the diameter. Our drawings specifically say that coring
is not allowed. The girder is not subject to uplift at the anchorage point
but does experience significant vibrations every ten seconds. Does anybody
know of a way to drill a 6" diameter hole and still have a rough enough
surface to ensure adequate bond between the mortar and the walls of the
hole. The contractor is squawking at using epoxy.
Gerard Madden, P.E.
Civil Engineer/Structural Designer
The Bentley Company,
A Division of Enron Energy Services North America, Inc.
Ph: 510.661.0527 (Fremont)
Fx: 510.661.0528 (Fremont)
Ph: 925.543.3810 (San Ramon)
Fx: 925.543.3551 (San Ramon)