Obviously, there are several issues to be
addressed. For gravity, I've used an angle of sufficient
strength and stiffness at the head with sufficient bearing at the jambs.
Most of the contractors I've worked with seemed to prefer this method because
they can cut the slot for the angle and then drive the angle in. The
angle is secured to a grouted cell with epoxy anchors.
For out-of-plane loads, I've used everything from strongbacks to cutting
the surface of the CMU to achieve the required strength. The final
question of the in-plane load has not generally governed for openings of this
size, but, of course, it depends.
Diablo Canyon Power Plant
From: Paul Feather
Sent: Monday, November 18, 2002
To: SEAOC List
Subject: Openings in Existing
What is the consensus regarding reinforcing
around an opening cut into an existing concrete masonry wall? (fairly
new construction, not URM) I am considering small openings less than
The code requirement for steel around the
opening extending beyond is empirical, and is for all four sides. I
have seen angles top and bottom with one leg cut away extending beyond the
opening both with and without a vertical member each side as well as inset
frames without extension beyond the opening.
Any input regarding current practice, or