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RE: MASN - CUTTING OPENING IN EXISTING CMU WALL[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: "'seaoc '" <seaoc(--nospam--at)seaoc.org>
- Subject: RE: MASN - CUTTING OPENING IN EXISTING CMU WALL
- From: "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com>
- Date: Fri, 29 Aug 1997 08:35:00 -0500
Richard, This is a fairly common occurrence in the land of ungrouted and partially grouted CMU. Alt. #1 (No needles required) Consider using the existing CMU as a lintel. Design a normal reinforced CMU bond beam and CMU jambs. 1. Reinforce the jambs. Cut vertical grooves in the CMU at the lintel bearing points. Clean out the void space, insert vertical rebar as required, place wood forms over the grooves, and grout to the jambs to the lintel bearing elevation. 2. Notch the existing CMU that will serve as the lintel. Remove one face shell and the web of the existing CMU. From the center of the future opening, remove the outside face shell and web of half of the opening and the inside face shell and web on the other half. This will allow placement of the rebar. You will have to leave a sufficient number of face shells in place to keep the wall stable. If the load is not too great, you might only have to leave only the center CMU face shells in place. Cut a hole in the webs that remain to allow rebar to pass through. 3. Cut openings in the CMU immediately above the lintel to allow the placement of grout. 4. Insert the required rebar. Clean out the CMU. Place plugs in the CMU cells immediately below the lintel. Place new solid CMU soaps in the lintel beam to replace the CMU face shells. 5. Place the grout into the lintel beam through the openings immediately above the lintel. 6. Patch the grout openings as required with a stiff grout or mortar. 7. After the grout has cured, you may then remove the masonry below the lintel. Trim the masonry, and patch as required with mortar. Alt. #2 (Needles required) Design a normal reinforced CMU lintel bond beam and CMU bullnose jambs. 1. Install needles. Provide openings above the bond beam and insert steel or wood needles through the wall. Shore and brace the ends of the needles. 2. Remove the CMU as required for the jambs and lintel bond beam. 3. Install a conventional reinforced masonry CMU bull nose jamb and CMU lintel bond beam. Grout can be placed into the cells through the same openings used for the needles. 4. After the masonry has cured, you may then remove the needles. Trim the masonry, and patch as required. I hope this helps. Regards, Harold Sprague Black & Veatch ---------- From: rlewis(--nospam--at)techteam.org To: seaoc(--nospam--at)seaoc.org Subject: MASN - CUTTING OPENING IN EXISTING CMU WALL Date: Thursday, August 28, 1997 4:50PM I have an existing 10" CMU wall I would like to cut an opening in. The wall is not grouted. It supports floor framing about 2'-8" above the opening, plus additional wall height. I would like to cut a double door into the wall. Since the opening is so large relative to the distance of the floor load above, the floor load must be support on the lintel (within the 45 degree triangle). I would like to cut the opening into the wall on one face at a time. I have checked precast concrete lintels but the shear is just too much. Does anybody have a good procedure for cutting openings into existing walls supporting loads greater than the triangle arch above? Any 2 piece steel detail that would not leave exposed steel? Thanks for your help and input. __________________________________________________ Richard Lewis, P.E. Missionary TECH Team rlewis(--nospam--at)techteam.org The service mission like-minded Christian organizations may turn to for technical assistance and know-how.
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