Tim,
You need to add vertical posts or stringers on both sides of the opening to transfer out of plane forces to the roof and floor.. Analyze the wall as a vertical beam. If you just add framing around the new opening you have not done anything to compensate for the stress increases adjacent to the corners in the remaining wall. These posts will also carry vertical loads that were former ally carried by the part of the wall that is cut out. The reinforcing should be installed before the wall is cut to avoid possible cracking due to vertical loads from the unsupported new lintel.
Richard Hess S.E.
562 799 9787
-----Original Message-----
From: Pinyon Engineering [mailto:Pinyonengineering@hughes.net]
Sent: Friday, August 17, 2007 10:09 AM
To: seaint@seaint.org
Subject: cutting a window into concrete block wallI have a client that wants to install a window in an existing block wall. what is the best way to install reinforcing steel around the opening. I have called out for a steel frame around the window and drilled 24" all thread epoxy anchors around where the code asks for extra steel. is there a reference book for this out there or any suggestions.This is in a 1974 era building -soild grouted and minimal steel -wood roof and 2nd floor - in seismic zone 4 - I am checking that I have enough shear wall.Tim RudolphPinyon EngineeringBishop CA