The most economical is kinda the way Jeff Says, c channel bolted above the opening such that there is room to cut out the CMU, you can use hilti wedge anchors and extend the header, furr out the inside. cut your opening and leave the steel.
Ben
I reading the ACI530-13.6.4 about minimum reinforcing in masonry shear walls, and it requires BOTH vertical and horizontal reinforcing to be the smaller of the length or height of the wall divided by 3 or 48", whichever is smaller(for Seismic Design Category D). In the past I've only designed...
