Thursday, October 20, 2011

RE: Infill opening in a tilt-up

You did not say if you were partially grouting or fully grouting. 
Weld the A 706 dowels to the top frame. 
You have 18 courses from bottom to top.  Course number 1 is at the bottom of the wall.  Use a bond beam in course 17 (for partial grouting).  If you are fully grouting this is not needed, but you may want to have one anyway.   Let the vertical bars lap the dowels at the top as required, but have the lap start at the top of course 17 and extend down. 
Use "A" block CMU for course 18.  If you have vertical bars at 16" OC or greater this will work.    Place the "A" bond beam CMU around the vertical dowels on course 18 (top course).  Provide notches at the top of the CMU "A" block course number 18 at about 32" OC sufficient to bag the grout into course 18.  Bag place the grout.  Plug the notches with anything handy to keep the grout from coming out.  After the grout is set remove the plugs and seal the holes with mortar. 
Having a bond beam at course 17 allows you to effectively consolidate the grout from 17 down. 
Frankly, I like to use "A" block throughout.  You can lap the dowels at the bottom to a single bar and let the rebar stick up the full height of the wall with a lap splice at the bottom and at the top.  "A" blocks go around the rebar.  This emiminates a lot of splices, and you do not have to lift the blocks up and over the rebar.  Most CMU suppliers have "A" block these days.  The US Army Corps of Engineers is fond of them. 

Regards, Harold Sprague

Date: Thu, 20 Oct 2011 09:16:56 -0700
Subject: Infill opening in a tilt-up

I need to remove some 12'x12' roll-up doors in 6" concrete tilt-up panels and infill with CMU

The current idea is to leave the steel frame, weld A706 dowels at the sides and epoxy dowels at the bottom.  Then use bond beam units, drop in horizontal #4 bars and grout.  That would take care of the sides and bottom.

I need an Idea for tying the infill to the steel door frame at the top.  Suggestions?

Mark Johnson