What is the strength (stiffness) that will result when 2 layers of 1/2" or 3/4" plywood are laminated by using 12" or 16" plywood strips with 8' joints staggered at the middle of adjoining layer for a length of 20'? This laminate will be glued, screwed, and bolted to the sides of a 2x10 box frame that is 3' x 20'.

Thanks!