Diaphragms With Openings - The Analysis of Irregular Shaped Structures - page 193

F i g u r e 5.2 Effect of opening size on diaphragm.

This length is less than the minimum recommended length. Assume that the opening
causes an upper bound horizontal force at grid line 2B equal to 1080 lb. Based on the
reserve capacity of the nailing scheme, the required embedment of a collector into the
diaphragm to the right of grid line 2 would be

L opening = 12 0 . ′ openingwidth

F 1080

290

L = = = 771 . ′

embed

nailingcapacityappliedshear - - 150

< 12 ft opening

Since the embedment lengths of the vertical and horizontal collectors are less than
the minimum suggested length, and the nail spacing does not have to be decreased, it
can be assumed that the opening has no significant effect on the diaphragm. Now
assume that the opening depth has been increased to 35 ft, as shown in configuration 2.
Everything else remains the same. The shears to the left of grid line 2 would increase to
360 plf, which requires a higher nailing capacity, say, 420 plf. Therefore, the nail spacing