Concrete Masonry Wall Shelter Specifications

ROOF SLAB
4" reinforced concrete slab (fc'=2500 psi); #4 rebar at 12" O.C. each or #3 rebar at 8" O.C. each way, placed at mid-depth of slab.

WALLS
8" reinforced concrete masonry walls; #4 rebar placed in vertical cells of blocks at 8". O.C.; all cells grouted with pea gravel concrete; use #8 ga. Truss type horizontal reinforcement every other course.

DOOR OPENING
Provide bond beam over door opening reinforced with two #3 rebar. Bond beam shall have a minimum of 8" bearing. Provide one extra #3 vertically at door jambs.

DOOR
Metal door frame shall be anchored to masonry wall with tee anchors (4 per jamb). Use a 1-1/2" laminated plywood door or a 1-3/4" 16 gage hollow metal door. Outside of door shall be covered with an 11 ga. (t0.1196 in. Min.) Steel plate that is attached with screws at 6" O.C. around perimeter of door. Either swing doors shall be provided with through bolted slide bolts top and bottom equal to Glenn Johnson #1718-t. (note: a sliding door may be substituted for a swinging door. When closed, the sliding door shall be supported continuously at head and on both sides.)

ANCHORAGE
Roof slab shall be anchored to top of wall with #3 rebar at 8" O.C. around perimeter of wall. This can be accomplished by bending over wall steel so that it extends a minimum of 12" into the slab or by extending slab steel a minimum of 12" into wall cells. Walls shall be anchored to slab at each corner and at 8" intervals of each wall with one #4 rebar dowel. These dowels shall be set in an existing slab with suitable epoxy anchors. They should be cast into a new slab with a minimum of 12" embedment. The bars shall extend into the masonry wall a minimum of 24". Other equivalent methods of anchorage are acceptable.

VENTING
Provide two 6" diameter openings in roof slab for venting purposes. These should be slanted or fitted with a steel pipe elbow so as to prevent debris from passing straight through to strike an occupant or the openings should be protected with a "saddle" or with covers to prevent debris passage.