Masonry Magazine February 1999 Page. 54
Appendix
The design of masonry between brace points and the bracing itself can be an important expense particularly on small projects built by small mason contracting firms. The Appendix of the Standard shows tables and illustrations for several bracing arrangements using wood, metal pipes and cable bracing schemes. Table 3 is a representative table for an eight inch, unreinforced concrete masonry wall. Table 4 shows results for an eight inch, reinforced concrete masonry wall. There are other tables in the Appendix for 12 inch plain and reinforced walls. Using Table 3 for eight inch, unreinforced concrete masonry walls, a 16 foot high wall will require pipe bracing.
Wall Height
Portland Cement/Lime Mortar and Mortar Cement
| Wall Height | Type M/S | Type N |
|---|---|---|
| | Height | Spacing | Height | Spacing |
| 8' | 6-8", 10°-8" | 15' | 6-8" | 12' |
| 16' pipe or cable | 6-8", 10°-8" | 15' | 6-8", 10°-8" | 12' |
| 16' wood br. | 6-8", 10°-8" | 15' | 6-8", 10°-8" | 12" |
| 24' pipe or cable | 6-8", 10'-8", 14'-8", 18"-8" | 15' | 6'-8", 10'-8", 14'-8", 18"-8" | 12" |
| 24' wood br. | no good | no good | no good | no good |
| 32' pipe or cable | 22-8", 26-8", 30'-8" | 15' | 22"-8", 26-8", 30'-8" | 12 |
Masonry Cement and Air Entrained Portland Cement/Lime Mortar
| Wall Height | Type M/S | Type N |
|---|---|---|
| | Height | Spacing | Height | Spacing |
| 8' | 6-8" | 10 | 6-8" | 8' |
| 16° pipe or cable | 6-8", 10°-8" | 10 | 6-8", 10°-8" | 8' |
| 16' wood br. | 6-8", 10°-8" | 10' | 6-8", 10°-8" | 8 |
| 24' pipe or cable | 6-8", 10'-8", 14'-8", 18"-8" | 10' | 6-8", 10°-8", 14'-8", 18"-8" | 8 |
| 24' wood br. | no good | no good | no good | no pood |
| 32' pipe or cable | 22'-8", 26-8", 30'-8" | 10 | 22'-8", 26-8", 30'-8" | 8 |
Table 3. Unreinforced CMU Wall Bracing Height/Spacing Summary for the intermediate Period, ft.
Note: (1) Braces shall be installed prior to intermediate period at the top of the completed wall or at the limited heights listed above. (2) Brace heights are based on the initial period allowable stresses as given in the Standard.
Wall Height Table 3 or 4
CMU wall per Tables 3 or 4
Wall plate typical@each Brace Height (Fig. 3(a))
See Figure 3(b)
Brace Height per Table 3 or 4
(a)
Section
(b)
CMU wall
1/2 in. thick plate typical
both sides
3/16 in
(2) 3/8 in. thick tabe with
hole for Pipe Brace bolt
Pipe Braco per manufacturer
(2) 3/8 in. dia. A307 through
bolts-finger tight phas
1/2 in. turn
Footing Plate
per manufacturer
Pipe Brace by others
(min. capacity 2000 lb.
horiz. load)
See Figure 3(c)
3 ft. min. dia. or
3 ft. x 3 ft. footing
36 in. deep
Figure 2. Typical Pipe Bracing Elevation
50 MASONRY JANUARY/FEBRUARY, 1999
3 ft. min.
3 ft. min.
(dis, or least dimension)
(e)
Figure 3. Pipe Bracing Details
Pipe Brace
Footing Plate
per manufacturer
(2) 3/4 in. dia, wedge or
epoxy act anchors
standard embedment or
anchor per manufacturer
Concrete footing