Foundation straps

[chris mc]

Codeman,
I cannot find the spacing requirements for foundation straps in an 8" brick wall, the question that has come up is distance from a corner.

We are under the 2006 IRC, any help would be greatly appreciated.

[Jerry Peck - Codeman]

Hi Chris,

If you are not in Seismic Design Categories C, D0, D1 and D2., then here is the code - even some requirements for these are in this section: (underlining and bold are mine)
- R403.1.6 Foundation anchorage. When braced wall panels are supported directly on continuous foundations, the wall wood sill plate or cold-formed steel bottom track shall be anchored to the foundation in accordance with this section.
- - The wood sole plate at exterior walls on monolithic slabs and wood sill plate shall be anchored to the foundation with anchor bolts spaced a maximum of 6 feet (1829 mm) on center. There shall be a minimum of two bolts per plate section with one bolt located not more than 12 inches (305 mm) or less than seven bolt diameters from each end of the plate section. In Seismic Design Categories D0, D1 and D2, anchor bolts shall be spaced at 6 feet (1829 mm) on center and located within 12 inches (305 mm) of the ends of each plate section at interior braced wall lines when required by Section R602.10.9 to be supported on a continuous foundation. Bolts shall be at least 1/2 inch (13 mm) in diameter and shall extend a minimum of 7 inches (178 mm) into masonry or concrete. Interior bearing wall sole plates on monolithic slab foundation shall be positively anchored with approved fasteners. A nut and washer shall be tightened on each bolt of the plate. Sills and sole plates shall be protected against decay and termites where required by Sections R319 and R320. Cold-formed steel framing systems shall be fastened to the wood sill plates or anchored directly to the foundation as required in Section R505.3.1 or R603.1.1.
- - - Exceptions:
- - - - 1. Foundation anchorage, spaced as required to provide equivalent anchorage to 1/2-inch-diameter (13 mm) anchor bolts.
- - - - 2. Walls 24 inches (610 mm) total length or shorter connecting offset braced wall panels shall be anchored to the foundation with a minimum of one anchor bolt located in the center third of the plate section and shall be attached to adjacent braced wall panels per Figure R602.10.5 at corners.
- - - - 3. Walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels shall be permitted to be connected to the foundation without anchor bolts. The wall shall be attached to adjacent braced wall panels per Figure R602.10.5 at corners.

If you are in one of those Seismic Design Categories, then this would apply:
- R403.1.6.1 Foundation anchorage in Seismic Design Categories C, D0, D1 and D2. In addition to the requirements of Section R403.1.6, ... (which I can post if you need it)

[chris mc]

Thanks Jerry, so I'm assuming anchor bolts and straps are considered equal?

Edit: After a little studying, is the answer to this question, exception 1?

I am in Rock Hill SC (York county). Looking at R301.2(2) I am very close if not in the C category, is there another reference that is easier than the map.

[Jerry Peck - Codeman]

Hi Chris,

Thanks Jerry, so I'm assuming anchor bolts and straps are considered equal?

I misunderstood your question of straps versus anchor bolts and read it as anchor spacing.

Edit: After a little studying, is the answer to this question, exception 1?

Correct, but that still does not answer your question as the answer to your question is based upon the strength of the 1/2 inch anchor bolts versus the straps used, i.e., you would need to see the engineering, and the engineering results would be based on the loads applied and the strength of the straps, which in a round about way could be compared to the 1/2 inch anchor bolts.

Here are two bolt strength charts I found on the internet which are the easiest to read from the charts I found (some are more technically oriented and complex, but show the same "Bolt Safe Working Loads (lbs)" or do not show that at all, where these two charts show those in easier to find and read tables:
(place cursor over link, right click, open in new window)
http://dodgeram.org/tech/specs/bolts/SA ... ength.html
http://www.derose.net/steve/resources/e ... bolts.html

The above tables show the "Bolt Safe Working Loads (lbs)" for a 1/2 inch Grade 2 bolt as 760 pounds, and without being able to see the embedded heads to see their Grade markings, I would presume the bolts to be Grade 2 and not Grade 5.

This means that IF the strap had a rating of 760 pounds or greater per strap the one strap would equal one bolt.

Here are two typical sill anchors and their ratings:
(place cursor over link, right click, open in new window)
- http://www.strongtie.com/ftp/catalogs/C ... 2-p023.pdf - The MASAP embedded strap has a rating of 903 pounds, so one of these straps would equal one bolt, or actually could be spaced slightly further apart than the bolts.
- http://www.strongtie.com/ftp/catalogs/C ... 9-p023.pdf - The MASB embedded strap shows the data differently, see the spacing and also make sure to see notes 5 and 6 for the straps.

I am in Rock Hill SC (York county). Looking at R301.2(2) I am very close if not in the C category, is there another reference that is easier than the map.

Nothing really anything easier, but I opened my Microsoft Streets and trips, located Rock Hill, SC, compared its location within the county and the state boarder with NC, then approximately located it on the figure: (click on drawing to enlarge it)

Seismic Design Category C - Rock Hill, SC.jpg

Yes, you are in Seismic Design Category C.

Hoping this helps more than my first replay where I was answering the wrong question.