# Anchor Bolt edge distance



## ajweaver

Here we have a lot of monolithic slab on grade foundations.

The anchor bolts are usually 6' o.c, within 12" from ends etc..

in compliance with 2006 IRC 403.1.6.....

Question:

Where can I find a mandated distance from the outside edge of the bottom plate, I do not see where code mandates anchor bolts to be centered in bottom plate, and sometimes the bolt is placed within 1/2" of the outside edge.

Is there a section applicable to this?

Thanks

Aaron


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## Francis Vineyard

Can put a couple of code sections together to achieve "positively anchored" and appear similar to Figure R403.1(1)Install bolts per manufacturers installation guide and install sill plates per R602.3

View attachment 432


View attachment 432


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## mark handler

ASCE 7-05

Anchor bolt edge distance 1.75 inches or 2.75 inches, dependent upon sill plate


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## Mark K

Anchor bolts with 1/2" edge distance are unacceptable for both the concrete and the wood.

When dealing with the IBC reference Table 1911.2.

The recommendations for The Simpson SSTB are only appropriate for that product.  Note that the SSTB has a greater cover at the bottom than at the top of the footing.

The edge distances of 1.75 and 2.75 inches in ASCE 7  are basically saying you center the AB on the sill plate.  For a 2x4 this is 1.75 inches and 2.75 inches for a 2x6.


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## brudgers

The amount of cover required depends on a number of factors such as the specified anchor and the imposed loads.

Personally, I never spec embedded anchors for slab on grade if there is any way to avoid it because they interfere with placement and finishing of the concrete, require additional labor on the form work, and frequently require field fixes accompanied by finger pointing between the concrete sub and the framer - drill and epoxy is the  way to go.


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## KZQuixote

brudgers said:
			
		

> The amount of cover required depends on a number of factors such as the specified anchor and the imposed loads.Personally, I never spec embedded anchors for slab on grade if there is any way to avoid it because they interfere with placement and finishing of the concrete, require additional labor on the form work, and frequently require field fixes accompanied by finger pointing between the concrete sub and the framer - drill and epoxy is the  way to go.


Won't "Drill and Epoxy" always invoke the requirements for special inspection?

Bill


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## brudgers

If it does, then Simpson anchors would by the same logic.


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## Francis Vineyard

Does the manufacturer installation guide comply with ASCE 7 for those of us that cannot afford or possess this reference?


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## mark handler

YES........


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## KZQuixote

mark handler said:
			
		

> YES........


Mark,

To which question are you replying?

Bill


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## mark handler

KZQuixote said:
			
		

> Mark, To which question are you replying? Bill


Does the manufacturer installation guide comply with ASCE 7 for those of us that cannot afford or possess this reference?

* I THOUGHT YOU COULD READ MY MIND*


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## TimNY

I would require SI for drill and epoxy.. But if you can use Titans instead I wouldn't require SI.

Retrofit is a labor saver in a lot of cases.


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## peach

the edge distance requirement (which is not less than 7 bolt diameters from each end or more than 12" ) is pretty clear in IRC R403.1.6 - 2006. The reason for the minimum set back from the plate edge is so wind or seismic forces dont pull the plate thru the anchorage. Further spacing of the anchor bolts is 6' after that.. but since most sill plates are not 40' long, the plate edge needs to be adhered to.. they will try to act independently. Minimum 2 bolts per plate.


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## mark handler

peach said:
			
		

> the edge distance requirement (which is not less than 7 bolt diameters from each end or more than 12" ) is pretty clear in IRC R403.1.6 - 2006. The reason for the minimum set back from the plate edge is so wind or seismic forces dont pull the plate thru the anchorage. Further spacing of the anchor bolts is 6' after that.. but since most sill plates are not 40' long, the plate edge needs to be adhered to.. they will try to act independently. Minimum 2 bolts per plate.


But Peach

It does not give the edge distance in the "other direction"....

We all know it should be centered on the plate, but it does not always work out that way


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## Daddy-0-

Here we require that drill and epoxy be witnessed by P.E. with a report when finished. Some of the manufacturer's like Hilti and Powers require a very specific installation where you have to blow out the hole with a special hand pump. For example you must blow out three pumps, then brush, then blow out with two pumps and brush. Sounds bizarre but they it is not an approved installation without the exact procedure. Simpson has several straps that are approved for embedment in slabs. No P.E. required. Giddy up.


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## Phil

mark handler said:
			
		

> ASCE 7-05Anchor bolt edge distance 1.75 inches or 2.75 inches, dependent upon sill plate


Mark,

I have never seen this in ASCE 7-05. What is the section. ASCE 7 primarily deals with design loads and has very few detailing requiremnts. The NDS has edge distance requirements for wood members that depend on the direction of loading. ACI 318 has edge distance requirements for concrete anchors (and small edge distances affect the anchors capacity).


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## Mark K

Adhesive anchors are not addressed in the IBC (and I assume also the IRC) at present and thus use would require building official approval as an alternate per Section 104.11.  When allowed special inspection would be reasonable requirement.  Requiring that the inspection be performed by a PE is unreasonable.  This inspection is essentially no different from other types of special inspections.

For the purpose of special inspection there is no technical reason to believe that a PE license is necessary.

I believe the detailing provisions of ASCE 7 occur in Chapter 14 of ASCE 7.  IBC Section 1604.10 specifically excludes Chapter 14 of ASCE 7.


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## mark handler

Phil said:
			
		

> Mark,I have never seen this in ASCE 7-05. What is the section. ASCE 7 primarily deals with design loads and has very few detailing requiremnts. The NDS has edge distance requirements for wood members that depend on the direction of loading. ACI 318 has edge distance requirements for concrete anchors (and small edge distances affect the anchors capacity).


Phil

I do not have a copy, the note is from my structural engineers general notes.


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## FredK

I actually like these mudsill anchors instead. http://www.strongtie.com/products/categories/mudsill-anchors_wm.html


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## mark handler

AnchorMate® Anchor Bolt Holders gives percise placement

http://www.strongtie.com/products/connectors/anchormate.asp


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## mark handler

HERE IS SOMETHING FROM THE WEB

http://www.seaoc.org/bluebook/sample_pdfs/1204030_AnchorBoltsLightFrame_smpl2.pdf

SEAOC Blue Book – Seismic Design Recommendations

Anchor Bolts in Light-Frame Construction at Small Edge Distances

Article 12.04.030 Page 3 of 8 June 2009

www.seaoc.org/bluebook

changes to the anchor bolt design methodology. Since issues with the old values were not apparent, the need for substantial change was puzzling.

Testing

The primary goals of the SEAOC Anchor Bolt Test program were to:

1) Determine whether the wood connection yielding controls the connection capacity when loaded parallel to an edge and if the equations found in each material standard are good predictors of behavior.

2) Determine whether the connection exhibits ductile behavior.

3) Propose rational design capacities for the connection.

It was decided to test the 5/8-inch diameter bolts since they are representative of most medium and heavy duty shear

wall applications. While much residential concrete construction is specified at f’c=2500 psi, in-service concrete is expected to experience some strength gain over time. For this reason, a range of 2500 to 3000 psi was specified for the test concrete compressive test. In actuality, the highest compressive test cylinder result was 2710 psi. As also detailed in the SEAOC “Report on Laboratory Testing of Anchor Bolts Connecting Wood Sill Plates to Concrete with Minimum Edge Distances,” the tests included two unique features. First, the effect of friction was isolated on half of the tests by providing a lubricated polyethylene membrane at the wood-concrete interface. This allowed the contribution of friction to be better understood from the test data. Second, impact-echo testing was conducted during the test to continuously monitor the status of delamination that developed in the concrete that may not have been visibly apparent. Aside from these unique features, every effort was made to test materials representative of the most common shear wall connections.

The independent variables tested were:

Item Configuration Tested

Sill plate size    2x4,    3x4,    2x6    and 3x6

Anchor bolt edge distance 1.75 inches or 2.75 inches, dependent upon sill plate

Testing protocol monotonic versus pseudo-cyclic

Wood-concrete interface condition friction versus “frictionless” membrane

To properly generate test data for the purpose of assessing behavior, a new displacement based loading protocol was

developed. Using data from an initial set of monotonic pull tests, cyclic tests were calibrated so that damage produced by the test would best represent actual in-service failure modes. For the new protocol, the SEAOC Seismology Committee used a hybrid approach essentially taking the CUREE protocol with additional cycles added at low load levels. Independently, the SEAOSC sequential phased displacement (SPD) loading was used on several tests to compare results.

Findings

The first result to note was that the monotonic tests were an accurate predictor of the elastic performance characteristics exhibited in the cyclic tests. Once the anchors were loaded to approximately 5000 pounds, the anchors slowly started to exhibit some plastic behavior as further displacement occurred. The frictionless membrane applied under the length of sill plate had a minor effect at small displacements within the elastic range. For loads in the range of design values, which were well within the elastic range, there was little difference between the pseudocyclic, monotonic, and sequential phased displacement test results.

Second, the test showed that fastener fatigue was not a limit state influenced by any of the various loading protocols.

This is an important observation since it limits the area of concern to the strength of wood and concrete elements tested.

http://www.seaoc.org/bluebook/sample_pdfs/1204030_AnchorBoltsLightFrame_smpl2.pdf


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## Mark K

The structural engineers in California realized that when you calculate AB capacity in concrete that you got very low values.  They then organized a testing program that resulted in the SEAOC Blue Book position Mark Handler quoted.  Sections 1908.1.9.1 and 2305 of the California Building code got modified to reflect these recommendations.  The low calculated AB concrete capacity would not be a concern if bolt sizes and spacings were explicitly defined in the IBC or IRC.

As Mark Handler pointed out there are aids to insure that the ABs are properly located.  While not always perfect the California contractors typically do a fairly good job of locating anchor bolts.  It is normal practice here to require ABs be in position prior to pouring of the Concrete.

While there is no special inspection requirements in the IRC, Item 3 of Table 1704.4 effectively requires placement of anchor bolts before placement of concrete.

The Simpson mudsill anchors are not appropriate if there is any significant wind or seismic loads.


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## Rio

We try and avoid special inspection so we accept having to work around the A.B.'s; We use the templates shown up the thread and on the plans have to note that all hold downs will be in place at the time of foundation inspection.  Don't know if it's called out in the codes but using the templates help ensure that for a 3-1/2" plate the edge distance will be 1-3/4" (which is usually the minimum for cover on a lot of the Simpson products we use)  and so forth as the plates get wider.  We set the J bolts with the end going in towards the inside of the footing.  One thing about coming back and drilling and using the correct epoxy, the uplift values are increased.


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## peach

for the same reason as keeping the bolts from the ends, they need to be centered if possible since not all forces will be imposed from the direction parallel to the plate.  Not enough meat on the plate, the plate will pull thru the bolts.


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## Daddy-0-

Mark K,

I meant a P.E. firm. The actual inspection can be done by the technical assistant as with many other special inspections. Sorry.


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## Mark K

In Northern California special inspections are typically performed by inspection agencies that hire and dispatch special inspectors.  The inspection agencies work with the numerous local jurisdictions to verify that the special inspectors dispatched  are acceptable to the local jurisdictions.  The inspection agencies have a registered engineer who reviews and signs off on the official reports.

The design firms typically do not have qualified special inspectors on staff and prefer to have the special inspections performed by an inspection agency.


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## GHRoberts

While there is no good reason that the anchor bolts are near the edge, it is difficult to show that such bolts are not sufficient.


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## mark handler

Paraphrasing the ACI 318-08  commentary

 Limited spalling does not necessarily mean the structure (member) will fail when loaded (wind, seismic); Especially when it is a repetitive member. It will reduce load values, but not necessarily a  reason to reject the work.


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## Mark K

Spalling in the absence of a well understood extreme load would be a reason for concern.

If we were talking about reinforcing steel that is developed beyond the spalled region I would agree that the capacity was essentially the same as before the loading.  But in the case of anchor bolts any spalling of the side of the concrete footing would call into question the capacity of the bolt.  Such spalling would indicate that a brittle failure was likely.


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## ajweaver

Thanks for all the info.

As far as I can tell, there is no specific verbiage related to centering the bolt on the plate-even though we all agree there should be.

Closest would be "positively anchored", and I could always ask for an engineer to evaluate if they argued correcting it.

I just thought it strange every other dimension regarding the anchor bolt is present.

I dont get to read this board as much anymore due to how busy I have been in the field, but I do want to say I am grateful for its existence.

Aaron


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## mmmarvel

TimNY said:
			
		

> I would require SI for drill and epoxy.. But if you can use Titans instead I wouldn't require SI.Retrofit is a labor saver in a lot of cases.


Depending on the jurisdiction and the BO - Titans can require SI as well (I know, I did SI on many of them).  Oh, and one of the easiest SI around, loved getting those.


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## brudgers

mmmarvel said:
			
		

> Depending on the jurisdiction and the BO - Titans can require SI as well (I know, I did SI on many of them).  Oh, and one of the easiest SI around, loved getting those.


I've seen more non-compliant Titan installations than epoxy - too closely spaced and lack of edge clearance is common.

Behind the counter, I used to see them submitted based on ultimate which at the time was the only thing Titan published.


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## KZQuixote

The reason I asked the question about epoxied bolts requiring special inspection is because of the high start up cost of a special inspection account. In order for a contractor to arrange to receive a special inspection, in this town, he'd have to first pay a $350.00 new account fee which includes up to three hours of on site time and then $200.00 for a final letter. It'd take a really unusual layout before I think the epoxy/special inspection would pencil out. Second time around it'd cost $55.00 per hour, est three hours, plus the $200.00 letter.

As long as I can get 'em right, I'll keep working around 'em.

Bill


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## Mark K

Since adhesive anchors are not addressed in the code the building code has no formal requirements for them.  These products are approved in accordance with IBC Section 105.11 with the building official free to require special inspections as he sees fit.

Because installation is sensitive for this product it is appropriate to require special inspections.

When adhesive anchors are used because the contractor does not want to locate anchor bolts before the pour the added cost of special inspections may create an incentive to use cast in place anchor bolts.


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## brudgers

Mark K said:
			
		

> Since adhesive anchors are not addressed in the code the building code has no formal requirements for them.  These products are approved in accordance with IBC Section 105.11 with the building official free to require special inspections as he sees fit.Because installation is sensitive for this product it is appropriate to require special inspections.
> 
> When adhesive anchors are used because the contractor does not want to locate anchor bolts before the pour the added cost of special inspections may create an incentive to use cast in place anchor bolts.


Titans are not part of the code either.

Installation of them is sensitive - If they are placed to closely together or in oversized holes they will not perform well.

It's just that they look like so much like screws that most people don't realize they cannot be used like them.


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## Rio

brudgers said:
			
		

> Titans are not part of the code either.Installation of them is sensitive - If they are placed to closely together or in oversized holes they will not perform well.
> 
> It's just that they look like so much like screws that most people don't realize they cannot be used like them.


_Also, if they're too close to the edge they'll blow it out._


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## globe trekker

In reviewing the discussions on this topic, is the conclusion that there is no specific

code section ( from the IRC ) that specifies a minimum distance from the sole plate

edges?   Or, is there something from the referenced ASCE 07 that does indeed

mandate minimum distances away from the edges?

Thanks !

.


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## peach

the IRC commentary is silent on the issue (which is odd to me); lateral to the grain the wood will have a little more strength than parallel to the grain so there may be an engineering reason it's not addressed... or no one has considered that someone would put the bolts any place but in the center of the plate (my vote).


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## brudgers

globe trekker said:
			
		

> In reviewing the discussions on this topic, is the conclusion that there is no specific code section ( from the IRC ) that specifies a minimum distance from the sole plate edges?   Or, is there something from the referenced ASCE 07 that does indeed mandate minimum distances away from the edges?  Thanks !  .


  ACI and NDS as incorporated by reference.


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## ICE

I ran into a bunch of it today.


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## steveray

At least they used the big square washers........looks like their nail plates are about 2" too short also....


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## kyhowey

The National Design Specification for Wood Construction (NDS), for loads perpendicular to the grain, states the minimum edge distance is four times the diameter of the bolt (measured to the center of the bolt).


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## steveray

One more reason to not build with 2X4's.....



			
				kyhowey said:
			
		

> The National Design Specification for Wood Construction (NDS), for loads perpendicular to the grain, states the minimum edge distance is four times the diameter of the bolt (measured to the center of the bolt).


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