simpson type anchor straps 1

[JBALUCI]

Colleagues:

Has anyone had to deal with the common mis-installation of Simpson (or equivalent)anchor straps and their incorrect attachment to the mudsill? (i.e., not spreading the straps to the "Y" position prior to embedment, and if spreading is not, done, the carpenters do not drill holes through the mudsill and wrap the straps out, but rather just wrap the straps around the mudsill, creating a "spring" condition.)

What are the possible problems that can arise from this mis-installation?

Are the building inspectors responsible for checking this critical detail? What action may (should) they take if they see this incorrect installation?

Corollary Question:
What is the minimum thickness of CMU block that can be used atop a trench footing as an extension of that footing for the attachment of a mudsill and wall? (i.e., a typical garage foundation detail.) Does the CMU block need to be mechancally attached to the trench footing with vertical rebar in grouted cells? Can solid CMU units be used? Has anyone seen the straps installed in the headjoints?

(Code reference: BOCA)

regards

 

[boo1]

This is typical detail over looked. All hardwear should be installed in accordance with manf details and instructions. In your case the header block should be ground with a bevel to allow the mud sill to lay at the proper angle. Not doing this puts the stap in a double bend, increasing the stress concentrations. The sill plate can also deform under high loads allowing the wall to lift before the strap is in full tension.

The responsiblity is with the contactor or contactor or record for checking this critical detail. While the building inspectors may catch most of the code requirements (in there area they were trained for) they are not engineers or structural savy. Many times I have had disagreement with inspectors over things in there little check list. What action to take now, most likely none. Check the loads and insure you have a positive margin of safety.

The CMU code thickness is a function of stem wall height. For residential less that four blocks high use 8x8x16. The vertical rebar with grouting is required to resist uplift. Without it you have the dead load plus the weak bond to resist the uplift forces. In the top row use the lental blocks so a top peremeter rebar can be added . This detail is required in your jusistiction ( see the SSTD manual).

Hope this answers most questions.

 

[JBALUCI]

Thank you , boo1 for your response.
I am not sure what you mean by grinding the header block with bevel...would you mind expanding on this detail, please.

thanks so much.

 

[boo1]

Often masons use a hammer and knock o hole in the block to gain clearance. I prefer to not induce stress risers, use a concerete saw or grinder to releave the block interference.