Sequence of truss shop dwg submittal 1

[AELLC]

Normally in this county, the Bldg Dept's do not require the Structural EOR to approve wood truss calculations for house construction.

But for some strange reason, the representative for a spec home approaches me with all the truss calculations for approval, saying that even though the house framing has just been COMPLETED, he claims the Bldg Dept requires my approval of the truss calculations.

At first , I thought, no big deal, everything is OK and I will do that.

(These calculations have been on my desk for 2 weeks because the representative is in another state and he appears to be in no hurry)

OK, I get curious because I am having so much trouble with two other another unrelated projects, and I look at the calculations again, more detailed than what we normally check, and I now I feel should stamp these as Not Approved - Resubmit.

How does that work? The house is already built. I feel I should contact the Bldg Dept before I call the representative back, and tell the Bldg Dept that I can't even glance at the calculations because the house is already built, and it is not my responsibility any more.

 

[charliealphabravo]

By "truss calculations" I presume that you refer to the truss design drawings. These are usually signed by the engineer from Mitek or Alpine. I have never been asked to approve "truss calculations". I would typically review the truss design drawings and the truss placement plan like I would shop drawings for conformance with my design intent and my roof framing plan if there is one. This usually happens as part of my pre-construction services for my client. Dont approve them if they don't have Mitek's signature on them. It is not your job to approve the calculations.

If the house is already constructed you can still review the truss design drawings for conformance with your design intent. That is not the same as an as-built drawing which is probably not what is being requested. Since construction is completed I would add a note to my usual shop drawing stamp stating that this is not an as-built.

Also since this is a spec home please make sure that all documents you sign or stamp are for a specific location/address. Don't approve documents that might be ambiguous and permit the client to build multiple structures and amplify your liability without your oversight.

 

[dcarr82775]

Can you elaborate on why you would reject them? I take it this is something more than your infamous girder truss?

 

[AELLC]

@ charlie:

This case is unusual, the Bldg Dept is demanding that I give them shop-drawing style approval.

@ dcarr,

They had a one-ply girder where I specifically noted on my drawings that particular girder needed minimum (2)-2x6 bott chord because the Bldg Dept here always makes us specify truss hangers. If an HUS26 is nailed into a single ply girder, the capacity is reduced to 64%.

Plus I noticed this on another girder:

http://eng-tips.com/viewthread.cfm?qid=361964

This is not the same house as the infamous sagging girder, and I am getting really cranky today because that one is getting uglier today.

I just am getting in this hyper-defensive mode because everyone including me was able to ignore truss design issues before.

The same Bldg Depts dictated a major addition to our calcs recently because they demanded that we calculate the bearing stress on the bottom of the bottom chords, which I would think is a truss mfr responsibility, so now we have to guess how many truss plies, and we have to specify if Simpson TBE is req'd

 

[msquared48]

Call the building department and see if this is the case.

Someone may know they screwed up and be trying to get you on the hook too.

If the Building Department does require it, ask "why now", and document the response. You will probably will not be able to get them to respond in writing unless you do an email.

Depending on what you find out, do your analysis of the trusses with an written explanation as to why your late involvement to perform the check, and write a letter to the client, the truss designer, and building department. Wait and see what happens.

Mike McCann
MMC Engineering

 

[AELLC]

thanks Mike.

 

[msquared48]

To me, it sounds like it suddenly dawned on the plan checker that girder trusses carry more load and it's CYA time.

Mike McCann
MMC Engineering

 

[AELLC]

somewhat,

What happened:

1) As I was saying , all the Bldg Depts in this county never required us to review truss shops, and they STILL doPr not.

2) I did the calcs for 2 large custom homes, both in the same subdivision for my "primary" client. They are accustomed to having very few plans check review comments.

3) The Plans reviewer comes back with a very long laundry list of structural problems, 99.9% derived from the fact that he was the first person, ever, to read all those pesky footnotes on each page of truss calculations.

4) Examples -

a)Provide mechanical connection (by others) of truss to bearing plate capable of withstanding 100 lb uplift at joint(s) except (jt=lb) V=106, L=3048, Q=1010

b)WARNING Required bearing size at joint(s) L greater than input bearing size.

 

[charliealphabravo]

How did we get on the topic of girders? I think the OP is just talking about a truss package in general.

EOR review of truss shop drawings is common in FL. Maybe not so much in other areas. It is part of the TPI consensus standard on truss responsibilities. If it is done after the fact it is just important to clarify that your shop approval is not a statement regarding the as-built construction.

Minimum bearing widths should be printed on the truss design drawings. This calculation does not fall to the EOR.

Connectors and anchors between the truss package and the structure most likely fall to the EOR and usually are shown on the roof framing plan.

I agree with Msquared that you should find out what is really going on before you change your normal practice.