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Re: Plan Check Corrections - Engineers responsibility

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I would have to agree with the contractors assertion that we have been doing for years and it works in many of these situautions.  I know that the code doesn't seem to allow for much cross grain tension, and rightly so, but unless this guardrail is being bolted to a 4x6, there seems to be know reason not to allow the beam to resist the load.  A 200# load at 3.5', with 700 ft-lb won't tear apart anything given that it will not be repetitively or long-term loading.  In fact I doubt that anyone could tear apart even a 4x6 with a 3.5' torque arm.  It would seem reasonable to beef up the beam and let it handle the torsion.
 
Pat Clark
 
----- Original Message -----
Sent: Friday, August 29, 2003 9:58 AM
Subject: Re: Plan Check Corrections - Engineers responsibility

Dennis,
 
See comments inserted below.
 
An architect I have known for over ten years contacted me a few days ago to help him solve a problem on a custom home that he designed. The engineer that he used has worked with him for over 15 years. The home uses Trus-Joist TJI floor joists that cantilever out to form the balcony at the second floor. He has attached a rim joist and showed the detail for the sheathing and finish on his plan.
The plan check agency wants a detail to show how the manufactured glass railing is attached to the end of the balcony. The Architect showed a conventional lumber balcony framing and at the end a 4x rim joist. The mullion for the railing was shown to be bolted down through the center of the beam at some uniform spacing. The connection is a threaded rod with a plate washer and nut that is recessed into the rim beam. The balcony framing (whether TJI or 2x) is cantilevered out from the floor framing. The framing is covered with plywood nailed to the top of the rim beam and joists. The sheathing is topped with lightweight concrete. 
 
The plan checker asked to show that the beam won't fail when a 200 pound lateral load is applied at the railing 42" above the deck.
 
I reviewed his problem and gave him my opinions;
 
1. There needs to be a step down (1 or 1-1/2 inch) from the 2nd floor level to the balcony to prevent water from flowing back into the house if there is no slope to the balcony joists (the TJI's are not sloped). This does not seem to be an issue in the TJI catalogs as it was a few years ago when they had step down joists or cantilevers designed by extending Microlam's; sawn lumber or Timberstrand joists extended in the web of the TJI's.
 
>>> Agree completely, though I have always seen this done with microlams or some other material that can be notched and / or ripped.
 
 
2. I believe that the sheathing nailed to the top of the beam will prevent rotation in the rim beam, but I see that if you pull on the railing there would be a possibility that the connection of the beam to the end of the joists might fail in pull-out strength of the connection.
 
3. I suggested he recommend to his engineer that a Simpson LTT strap be used where the failure is likely to occur. For safety reasons, I would use on one each joist alternating between top and bottom so that the rim-beam is tied back to the joists at top and bottom (where the couple is likely to occur).
 
>>> You are on the right track.  I would look at angle clips with bolts between the joists and rim beam rather than cross grain tension.  Or install straps top and bottom.  This is one of those areas where the contractor will have have a fit with the usual "We have been just bolting the damn things to the plywood for years....".  The problem is that very often these details are not engineered but are simply provided by the Architect and no-one questions the validity of the design.
 
 
His engineer is refusing to deal with this issue and the architect asked if I would intervene. If this were conventional construction, I believe I could take care of the non-compliant portions of the home, but in this case there is an Engineer in Responsible Charge who is, in my opinion, required to complete the plan check requirements.
 
>>> Is he refusing to deal with the issue or indicating that it is not in his scope?  If they have worked together for 15 years I am surprised there would be an issue now on this project.  There might be other underlying factors.
 
 
 
Can the architect contact BORPELS to file a complaint against the EOR if a permit can not be pulled until the corrections are complete?
 
>>> He could.  Depends on the actual contract obligations and what the "real" circumstances are.  All kinds of nasty litigation could be enacted if in fact the engineer is refusing to do something he is contracted to do.  I would be very reluctant to go down this road without a thorough understanding of all the relative facts and positions.
 
Can the architect hire another engineer to supply the calculations needed and have the architect wet-stamp the details and calculations provided to him?
 
>>> Yes, the Architect can hire another engineer for this component and then assume responsibility under his stamp.  Alternatively the other engineer can provide a rail and rail connection design as a separate deferred submittal subject to the EOR's approval.  This is done all the time for stair and related systems.
 
I don't think this is such a difficult problem and don't understand why the engineer of record will not complete the design. I've reviewed his drawings and details and other than the coordination between the architect, who shows conventional sawn lumber, and the EOR who specifies TJI's, the drawings are light on details, but adequate compared to what I have seen out here.
 
 
>>> I think that for the reasons you describe above, there must be more to it.  The EOR may have had his fee haggled down to the ridiculous and the exclusion of these detail items is part of the agreement.  This is one of the reasons I try and stay away from residential design.  I am always amazed that the realtor can earn a higher fee selling the place than the engineer can justify designing it.  Custom residential is an art and extremely detail intensive if it is done correctly.  Half of what we see presented as "engineered designs" is pathetic.  The fact that the EOR actually provided an adequate design other than the rail issue is another indication that there must be more to it.
 
>>> You state that you are "caught in the middle".  I would simply step out of the middle, present a fee and contract to perform the rail design as a deferred approval or separate contract, and let the Architect, Owner, and EOR work out the issues whether or not you are to proceed.
 
Your opinions would be appreciated.
 
TIA
Dennis S. Wish, PE
Caught in the Middle