Joist modification approval?
Joist modification approval?
(OP)
I designed modifications to some existing KCS joists to carry heavier point loads than they originally were designed for. Our client asked if the modifications had been approved by the joist manufacturer. I have never gotten any approval before for modifications and since we are the engineer of record, I don't see why I should.
Is the warranty void if modifications are done and what other reasons would approval need to be received?
Is the warranty void if modifications are done and what other reasons would approval need to be received?






RE: Joist modification approval?
1. Any warranty or liability that the joist manufacturer had is void now that you modified the joist. I can't imagine a joist manufacturer approving your design without notifying them prior to the start of the work.
2. The first thing to do in this situations like this is to contact the joist manufacturer and see if they are willing to design the modifications. If, and only if, they decline to design the modifications needed would I then consider making the modifications myself.
3. Now that you have made the modifications, you own the design and any potential liability that may entail - you are now the EOR. So, make sure you are right! Check and recheck you design and be sure to field inspect the modifications while they are being performed to verify they are being done per your design.
RE: Joist modification approval?
1. Yes this wouldn't surprise me, even though I am only modifying 5' of one end of the joists, the mfr.'s policy is probably that any modifications will result in warranty be void.
2. I never thought to ask them to design the modification themselves, I would think since I signed the original drawings (and modifications too if asked), my company of course wants the money for the job, and working with the client on adding these loads will affect the footings and beams which support the joists, (and removing part of my roof deck to make the changes is involved),I think it would be best for me to handle the situation. The loads in this case have been changing daily due to the uncertainty of the cabling being hung from the joists.
3. Good idea,
RE: Joist modification approval?
Very likely, the joist manufacturer will want to participate in redesigning his product, because bottom line, if something goes wrong everyone gets dragged in.
also, if you are modifying something that another engineer has stamped without notifying him, you may be guilty of misconduct according to your local engineering association.
dutchie
RE: Joist modification approval?
Can you cite any examples of language in your state's licensing laws that refer to this? I'm curious.
RE: Joist modification approval?
Just to clarify my earlier comments, I don't think I implied nor did I mean to imply you shouldn't modify the joist. I have encounter similar circumstances many times and modified the structural member as I saw fit. I just meant that we should be aware of the liability we assume in that situation. If the the member happens to be a "pre-engineered" truss, joist, precast or some other component, I usually try to contact the manufacturer to confirm design loads etc. They are sometimes very helpful and sometimes very standoffish (sp), but I try to get as much information as I can just to confirm my own design thoughts.
dutchie,
I have to agree with JAE, if it weren't for additions and remodeling of existing structures we'd all have a lot less work. Also, there are many times the original designer is not known or unavailable or dead (of natural causes we hope). So, we are left to our own devices and proceed as best we can making use of current codes and design practices.
RE: Joist modification approval?
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: Joist modification approval?
I just got done doing a series of Joist and Girder truss modifications, we sent the loading diagram to the orginal truss manufacturer. They sent us detail diagrams for each modification. They were able to review the orginal shop drawings and determine if any welds needed to be beefed up, as well as which members needed to be reinforeced. There was no cost to our office by the truss manufacturer's design time.
RE: Joist modification approval?
I think that is true if the engineer's design is currently "pending" - that is, the design has yet to be built. In that case, you are taking another engineers design and altering a part of it which may affect the whole. This allows the original engineer to respond as they have a vested liability in their design - again PRIOR TO CONSTRUCTION.
But once a building is constructed - it is a finished product and the owner has the right to hire anyone they choose to provide additions, alterations, etc. The new engineer then has the obligation to protect the public safety and welfare and consider all the ramifications of their work on that structure. But the new engineer does not have the obligation to seek out, contact, consult with, or otherwise notify the original EOR. -
RE: Joist modification approval?
RE: Joist modification approval?
with respect to the rest of the points raised, i agree that in many cases we have every right to modify and change existing construction to suit the owner's requirements. my point is that when the item we need to modify is a pre-engineered product (ie: wood I-joist, owsj, precast panel etc.) why take on the liability for the whole item when the manufacturer is likely to want to get involved and protect their investment in the project. after all, their liability does not end just because the project is completed. As stated by scottmad, i have often gone to the manufacturer to request changes to their products and have had generally good response. otherwise, any changes we make have the effect of making the component "ours".
having said all that, quite often getting the manufacturer to assist just isn't feasible, then we all have the obligation to do a full design review on the item being modified.
Again, I'm not here to argue that we shouldn't be modifying construction, that's how I make 80% of my living, just to argue that the proper channels should be followed.