How do you work with PEMB manufacturers?

[Boiler8019]

I work at an A/E firm and it usually comes up once or twice a year that some architect wants to make a PEMB fancy by making an odd column layout, cladding it with brick, adding mezzanines, adding cantilevers, and using odd roof pitches. For example, an architect came to me today wanting to know the wall detail required to cladd his PEMB in full height brick with windows, etc. Without having done this particular detail before I really dont have any resources to give him a great answer of industry standard.

Have you guys found a good way to work with PEMB manufactuers on odd conditions? Are there any design manuals w/ details out there? We've tried contacting various manufacturers but usually nobody will work with you unless they've already got the job, and even then its usually a month wait just to get a decent response. Any help/experiences would be great.

 

[jike]

Many metal buildings are built with brick wainscot but with full height brick walls, the building frame must be limited in lateral movement to prevent the brick from cracking. I would suggest checking with BIA on recommended sway limits. Depending upon the height of the building, I would try to span backup light gage metal studs from foundation to roof. I would try to avoid using metal building girts because of their flexibility.

Good Luck!

 

[lkjh345]

Boiler:

IMHO, This is a area that there is a lot of confusion over. Your responsibilites and those of the PEMB suppiler need to be clearly laid out in your contracts. You need to press the owner, or architect, up front to define the responsibilities of each team member. If they don't how to define them, or what the ramifications of their decisions are, you need to work with them to eductate them on these matters.

If the owner, or the architect, is expecting you to design cladding, offsets, building protrusions, architectural features, etc, etc, etc, then they need to make that clear to you upfront, so that you can price your services accordingly.

FWIW: Our basic PEMB contract clearly states that we will design footings and foundations only, and that the design of these footings will be based upon column layout and reactions provided by the building suppilier. We use this contract wording when we get the generic " what will your fee be to design a foundation for a metal building of x' by y' " question, before the owner or architect really know what the building will look like.

If the owner, or architect, has some idea of what the building looks like, then we ask them 'Do you want us to design the brick cladding and back up supports? Or are you leaving that to the Metal Building supllier?', 'Do you want us to design that vesibule lobby? or will that be done by the Metal Building suppilier', etc, etc.

Then we modify the contract language to reflect these decisions and price our services accordingly.

For you specific question of full height brick: If possible, we design the brick and back up system ourselves with support from the metal building only at the eave line. We then specify on the drawings and in the metal building spec the allowable drift of the metal building at the eave line, and enforce this criteria when we recieve the metal building shop drawings for approval.

If it is not possible, or practical, to span the brick and backup system full height, we occasonally spec the metal building suppiler must provide a girt of minimum moment of inertia at some intermediate elevation and use this to provide support to the veneer system.

Just our humble opinion on how to tackle this problem. I'm sure there are many other, better ideas out there.

 

[Boiler8019]

That is really good advice and it does help me, though I cannot limit my structural contract because I work beside an architect under one roof.

My question has to do more with how to detail a lot of these different conditions. Basically I need something to help me with details. If you design backup for the brick, do you use studs and keep them in line with the girts or run the past the face of the girt? Things like that.

Have any of you used this manual?

https://www.mbmamanual.com/Contents.aspx

 

[lkjh345]

Sorry if I mis-understood the thrust of your question.

We have a older version of this book. It is very good for laying out how basic metal buildings work, the function of each componet, how things are typically detailed, etc. Our version is not all that good on describing how to handle out of the ordinary conditions.

To be honest, its been a long time since I done a PEMB were the building suppilier was not known ahead of time. Seems like we are the last people on board when a PEMB project is done.

For metal studs laterally supporting brick, we try, where possible, to use full height studs that do not rely on intermediate support. When we can achieve this, there is no need for intermediate girts. We line up the exterior flange of the studs approximately 1" outside of the exterior flange of the building frame. At the top, we show an eave girt for the studs to attach laterally to. This is suppiled by the metal building suppilier, but we usually set some criteria it must conform too (miminum I, miminum S, etc).

For other unusual stuff, we show the required framing, and attachment to the PEMB if required. If we are attaching to the PEMB, we show a proposed connection, and the reaction from the member that the building suppiler must consider in his design.

Its always good to work with their engineer where possible, but remember, you are the Engineer of Record, not the building suppilier. He has to conform his system to your needs, not the other way around.

 

[blake989]

I highly recommend you get a copy of "metal building systems" by alexander newman, you may also want to look into getting a metal building systems manual published by the metal building manufacturers association. when PEMBs get anything but plain jane...they can become a snake.

 

[mrengineer]

Agree with Blake989 - Newman's book is excellent.

 

[DaveVikingPE]

Newman even answers e-mail questions sent to him!

My experience(s): the Owner's rep - usually my PM shilling for the owner for some bad reason - sells the "quick and cheap" aspect of a metal building system and then tells me that adding a mezzanine, etc. is "easy." Well, it's not easy and the minute I change anything, the PEMB warranty is in question. So, we FORCE the construction contractor to "provide us a metal building system with mezzanine." They end up picking a supplier (Butler, Chief, et al.) and working with them.

 

[Boiler8019]

I have newman's book on order, thanks for the advice guys.

 

[ChuckerD]

Boiler,

As one of blake989's "snakes" perhaps I can offer some general advice on dealing with metal building manufacturers.

1) Metal building companies are manufacturers of steel buildings, not a provider of engineering services.

2) We design metal buildings and their components.

3) Give us required design specs and we will provide the building accordingly.

4) Need attention from a manufacturer pre-sale? Call a company's salesman for the region. These guys can provide a lot of answers...as long as they're getting a chance to sell a building of course.

I tend to think blake989's perception comes from the fact that metal building manufacturers generally want to avoid items in our scope of work that we aren't familiar with, good at, or don't have the experience to provide the best solution to the building owner. Nobody would ask us to design their HVAC system right? Well, we don't know a whole lot more about hardwall systems and their details. But we can sure design an economical tapered steel rigid frame that meets the necessary sidesway limits.

Boiler - if these companies aren't responding for a month they are the kind of competitor I like. Check for a company located in Waterloo, IN...a division of the country's largest steel producer.

 

[MikeE55]

I've found that exterior masonry walls with a non-diaphragm roof need a wind girt at the top of the wall, or perhaps on the inside face of the wall near the top. This girt can either be designed by the engineer of record, or by the MBS vendor, but if you have the MBS vendor design it, do as ChuckerD says and give them the design specifications. For example, "design girt for wind load on masonry, using 10 year wind interval, limiting deflection to L/240, with a maximum deflection of 1 1/2." (the more conservative among us may not agree with these limits) The engineer of record should specify the connection between the wall and the girt, and then make sure these get installed in the field because it is a very common error to leave the tie out.

 

[blake989]

ChuckerD....I don't think PEMBs or their designers are "snakes", I was attempting to refer to the typical creep in scope that I associate with "fancy" metal buildings. I apologize for the offense. I've got a "fancy" one on my desk right now that I will be contacting you about!

 

[Boiler8019]

For confirmation, Newman's book provides a lot of the answers everyone in my office has been trying to get PEMB salesmen to answer. Industry details, cost efficiency, and structural contract document requirements. Three architects have stopped by my desk to check it out already, and am hearing a lot of "so thats how its supposed to be detailed!".

Unfortunately, when I talk to PEMB salesmen I get a lot of information but little answer to the problem at hand....a lot of oversimplification. Then when the building is in the shop drawing phase we hear nothing but coordination problems.

Funny you mention a company from Waterloo IN. I've had firsthand experience with that company and had the same problems. They have a nice brochures, but nothing that answers the hardcore design questions we had.

 

[ChuckerD]

I hate to hear that Boiler - I'll give someone a kick in the seat.

I agree that oftentimes coordination is difficult due to the fact that the customer of the metal building company ends up creating an intermediate step in communication that we can't leave out. This is constantly a source of error, confusion, etc.

Here's a link to what is called a product & engineering manual that shows a lot of standard details used by this particular manufacturer. I hope this can be of some use to you.

http://www.nucorbuildingsystems.com/nbsproductandengineeringmanual/index.htm