Pre Eng Building

[nilaypathak]

I am link between Architect structural engineer Engineer of Record and Pre Engineered Building structural Engineer. PreEng Building Structural Engineer provided column reaction to Architect EOR to finalize pile foundation design. What level of the detail Architect EOR need to review to accept column base reaction value for foundation design. Does Architect EOR review the detail at the same level professional Engineer stamping the drawing on the design.



Thank you for your time to share your thought.

 

[hokie66]

That is up to the EOR. He needs to perform whatever review is necessary to assure himself that the reactions being used to design the foundation are correct.

 

[connectegr]

I agree with hokie66, whatever review is necessary to be comfortable with the reactions given. Blind faith has no place in engineering.

http://www.FerrellEngineering.com

 

[Ron]

I agree with hokie66 and connectegr. PEMB's are generally stretched to the limit in design (and sometimes beyond!). In my personal experience, I've found understated loading in PEMB's, so yes, the EOR has to do enough to satisfy himself of proper loading and analysis.

Blind faith in engineering feeds lawyers.

 

[woodman88]

Tell me, have anybody else ever wonder why the PEMB's do not take it to the next step and become the EOR for their buildings? I mean give me a break the foundation design is not that hard to do and if they don't want to do the foundation themselves they could always find a loco (sorry I meant local) engineer to do it for them. The only possible reason I can think of is the liability issue.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[connectegr]

Site and soil conditions can be a big variable. I am sure some bean-counter with the PEMB decided it costs to much to include a range of foundation options, and to be responsible for choosing the right one. If something does not fit during erection or something settles, they can pass the responsibility or at least share it with another party.

http://www.FerrellEngineering.com

 

[TXStructural]

Foundations are a primary reason for lawsuits against structural engineers. On top of that, a pre-engineered building may be something which is designed once and built/erected many times and in many places. The manufacturer may or may not have an engineer on staff if they only produce stock designs.

If the owner/architect purchased the PEMB without the EOR specifying or otherwise involved in the decision, the EOR isn't really an EOR, and is responsible ONLY for designing the foundation elements with the loads specified by the PEMB manufacturer. Give the owner what they paid to get.

On the other hand, if the EOR provided loads to the PEMB mfg. and was involved in the procurement process, then maybe a check is warranted in keeping with good practice, if the EOR isn't comfortable with the designer. I don't think it is required, and while something as simple as a gravity load check using trib area is a good way to be sure that the building design used the correct loads, this then puts the EOR on the hook for potentially shoddy work by the other engineer.

Whatever the decision, engineers should not give away their services to clients. Doing so removes value from what we do. If the EOR was hired to provide oversight, the level of work required was part of his/her agreement.

 

[Ron]

Depending on the building department reviewing plans and spec, the PEMB engineer is sometimes the ONLY engineer involved, so by default he/she becomes the EOR. In my opinion, not a good idea because of the site variability and locale variables.

 

[spats]

In my mind the EOR explicitly specifies all of the building codes and loads, and makes certain that the PEMB engineer uses the same parameters. It's also wise to do some quick hand calcs to make certain the reactions look reasonable. Ask for full signed & sealed calculations from the PEMB engineer. He is responsible for the design of the metal building as the specialty engineer.

One other comment on PEMBs: beware of "preliminary" reactions. They can almost never be trusted. Usually a salesman or technician with access to the manufacturer's software will run the "black box" and give you answers, but they are inevitably way off! It's sometimes hard to understand why they're incapable of checking the right box, or filling your design criteria into the input form. It's only after they have a contract signed on the dotted line that a real engineer will look at it.

 

[cmbyrd77]

I completely agree with "spats." Be very cautious of "preliminary reactons." I just had this happen to me where I was the structural EOR for the foundation and I had to go back and redesign almost every footing, pier and anchor rods due to the fact that the reactions changed so much after it went through their engineers.

That being said, we, unfortunately, get a PEBM foundation design about once every three months. As the EOR we typically will "review" their reactions so we can use them for our foundaton design. Also be careful because a lot of times they will give you service reactions, which need to be factored for conc. design. I typically have to call their engineers and ask them for reactions for each load case so I can factor them using strength design. I also agree with "spats" that you should ask for sealed calculations AND a sealed anchor rod layout drawing.