over my head

[broncosfan]

I work for a large engineering firm. I've been there for about 5 years. I am licensed and normally work on warehouse type structures. I'm in my early 30's. I was recently asked to get licensed in another state for an upcoming project. I agreed not knowing much about the project. We are just now starting prelimary design plans and column layouts. After a couple meetings, I've learned about the scope of the project...

It's basically a large 800000SF manufacturing facility with overhead cranes in every single bay. The cranes vary in size from 20 ton capacity to 250 ton capacity. The building is also in a hurricane flood zone. The building varies in height from 65' to 100'. Up until this point, I've never designed a crane. I just read another forum where a structural engineer was told that a 50 ton crane is serious business and you better know what you are doing structurally. Well, this is a 250 ton crane. There are also large 100' megadoors everywhere in the building. I've never designed doors of this magnitude.

I understand there's a first for everything. I remember the first time I designed a tilt wall. But I feel like I've skipped completely over crane design 101 and went straight to crane design 401. I'm trying to go through all of the literature and codes. It's sort of overwhelming. To make matters worse, the project looks like it is going to be fast tracked. I'm think I am a pretty good structural engineer and I feel like I could probably do a good job here. But I feel like this is way over my head. The only other structural engineer in my office (my boss) is not super helpful and I'm not getting great answers when I go in and ask something. I don't think he has ever designed cranes of this magnitude. However, I do think that without the large cranes and doors, this would be a fairly straightforward structure. But the cranes impact everything...column sizes, roof bracing, footings, expansion joints...etc.)

Now I do work for a large company and I think another office in our company does have experience with cranes like this. I'm not exactly sure why that office is not doing the job. It might have something to do with scheduling. Or maybe my boss felt like I could do this job. Or maybe someone is trying to push more structural work to our office. In either case my boss agreed to the work. And my boss also decided I should get licensed for the project. But, I feel like maybe my boss should have went for the license if he felt comfortable doing this work. I certainly don't now that I am fully aware of the scope.

I am not currently feeling comfortable acting as the EOR for this project. Can I be fired for refusing to stamp a project? Would it be irresponsible of me to continue with this project? Or should I suck it up and do the best I can?

 

[MintJulep]

It's all about spin.

You need to convince the powers that be that the project would benefit greatly from the involvement of the right guys from the other office.

"Benefit greatly" meaning be more profitable because the guys who have the right background and experience could do it faster and more efficiently.

 

[BRGENG]

If you are not 100 percent positive about the design or your capabilities then no you should not sign it. However, the only difference between a 25 ton crane and a 250 ton crane is a factor of 10. The same theory’s and formula’s apply the loads are just larger.

Do you have someone qualified to check your work when you are done? Every job should be checked by another set of eyes before it goes out the door.

 

[Senselessticker]

subcontract...

 

[hokie66]

There are a lot of lessons which have been learned in designing large buildings with cranes, particularly with heavy cranes such as you have. You are right in questioning your knowledge base. You may have all the technical capability required, but without the requisite experience, you are almost certainly doomed to repeat mistakes made by others.

I doubt that you are actually designing the cranes, but rather the building in which the cranes operate. The first step in designing the building is to select the crane manufacturer, who will provide the crane wheel loading on your runway beams. Without having the loading from the cranes and knowing how the different cranes will interact, you are operating in the dark. You must know not only the crane capacities but the service class of the cranes, and you must decide on the appropriate combined load cases considering wind and gravity loading on the building frames. Fatigue is likely to be a major consideration.

Get a good reference, or preferably more than one, on the design of industrial buildings with cranes. Read and gain an understanding of why things are done in certain ways. The one I started with was "Light and Heavy Industrial Buildings" by Fisher and Buettner. It is a good reference, although my copy is from 1979, so hopefully an updated version of this book or something similar will help.

It is the duty of any engineer to seek assistance when designing outside his/her area of competence, so let this be your guide. You should look on this project as an exciting challenge and an opportunity to become proficient in designing buildings with cranes, but at the same time you don't want to just muddle through.

 

[KENAT]

The normal advice on this site for situations similar to this is that being stretched is how to grow.

Obviously the kicker here is the issue of safety and EOR, especially if you don't really have anyone to check your work.

When it comes to safety it's sometimes necessary to take a stand, I had to do it once, tell a CEng (equivalent to PE) that he was wrong and what he was proposing was unsafe. He didn't like it but I was right, convinced a couple of other people and won the day. The CEng didn't last much longer.

KENAT, probably the least qualified checker you'll ever meet...

 

[melone]

The good news is that you are nervous. I would have been much more concernerd if you thought that this would be a no brainer, and just went about your business. This shows that you truly care about putting out a good product!

With regards to getting the help you need. Could you take a swipe at the design, and simply review it with the other office? Just because you would be the EOR, that doesn't mean you have to design it in a vacuum, right?

View this as an opportunity to expand your boundries professionally (technically and working with remote teams).

Just my 2 cents....

 

[graybeach]

Broncosfan,
You are very smart to be worrying about this now instead of down the road when it is too late to do anything about it. We had a consultant who did not know what they were doing design a rehabilitation on one of our cranes (200 ton gantry). We ended up having to give a change order to the crane contractor to redesign. If the experts from the other office work for the same company as you, it should not be such a problem to add them to the team. It is probably political, but you need to make your company understand that the expertise is necessary. I got into many similar situations when I worked for a large company. People may get annoyed when you continue to pester them to make sure the job gets done right, but eventually you will get a reputation as someone whose projects don't tank.

Another option might be to explore structuring the project such that you come up with overall performance objectives and the crane contractor does the job design/build, which is how our 200 ton job ended up getting done.

 

[Helicopterjunky]

Some good advice from hokie66. Get ahold of crane manufacturer. Have him get you in at some sites they have installed the big cranes. Look at the layouts others have used. Beam sizes, anchoring, re-inforcement, etc...Talk to their plant engineering folks and talk to specific design firms who have already been down this path. The crane manufacturer should be able to open these lines of contact. They probably have their own structural people also. Get your other office with more experienced folks involved as early as possible. Include them with discussion and tours with crane/door manufacturers. I'm sure it is a bit scary, but it should also be an exciting job.

 

[KiwiMace]

It also sounds like you are lacking an effective mentor.

A large company should be aware of the importance of assigning this role to all levels of staff, and it is really up to you find someone you can work effectively with. Mentors in return for their guidance, get the fun of design without the responsibility of deliverables.

Find someone within your company that has the experience, and check design progress with them regularly, not just reviewing the set of final drawings.

 

[csd72]

1. get client to confirm crane manufacturer then get crane loads from manufacturer - you cant design it without them.
2. Consult other office, obtain drawings and calculations for a similar project if possible. Pick their brains on items to look out for in this type of thing.
3. meanwhile do your own research, both AISC and the Canadian Steel society (or whatever it is called) have guidebooks on buildings containing cranes. Also look through this site for discussions.
4. Get other office 'experts' to review you design prior to issue.

 

[Gymmeh]

SO, your team is doing the building and runway structure?

Are you building the actual cranes with end trucks, hoist and any other jazz?

Are you doing the installation?


My back ground is designing cranes to CMAA 74.

The way your OP sounds, you will be doing at lest the structure? You imply you will be designing the cranes, is this true? Bridge cranes are a pretty well established field, with lots of documentation. For most applications there is nothing really crazy about them.

Don’t panic, but from what you say about the size of your office, you may need to hire more people, or sub contract. From the impression I get, correct me if I am wrong, most companies in your position will hire a middle man specifically for the crane design and installation. Basically project managing the crane suppliers, but not actually doing the design work. (yes, supplier(s), you may want to employ a firm which specializes in the smaller cranes, and also one for the larger cranes)

Here is why: The design work has many sub categories Structural, mechanical, and electrical. Most of the software structural engineers used for structural design analysis may not be adequate to design of mechanical component analysis and vis-versa. The electrical design can get interesting also, which should also have someone with experience which knows the soft design aspects which easily get overlooked.

Examples:
1) Two guys (where I work) designed the same part, the analysis using RISA vs. the COSMOS analysis predicted two different failures. The component was a truss structure which was correctly analyzed by RISA. The part was actually built to the COSMOS engineers spec (he pushed his design the hardest)… the part failed testing. Then later the RISA design was used. COSMOS is better for end trucks and hoists. It is important to know the limitations of your tools, “The devils in the details.”

2) Matching the drive voltage of the end trucks with the drive voltage of the hoist trolley, simple buy easy mistake mixing voltages, amps…

3) Most crane manufactures I know will outsource the different sub components like tractor drives, electrical, different capacity cranes… just because of the small details.


I hope this gets you headed in the right direction, good luck.

 

[broncosfan]

Thanks to everyone for their responses. We aren't designing the actual cranes...just the building in which the cranes operate. The crane manufacturer is not selected yet. I expressed my concerns to my boss and the project manager and we all think we should get the other office involved. I just ordered the "AIST Guide for the Design and Construction of Mill Buildings." Hopefully that will help. I also have a bunch of downloads from AISC regarding crane support structures, including "Design Guide 7." I will look into getting a copy of "Light and Heavy Industrial Buildings." Thanks again.

 

[hokie66]

You are welcome. Good luck.

 

[whyun]

Stamping drawings is serious business. I have no idea how many engineers from how many branch offices will work on this project but I can say that if you feel that you will not be able to excercize direct control over the entire project, give the stamping responsibility to one with a fatter paycheck. I am pretty sure you are competent enough to execute the work under "some" direction, but knowing that you are new to this type of building (in addition to the time pressure), you are completely entitled to feel uncomfortable.

To reduce the learning curve, if any of your branch offices did a similar structure, get a copy of the plans and design calcs, if you can.

 

[PSE]

broncosfan,

You might want to check whith the other state your boss wants you to get licensed in for any unique codes/statutes you may need to consider (you mention hurricane flood zones). Large buildings + large doors + hurricane = large engineering challenge regardless of the presence of cranes (in my inexperienced and unlicensed opinion). Good luck to you.

Regards,

 

[Gymmeh]

Bron,

You may also want to look at, AISC design guide #3.