Do the calcs or not 7

[mrMikee]

I am currently working on a project that involves agg bins (elevated bins of sand and gravel,) conveyors, machinery platforms, and a drawing with anticipated foundation loads. This job was underbid and is falling behind schedule. Company management wants me to skip the calculations and just over design everything and get done. Now the customer wants us to design the foundations and the boss wants me to do that too. I have explained that I can't just guess at member sizes, plate thicknesses, bolts, rebars, and so on. I've had this discussion at other companies I worked at but have always been able to communicate to them the need to do the engineering and comply with codes. This time I can't get through and I don't know what else to say. It's a new company with a staff from unrelated businesses and they don't understand the engineering and construction industry.

Has anyone else been in this situation?

Anyone have a suggestion?

Thanks,
-Mike

 

[OutToLunch]

maybe you should introduce them to possible ramifications if something should fail or worse - someone gets hurt or killed.

 

[whyun]

Structural engineers can usually determine conditions that warrant calculations and conditions that don't. It is my opinion that not everything needs to be calculated.

On the other hand, being led by non-engineers to "eye-ball" and just over design is not quite right either. Quick calc maybe, no calc... dangerous.

Perhaps you can convince them that certain amount of calcs are absolutely necessary to ensure a safe product.

Not "all" calculations need to be submitted to building officials.

I am very hesitant of risking MY career and license so that OTHERS can have more money in their pockets.

 

[MikeHalloran]

I have the t-shirt.

Say goodbye.



Mike Halloran
Pembroke Pines, FL, USA

 

[MintJulep]

"Over design" implies at least some minimum calculations need to be done, otherwise how do you know if it is overdesigned or not?

Start with known loads and reasonable safety factors. From there some quick and simple calcs to divide things into two general categories: "way strong enough" and "need to look at this more closely".

Stuff in the second category either gets moved to the first by upsizing members, or gets calcs of sufficient detail to satisfy you.

Essentially this is a triage for detailed design calcs.

If the bosses bitch you can say that you are following orders and making sure that everyting is over designed.

If you can't make peace with this, take Mike's advice and say goodbye.

 

[TheTick]

Suddenly, everyone's a designer!

As a mechanical design engineer, I often hear "double the thickness" as someone's proposed quick-fix solution to a strength issue. Well over 2/3 of the time, that fails to do the trick.

Another sheet metal-related favorite is "use HSLA" to adres a stiffness issue. HSLA (High-strength low alloy) steel has the same modulus as its weaker cousins. Result: lost time, great expense, and no solution.

Usually these lessons arer repeated ad nauseum, probably by the same compulsion that keeps compulsive gamblers at the track. No amount of reality is enough to stem this disease.

In closing, two words: due diligence!

 

[mrMikee]

Thanks. This all good advice.

I've been with this company only for a month, but have worked in the bin and silo industry for over ten years. They all have been pretty much the same in that they think the codes do not really apply to them. In the past however I have been able to get around the problems by getting more time or additional help. A few times I had to take the work home and put in a lot of hours to get things right.

But with this company it's different, there seems to be no flexibility. I will keep working the issues as far as I can, but maybe I need to get a t-shirt like MikeHalloran has.

Thanks again.

-Mike

 

[kenvlach]

If you're lucky, you may be able to find a nearby structural engineer with a lot of experience and a good FEA computer program. Hire him for about 2 days of contract work. Tell your company it's the only way to get it done right & on time, with nothing unexpected turning up during construction. Collect all plot plans, other drawings & the relevant data, spend 2 hours explaining it to the contract engineer, give him a day to work (& be handy for questions & FAXes or email), spend 2 hrs while he shows you the drawings on computer & modify if necessary, then get printouts.

 

[MikeHalloran]

This is not how I got the t-shirt, but this story is almost on- point.

;--

I worked two summers as a very junior drafter for a consulting structural/ piping engineer who did mostly paper mill water systems. He hired an ex-aero engineer and told him to design a support for a couple of cartridge type water filters. Big filters; 8" connections, with cans you could hide a body in, plus two switching valves so they could be serviced alternately.

On the day he was fired, the aero guy showed me his calculations, maybe 40 pages of neat sketches and equations, and his layout and details. It was all incredibly detailed and beautiful. Definitely "A+" level work, like I could never do, before or since, in any amount of time. It had taken him at least a couple of weeks, maybe more. The structure, mostly 1"x1" angles, was really elegant; it probably didn't weigh 100 lbs, and could provably support the 800+ lbs of filters and valves and such, up in the air 8 feet or so, no problem.

Ever impertinent, I asked the boss why he fired the aero guy. The response: "What happens the first time it gets hit by a forklift? ... Now, you do it over, and don't use anything smaller than a 4WF12.". So I drew something simple and heavy and ugly, and nobody analyzed it, and it's probably still there.

;--

Now, if you've done similar bins before, maybe your boss is assuming that you would feel comfortable just eyeballing the proportions and adding a little lagniappe to come up with a conservative design that would turn out to be good enough if anyone bothered to check it.

I'll admit that the older I get, the less comfortable I feel about doing stuff like that, especially because I work in industry, where nothing never gets checked until a problem surfaces.







Mike Halloran
Pembroke Pines, FL, USA

 

[mrMikee]

That's an interesting story and it's a good point to make. In my early days as a new engineer I realize that I overanalyzed things myself but I think that's probably more the case than not for someone just out of school. Part of experience is realizing what can happen in the real world and having spent time in a plant engineering department I do understand the fork truck issue.

In the past I did work at a company where we would occasionally over design bins and structures to meet a schedule. We had a product line with years of history to borrow from so it wasn't that hard to come up with something special and be confident we had a safe structure. In fact sometimes we would just ship a heavier design and be done. The company I'm at now is new in the business and has almost no product history. Building codes, wind, seismic, and bin design is all new to these people. It seems to me that anyone who can run Solidworks is considered a design engineer.

There is a lot more to this than just drawing it up.

Thanks,
-Mike

 

[Slowzuki]

As a new engineer one has to overanalyze as you don't yet have a feel for the field. I can tell looking at a plan if a pipe size is too small for how much friction loss we can have, a junior (well, more junior) has to calc the whole thing to know how much friction loss is allowed on the whole and how this piece will fit in.

Eventually you get a feel for things and can cut a bunch of iterations out of the design process.

If you have been in the field 10 years and you have a comfort level that enables an efficient design process, I wouldn't trim more. The suggestion of help from another fellow is wise.

A collapsed bin with your name on it is your problem, not the people who made you do the work fast.

 

[MikeHalloran]

Certain companies of my acquaintance paid for their first CAD systems by dumping their checkers. Of course they never overtly admitted it.

Then they paid for Pro/E by dumping their engineers. Of course they never overtly admitted it.

Hey, the /E is for 'Engineer', right, so who needs actual engineering trained people?

I'm pretty sure Solidworks was sold on a similar basis, though at least the SW salesmen don't grow their own sharkskin suits, like the PTC salesmen do.



Mike Halloran
Pembroke Pines, FL, USA

 

[tombmech]

There are realities with business. As Mike and others have suggested, sometimes those realities don't allow for adequate engineering. A tragedy may result - either from a failure or from you leaving the company - by choice or not.

As an Engineer, you should always "run the numbers." I can't tell you how many times in 25 years that I've been surprised at the difference with my own assumptions. Rule-of-thumb's and/or winging it do an injustice to the company and to you.

However, as mentioned, there are business realities. The scenario you've described means that Mgmt has decided they can't afford anymore Engineering costs. It also means that you are either unaware of the solution, or are unwilling to do it: putting in the extra hours on your own and outside of company paid time - until the calcs are done.

The real question is whether you will decide if the company is worth the effort, or whether you must leave.

 

[EddyC]

I think that you have to give your superiors a crash course on the various requirements that must be complied to when designing a structure. They also have to be made aware that structural engineering is heavily mathemathical and one cannot design structures successfully by eye or by feel. The bosses also have to be made aware of the consequences if one does not design to code. I think that communication is the key here. If they over time refuse to listen, then you will need to jump ship down the road. Best of luck to you and I hope for a successful resolution.

 

[mrMikee]

Once again I am impressed with the quality of advice you can get at eng-tips.

There have been some very good points made here and I am thankful to all of you for the help.

Regards,
-Mike

 

[BJC]

Your superiors need a crash cost on what lawyers and lawsuits cost. If what you design falls on or otherwise injures someone, causes a loss in production etc. they may come after the company and you. You may have to hire your own attorney to defend yourself.
Wheather the design was good or not may not be relevant. It may be someone runs into your structure with a semi-tractor and it falls on someone. If you did not have backup to show that the design was adequate, they may go after you and other deep pockets. Rmember theres one under every rock.

 

[Blackcountryman]

Something I was reminded off recently.

"If you think the engineering is expensive wait until you see the cost of the accident"

In the past when I had a 'Money' manager saying I had to do something that I knew was ify. I wrote to him asking him to confirm that he was giving me this instruction and accepting the risk as an individual. I also pointed out that as safety issues in the UK come under criminal not commercial law it is not possible to insure against this risk. Of course I never recieved that instruction.

I'm also aware that I could not evade my duty of care like that but it sure care the little erk a fright.

 

[RDK]

Good construction is so expensive that the only thing more expensive is bad construction.

You have to do enough calculations to know if you need to do more detailed calculations.

If they don’t have enough time and money to do the calculations that will result in a more cost effective and quicker to build end product they why do they have the time and money to over build the product?


Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[AngeloPapadakis]

kenvlatch,

You wrote, "spend 2 hours explaining it to the contract engineer, give him a day to work (& be handy for questions & FAXes or email), spend 2 hrs while he shows you the drawings on computer & modify if necessary, then get printouts."

Do you think that any structural engineer is going to be pressured into reviewing someone elses work in the span of a few hours, signing off on it and accepting responsability?

mrMikee,

Being a structural engineer yourself, surely you wouldn't consider this as an option. If your boss relented, would you be happy with this time constraint?

 

[mrMikee]

AngeloPapadakis,

I've done this work myself and it takes more than 2 days, and I use both FEA and frame software. I appreciate the fact that kenvlatch took the time to make a suggestion, but that's not how I would personally like to do it.

The issue in my situation is that the company doesn't want to wait for me to do it or anyone else either, or to pay for extra expenses. In the past (at other companies) when I needed outside help I would subcontract to an engineer registered in the state where the equipment would be installed in case the customer requested stamped calculations. In my opinion it is difficult to evaluate work done with unfamiliar software, so I only worked with people I thought were qualified and they understood they were responsible for their work.

Concerning my original post I am currently doing the design work myself with the understanding that the time can be made up later in the schedule. So I've delayed the crisis at least for now.

Regards,
-Mike