Trying to explain to non-engineers that it may be OVERKILL, but it is NECESSARY 38

[matty54]

I constantly here non-engineers complaining about how everything structural engineers design is so unnecessary and overkill. It is hard to explain to someone unfamiliar with design codes and engineering theory why certain members need to be sized the way they are sized even if using a smaller member (or no member at all) would not cause the structure to fall down.

I am wondering if anyone has had any discussions with members of the non-engineering community around this topic, and how you explained to them that the seemingly unnecessary sizes of the components are indeed necessary.

My personal explanation includes three main reasons. Please add to this if you have more.

1) Proof
any design that you come up with, you have to be able to show or prove what the forces in the members will be. and If you don't have all the information to start out with (ex. proper loads) then you have to make educated approximations of this missing information that will almost always be conservative. People always say, "it's not going to fall down, it's common sense, just look at it, others were built just like it and they are still standing". But if you can't prove it through applied scientific principles or scientific models, you can't just say its fine no matter how overkill it looks.

2) Time
For most of the designs that I work on, there are very short timelines for projects. These short timelines mean that there is not enough time to do proper analysis on the entire structure so some vary broad assumptions get made. And the broader the assumption, the more conservative it has to be. The less time that is available to analyze, the more excessive the design becomes

3) Code
Specifications like the ANSI/AISC 360, CSA S16, ACI 318, CSA A23 which get incorporated into building codes specify exactly what strengths you are allowed to assign to members. Given that inelastic and plastic analysis is allowed to be used, time often only permits the use of linear elastic analysis in my case. This is one item that always gets brought up. In a linear elastic analysis the member fails, but in reality the forces will be redistributed throughout the structure to different members. If you don't have the time, tools, or expertise to do more complex analysis, and you are stuck with first order linear elastic, you can't rely on the force being redistributed, because you can't show it.

 

[David Deck Guy]

The line I've been using lately is that its probabilistic, and that while you may be OK with only a 1% chance your structure fails, the city is not OK with 1% of their buildings failing and that we need to follow the law.

 

[3DDave]

I am surprised that non-engineers care. Is it about cost of the materials?

Most of this nonsense will evaporate if you point out they are welcome to accept in full any future failure and resulting deaths. If they want to take over technical design they also take over responsibility for the outcome. Ask how far they will get without a stamp on the plans.

Not many engineers make it to the national news because the building they designed did not fall down today, but those who did have a building collapse - yeah - they can end up on the news, in civil court, maybe criminal court. Even when that isn't the case immediately, such as Millennium Tower, the costs of trying to fix a problem can be a significant part of the original cost, far exceeding whatever a better design would have been. Even in the case of that goofy rail-trail bridge in New York. See

https://www.timesunion.com/news/article/albany-county-releases-report-rail-trail-bridge-18353527.php

$600k just to clean up the mess and prep to install a rental bridge until they can do something else.

Best of luck.

 

[Tomfh]

I just tell them there are two options; over engineered, and under engineered, and ask them which one they want.

 

[SlideRuleEra]

...everything structural engineers design is so unnecessary and overkill.
It is hard to explain to someone unfamiliar with design codes and engineering theory...

Explaining that to senior Owner management on industrial projects was a good bit of my job, often with structural steel. Use understandable non-technical reasons such as:

1) Upsize a beam the get a thicker web to greatly extend usable life in a corrosive environment.

2) "Heavier" (higher moment of inertia) beam to reduce deflection to minimize vibration and/or liquid ponding.

3) Select beam with greater allowable unbraced length to simply (lateral) bracing.

4) Provide higher capacity for future modifications (which are common in industry) minimizes (expensive) future structural upgrades.

 

[phamENG]

David the Deck Guy has a good one, though if you use the word probabilistic with most people, they'll tune you out.

In my area, these complaints are usually centered around lateral force resisting systems - shear walls, etc. So when they complain or tell me it'll survive <insert ridiculous claim here>, I ask them when the last time one of the buildings they built was tested to withstand the wind loads required by the building code. I usually get a confused look out of them at that, and go on to inform that the last time our region saw current design level wind gusts was in 1953 (+/-). And even then, it was a fairly small area that got them. So unless you went back in time and built a building that experienced that storm 60 years ago that is still standing, your 40 years of experience do not let you circumvent the building code.

For more sophisticated clients, I'll explain to them the building code isn't just about making a building stand up, it's about making it reliable. I can use hot glue and popsicle sticks to build a structure that doesn't fall down. But is it reliable? And that's the tricky part. Anyone can build something and show that it will stand up right now...I'm designing something to be built and relied upon for decades to come. Most of the smart ones get that, or at least accept it.

 

[RPGs]

A brief discussion of liability has usually worked for me. Someone said it here that all engineers really do is trade liability for cash and that's stuck with me. The modern world we live in contains some extremely litigious clientele.

If they bring up the classic "it's been that way for XXX years" I just agree and pose the counterpoint that the statement is true for anything until it fails and wont hold up in court.

He beat me to it, but I was just about to mention phamENG's excellent point about the tiny area of a storm event that governs lateral wind design. I've used that one plenty of times since I saw you post it a while back--thanks pham.

 

[countervail]

We get this quite a bit on smaller jobs. Most of the time the client is "probably" right and it will be fine and I agree with them, but I can't prove it or am not 100% sure so I have to go with a designed solution which is "more". When its somone in the trade a contractor I will often say yeah I'm 99% sure it's fine but we do 300+ projects a year and you wouldn't touch us if three of those collapsed every years so we have to take the conservative approach, once the contractor kind of sees your point they normaly help out with the client.

 

[AaronMcD]

I had 2 projects recently that are relevant. Both on different mountaintops in NorCal. Both get strong winds. Both got extremely strong storms during construction.

One huge covered outdoor patio with clerestory windows all around the top and a thin roof above that, cantilevered out 8 feet. A lot of heavy steel in that, that didn't budge during a huge wind storm. They understood after that.

The other has a 1300 square foot covered patio, with up to 220 sq ft tributary to columns. This requires some crazy huge foundations, and careful detailing of all the connections (wood). A huge storm of wind and atmospheric river came through, blew over a construction trailer and a bunch of sand bags, and 100s of yards of soil slid down the hill. They understood the foundations after that.

 

[271828]

They don't understand that because of public safety, structural engineers don't get to make up their own rules for design.

You have two options:

1. Design per the Building Code, state that on the drawings, seal the drawings (tell the truth).

2. Design other than per the Building Code, state on the drawings that you designed per the Building Code, seal the drawings (lie).

They probably don't know they're complaining that you do #1 and not #2.

Whenever I hear a complaint like you're talking about, I just say we have to design per the Code and it requires whatever I've done. I don't hear much after that.

 

[WesternJeb]

I am in a high seismic zone that hasn't had a large earthquake in over 100 years. I constantly agree with them how overdesigned and silly it is for us, but the code is the code that we have to follow. It requires the sizes we spec. out and we try to find every exemption possible because we agree with how silly it can seem.

That usually gets us on the same page. If they still want to argue then I get technical with them and point to code references then explain why it applies. They appreciate the effort enough and we both giggle about how overkill some of these requirements can be for a building that is going to occupy 10 people at any given time. For larger buildings, I usually don't hear this kind of kickback from owners/contractors though.

I also point out that we design for a one in 2,500 year earthquake, or roughly a 9.0 magnitude earthquake. That is why so many buildings have held up with so much less robust structure, because it has never seen close to the design load.

 

[JAE]

There are structural engineers who excessively pad their designs.

Some due to their limited expertise - so "when in doubt make it stout".
Some due to how they were originally trained by older, mentor engineers who didn't have computers to create exact axial and moment data.
Some because they are afraid of lawyers.

It is hard to explain to an owner why their 50 year old building "doesn't meet code" and needs strengthening despite it standing there for all those years and experiencing a good deal of wind events, seismic events or occasional gravity overloads.

 

[straub46]

A lot of the other engineers here have given good advice on how to handle the situation. In one of your other threads you said you work for a construction company. I feel like pointing out the liability the construction company would have, especially if they're doing the design acting as an EOR, would be another option to help show why you design to what the code requires, not to what seems like it should work, regardless of whether you go for permits or need sealed drawings.


Go Bucks!

 

[GregLocock]

You either design to code, or you design to pass tests. If they want you to prototype each structure and test it to demonstrate compliance, then they'll have to pay for it.

This is the essential (logical) difference between industries that require PEs and those that don't.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Greenalleycat]

I think the operative point is the 3rd one really
Code requirements are not "it should pass the 'seems sturdy enough' slap test' or the "it's stood this way for 40 years" test
Some requirements I think are definitely too onerous but it's about having known, dependable properties with reliable failure hierarchies
To most observers, the Factor of Safety of 1 is no different to Code unfortunately - they think that, if it's still standing, it's Code

In my experience, gravity stuff is usually not too bad to explain to clients
You can talk about minimising excessive timber sag (say a small extra cost on a steel beam to keep things rigid) - people can conceptualise gravity because we obviously all deal with it every day, and most people have experience with bouncy or saggy floors etc to use as a reference

Trying to explain lateral (particularly seismic) stuff is very difficult though
We are designing for events that occur once every 50 or 500 years...people don't see why they should put money in for an 'imaginary' event that probably won't occur during their ownership anyway
People also can't really conceptualise lateral events very well or what the difference between a 250UB26 (lower stiffness, non-compact section) vs a 250UB37 portal frame (50% stiffer and compact) - all they see is that the beams are both 250mm deep yet one is costing them 11kg/m x ~$10kg of steel = $100+ per metre extra to buy

 

[matty54]

Ya so my situation is a bit different than having to explain to the owner/client. It is having to explain to management and colleagues. In the company I work for 99% of the employees/managers are not engineers. Also 99% of the designs and drawings do not get stamped because client doesn't require it because most projects are built out in the more rural areas where there aren't strict or any reinforcement of building code. It's been that way for years and structural designs are basically determined from past designs not falling down. No real engineering involved, given most of the stuff is pretty straight forward 1 or 2 story industrial structures that just get re-manipulated a bit for new projects. But every once in a while there are some items that definitely should be properly engineered because it is complicated modifications to existing structures or taller structures than just single story, or crane supporting structures, Which is why they hired myself an EIT and one PEng to deal with the unique stuff. Because there is no building code reinforcement, stuff just gets pumped out and jobs are done at lightning speed. Any issues just get fixed by contractor on site. No revised drawings, no as-builts, no reviews. So as I an EIT pursuing my structural PEng I have to explain to my boss most of the time that I can't do things the way its always been done and the way everyone else in the company does it. For me I would require a few weeks to do a job someone else would do in a few days because I actually have to practice engineering. What I here all the time is that it's not getting stamped so it doesn't need done. Nobody seems to understand the extra responsibilities of being a professional engineer (or in my case an EIT) regardless if the structure gets stamped or not.

 

[Greenalleycat]

Well that's quite the different situation than I initially imagined...

That honestly sounds like a shitshow.
Building Codes don't cease to exist just because you're building in the wops, and as an engineer your stuff should always comply and be done properly
If your business doesn't support that then that's not because they're "not engineers" it's because they're greedy, ignorant, and dangerous
If they won't support you to do it properly then I'd be documenting your concerns to management and getting the hell out of there

Edit: the other thing to consider is what your intuition tells you will happen if there is ever a failure of your building
Do you think they will shield you from blame as the failure resulted from their business practices and pressure?
Or do you think that they will throw you under the bus - after all, you're the engineer, it's your responsibility not theirs....

 

[matty54]

Greenalleycat, as with most things in business, money is the driving factor. Ignorance comes in a close second.

 

[Greenalleycat]

I've no doubt of that. It's a tough spot for you to be in, especially as an employee
Ignorance is OK because it can be fixed - though willful ignorance is a huge red flag.

I've worked for clients delivering high-volume, low complexity rural buildings before - this is a highly cost sensitive market and people really don't care about "Code", they just want a building
Our firm picked up previous consultants' work and started receiving complaint from our client's clients as our designs were beefier than the previous guys
We lost some work as people found engineers willing to do it cheaper - so be it, our numbers were what they were and we didn't see that we could budge
Others understood, and we adapted our processes to help them
It turned out than one of the biggest issues was that they had standardised pricing tables based on the old guy's work - they kept losing money when we upspecced stuff down the line
So we implemented a concept design phase where we could pick up on areas likely to change from the old standard
This allowed them to price effectively and the clients that we retained became significantly more loyal as a result of getting personalised service

I know this isn't exactly your scenario, as your 'clients' are actually the managers at your organisation
But perhaps there are ideas there that can help - are there better processes that can be implemented that would allow you to do your job properly but would also demonstrate value to your managers and your business' clients?

If they're just not doing it properly deliberately and it's all about the money then I think you need to have a firm look at your own position and whether you can be comfortable in that environment

 

[matty54]

Greenalleycat, Yes I have made well aware to my direct boss that once I become a PEng all the stuff I work on will be done as I see fit otherwise I will not be touching it. I admit that now working as a EIT there are certain things I let slide that I would not let slide as a PEng. Maybe that is unethical of me, but I find myself in a vary precarious situation trying not to cause so much disruption within the company that I become unemployable, but still trying to hold true to my responsibilities as an EIT. The way the business is run is a result of "the machine" that everyone has become a cog in since its start. There has been so much profit made throughout the years as a result of being able to produce so quickly without the red tape that so many other industries would have to deal with, it is impossible for those at the top running the machine to say "yes lets go backwards and loose all this profit and charge the clients so much more money and time and become less desirable as a company" even if they were aware of all the corners that were being cut (I'm not saying they are or are not aware). But it would take something vary drastic happening to change the momentum of the machine.