What good does signing off on drawings really do? Besides having someone for the lawyers to blame, consider this:
The History Channel recently ran a recap of that 1980’s disaster in a Kansas City Marriott where a fancy stairway collapsed. (The news, at the time, called it a mezzanine.) Anyway, I tuned in right as they were explaining that there were two inspections - one on the suspended supports and one on the interlocking beams - but no check once the final assembly was made, if I understood correctly.
Anyhow, my point is that an PE signs off on drawings which means, in theory, everything has been designed correctly and proper materials were selected. But, still anything can happen! So, why does the PE’s seal carry all the burden? Surely, it is NOT the final word in the construction of any structure! - Jinx
Signing off on a drawing is the professional engineer attesting that the structure was properly and safely designed. I’m not really sure what you’re asking. The Kansas City disaster wasthe engineer’s fault ultimately.
This page has a good overview of the reasons for the collapse and the legal repercussions.
I’m not sure why you call it a stairway. It was a suspended walkway – level, with no stairs. Not exactly a typical mezzanine, but a lot closer to a mezzanine than to a stairway.
The PE’s seal does not carry all the burden. The PE designation is not easy to procure and represents that the engineer has achieved a level of expertise in his/her field.
In a construction project, the PEs/Architects submit their drawings to the local jurisdiction and they are reviewed by plans examiners. Those reviewers are experts themselves and review mainly for national/local code compliance. The building codes in this country are some of the best in the world (although not perfect and changing and getting better every year) and that is why you see so few buildings collapsing as you do in many third world countries.
After the plans are approved, they are built by a General Contractor. In many states, contractors have to establish profeincy/experience in their field and pass difficult exams prior to being issued a license. (This includes sub-contractors)
During the construction, there are regular inspections. This includes “pre-rough”, “rough” and “finish.” On a complex project, those performing inspections include representatives from the Engineer, General Contractor, City/County, and Owner.
Inspections have to completed at every stage of construction. I once saw an inspector require a contractor to remove all the drywall off the walls because the electrical rough inspection wasn’t completed before the drywall was put up.
In a catastrophe, everybody gets sued. Everybody. I’m not familiar witht he KC situation, but if final inspections weren’t done, I would imagine everyone is in trouble, including the city. However, on any given project, if the PE designs it, and it is installed exactly per specs, and then there is a failure, the PE should be liable! If it wasn’t, then the General Contractor and likely one of his subs are in trouble. On most projects however, the PE is also paid to monitor/inspect the project during the construction. The documention/sign offs can be mind numbing. The PE is the most knowledgable person on the project and is held to the highest standard. (and paid accordingly)
If a contractor substitutes an inferior material, or construction method, I would imagine that sub has the biggest liability.
I am a PE (Professional Engineer) in Civil Engineering, roadway design. The PE is an added level of assurance for people who use the services of an engineer. It is not and cannot be an absolute assurance of accuracy but more a matter of “this person has training in this field, meets a certain level of competence and is doing the best that he/she can.” Being human, the level of competence varies appreciably so in reality, one PE is not the necessarily same as another. This is why experience of a firm/person needs to be checked as well. But, is does serve as a sign of where the responsibility lies, and yes, who the lawyers can go after if problems arise.
The PE label also prevents people untrained in a task from legally claiming that they have that capability. Imagine how many structures would fail if anyone who had a whim to do so could design a bridge, building, roadway, etc.
I have not found this to be the case. I’ve reviewed drawings for a project that had obvious flaws, and the PE refused to fix them. We handed the drawings back to the client and refused to build it. The client made the mistake of accepting and paying the PE for the plans. Unfortunately, the client had no way of knowing that they were defective.
On the other hand, the flaws were something that I could have fixed, but the PE is the one who stamped the drawings. No way in hell I’m going to make changes and take on that risk.
Some PE’s are worth their weight in gold and an absolute pleasure to work with. Others less so.
I assume that you are a non-PE contractor. The plans cannot be changed without notifying the original Engineer of Record in writing. The thing to do would be to retain another PE willing to revise the drawings. This Engineer would be responsible for notifying the original Engineer of Record.
If the original design flaws presented a danger to public health or safety, the new Engineer would also be responsible for making a complaint against the original Engineer to the state board of Professional Engineers.
I’ve never had to do this myself, except for modifying plans sealed by a co-worker who had retired between the original design and construction. The changes were due to modifications of the building and required mechanical, electrical, and plumbing elements to move around. I did have to write a letter outlining the changes and the reasons for them, and send this letter to the original Engineer (with copies to just about everyone involved in the project and the plan reviews for the city, state fire marshall, ADA compliance folks, etc., just to CMA).
Disclaimer: The above might or might not be valid in your jurisdiction (or mine for that matter). I am a PE, not a lawyer. As far as I know, you haven’t retained my services, and I accept no responsibility for your (mis)use of any information dribbled out here.
This is very true. I’m only an EIT, and gladly so, because I know I’m not ready to go around stamping plans.
Many PEs get a god complex, especially when dealing with contractors. Sometimes things get designed in ways that they just can’t be built. That’s why I am glad for the opportunity to do a substantial amount of field work before I get into the PE world.
My contractor colleagues respect me because I will listen to their concerns. It made my relationship with a particular former PM a little difficult, because he told me he wanted some geotechnical drillers to do work that couldn’t be done (drilling very close to an active gas line). He was the engineer, and thus should be considered infallible, even if he has never seen the site.
If you’d like a detailed and well-written analysis of the collapse of this walkway, specifically written for the interested lay reader, please see Henry Petroski’s book To Engineer Is Human. He goes through the whole design, construction, and (after the failure) investigation cycles, and explains how the thing was put together, why they thought it would work, why it didn’t, and how the flawed design got through all the reviews and was actually built.
The rest of the book has a bunch of similar anecdotes and analysis. If you’re interested in the subject of engineering failure, I highly recommend it.
I have a Mechanical PE and briefly worked in construction. Any PE who doesn’t listen to the contractors and at least consider their suggestions is an ass and is to be avoided at all costs.
To answer to OP, I agree with what others have said. If the building was built according to the plans and there is a problem, the PE is at fault. If the contractor didn’t build the project according to plan and there is a problem, the contractor is at fault. In reality there is so much grey area that the courts have to sort it out.
That is exactly what I tried to do. The client balked at the added cost, and defended the original PE. Despite my demonstrating exactly how the original PE’s plans were defective, the client refused to hire another PE to fix them or press the original PE to deliver good plans. His opinion ws that he paid for a PE once, and he shouldn’t have to do it again. The original PE claimed he provided exactly what the client asked for.
Eh, at that point refusing the job was the best choice for me.
Just to clarify my OP and address some statements in this thread:
a) True, I always thought it was a walkway, as well. Perhaps I got the wrong impression, but the History Channel made several references to an etherial-looking stairway that, once rebuilt, was overdesigned 20 times over, and it lost all its aesthic appeal. It seemed the (original) stairway may have had suspended supports, IIRC, to avoid “junking up” the lobby with column support posts.
b) As I understand it, the PE’s signature makes him ultimately responsible should the design fail. Still, isn’t that just an easy scapegoat? The drawings and actual construction are totally two different things. Just because the design is sound, doesn’t mean the inspectors didn’t miss something in construction, right? I suspect that is why there’ll always be lawyers because it just might be an inspector’s neglegence. - Jinx
You’ve got it right, the PE is responsible if the design fails. If something happens during construction but the design was good, it’s the contractors fault. The inspector is an added safeguard but the contractor is respnsible for seeing that the design is built correctly.
If you have a good PE, he tries to make it easy to build. Bad designers can make things difficult. Still, when a contractor gets a job, he has to build it according to plans even if it’s not efficient. If a contractor sees an easier way to build things, he can submit shop plans to the PE and ask him to approve a different way of building things.
We see this a lot in bridge design. We’ll design prestressed concrete beams with the most efficient use of steel. The concrete guy will want to use a different strand pattern that will maximize the use of his casting beds and utilizes straight strands (draped strands, while more efficient, are more dangerous before the beam is placed). As long as the beam has the same capacity, we, the designers, have no problem with this.
In another thread, I talked about a construction accident that happened at a former company. (for the record, I’m not a PE, I’m still an EIT - I’ll probably go get my license next fall but I’m kinda puttin’ it off because I don’t feel that comfortable with the responsibility of sealing drawings yet) The project was a water treatment plant at a local lake and had a pretty high intake tower with a walkway leading out to it. The walkway and intake tower was supported on fairly tall (120’) columns. During the concrete pour of one of the columns, the forms collapsed with three workers strapped in at the top. They all died. Who’s responsible?
In this case, the design of the column was good. But the contractor poured the concrete too fast and it didn’t have time to set up. So there was a structural failure but, because the contractor didn’t follow safe contruction techniques, it was his fault.
So, when you have a failure, you investigate whether the design was inherently flawed or if there was a problem during construction. In the Kansas City case, the contractor wanted to make a change to make the walkways easier to build. The engineer said OK without really looking at them and didn’t realize the change majorly changed the loads. (the page I linked above has a good, easy to understand, illustration of the change) Upon investigation, the origianl design was found to have been flawed but it wouldn’t have failed so catastrophically withou the change. So the engineers was liable because 1) he used a bad design and 2) he approved a change which radically changed the safety.
You’ll always have lawyers because nothing is perfect. We’ve got such high safety standards in this country that when there is a collapse, it’s front page news. You just don’t see it very often. Yeah, there’s always a chance that something got screwed up during construction and an inspector didn’t see it or that the design wasn’t properly checked. There’s also a chance your car might be missing a few crucial bolts which you’ll discover rocketing down the highway at 70 mph. Or that the doctor left a sponge inside you during a routine operation. Stuff happens…
IANAPE, but from my reading of that book, I was under the impression that the design, while probably not leaving enough safety margin, was capable of sustaining the loads necessary. The real problem developed when the contractors took a shortcut while connecting the supports to the structure. Did I misread?
I agree however, that the book is a good read for anyone interested in engineering or why engineering can fail.
“original design of the rod hanger connection would have supported 90 kN, only 60% of the 151 kN required by the Kansas City building code. Even if the details had not been modified the rod hanger connection would have violated building standards.”
So the original design did not meet code. Also the original design was unbuildable – it specified a nut on threads 20’ up a rod, without threads over most of the rod. How was a builder supposed to get that nut up there?
“This original design, however, was highly impractical because it called for a nut 6.1 meters up the hanger rod and did not use sleeve nuts.”
So that partly explains why the builder modified the original design. Unfortunately, the modification made an already weak design much worse:
“The contractor modified this detail to use 2 hanger rods instead of one and the engineer approved the design change without checking it. This design change doubled the stress exerted on the nut”.
This meant that the design
“As-built, however, the connection only supported 30% of the minimum load which explains why the walkways collapsed well below maximum load”.
Well there’s plenty of blame to go around here, the majority seems to fall on the engineer. And fellow engineers seem to agree; they found him guilty of gross negligence, misconduct, and unprofessional conduct, and threw him out of the professional society.