Jae, i don´t agree with you but i don´t totaly desagree. First of all did you know wich was the reason because the top structure collapse happend, bad details...So i think that a good structure design is a proces that starts with a good structures design and finishes with a good detail drawing. But a agree with you that is tedius job and someone has to do it, but someone has to check specialy if the person who has thought the design is not the person who draw it.
But i like to get to the beginig of this discussion, I think that the quality of all data is being damaged because the deadlines are often too short because today be have cad programs, excel spred sheets, and all of the software tools that are available to do what we must do , but this makes that the person who does the construction details often has the shortest time to do his job, and must do it in the best way.
"In fact, shop drawing preparation is NOT engineering."
In fact, that depends on the nature of the "shop drawing" in question, and many "shop drawings" of various kinds are considered engineering, and do require preparation by a PE.
My statement that shop drawing preparation is not engineering is based on this idea:
"Let's see, here's a steel wide flange shown on the engineer's design drawings spanning from column A-3 to B-3 and its a W24x76 - top of steel at elevation 113'-0" and the design drawings show 4 bolt connection with double L4x4x3/8. I need to draw out the beam with the four holes cut into it at each end. Add a series of connector holes along the length at 8 ft. centers for intesecting beams. I then draw it up and dimension where all these holes go...."
What part of that involves the application of engineering principles? Nothing in my view.
The 2 consulting firms that I worked for in the last 7.5 years did not put any connection info on their drawings like you described. All they called out were member sizes, member loads and member locations. Perhaps these 2 firms were an anomaly.
EddyC - I don't think so - I think your two firms are probably more the norm, although after the Hyatt Regency collapse, and especially in the last 10 years or so, I think a lot more structural firms are setting up their own connection schedules or at least showing standard connections based on beam depth, etc.
I would agree that if a firm doesn't do the connection design, then they at least have to show the reactions. One firm I worked with some years ago used to refer to the AISC Manual where they had (and still do have) tables of max. uniform loads that various WF beams could support (based on zero unbraced length). They essentially told the fabricators to go find those tables, find the beam, the span, and look up its max uniform load. Then take it times half the span and voila - you have an end reaction.
In recent years I've leaned toward actually dictating the connections...even the simple framed connections, just due to the uncertainty of what quality of fabricator I'd get.
I understand your position and don't blame you for looking at printouts over looking at a screen. I usually print things out as well since you can go crosseyed looking at screens at times.
I just see so many frustrating things (as a whole in business) that I just have to shake my head. I am no less guilty than the next guy and have contibuted my portion to chaos, but most times it is ignorance than lack of attention. I see so much berating vs training and complaining about people who try but just don't know any better. Then there is the issue of not enough time or resources to accomplish a job adequately. My last position I had to implement ISO:9001 at a start-up facility (no training - no experience), purchase all the tooling, handle design, and in the beginning putting together the safety program. All on my own to be done within a year. In the beginning I worked 7 days a week putting together most of the ISO program at home because at work I had all the other details to attend to. Of course I came under the gun because I wasn't doing a "good job". I did the best I could with what I had to work with. (My wife transfered so I left at the end of the year. I stayed an extra month until the first audit which they had only 6 findings. A few months after I left they became certified and my replacement commended me on the quality program I put together.)
Anyway, I did not mean to imply you were part of the problem and that you are not part of the solution. So I apologize if you took that directly. There are just so many better ways to do things that we don't do...
I just received alleged "shop drawings" today from a fabricator who photocopied my plans and details, and put a note on the drawings that "anything circled is not by steel fabricator" and circled the metal studs, concrete work, etc.
No piece marks, nothing!
HAHA! Am I really expected to approve these?! Ha, I needed a good laugh today.
Someone above said that the fabricator was designing and/or engineering parts of the structure - NOT ALWAYS!
Let me preface my comments by saying that I'm a recent grad (August 04) and have only the limited experience since then.
Some of the items that have been discussed are issues we're currently dealing with. My firm is currently designing a large project for a hospital in several phases. The first phase (parking garage) started at the first of the year and is due in about six weeks and to date we've recieved typical floor plans from the architect. That's it. No sections, elevations, etc. On top of this there seems to be a propensity for the architect to make changes without alerting us. As this is a post-tensioned structure, changing column spacing/locations, adding stairwells, changing bay sizes (all that have happened in the last two days) vastly affects the design. There are sections of the project that we've basically had to tell the architect he couldn't change because we're done and a redesign ($$) would be required. As the PM on this project says, "We're about a month ahead of the architect right now."
Is this the usual mode of operations for architects?
How can we turn out drawings with any quality without timely input from the architect?
Are there ways to increase quality without taking on more than our fair share of duties (i.e. design development)?
started too late on the project
does not have sufficient manpower on the project
has an inexperienced team leader
or
the schedule is unrealistic
or
possibly all the above.
Your PM needs to have a real serious talk with the architect before the problems get out of hand.
Finding structurally significant changes by the architect is sometimes like finding a needle in a haystack. He needs to be "communicating" with the structural engineer not just changing his drawings and hope that you find his changes. "Communication" is not a new concept but I have seen this sort of thing happen when everyone is scrambling on a project that has an unrelistic schedule.
Some architects like to continue to tinker with things without realizing the ramifications to other disciplines. The only thing that seems to get their attention and put a stop to the changes is a request for additional fee and additional time.
Jike, Right on.
By the way our requirement is that the fabricator always supply shop drawings bearing the seal of a PE. We provide reactions, shears, moments, FF or PR requirements, minimium 2 bolt where not specified. and exact connection details when we feel it's required and of course the required dim stuff. Never seem to have this problem with reinforced concrete, the real engineering material(s). That should elicite a few posts! This is a huge posting.
My understanding of the problem with the Kansas City Hyatt wasn't so much connection detailing as it was a rerouting of the load path so that the load exceeded what the connection was intended to handle. That was a design *change*, not a conventional filling in of details.
The original design by Gilliam called for a pair of channels welded together to form a box section. According to the NBS investigation, that detail had problems of its own even before the changes later took place via the fabricator's detailer.
The flaws, the way I understand the history, were:
1. Original design was flawed to begin with and Gillian assumed that the fabricator would do the entire design anyway.
2. The original fabricator got too busy and farmed the job out to another fabricator after getting the connection somewhat drawn. The second fabricator assumed that the connection design had been completed and just shined up the detail a bit.
3. Gillian's engineer's apparently only did a cursery review of the shop drawings, not catching the connection detail.
4. The contractor saw the long all-thread running up through two levels of skywalk and requested an alternate detail to change to two sets of rods, which resulted in a doubling of the load.
5. Gillian's office didn't check this change either.
JAE-that's the point I made previously. There is virtually no mentoring of new engineers in the consulting office. A mistake such as assuming a long steel rod could be threaded its entire length is typical of a newbie engineer. It could have been easily detected by anyone with some experience. Another factor is: there was no attempt to reinforce the flanges of the channels for induced bending. To me, that indicates the office policy was to get things done as fast as possible for maximum profit, and there was no training or QC by more experienced engineers. How typical.
These days many engineering firms are having to operate as you described just to stay in business, not for maximum profit. As an employee, I absolutely hate it since I usually don't learn much on the job. I end up learning more reading in the evenings on my own time. This is what happens when engineers are selected based upon price rather than ability.
EddyC,
Exactly. Typical want ad in the papers: Engineer wanted, 2-4 years experience. Energetic, enthusiasm a plus.
Translation: Engineer wanted to work for minimal salary, will not ask too many questions. Will not have too much "baggage", will not have deeply ingrained philosophies contrary to established office policies.
Under the conditions in most offices, you need plenty of enthusiasm to overcome all the negative conditions. Luckily for me, I am in a much better situation now.
Right on.
We are sacrificing real world experience and knowledge to compensate for lower wages to increase profits. Then we can't figure out why the quality is going down. Hmmm....
jike,
I agree, we need to look at ways to try and resolve issues. Posting a thread will help, but does anyone write articles in any magazines? (engineering or business) I am going to be working on one concerning a confusing issue in the packaging business as soon as I gather enough data.
I got into this forum to look for things concerning the corrugated business and found so many echoing complaints. Details may be different, but the scope of the problem is the same.
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