几何尺寸与公差论坛

 找回密码
 注册
查看: 882|回复: 0

dots requiring pe stamps on shop drawings

[复制链接]
发表于 2009-9-8 19:18:50 | 显示全部楼层 |阅读模式
dot's requiring pe stamps on shop drawings
we have a client who does traffic signal structures for different jurisdictions.  this isn't our normal line of work, but we know how to use the aashto 2001 "highway signs, luminaires and traffic signals" code, and it is just like any other type of structural design.  
anyways, the project that we are doing now has a completed design in the form of a state dot standard detail, that appears to be very specific and well put together.  but the project specifications require the contractor to hire an engineer (which happens to be us) and submit engineer stamped shop drawings.  
i was mostly curious why this state dot has this requirement . . . is it to spread the liability around on this design?  or is it to get some other engineers to help the contractor read the standard detail?  has anybody ever come across this type of requirement?  (note: we don't intend to stamp this drawing until we do some design work to verify connections and members, it just struck me as being a strange requirement).  
you also run into the problems of stamping drawings that are not completed under your direct supervision, and we will be exploring these requirements in this particular state . . . but it just seems like the state is forcing engineers to stamp drawings not completed under their direct supervision?  any thoughts?

dots have had bad experience with their standard detail.  soils vary, reinforcing gets misplaced or under sized, anchor bolts fail after corroding or worse, do not fail when hit by a vehicle.  the installation is just as important as a good design and you should put paragraphs on your plans stating what needs inspection.
so, how would that different problem be cured by del200 stamping a dot standard design?
i've seen the process applied in various ways.  it boils down to this:
1)  call the contractor and ask how to design it, since he is the expert in that field.
2)  design it yourself while ignoring the advice you just got.
3)  require the contractor to pe-stamp his shop drawings and take full responsibility for the design, since he is the expert in that field.
4)  refuse to consider any changes proposed by the contractor, as he is obviously an idiot or dishonest.
5)  require the contractor to furnish an affadavit saying it was all designed per pertinent codes, etc., as he is the expert in that field.
when it's all said and done, it's some very muddled thinking- wanting it your way, with someone else held responsible if anything goes wrong.  
this thread has gone way off course.
1.  no one said the contractor is an expert in design.
2.  if the contractor were an expert, he would not have hired del2000.  therefore, i don't believe that the contractor is not giving del2000 any design advice.
3.  if the contractor needed to hire del2000, he isn't going to design or stamp anything, let alone take full responsibility for the design.
4.  no changes were proposed by the contractor, as far as we can tell form the post.  he can't be too stupid or dishonest or he would not have hired an engineer per the specs.
5.  see all of above.

now, the posted question was "i was mostly curious why this state dot has this requirement . . . is it to spread the liability around on this design?  or is it to get some other engineers to help the contractor read the standard detail?  has anybody ever come across this type of requirement?"  the answer is that most dot's want you do do it their way but want you to be responsible.  consulting engineers for dot's are doing less and less nowadays because they need a cheap price to get the design contract.  therefore, they push off as much as they can onto the contractor - both design work and responsibility.
if del2000 does not design the signal structure, he should not stamp it.  if he stamps the dot design without checking the design, he's plan stamping.  the problem is that the contractor signed a contract requiring him to provide an engineered, stamped design for the sign structure.  therefore, unless he can talk the dot into letting him prepare a shop drawing without the stamp, he's stuck and he should pay del2000 enough to design, stamp, and be responsible for a structure that meets the dot's minimum requirements shown in the standard detail.
i just went through this on a very large, private, building job.  the owner's engineer designed tiedown anchors.  the specs asked the contractor to provide a shop drawing (no mention of a p.e. stamp).  i prepared the shop drawing for the anchor subcontractor.  i was then asked by the gc where my p.e. stamp was.  i told the gc that the owner had already paid the other engineer to design the tiedown anchors and that i did not, and was not required to design anything.  i just provided drafting services to the anchor subcontractor.  eventually, they agreed and the whole thing blew over.  i don't think del200's client will be so lucky.
sorry, peinc, i was generalizing there.  let's just say that the contractor's engineer is an expert in the subject, and it's a moot issue whether he's an employee of the contractor or a consultant hired by the contractor.  and in response to "has anybody ever come across this type of requirement?", the answer is yes, with the variations as detailed above.
as a former dot employee, i can tell you part of what they think of this.
foundations need to be designed for the site.  dots rarely have adequate manpower and information to do these designs in time to award the contract on schedule.
dots are told by the industry that the fabricators of o/h signs and signal supports etc. that the industry is only capeable of delivering the economic product when they have designs tailored to their production processes.  ok, then we award these as a design/build lump sum item and give them that freedom.  then they turn around and squawk that they don't have the resources to design and stamp and have to hire an engineer.  in the dots view, that's the cost of doing buisness. put it in your bid for lump sum, but make sure to communicate with your engineer what processes you want so he will design it to your fabrication methods.
the dots still publish generic pictures of the designs just to provide guidance for what the final product will look like, approximately.
i've been in the transportation industry for close to twenty years.  it never ceases to amaze me how often workers with no more than a ged gripe about how stupid the engineer is.
one more thing, it is going to get much worse for everyone on both sides of the fence as dots downsize after the interstate program has been "completed."  there are fewer people at dots that understand the technical issues anymore so they will be passing off more and more to others under contract.
check the dot standard design and modify as required.  make sure that the sealed drawing is project specific and that geotech conditions do not vary significantly for the project.
dik
i agree with alot of the responses here relating to stamping design-build work or stamping drawings which may be partially based on standard dot details and partially based on site-specific design by contractor or fabricator. i completely agree with the statement about economy of items such as overhead sign supports let as design-build rather than per dot standards. when performing design build work on overhead structures it goes without saying that the site specific fonudation design must be stamped by a pe.
however, i don't think that was the original question. i think the original question here is why would a dot require pe stamp on a shop drawing where there is no additional design required by the fabricator. getting away from the overhead structure examples, i've seen numerous cases where simple railings for use on bridges or sidewalks require pe stamp. again, these are not design-build projects. every structural   
thanks for all of the input.  the design we are asked to review and stamp is a more complicated cantilever luminaire and traffic signal light pole (40' tall pole with a 45' arm attached to the pole).  we are working directly for the manufacturer of the pole, so are not even involved with the foundations.  we've told our client that we are simply running calcs on the equipment as detailed in the standard details, but are not "optimizing" the pole for a reduced, project specific loading.  
i work in the wood industry for a fabricator of heavy timber trusses and other structures.  i too run into specifications that require the shop drawings to be signed by a pe.  in most cases it appears that the eor is just trying to spread the liability around.
the company i work for always uses an outside consultant when ever we are required to provide stamped calculations and or stamp shop drawings.  we do this because the company doesn't carry errors and omissions insurance: although we have four pe's on staff including myself.
like del2000 i have seen complete designs we have prepared shop drawings for where we had no choice on beam size ,connection type and quanity ect.  however in many of these cases we have been required to provided stamped drawings.  
we normally will argue that another pe can't certify the eor's design, but only a design prepared by the pe or under his direct supervision.  most state require that the design embodies the design judgement of the certifier.  sometimes we win some times we don't.
the biggest problem we have is the requirement to cerfify shop drawings.  in most case we will not argue if the specifications only require certified calculations.
shop drawings contain many items, such as material lists and layout drawings which have little to do with safety concerns.  most consultants shy away from stamping shop drawings because it then makes them responsible for beam lengths, quanity ect.
in alot of cases where we are required to submit stamped shop drawings, we actually just submit very complete design drawings.  those drawings include all member sizes, connection details ect.
您需要登录后才可以回帖 登录 | 注册

本版积分规则

QQ|Archiver|小黑屋|几何尺寸与公差论坛

GMT+8, 2025-1-16 02:34 , Processed in 0.040815 second(s), 19 queries .

Powered by Discuz! X3.4 Licensed

© 2001-2023 Discuz! Team.

快速回复 返回顶部 返回列表