Reinforcement Detailing: By Engineer or Contractor

[suqlainUK]

One of the possible reasons that the UK Steel framed building industry has a major share of the building frame market is that the Contractor carries out all connection design and detailing for the steel frame structure........ saving on the Consultant design time and fees.
The Concrete framed industry is now going down the same route, whereby the contractor is being asked to carry out the reinforcement detailing and scheduling.
Is this the norm elsewhere in the world, and if so, what are the problems experienced with this split approach to the concrete frame design and detailing responsibility?

 

[bjb]

My experience in the USA for building structures has been to just call out the rebar size, spacing, and pertinent dimensions and details on the design drawings, and then the rebar fabricator submits to me for approval details and schedules of the reinforcement on the shop drawings. A problem that I see with this approach is that the reinforcing detailers are usually squeezed for time and money, and often times their submittals are not so great. On the whole, it seems to work out OK, but I should point out that in my area of the US most superstructure framing is either steel, masonry, or wood, and concrete is mostly used for foundations, where the complex detailing is not required.

 

[kayah]

Canadian standard practice is now for the consultant to show basic details (size, spacing etc) and the detailing is left to the contractor (with shop drawing review by the engineer). In cases where the details are particularly tricky then the consultant should still show what is required.
I believe there are several reasons for this change - firstly because the reinforcement detailers specialise in this stuff they should be able to do a more efficient job than the consultant. Also, where there are different approaches to detailing the same thing, the choice should be with the contractor to ensure best value (subject to design requirements of course). Also, with consultants doing the detailing there is much greater potential for extras - which consultants like to avoid.