Engineer's responsibility to check rebar shop drawings? 9

[livewire9]

Do other structural engineers out there typically check the rebar shop drawings for a 3rd party contractor (different from in-house construction crew at a Design-Build or IPC firm) prior to construction? IMO, that is edging over the line of responsibilities. I have been doing this for an employer who, I believe, takes on too much. I think it should remain the responsibility of the contractor, or their rebar fabricator, to read the plans correctly.

 

[jayrod12]

Yes 100% we review the reinforcing shop drawings for conformance with the design intent.

Do we make sure all of the bar counts and lengths are correct, no. But we review the reinforcing specified in beams, slabs, columns etc. match our specifications. We ensure that where we've needed specific laps provided, or specific bar placement, that it is detailed appropriately.

It is your job as the EOR to ensure that the product being provided meets the design intent. Regardless of what that product is.

 

[bridgebuster]

I work mostly on public projects. If we provide a bar list in our plans we don't review any shop drawing(s); the contractor is required to follow our list. If we don't provide a bar list then we review the shop drawing.

Assuming the plans are correct or the contractor knows how to read . Seriously, if the contractor is doing the bar list, someone familiar with the design should look it, not necessarily down to the gnat's @$$, just to make sure everyone is on the same page. I've seen too many errors on rebar shop drawings.

 

[phamENG]

Agree with jayrod. The responsibility to read the documents and comply with their requirements falls on the contractor, but you have a duty to the owner (and, more importantly, the end user/occupants) to ensure that the contractor has correctly interpreted your design.

In my jurisdiction, review of the shop drawings and product data is a required step for special inspections.

 

[IRstuff]

Rather than taking on more work, I see it as prudence. Miscommunications and errors are not so rare, particularly when cost and schedule rule.

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[birneys]

Are you talking about rebar shop drawings for buildings or bridges? I think the responses might vary depending on which type you're asking about.

 

[STrctPono]

I absolutely check a 3rd party Contractor's rebar shop drawings. The way I see it is that the owner has hired you under a post-design contract to do exactly that! Verify that the submittals sent by the Contractor are interpreted correctly. It's Quality Assurance. I even go so far as checking the rebar bending schedule to make sure there are no errors with the interpreted lengths. I don't tell them how to fix their mistakes but typically point it out when their is a mistake and tell them to "verify".

 

[RPMG]

IBC 107.3.4
The registered design professional in responsible charge shall be responsible for reviewing and coordinating submittal documents prepared by others, including phased and deferred submittal items, for compatibility with the design of the building

 

[livewire9]

I do provide a rebar schedule with length, size, and weight. I provide location of and required lap lengths. And, I provide schematics showing type and geometry of bent bars. So, the plan set is complete and can be fabricated and built directly from. All project are custom.

 

[phamENG]

livewire - I imagine we all do the same thing. But have you ever seen a concrete sub laying out rebar with your drawings in hand? I haven't - they have the rebar shop drawings. That's because no matter how much I show, if I want to be anything close to efficient I cannot show all of the detail required for each and every bar. That's why rebar shops exist. And it's up to you to make sure they correctly interpreted your design.

Thanks, RPMG, for posting the IBC reference. It's a standard code requirement that you verify these.

 

[Ingenuity]

But have you ever seen a concrete sub laying out rebar with your drawings in hand? I haven't - they have the rebar shop drawings. That's because no matter how much I show, if I want to be anything close to efficient I cannot show all of the detail required for each and every bar. That's why rebar shops exist.

You need to get outside North America

For example, in AU (when I practiced there) the SE drawings were sufficiently detailed that rebar was fabricated and placed directly from these drawings. It was not until I worked in Canada and then the US that rebar shop drawings were the norm.

Often, in complicated flat slab building floors, we used to produce a formwork layout drawing, a bottom reinforcement drawings, a top reinforcement drawing, and PT drawing, if applicable. Similarly, when it came to structural steel, we used to design/detail all the member connections too.

 

[livewire9]

Thanks for the feedback, folks. Not trying to start an argument here. I see that wayyyy too often on this forum. Just trying to hear some others' experiences.

Thanks, RPMG, for the IBC reference. Thanks, Ingenuity for sharing a good perspective.

It sounds like my practice lies more or less with the norm.

 

[phamENG]

Ingenuity - I'd love to. Sadly, though, my family wouldn't appreciate me running off to Australia to work...

I'd love to be able to produce drawings to that level of detail. Unfortunately, for reasons enumerated ad nauseum elsewhere on the forum, it just isn't in the budget.

 

[mtu1972]

Birneys - Good point!

I spent my career working on buildings and industrial facilities. Late in my career I was assigned to a pedestrian tunnel below a highway in that city. As I had done many industrial tunnels, I designed and detailed this one the same way.

After a couple weeks I got a call from one of our companies highway engineers (who I had never met) from our main office. He said he had heard from the State Highway Department that this was the worst tunnel drawing they’ve ever seen, and it was unacceptable. Primarily it was a missing bar bend schedule that needed to be added.

I had also extended the base slab 4” beyond the walls on each side, to support the wall forming. They had to be removed to minimize the concrete costs.

Any industrial contractor would have had no problem doing the construction from my first drawing. The Highway Department wanted their Contractor to have all the rebar fully detailed and quantified so as there could be no room for error.

gjc

 

[BridgeSmith]

...have you ever seen a concrete sub laying out rebar with your drawings in hand?

I have. Granted, I've only been on-site for one bridge widening, and most of the rest of my 18 years at the DOT in the office designing and checking shops for SIP forms, railing, etc. but I haven't ever seen any shop drawings for rebar. As far as I know, the rebar fabricators work from our bills of reinforcement and provide the rebar, which the contractor places based on our plans. All the quantities of bars, lengths, bending diagrams, cut sets, and total weights for each component, complete with prefix numbers designating the bars for each component, are all right there in the contract plans. Shop drawings would be completely redundant.

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[hokie66]

Bar bend schedules, prepared as part of the contract documents, are typically used for bridges, but not for buildings. But my experience in Australian buildings differs somewhat from that of Ingenuity. While the rodbusters do use the engineer's drawings, they also work from schedules prepared by the reinforcement suppliers. These schedules typically identify the bars, and describe in words or diagrams where they are to be placed.

 

[r13]

I agree with hokie66's comment. I've been stationed onsite, and reviewed tones of reinforcing steel shop drawings. With a good/decent detailing shop, the erection crew usually only relied on the shop drawings. The design drawings were largely used by the construction management personnel for double check, and when encountered problems.

 

[phamENG]

Sounds like there's a pretty big gap between bridges and buildings, and also one of varying degrees across borders. For what it's worth, my observations were about building construction on the east coast of the US.

 

[r13]

Public works usually require the engineering office to prepare bar list, bending schedule and detail drawings. Some large utilities have the same requirement spelled out in contract document.

 

[r13]

The reasons are two fold - minimize mistakes during construction, and most importantly, get exact QTO before bidding for budget purpose, and help contractors estimate during the bid.