Should the Designer Consider the Construction Process
Should the Designer Consider the Construction Process
(OP)
AggieYank asked in "Contractor Calls About Construction Loading" what responsibility does the Structural engineer have to check the suitibilty of the structure for the contractors equipment. The subsequent discussion has brought me to ask the following question: How much should the engineer consider the construction practice in his design, and what should he communicate to the contractors about the construction loads and sequence to the bidders and contractors.
My take is that although the designer can not consider exactly how the structure will be built, some consideration of the construction process and communication of those thoughts will go a long way in achieving more constructable projects that will go more smoothly and more profitably for everyone. What does everyone else think?
My take is that although the designer can not consider exactly how the structure will be built, some consideration of the construction process and communication of those thoughts will go a long way in achieving more constructable projects that will go more smoothly and more profitably for everyone. What does everyone else think?






RE: Should the Designer Consider the Construction Process
Dik
RE: Should the Designer Consider the Construction Process
Regards,

Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Should the Designer Consider the Construction Process
Means and methods are not something an EOR should specify, however an engineer should have a basic understanding of how buildings are constructed. A designer looks really foolish if his or her design is not buildable.
I dealt with a project where once the beams and columns were in place it was not physically possible to place the roof rafters. In this case a modification in the design solved the problem.
There was a way that the building could be built. It would have required placing the rafters providing temporary support for them, sliding the 70' long supporting beam in horizontally under the rafters. Holding the beam in place while placing the support columns for the beam. This would have required at least two cranes, probably three and a large number of man hours to complete.
The argument,that when the contractor submitted a bid on the job, he was agreeing that the building could be built: only goes so far. In a case like the one I described above a large contractor will refuse to construct the building until design changes are made. Smaller contractors might walk away from the job, figuring that the loss incurred would be less then the loss if he or she actually tried to complete the project with no changes.
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
I have given guidance on the drawings the stages by which something is to be constructed if it is critical for the design to actually work. But 99% of the time I do not give instructions and leave it to the contractor, unless I notice when something may not be buildable by ordinary methods or if the ordinay methods adversely affect the capacity of my design. There is also something called staged construction analysis that might be of interest to you.
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
The bottom line is: documents must be buildable.
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
You should not specify 'HOW' it is to be built as the contractor usually has far more knowledge and experience at this than the designer.
Calling up a specific construction method may in fact cost the client more money as the contractor may have put in a better tender if they were allowed to do it their way.
The exception to this rule is when the project involves demolition or underpinning. In these cases I always call up where shoring is required even if I dont call up a capacity.
RE: Should the Designer Consider the Construction Process
The posts I have read in this thread, buttress the widely held view that, the pratice of strucural engineering, depends amongst other things on: the region/area one is located, insurance and litigation concerns, client, nature of project,.....
RE: Should the Designer Consider the Construction Process
VB
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
And,yes, I've worked on structures that require staging and construction related analysis. What we do for such structures is to have available to us an inventory of erection equipment and use probalistic methods to determine the load for the structural element that is under construction in that phase. Typically in these structures the construction loads and vertical loads, wind loads on the structure are very large. Yet, in most if not all of those types of structures the contractor will revise the structure based on his equipment and submit calculations to EOR for review. And that is usually part of our scope for the construction phase.
For Design/build we evaluate specific contractor methods also.
Otherwise we don't design for contractor equipment, we use the applicable codes.
Regards,

Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
Dik
RE: Should the Designer Consider the Construction Process
Your original question - I believe that an engineer has a responsibility, but more importantly, an opportunity, to perform great engineering when they do consider somewhat the contractor's means and methods of construction....for exemplary projects.
For the vast majority of construction, though, the systems are usually tried and true and the construction equipment and methods aren't really that big of an issue.
I'd say its a good talent to have, as an engineer, to know when the construction equipment, means, methods, whatever, can become serious issues on a unique project.
RE: Should the Designer Consider the Construction Process
This may be similar to the British spec Valleyboy was refering to. If you have a link, could you please post it?
RE: Should the Designer Consider the Construction Process
Second, I think that when you start up a unique, difficult project, where you know there will be constructibility issues beyond the normal framed building, then it makes sense to start talking to contractors or other experts to work through the initial design concepts. Some of those guys are simply walking talking constructibility guide books.
RE: Should the Designer Consider the Construction Process
You can find such by going to ACI, AISC, TMS, etc and searching for details or design details. Most of the publications for these societies actively support these documents where possible for constructability.
They may not be in a single document but you'll find them.
Regards,

Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Should the Designer Consider the Construction Process
The easiest project arrangement is an alliance or D&C project where the contractor and designers are in together from the start. discussing and understanding the intended method of contruction at the start saves a lot of time evaluating and reworking designs to suit construction.
In a conventional tender contract, where the design is finished by the time contractor gets appointed, it is vital to have and experienced designer and/or reviewer who know what can and cant be constructed.
In this situation, I always meet the contractor before the start of the contract to go through the design intent and the method of construction.
Just on another subject, I have on numerous occasions come across designers that instead of taking the time to develope a specific detail, they say "they can sort it out on site". Just remember, if you can not draw it, the contractor can not build it.
Cheers
HvZ
RE: Should the Designer Consider the Construction Process
RE: Should the Designer Consider the Construction Process
This was quite some time ago, and I know that now I am digressing, that we used to talk about the demolition plan as well at the design stage.
And of course as has been alluded to by some already, the legal issues, the insurance issues, the accountability issues, the liability issues, ... have been a big facor lately on what and how we do, are willing to put on paper, and willing to document.
Yogi Anand, D.Eng, P.E.
Energy Efficient Building Network LLC
ANAND Enterprises LLC
http://www.energyefficientbuild.com