Constructibility 1

[CivilArch]

Re: checking prints for [onstructiblity]

I am trying to locate a book to learn more about what to look for, a check list or similar, any suggestions?
This inloves, architectural , mechanical or electrical trades. Commercial construction is my main concern.
Thank You

 

[bltseattle]

I've never seen such a book. One way to check constructability is to forget everything you think you know about the project (because the contractor will have none of your inside knowlege, only whats in the contract documents - plans & specs), put yourself in the contractor's shoes, and mentally go stepwise sequentially through building the project using only the plans and specs. Someone with construction experience should be included in the constructability review process.

Some important questions to consider are:
Can you get the materials to the locations needed? Will the construction activities fit within the allocated space? Is there adequate clearance for all needed equipment? Have all materials been specified? Can the project be staked from the information on the plans? Will there be disturbances proximate and possibly damaging to adjoining properties & buildings? Is there adequate room for staging?

One example of poor constructability would be a deep excavation near the property line that could undermine an adjoining structure with no shoring plans provided for in the contract. Another example is inadequate horizontal controls so that there is no efficient way to stake the locations in the field.



Good luck

 

[HgTX]

For bridges, there's this:

http://steelbridge.org/AASHTO Docs/GDC-2 AASHTO.pdf

Hg


Eng-Tips policies: faq731-376

 

[dicksewerrat]

Go talk to afew contractors. Ask them what really fries their BUT... about plans. One thing that used to irritate me was pipe clearanves. The designer would put two pipes crossing, one a 12 inch inside diameter and the other a 24 inch inside diameter. Both RCP. Distance between centers at 19 inches. They seem to forget that pipes also have an outside diameter.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[LCruiser]

Arizona has a good guide.

 

[henri2]

Constructability from CM, GC or RDP's perspective?

 

[LCruiser]

Good point. The guide I have is from Arizona DOT.

 

[CivilArch]

Thanks for all the responses.
The purpose of this consructiblity review is to reduce change orders. This is after the construction drawings are complete and put up for owner's review. I am looking to check and see the practical aspects of putting these prints on the ground. Examining size of equipment foot print and allocated space like bltseattle mentioned above is a good example.

Other examples:
1. Mechanical : Is there a backlow preventer on the sprinkler line?
2. Civil: Comparing the invert elevation at the new facility and the city. The former should be higher than later.
3. Civil: Existing Asphlat pavement and added concrete pavment. No dowels should be placed. Differnetial expansion might cause one to lift more than the other , thus causing cracks. This is a quality issue.


I know this encompass so many disciplines.Experience is the key to gather these pointers.

I wonder if there is no such a publication(s), will it be a worthy endevour to start one?

 

[GeoPaveTraffic]

Experience is the only teacher in constructability reviews. To be effective the person doing the review must have experience in the type of construction being reviewed. They must also have an eye for detail and have/be willing to spend the time needed to look at the plans/specs several different times over the course of at least a week, longer is better.

I do not believe that this is something that can be taught. If it could be taught then design engineers could do their own constructability review and any of us who use plans to get thing built know that the reviews done by the disgners are lacking, at best.

 

[ACtrafficengr]

While it would be hard to teach this in a classroom, engineers can benefit from the experience of others. Or, as bridge engineer I work with commonly states, "I learned more in half an hour from a field engineer than I ever did from office engineers."

This is why the best highway designers, in my opinion, have at least a modicum of experience in costruction, maintenance, or traffic operations.

------------------------------------------
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."

Wm. Phelps Eno, ca. 1928

 

[cvg]

In order to review a set of plans for constructability, you must understand the construction process. This usually requires a fair amount of field experience. In addition, without this experience it is difficult as a designer to put together a constructable set of plans. There is a lot of talk these days about continuing education. I think that field work such as surveying, inspection and testing should be considered a vital part of this continuing education.

 

[LCruiser]

Constructibility results are, like "Value Engineering" gains, an inverse measurement of the quality of the set of plans. I have seen many designers who put together a set of plans, then when the plans go out to bid, think the project is "done". Well, it has barely started. I agree that designers should spend time in the field (years) before beginning to design projects.

 

[RDK]

Some other things to consider are

Tolerances

Is the installation tolerance specified and realistic? If not realistic can it be relaxed or will some other technique be necessary to achieve the required tolerance?

Weather

Can the thing be built considering the weather to be expected at the time of the construction? Here in Canada sometimes special measures have to be incorporated into the specifications to allow for construction in the winter.


Interference of other trades? Mechanical systems interfering with structural is obvious one, electrical requirements matching the equipment loads is another one.

Code checks

Exits to code?

How about hazardous electrical areas being clearly identified? I once had a set of drawings that showed an electrical hazardous area on the electrical but specified non rated door operators. This needed a change order and additional money from the owner and caused a delay in occupancy of the project.

Repeated information the same every place it is repeated? Information should only be repeated as few times as possible to avoid getting any information incorrect, however if repeating information is necessary it should be consistent.

Is all the information in the correct place in the tender package? For example the geotechnical report should not go in the contract but is separate section called information for bidders. That way you are presenting the information and allowing the bidder to make up their own minds on the impact of the report and not being contractually bound for the report to be correct and 100% accurate.

Also anything that applies to the bidding process should be in the information for bidders and not in the contract. If it’s in the contract then you are saying that here is the contract and it will not have effect until it’s signed but you are expecting that something before the contract has effect to be done and be binding.

Are the materials specified available locally? When I worked for the federal government it was common for material only available in one part of the country to be specified for jobs in another part of the country.



Is there a simpler way to do the task? I once worked on a project that had a number of tanks and liquid was to flow by gravity between the different tanks. The design called for all the tanks to be constructed on concrete stands at many different levels. We changed the design to steel stands and were able to save a lot of money and time on the project.


Mostly it is an experienced based task. You can learn design from a book and by doing it, you can only learn constructability reviewing by having actually built many projects. It also should not be a final check of the package just before tender call but an ongoing part of the design process. That way the concrete stands would never have been designed in the first place


Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[cvg]

typically around here, we have a constructability review at the 60% design phase. this is typically before details are finished and often with the first draft of the specifications. that way, the design can be tweaked for constructability without making major changes to the plans

 

[LCruiser]

"You can learn design from a book and by doing it, you can only learn constructability reviewing by having actually built many projects."

A good definition of an engineer is someone who can do with one dollar what any fool can do with ten.

Pretty much anybody can draw lines on paper. To actually be a competent engineer you need to understand constructibility (and value - as in value engineering). I would say if you can't design constructible projects you're not a very good engineer. It should be in the forefront at all times.

Incompetent engineers stand by their inadequate designs and use the term "engineer's prerogative" or some variant.

Different contractors have different specialties and equipment. You can't design the most cost effective project without knowing what those are. That's a severe limitation of Design-Bid-Build as opposed to Design-Build.

 

[BigH]

Picking up something that RDK said - be sure that the terminology for a specific item is the same on each drawing - while not specifically a constructability issue, it is one that can cause problems in construction. I once saw a single drawing for RE Wall (yes, the patented one) that referred to the sand used in the reinforcing area with three different wordings. On other drawings I have seen the use of "50mm dia pvc pipe" - yet on another it is just "50mm dia pipe". It clearly was the same, but confusion does reign due to inconsistency of terminology.

 

[henri2]

Clearly if an architect or structural engineer will be involved in constructability issues, field experience should help tremendously. Relying on information obtained from books and attending seminars/courses can add to this experience but cannot replace it. In fact, some engineering and architectural licensing organizations require candidates to have had some relevant field exposure...example: many US state arch boards/NCARB and the UK's IStructeE

In the Initial Professional Development (IDP) program of IStructE one of the core objectives for candidates for membership is :

" 2.5 CONSTRUCTION (Minimum standard E)
Objective: Experience in construction techniques
Guidance Note:
The Candidate should complete a period of experience on one or more
construction sites, for an aggregate period of at least six months. This should
normally include at least one continuous period of two months.
The Candidate should develop knowledge of basic construction techniques,
construction machinery, temporary support systems, material testing procedures,
construction programmes and construction sequencing."

Source

http://www.istructe.org.uk/membership/files/IPDleading2CM.pdf

For the NCARB Intern Develpment Program IDP criteria check

http://www.ncarb.org/idp/idpdescrip.html

 

[Ashereng]

For electrical stuff, here are some "gotchas" that I have come across:

1) Leave ample room in the junction boxes, field termination panels, etc. for all current wiring and future spares. On one job, we literally did a "mock up" using actual equipment of a local field panel, using a lot of duct tape and a few extra hands to hold things in place while we stuck our own hands in to see if there is enough space, bend radius of wiring, space for lamacoids, panduit, the door fan, all that.

2) Specify the wire guage and add (No Equivalent). See above for bend radius and room in panel. Also, some termination blocks will only accept up to a certain guage (espeically if tight for room from the beginning).

3) If outdoors, check the NEMA ratings. If indoors, check NEMA ratings.

4) If cold, add a heater inside the panel.

5) This one caught me more than once. Make sure you protect the vents from sand if working in the desert, white fuzzy floaties (I forget where), and bug ingress (I also forget where).

I am sure the list is long and distinguished. These are my 2 cents worth.