Building Sub Floor Drainage

[GoldDredger]

I am a civil engineer helping to coordinate a project that proposes a multi story building with a basement storage.

There is expected to be groundwater near the bottom of the basement, so sub floor drainage would be prudent. I envision granular material below the slab, with perforated pipe. Gravity flow to outside storm is not possible, so the groundwater will need to be collected at a sump and pumped out.

My question is who should handle the design of the sub floor drainage? The structural engineer claims it is the site civils responsibility. The site civil says their responsibility is to within 5-feet of the building perimeter.

The MEP will design the pump and plumbing out. The architect claims the engineers have to design the waterproofing.

Any ideas? Seems to me it is the structural engineers responsibility.

 

[ishvaaag]

It will depend on the contract. Normally the architect cares for these things but when affecting the structure should be in agreement if not with the structural designer at least yes with the mandatory waterproofing regulations. Obviously coordination is required or details won't fit together.

 

[tsgrue]

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I have always seen geotechnical do the drainage design, though I'd think the civil would have more background than the structural. If your not familar with the process, I suggest subcontracting a agricultural drainage engineer - it would pretty much be straightforward to one of them.

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[Ron]

It is clearly not a structural engineer's responsibility. I do both structural engineering and waterproofing, so I know the differences.

The drainage design should be a coordinated effort between the civil and mechanical engineers. The civil could handle the whole thing, but might get into contractual issues.

You seem to be going through a whole lot of effort to reject something that you could easily do. Take on the charge (with pay of course) and move on!

 

[bimr]

Foundation drainage would be handled by a General Civil Engineer.

General civil engineers plan, design, supervise the construction of, operate, maintain, inspect, and manage many of the physical facilities and systems in both public and private sectors.

General civil engineers are often responsible for site design (grading), facility location studies, utility design, environmental compliance issues, code enforcement, public decision making, and project management issues.

As such, general civil engineers must have broad-based education with knowledge of the several civil engineering specialties.

https://www.civil.tamu.edu/areas/general/index.html

 

[brandoncdg]

We would normally place the pipe location, inverts and where that pipe daylights. The cities around here recommend what they want as far as waterproofing.

Civil Development Group, LLC
Los Angeles Civil Engineering specializing in Hillside Grading

http://civildevelopmentgroup.com

http://civildevelopmentgroup.com/blog

 

[GoldDredger]

I'm not sure I understand how it is anything BUT the structural engineers responsibility.

The SE designs the foundation of the building. He has to reference the geotech report to know what allowable soil bearing pressure he is designing above, especially if it is slab on grade not pier and beam.

The SE would also need to know if there is groundwater becuase there would by hydrostatic pressure acting on the foundation. It seems that would certainly affect the strength requirements of the structural members.

Lastly, if it is french drain type situation under the foundation would not the SE want to determine the type of material being used under the foundation?

 

[bimr]

Some time ago in thread194-214450, someone asked what was a general civil engineer.

Many engineers now specialize in defined areas of work. For example, a structural engineer may not know anything about site drainage if he specialized only in structural engineering aspects of civil engineering. This is market driven because one is more efficient if you are dealing with something that is familiar. You can work faster and more efficiently if you are doing the same thing over and over.

What you need is a general civil engineer that has broad-based education with knowledge of the civil engineering specialties, not a specialist.

Having said that, there are discipline specialists who also have broad based knowledge. But these people are rare and will be harder to find.

 

[civilman72]

I'm a "civil engineer." To me, and most of my "civil engineering" colleagues, we generally do nothing inside the building or "within 5' of the building." But I know many of my clients do not have the same expectations. Some of my clients go so far as to think that I should be able to figure out the electrical loads for the building, as an example. Like someone mentioned above, determining who is responsible for the foundation/floor drain design should come down to their contracts with the client. In this case, I'm willing to bet no one mentioned a foundation drain in their contract. In general, a civil engineer’s contract may mention the design of the foundation drain discharge pipe, but will more than likely not include the design or location of this pipe while it is in the building or runs along the building foundation.

My general thought is that the structural engineers SHOULD be the one that are most concerned that the floor/foundation drain system is designed correctly, particularly if they are in high groundwater - and if they do not have the expertise to design it, it is in their best interest to make sure that someone correctly designs the system. The geotech should have some information on groundwater levels, soil types, percolation rates, and may even be able to quantify the amount of water to be drained. But that geotech and/or structural engineer may not have the hydraulic background to properly size the pump or conveyance pipes.

BUT, the structural engineer is almost always the one that depicts this foundation drain on their signed/stamped plans (usually on the typical foundation detail), so ultimately they are the ones responsible to make sure it is designed correctly. If the floor/foundation drain discharges to the surface, outside the building, then eventually the civil engineer will get involved.

Just my two cents…

 

[cvg]

as a civil engineer in most states, we are allowed to design small buildings given that we have the experience to do it. in most states, civils are allowed to do structural calculations and designs, often are allowed to do surveying and generally any type of utility design. we are allowed to do pumping plant design which is sometimes done by mechanicals. Site design is commonly done by a civil. Building design is often done by an architect.

Geotechnical engineers rarely take on design responsibility unless possibly for a dam or levee.

Responsibility for subdrainage would fall to whoever is doing the foundation plan. If that person doesn't have the experience, they should find somebody who does.

 

[bimr]

If you are really interested in finding a specialist in this field, then you should locate a foundation engineer.

Foundation Engineering is the engineering field of study devoted to the design of those structures which support other structures, most typically buildings, bridges or transportation infrastructure. It is at the periphery of Civil, Structural and Geotechnical Engineering disciplines and has distinct focus on soil-structure interaction.

Foundation engineering applies the knowledge of geology, soil mechanics, rock mechanics, and structural engineering to the design and construction of foundations for buildings. Soil mechanics is defined as the application of the laws and principles of mechanics and hydraulics to engineering problems dealing with soil as an engineering material.

http://epdweb.engr.wisc.edu/Courses/Course_Date_To_Be_Announced.lasso?myCourseChoice=L274