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Retaining wall compensation

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Roger, the skeptic, will design retaining walls only if the client will 
provide a topographic map prepared by a registered land surveyor, regardless 
of how much the client guarantees that the height of the wall does not 
change.  (Client's idea of wall height is height above ground.  Roger Turk's 
idea of wall height is height above top of footing plus any fence or wall 
constructed on the top of the retaining wall.)

That said, back to your question on compensation, I would probably calculate 
the total construction cost of the wall, including drainage provisions, base 
a fee on that construction cost, and then propose a fee of half of that 
amount.  For a wall 1/4 mile long, there will be design considerations that 
would not occur in a wall 50 ft. long.  Is the wall straight or a portion 
curved?  If it is curved, it will no longer behave as a cantilever wall, but 
will have to be designed as a shell unless numerous expansion joints are 
provided in the curved section.  If it is concave outward, then an edge beam 
has to be constructed at the top, and deadmen or some tieback installed at 
the ends of the curved section;  if it is concave inward, the wall will be in 
compression, but something has to resist the compression at the ends of the 
curved section.

When something seems simple you should expect it to become complex beyond all 
conceivable expectations.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Paul Feather wrote:

>>I am curious how others throughout the country charge for retaining wall
design.

Most of the retaining wall work I have been involved in has been project
specific as either part of a building structure or structural foundation
system.
The project fee is typically determined for the project as a whole via the
usual methods; estimated time and effort, percentage of project cost, tarot
cards, the magic eight ball... :-)

What I am curious about is when the amount of design and drafting time is
minor, two or three different conditions maybe, yet the walls are long and
numerous with a quantifiably higher level of exposure.

To create an example, say a wall 12' high and 1/4 mile long, and regular
enough that only one wall section will cover the whole thing. How do you
charge for the increased exposure over a design for the same wall only 50 ft
long?

Paul Feather<<