×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Cantilever retaining wall vs. counterfort retaining wall

Cantilever retaining wall vs. counterfort retaining wall

Cantilever retaining wall vs. counterfort retaining wall

(OP)
I've been requested to design a salt storage shed will a 10'-0" tall concrete retaining wall.  The stucture sits on top of the retaining wall.  The retaining wall shall resist the forces for the salt/sand material and also forces from equipment.  Any ideas on what sort of lateral loads shall be used for the loaders loading the material?  It has been suggested to design the walls with counterforts or buttresses.  What are the advantages of butresses?  With butresses the concrete wall is designed to span horizontally between butresses.  Is this correct?

Thanks for the help.

RE: Cantilever retaining wall vs. counterfort retaining wall

It is much more expensive with build with buttresses. This is why most walls are designed as cantilever these days.

csd

RE: Cantilever retaining wall vs. counterfort retaining wall

It is true that with butresses, the wall steel spans horizontally, and the increases with the depth of burial.

It is also true regarding the higher cost of a butressed wall due to the extra forming and extra time involved in the construction of the wall.

Mike McCann
McCann Engineering

RE: Cantilever retaining wall vs. counterfort retaining wall

I have designed cantilever, buttress & counterfort walls up to 10 m depth.

Checking several designs (some years ago), the optimum maximum height for a cantilever wall was about 6 m (about 20 ft).  After that, counterfort or buttresses.

Counterfort if you require an open area (for a spillway with water, or for a loading area where you require a clear floor with no obstructions).

Buttress is usually cheaper (fins are in compression, not tension) for the same height compared with counterfort, however, a counterfort has the additional earth load on the the heel slab for overturning efficiency.

You really have to do the sums for your local conditions (local construction costs, type of backfill, cost of materials etc etc).

As far as design is concerned (for the front wall of counterfort & buttress walls), use 'Moments & Reactions for Rectangular Plates' a water resources technical publication 27.

Have a look at my answer to flat plate design in thread181-27567 for more info (for a rectangular tank).

As far as loads are concerned, why not design the wall for an extra 0.5 m or 1 m of fill (also checking on angle of repose of the fill material etc) to take care of construction loads?  This method is acceptable (& relatively easy), in some bridge codes (abutment wall design).

RE: Cantilever retaining wall vs. counterfort retaining wall

Sorry about that - I just read bridgebuster's answer above (I should have done that first, before starting to write).
That would have saved me some work.
Check that thread for finding the detailed info on rectangular plate design

RE: Cantilever retaining wall vs. counterfort retaining wall

To accomodate the loaders I would consider using a construction type surcharge (I assume we are talking about loaders running around the structure) I think this is typically 80 psf.  I don't have my IBC on me though.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources