×
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

Minimum Retaining Wall Height below which Design is not Required

Minimum Retaining Wall Height below which Design is not Required

Minimum Retaining Wall Height below which Design is not Required

(OP)
I am trying find some guidance stating minimum heights below which a design is not required for a retaining wall. For example, if a wall height is 3 in, 6 in, 9 in, etc. is a design required for a retaining wall? Appreciate your advice.

Thanks

RE: Minimum Retaining Wall Height below which Design is not Required

In Ontario(Canada), any retaining walls under 1.0m in height (39.4") are not considered a designated structure under the building code, therefore a design is not required.

RE: Minimum Retaining Wall Height below which Design is not Required

It varies a lot with jurisdiction. Where I am, the last time I looked, it was 1.2 metres. You see a lot of walls lean and some fall over, but if it is less than 1.2 metres, it normally won't kill you.

RE: Minimum Retaining Wall Height below which Design is not Required

I believe anything 4 feet or higher is the magic number but I haven't checked in a while.

RE: Minimum Retaining Wall Height below which Design is not Required

Under the IBC 2012, I don't think any wall is exempt from design (regardless of height). However that particular code does exempt walls that are not over 4' in height (measured from the bottom of the footing to the top of the wall) from requiring a permit (if they are not supporting a surcharge or retaining certain liquids).

RE: Minimum Retaining Wall Height below which Design is not Required

Measuring to the bottom of the footing is strange. After the fact, how is an inspector to know?

RE: Minimum Retaining Wall Height below which Design is not Required

Quote:

Measuring to the bottom of the footing is strange. After the fact, how is an inspector to know?

Get out the shovel I reckon. (Or guess.) wink

Wouldn't be that much different from a lot of other "inspections" I've seen.

RE: Minimum Retaining Wall Height below which Design is not Required

Here - 4 feet of finish grade difference.

Footings are a luxury.

Mike McCann, PE, SE (WA)


RE: Minimum Retaining Wall Height below which Design is not Required

But Mike, aren't you in IBC territory like WARose?

RE: Minimum Retaining Wall Height below which Design is not Required

Whether it needs permits- see above.
Whether it needs PE seal- would depend on the project it was on, not just on the wall.
Whether it needs design calculations- judgment issue, if in doubt, make up a spreadsheet with your typical or minimum dimensions/ reinforcement, and then see how high you can go before those don't work.
It is appropriate to say "Based on prior experience, design loads will not govern the dimensions or details" or however you care to word it.

Around here, I've seen a few low retaining walls that won't kill anybody, but long-term poor performance may mess up the foundation of the house that they are next to, so there could be some low liability even if there's no danger to life.

RE: Minimum Retaining Wall Height below which Design is not Required

Yes Hokie, but he was talking permit, not engineering. Some jurisdictions have their own pre approved standard details. Fall out of that scope, and you need engineering.

Mike McCann, PE, SE (WA)


RE: Minimum Retaining Wall Height below which Design is not Required

Here (central NC), the inspectors use 4 ft. I have no idea where they measure that from.

RE: Minimum Retaining Wall Height below which Design is not Required

IBC tables 1807.1.6 provides prescriptive design

RE: Minimum Retaining Wall Height below which Design is not Required

@Canuck65, can you provide the code references? I'd like to read it

RE: Minimum Retaining Wall Height below which Design is not Required

I'm not sure of your layout and where the wall is going, but could you change the name on your sheets to 'oversize curb' versus 'retaining wall'? That might attract less scrutiny by building officials.

RE: Minimum Retaining Wall Height below which Design is not Required

@Shotzie,

OBC, Division A, Part 1 (Compliance and General), cl. 1.1.2.2(2)c states (paraphrased):

Parts 3, 4, 5 and 6 apply to (c) a retaining wall exceeding 1000mm in exposed height adjacent to, (i) public property, (ii) access to a building, or (iii) private property to which the public is admitted.

RE: Minimum Retaining Wall Height below which Design is not Required

@Shotzie,

Also repeated in Division A, Part 1, 1.3.1.1 - Designated Structures

RE: Minimum Retaining Wall Height below which Design is not Required

@Canuck65, Very useful! Thanks for the references.

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