Posted on by

Designing a Reinforced Concrete Retaining Wall

Introduction

Although retaining wall was the subject of the last post, their design was not covered. This post will focus on the design of reinforced concrete cantilever walls. There are three different forms of this type of wall, all of which are designed to resist overturning and sliding failure. The primary difference between them is their height. The taller the retaining wall, the more likely that counterforts and beams spanning between them will be necessary. This note describes how all of these forms of retaining wall can be designed.

Design Principles

Reinforced concrete retaining walls have to be able to support the forces that originate from the lateral earth and water pressures that exist within soils. They have to be sufficiently stiff, so not to let the retained material shift to the extent that it will cause the resultant force to move to a location that would cause the retaining wall to fail. It is because of this, as well as the magnitudes of the forces that are being exerted onto the retaining walls, that stiffening elements become necessary, in order to reduce the lateral movement of the wall at higher elevations.

For the shortest form of retaining wall, only two elements need to be designed; the wall and the base it is supported from. Both are subjected to high bending moments and shear forces and care must be taken to ensure that these are addressed. These are referred to as cantilever walls due to the monolithic connection they have with their base

When designing cantilever retaining walls, two separate checks are required. The first is the stability of the wall and the second is the design of the wall’s elements. Stability is dependent on its dimensions and how the various forces that are exerted onto the wall affect it. As with pad foundation design, it is preferable to ensure the resultant force from the soil and any surcharge placed upon it, lies within the middle-third of the base to the retaining wall. In instances where such a condition is not possible, there is likely to be an increase in the bearing stress applied to the soil due to the reduced area of contact between the base and the bearing strata. This is a result of the uplift that occurs in the base of the retaining wall, causing the area bearing onto the soil to be reduced

The combination of forces (when checking for stability) has been explained in the previous post on Analysis of retaining walls. All of the analysis so far described assumes that the consistency of the founding soil material is relatively well understood and uniform. In cases where there is significant doubt over the nature of the soil (due to a lack of site investigation survey data), further geotechnical analysis of the retaining wall’s impact on the soil profile is recommended. A good example of this would be a slip-circle mode of failure analysis.

It is also important to note that the design of retaining walls is very much an iterative process, with the various geometric elements altered until the entire structure complies with all of the design criteria. It is not unusual therefore, for engineers to design multiple wall configurations before an optimum solution is found.

Design of Elements

Cantilever retaining walls have the base designed as a slab with a concentrated bending moment where it interfaces with the retaining wall. It must also be designed to resist the effects of soil pressures, from both the retaining wall and the soil on which it is founded. The wall itself is a cantilever beam/ slab that is considered per metre length

Taller gravity retaining walls typically adopt the counterfort form of construction and their design can be broken down into simple components. The counterfort acts like a cantilevering beam and the retaining wall is a continuous slab supported by the counterforts. Where additional beams are included for taller walls, they are designed as continuous flanged beams that span between counterforts.

Steps in Designing a Cantilevered Retaining Wall

Establish all the design criteria based upon the building codes and compute all applied loads, soil pressures, seismic, wind, axial, surcharge, Impact and others.

Proportion the footing as described in the next section

Check stability of the wall for overturning and sliding: A key or adjusting the footing width may be required.

Calculate the eccentricity of the footing or take moment about the centerline of the stem. Verify if it is within or outside the middle-third of the footing width.

Calculate the soil pressure at the toe and heel (must be less than the allowable bearing pressure)

Design the stem and the base for flexure and select reinforcing 

Proportioning Pointers

The width of the footing for most conditions will approximately be 2/3 of the retained height.

It is usually most advantageous to have more of the footing width on the heel side of the stem. This will put more soil weight on the heel to improve sliding and overturning resistance.

If there is a property line on the toe side try to keep at least some width for additional soil weight, otherwise you’ll have a sliding problem

If you need a key for sliding resistance, try to keep its depth less than one-fourth of the retained height

If there is a property line on the toe side, the footing may need to be wider because soil pressures are usually greater at the toe

Worked Example

A worked example have been carried out to BScode & Eurocode kindly click on the link to view and download.

http://structurescentre.xyz/cantilever_retaining_wall_to_bscodes1/
http://structurescentre.xyz/cantilever_retaining_wall_to_eurocode1/

Thankyou for Visiting Structures Centre!!!

Published by Omotoriogun Victor

A dedicated, passion-driven and highly skilled engineer with extensive knowledge in research, construction and structural design of civil engineering structures to several codes of practices

4,518 Replies to “Designing a Reinforced Concrete Retaining Wall”

  6. Hi there! This post couldn챠t be written any better! Reading through this article reminds me of my previous roommate! He constantly kept preaching about this. I am going to forward this article to him. Pretty sure he’ll have a great read. Many thanks for sharing!

    Reply

  8. Good post. I learn something new and challenging on blogs I
    stumbleupon everyday. It will always be useful to read articles from other authors and use something from other
    websites.

    my website; Loretta

    Reply

  9. Everything is very open with a clear description of the challenges.
    It was truly informative. Your site is extremely helpful.
    Many thanks for sharing!

    Also visit my web-site; Tia

    Reply

  12. Howdy! This blog post couldn’t be written any better!

    Going through this article reminds me of my
    previous roommate! He always kept preaching about this.
    I’ll send this information to him. Pretty sure he’s going
    to have a very good read. I appreciate you for sharing!

    my page … casino4d.online

    Reply

  14. I simply couldn’t go away your website before suggesting that I extremely loved the
    usual information a person supply in your visitors?
    Is going to be again frequently to investigate cross-check new posts

    Here is my webpage :: Angelita

    Reply

  178. I’ve been browsing online greater than 3 hours as of late, but I by no means
    discovered any fascinating article like yours. It is pretty value sufficient for me.
    In my opinion, if all website owners and bloggers made good content material as you did, the net will probably
    be a lot more useful than ever before.

    Reply

  215. Very nice post. I just stumbled upon your weblog and wanted to say that I have really enjoyed browsing your blog posts.
    After all I’ll be subscribing to your rss feed and I hope you write again very soon!

    Reply

  260. With havin so much content do you ever run into any issues of plagorism or copyright infringement?
    My website has a lot of unique content I’ve either created myself or outsourced but it appears a lot of it is popping it up all over the internet without
    my authorization. Do you know any techniques to help
    reduce content from being ripped off? I’d definitely appreciate it.

    Reply

  267. Thank you, I’ve recently been searching for info
    about this topic for a long time and yours is the greatest I have discovered so far.
    But, what about the conclusion? Are you sure
    about the supply?

    Reply

  271. Thank you a lot for sharing this with all people you actually know what you’re speaking approximately!
    Bookmarked. Kindly also visit my site =). We could have a hyperlink exchange
    agreement between us

    Reply

  284. With havin so much content and articles do you ever run into any issues of plagorism or copyright violation? My blog has
    a lot of unique content I’ve either written myself or
    outsourced but it appears a lot of it is popping it up all over the
    web without my authorization. Do you know any solutions to
    help stop content from being ripped off? I’d certainly appreciate it.

    Reply

  287. Hello, I think your website might be having browser compatibility issues.
    When I look at your blog in Safari, it looks fine
    but when opening in Internet Explorer, it has some overlapping.
    I just wanted to give you a quick heads up! Other then that, awesome
    blog!

    Reply

  302. Thanks for the marvelous posting! I certainly enjoyed
    reading it, you happen to be a great author.I will ensure that I bookmark your blog and definitely
    will come back sometime soon. I want to encourage yourself to continue your great work, have a nice morning!

    Reply

  613. Valuable info. Lucky me I found your website by accident,
    and I am surprised why this accident didn’t took place earlier!
    I bookmarked it.

    Reply

  659. I don’t even know how I stopped up right here, however I believed this submit was great.
    I do not realize who you might be however definitely you are going to
    a well-known blogger if you aren’t already.
    Cheers!

    Reply

  699. Right here is the perfect webpage for anybody who hopes to understand
    this topic. You realize so much its almost tough to argue with you (not that
    I actually would want to…HaHa). You definitely put a new spin on a topic
    that’s been discussed for ages. Wonderful stuff, just great!

    Reply

  705. Hey! Someone in my Facebook group shared this website with us
    so I came to check it out. I’m definitely loving the information. I’m book-marking and will be tweeting this to my
    followers! Outstanding blog and outstanding design and style.

    Reply

  716. I’m really impressed with your writing abilities and also with the layout on your blog.
    Is that this a paid theme or did you customize it yourself?
    Either way keep up the excellent high quality writing, it is uncommon to peer a nice blog like this one today..

    Reply

  731. What i don’t realize is in fact how you are now not really a lot more neatly-preferred than you may be now.
    You are very intelligent. You understand thus considerably when it comes to
    this subject, made me personally consider it from a lot of numerous
    angles. Its like men and women are not interested until it is one thing to
    accomplish with Woman gaga! Your personal stuffs excellent.
    Always take care of it up!

    Reply

  738. It is the best time to make some plans for the long run and it’s
    time to be happy. I have learn this submit and if I could
    I wish to suggest you few attention-grabbing issues or suggestions.
    Maybe you can write subsequent articles referring to this article.

    I desire to read more issues about it!

    Reply

  1228. I’m curious to find out what blog platform you happen to be using?
    I’m experiencing some minor security issues with my latest
    blog and I’d like to find something more secure. Do you have any suggestions?

    Reply
  1455. Pingback: hovden zovirax

  2196. Admiring the commitment you put into your site
    and detailed information you present. It’s nice to come across a blog every once
    in a while that isn’t the same unwanted rehashed material.
    Excellent read! I’ve bookmarked your site and I’m including your RSS feeds to my Google account.

    Reply

  2835. Hey there are using WordPress for your site platform?
    I’m new to the blog world but I’m trying to get started and create my own. Do you need any coding
    knowledge to make your own blog? Any help would be greatly appreciated!

    Reply

  3021. Great web site you have here.. It’s difficult to find high
    quality writing like yours nowadays. I truly appreciate people like
    you! Take care!!

    Reply