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

Modeling a Soldier Pile Wall with Raker Support

Modeling a Soldier Pile Wall with Raker Support

Modeling a Soldier Pile Wall with Raker Support

Hi, I'm designing a soldier pile wall with raker support for a temporary 4m excavation in a medium dense silty sand (phi=30, c=0) using SAP2000 FEA software. The wide flange IPB section piles are to be buried in 1.0m height, 0.8m diameter cast in place reinforced piles below dredge line and the rakers are pinned UNP sections resting on 1m by 1m square footings of 0.5m height. Piles are to be placed with 3.0m spacing (Attached drawing).

I use Coloumb's theory for calculating lateral earth pressure diagram on piles, their concrete footings and the square footing that rakers rest on, as suggested by USS Steel Sheet Piling Design Manual, 1984. I use pined support at the button of each pile, assuming that it is the point of fixity of piles, (not sure if I'm doing it right though) and I use a rolled support in horizontal direction at the end of rakers, simulating square footing behavior, I then apply the resultant force of active, passive and friction force acting on square footing to this support in that direction (Attached drawing, The units shown are of KN and m).

1- Is there anything wrong about my assumptions on modeling the whole system or the soil pressure diagram?

2- I can find the required length of cast in place concrete pile below dredge line by simply doing external stability analysis, by taking moment of acting forces, including piles weight and their skin friction, about raker's resting point and putting M-R=M_D and solving for required depth of embedment of piles... but the question is, how can I find the point of fixity to put pinned support in my model? Does simply assuming that the pile is rotating about it's tail is a rational decision for you?

3- Does assuming a horizontal rolled support in rakers resting point and applying resultant horizontal forces on the square footing in that direction is a right procedure? If so, how do you think I can calculate the frictional horizontal force below square footing, without knowing exact vertical loading acting on it?

Unfortunately there is no thorough documentation about modeling raker supported soldier pile walls and many books just simply mention this type of supports without much talking about their behavior or design procedure or even about lateral earth pressure diagrams acting on them, so I will be thankful to you if you could help me complete designing my model.

RE: Modeling a Soldier Pile Wall with Raker Support

1) Look for Tergahzi and Peck's Apparent pressure diagrams for propped walls. It has been tested in the field and has produced more accurate results regarding the actual pressure seen by flexible walls.
2) The point of zero moment below the dredge line is where I would be placing the pinned support for the model. The canadian foundation engineering manual has information on determine that point for flexible cantilevered walls.
3) My feeling is your raker footing may be undersized. I neglect friction and only rely on passive pressures to restrain the raker.

Keep in mind the extreme uplift that is induced into your soldier piles from the raker. Your 1m deep plug likely won't have enough restraint. I know it seems odd to picture the soldier coming out of the ground but when you perform the force balance of the system the uplift is there.

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! Already a Member? Login


White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why it’s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now
White Paper - Moving to a Driverless Future
This white paper describes what we see as the best practices to support a sustainable engineering process for autonomous vehicle design. It exposes how to use simulation and testing in common frameworks to enable design exploration, verification and validation for the development of autonomous cars at a system, software and full-vehicle level to drive a mature product development process for automated driving. Download Now
Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close