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

AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock

AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock

AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock

I am developing a MathCAD worksheet to provide a design check for temporary shoring using soldier piles and timber lagging. I have a copy of AASHTO 2010 and would like to develop the solution for the configuration shown in Figure, which is for a discrete vertical wall element embedded in rock (see attachment).
The free body diagram shown in the figure shows the earth pressure distributions above and below the dredge line and the resultant forces, which I am able to use for the solution of the embedment depth, D; however, there is a force, F shown at the base of the rock socket which is defined in the spec. as "force at base of nongravity cantilevered wall required to provide force equilibrium (kip/ft)", which can be solved for, but I am not sure how to evaluate the capacity of the rock socket to safely distribute the force into the surrounding material, which in this case is the rock.

Your comments and suggestions are appreciated.

RE: AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock


required to provide force equilibrium

Doesn't that mean "sum forces and moment at the bottom equal to zero"?

RE: AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock

I had the same dilemma the first time I used the diagram for a design. It turns out that the force "F" doesn't actually exist. It's only there to make the numbers work for the model. The method itself is a simplified linear approximation of a non-linear analysis, so as I understand it, it never works out where the forces and moments can both be in equilibrium at the same time.

It's as retired13 alluded to - you find the embedment depth where the sum of the moments equals zero, and you add a force at the point where you summed the moments in order to satisfy the sum of the forces equal to zero.

Rod Smith, P.E., The artist formerly known as HotRod10

RE: AASHTO Nongravity Cantilevered Walls - Soldier Piles w/ Timber Lagging Embedded in Rock

Read about Wayne C. Teng's Simplified Method for cantilevered sheeting on Page 359 in Foundation Design, 1962. Teng calls the force "C" and calculates the overturning moment about the tip of the sheeting where he applies the force. Therefore, C does not enter into the moment calculation.


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 - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. 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