Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations GregLocock on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Active Anchor Earth Pressure

Status
Not open for further replies.

SteynvW

Civil/Environmental
Feb 1, 2016
108
Hi All

I currently have a situation where we are building next to a railway with a retaining wall between us (our property on the higher level). They require us to compile a report of what our structural effect/loadings it will add to the retaining wall. I have calculated this according to the relevant surcharges applicable to the area. They will ultimately decide whether or not the retaining wall can accommodate the load.

I just want to get a rough idea of how much of a influence my loadings will have. The retaining wall has active anchors, does this imply the that the passive soil pressure against wall (as it is being "pulled" into the soil) is a function of the tension the cables have in them?

Kind regards
 
Replies continue below

Recommended for you

What do you mean by "active anchors?" I have never heard of cables being used to anchor a retaining wall.

DaveAtkins
 
A sketch with offset distances and retaining wall heights with soil parameters would go a long way with getting better responses.

As a minimum foundations need to extend beneath the active soil wedge.

Or if you can review the retaining wall design and prove that the wall still have sufficnet FoS with your additional load. This wouldn't be my choice, I'd pile it
 
To answer this question, you need to know how close to the wall the new building will be, what the new footing loads will be, and at what elevation the new footings will bear. Then, you use the railroad-specified Boussinesq equation(s) for strip loads, area loads, line loads, or point loads (whichever your building may cause). Then you can compare the resulting lateral surcharge pressure(s) to the lateral surcharge pressure that the existing wall may have been designed for.
The anchors should not enter into your analysis unless the new, lateral, surcharge pressure(s) exceed the original design pressure. After you provide the new lateral surcharge pressure(s), I assume the railroad will tell you (as you mentioned above) if their wall, including the anchors, is OK.
If prestressed anchors are doing their job, they will be pushing the wall back more than the retained soils and surcharge are pushing the wall forward. If the anchors are not prestressed, they are holding only the load that is actually being applied.

 
Agree with PEinc, but back to DaveAtkins's question. Active anchors are prestressed, so typically use either prestressing strands or bars. Passive anchors are not prestressed.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor