Anchor Rods
Anchor Rods
(OP)
What's the most common practice for applying tension during construction of an anchored sheet pile wall (waterfront bulkhead)? Anchorage is a steel anchor rod, with end nuts, attached to a concrete deadman.
Is it: a) tighten the end nut at the wale? b) tension the anchor rods by means of a turnbuckle somewhere between the wall and the deadman? or c)who cares because the wall isn't going to move that much.
I say it's "b" - use the turnbuckle.
Is it: a) tighten the end nut at the wale? b) tension the anchor rods by means of a turnbuckle somewhere between the wall and the deadman? or c)who cares because the wall isn't going to move that much.
I say it's "b" - use the turnbuckle.





RE: Anchor Rods
The general testing procedure might be similar for anchored sheet pile bulkheads, but in lieu of a hydraulic jack the turnbuckle could be used with strain gauges on the anchor rod. You would also need to measure deflection of the sheet piles and possibly the deadman.
The need for such intensive testing is that, even when many anchors are used, the whole retaining system might not have enough redundancy to withstand failure of a single anchor. If a single anchor fails the whole bulkhead system can "unzip." Their are different degrees of failure, but what may seem to be insignificant movement could cause reorientation of loads thereby overstressing critical elements of the system.
You could overdesign the anchors with a higher margin of safety and feel better about not testing, but the cost of the overdesigned system might far exceed the expense of a thorough testing program.
RE: Anchor Rods
Question(s): assuming "tiebacks" mean grouted soil or rock or similar anchors, my understanding is that tension is applied at the sheet pile/tieback connection for these kinds of anchors as there's no place for a turnbuckle, really. In my case, the steel anchor rod's connection to the sheet pile is by an end nut and a plate (washer). The only way to apply measured tension to the anchor rod is by a turning the end nut with a torque wrench or similar tool.
In my case, and here's more information, I'm in an argument with the designer who's challenged my assertion that a turnbuckle at the midpoint between deadman and sheet pile wall is the proper way to go. He believes the all that's required is the end nut to which enough tension can be applied - by visual observation alone. He also asked me "...do you think the wall will move that much...?" He design load is 20 kips, how he's going to get that much without poper measurement is beyond me...
RE: Anchor Rods
RE: Anchor Rods
How does one attach a jack to apply the tension in the case I've described? I found good information (i.e., installation photos) at www.earthanchor.com, but it's related to their Manta Ray product, a driven anchorage system, rather than the two-piece anchor rod I've described. What I've found on other sites (e.g., the Corus Geotechnical site) is that postensioning the anchorage is by tightening the turnbuckle. Any recommended books, web sites with photographs of anchored sheet pile bulkhead construciton would be most appreciated.
RE: Anchor Rods
RE: Anchor Rods
I'm not sure I understand that, though. Are you saying that the jack would apply tension to the anchor rod at the sheet pile wall? Would a turnbuckle even be used, then?
RE: Anchor Rods
RE: Anchor Rods
Good Luck!