Single Row Piles question

[JStructsteel]

anyone have any insight for a retaining wall on piles, and every other pile would be battered to take the lateral load. What are your thoughts on doing this? I figure if the vertical pile takes some lateral load and deflects, then the battered piles would be engaged.

 

[KootK]

I've done something similar. The detailing is much more intensive than it is with a regular retaining wall as it becomes a system characterized by localized forces rather than distributed forces. Punching shear, anchorage, and all that jazz. Mine have been on two rows of piles. Are you putting the single row near the heel or the toe? What's driving the use of piles?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[JStructsteel]

Its bad soils, so i assume settlement. I am just in prelim design phase. The more I think of it, the harder it will be, I would have to develop a moment connection at the pile to ensure stability. Location would be towards the center of the pile cap.

 

[KootK]

Ah, I was thinking of something different. Other than the battered piles, I think it's a pretty common system. You just need a healthy grade beam to deal with the torsion and the pile moment connections. And the lateral load between batter piles I guess.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jdgengineer]

How tall is the retaining wall? For relatively shallow retaining walls, we do just a single row of piers that are designed for moment (similar to philosophy for soldier beam retaining wall). The gradebeam would be sized and detailed for torsion (or preferably we size gradebeam to be below threshold torsion so no torsional detailing is needed).

If the retaining wall is tall, we would provide two rows of piers to form a moment couple. Is there a reason you can investigate either of these options? Space?

Can you do a tieback instead of a battered pile?

 

[SlideRuleEra]

Cantilevered vertical piled waterfront bulkheads, with or without tiebacks and no gradebeam, are common on the southeast US coast. Being on the water, the piles can be jetted without bringing in true pile driving equipment. For modest heights, should work well for inland areas, too, but pile driving equipment needed:

IMHO, alternating vertical and battered piling would be a nightmare to construct. Just add more vertical piles if needed. Much of the cost of pile driving is equipment mobilization. Once that is done, adding more piling is usually cost effective.
If battered piles are desired, or required, pair all of them with vertical piles. This will keep all horizontal deflections essentially the same, making a better looking finished product.

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[JStructsteel]

8'-12' walls, the soil is not good enough for any passive pressure, thus the battered. Im more concerned the non battered pile taking lateral load, but as mentioned it would deflect and the battered pile would pick up the slack.
Thanks

 

[KootK]

When the battered piles get loaded, they will create an uplift demand on the system that may need to be at least partially resisted by the wall and the vertical piles. Just something to keep an eye on.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jdgengineer]

Tiebacks or helicals instead of battered piles?

 

[Teguci]

Are you using the backfill above the grade beam/pile cap to resist overturning?