Sheet piling waler system design
Sheet piling waler system design
(OP)
I am designing an unusual waler system for an L shaped sheet pile wall. The waler system consists of two beams welded along the sheet piles near the top, one on each leg of the "L". There is a corner brace that spans between the two beams, making each beam what I would call "simply supported with a cantilevered overhang". The beams welded on the sheet piles will support the anchor force and be in flexure. The corner brace will be in compression. Determining the moments in the support beams is easy enough--they can be modeled as a beam on two supports with an overhang. The compression in the corner brace is the issue.
I attempted to model this in an FEA program as a simple frame, but in its current state, it's underconstrained. The unbalanced loading (as a result of the difference in length of the sides of the L) causes the frame to spin. If I fix one of the joints between a waler and the corner brace, the reaction force is all absorbed by the node fixity rather than the brace.
Any way to go about modeling this or simplifying it better, or tips on where else I can constrain my model?
If not, can I just run two simple beam analyses for each waler and design the brace for the largest reaction at the brace?
A pic of the basic layout for reference (without supports of loads shown):

Frame model:
I attempted to model this in an FEA program as a simple frame, but in its current state, it's underconstrained. The unbalanced loading (as a result of the difference in length of the sides of the L) causes the frame to spin. If I fix one of the joints between a waler and the corner brace, the reaction force is all absorbed by the node fixity rather than the brace.
Any way to go about modeling this or simplifying it better, or tips on where else I can constrain my model?
If not, can I just run two simple beam analyses for each waler and design the brace for the largest reaction at the brace?
A pic of the basic layout for reference (without supports of loads shown):

Frame model:






RE: Sheet piling waler system design
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RE: Sheet piling waler system design
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.
RE: Sheet piling waler system design
KootK - I've actually tried adding axial restraint to the walers (representing the weld to the sheeting) and I still get an unconstrained model and massive deflections. I need to somehow model the effect of the soil on the back sides of the wall restraining the walers from moving in that direction. The soil is really the complicating factor in all this.
RE: Sheet piling waler system design
This method should work and is appropriate in opinion. You would add an XY translational pin to one end of the brace, get your numbers, and then move the pin to the other end of the brace. Or, if you just want the worst case result, just pin the end of the brace where the cantilever is longest.
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.
RE: Sheet piling waler system design
RE: Sheet piling waler system design
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.