Single Pipe Piling Question

[maweilian]

I am working on calculating the maximum allowable lateral working load that may be applied to a marine bollard that is sitting on top of a foundation that has a single pipe piling set 25ft deep. I have used Broms Method and the CLM2.0 spreadsheet to arrive at similar values. However, the bollard sits at the top of a tall river embankment. Thus, the riprap slope drops off in front of the bollard towards the river. The lateral force would come from vessel mooring lines and would therefore be pulling in the direction of the dropoff. My question is this: how far back must the bollard sit from the edge of the embankment for the maximum allowable loads I have calculated to be valid?

Thanks,
Will

 

[BigH]

I would say the passive pressure must exit before the dropoff or you must reduce the passive pressure that acts.

 

[maweilian]

BigH,

Thanks for the response. It is helpful.

Looking at this problem from another perspective. Suppose we drove the piling at the top of the riprap slope with little or no offset back from the edge. This would then essentially reduce to a problem of a single piling under lateral load driven into a slope. I would then need to find the minimum embedment to achieve a particular lateral working load. However, all the material I have found so far applies only to level ground. Can you (or anyone else) point me to a method (analytical or numerical, i.e. computer program or spreadsheet) that would allow me to solve this problem of a single pile under lateral load driven into sloped ground.

Thanks, Will