Laterally loaded Pile. Point of zero shear
Laterally loaded Pile. Point of zero shear
(OP)
This is a cross post. Not sure if thats frowned upon, but I know you structural folks will have good input:
Happy New Years Eave everyone. I have a question that I know is relatively basic, but I cant seem to wrap my head around.
At the most basic level of my design, I have a pile that will be embedded into native soil some distance to be determined. It will also be exposed about ground a distance of about 5.5 ft, and functioning as a retaining element of wall. I need to stress that this is a SMALL project and Im not looking for a rigorous driven pile analysis. for now using the embedded pole formula in Enercalc and the California Building Code is just fine. I am curious though how to approach a simplified bending design for the pile. My mentor gave me the following instructions before he left out of the country on vacation:
" Resolve the the forces on the retaining side of the wall such as active pressure, surcharge, wind load if applicable, into a resultant force. Do the same for the passive pressure side. Now determine the location of the point of zero shear. This is where the moment will be maximum. Design the post for bending based on this moment."
My confusion is that when I draw a simply picture of this scenario, I'm not sure what assumptions Im making in terms of where this pile is supported. Am I assuming pinned supports? If so where. As is, all I see is a vertical beam with two unequal loads, both of which will cause the pile to rotate counterclockwise.
Can you guys help me resolve this confusion?
Happy New Years Eave everyone. I have a question that I know is relatively basic, but I cant seem to wrap my head around.
At the most basic level of my design, I have a pile that will be embedded into native soil some distance to be determined. It will also be exposed about ground a distance of about 5.5 ft, and functioning as a retaining element of wall. I need to stress that this is a SMALL project and Im not looking for a rigorous driven pile analysis. for now using the embedded pole formula in Enercalc and the California Building Code is just fine. I am curious though how to approach a simplified bending design for the pile. My mentor gave me the following instructions before he left out of the country on vacation:
" Resolve the the forces on the retaining side of the wall such as active pressure, surcharge, wind load if applicable, into a resultant force. Do the same for the passive pressure side. Now determine the location of the point of zero shear. This is where the moment will be maximum. Design the post for bending based on this moment."
My confusion is that when I draw a simply picture of this scenario, I'm not sure what assumptions Im making in terms of where this pile is supported. Am I assuming pinned supports? If so where. As is, all I see is a vertical beam with two unequal loads, both of which will cause the pile to rotate counterclockwise.
Can you guys help me resolve this confusion?






RE: Laterally loaded Pile. Point of zero shear
RE: Laterally loaded Pile. Point of zero shear
Cheers
RE: Laterally loaded Pile. Point of zero shear
RE: Laterally loaded Pile. Point of zero shear
Perhaps the program RetainPro would do this design better, give the Enercalc guys a call because they own RetainPro now.
The problem with embedded "poles" on Enercalc is that it only analyzes the required embedment depth but not the "pole" itself
RE: Laterally loaded Pile. Point of zero shear
It is easy to say maximum moment occurs at zero shear, but how to determine zero shear is unknown in this situation.
RE: Laterally loaded Pile. Point of zero shear
Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin
RE: Laterally loaded Pile. Point of zero shear
Don't use 1/3 the embedment depth. Not a terrible number for a trial, but it varies with soil properties. Figure it out yourself based on the actual soil properties you are working with.
RE: Laterally loaded Pile. Point of zero shear
The pressure distribution shown by AELLC is about right, but an exact solution is not possible without considering the stiffness of the pile and the properties of the soil.
BA
RE: Laterally loaded Pile. Point of zero shear
Short piers often work in real life but it can sometimes be difficult to get the numbers in the analysis to work out, especially if you discount the first few feet of embedment since the soil is "disturbed".
One way to get the additional horizontal force BA mentions is through friction at the bottom of the pile. Of course, you need dependable vertical loads at the bottom of the pile to give you that friction force.
Sometimes I look at the old UBC method as a baseline, but I find that it yields fairly liberal results.