approach to check circular secant shaft with an unbalanced loading

[HanStrulo]

Hi everyone,

I am checking a circular secant shaft (I am new to secant shafts) with an unbalanced loading from heavy equipment at the top.

I found an example from a calculation note and it has the following approach (based on work by Burns and Richards (1964) and Peck et al (1971)):

1. calculate the moments due to the loads: the calculation used the ratio of pressure along two perpendicular directions to represent out of balance loading. This factor is used in lieu of the at rest lateral earth pressure coefficient.
2. calculate the moment resistance based on the ACI plain concrete chapter.

my question is: does anyone know anything about the ratio of pressure along two perpendicular directions. This is the first time I hear of it. Does anyone have an example calculation using this ratio? or an explanation of it? I assume it's based on the work by Burns and Richards (1964) and Peck et al (1971) but i could not find it online. If anyone has the papers, i would really appreciate it?

is there any other approaches to check for the integrity of the shaft using the unbalanced loading other the above mentioned approach.

Thank you,

 

[geotechguy1]

To me it sounds like a 3D FE problem

 

[HanStrulo]

yes. that is how I would do it too. However, the moment calculation I mentioned above is really handy for a quick check. Hence why I wanted to find out where it came from.

Thanks,

 

[PEinc]

Is this a temporary or permanent secant structure? What is the maximum excavation depth and how much is the imbalance from one side to the opposite? If a temporary secant structure, can you temporarily place some excavation spoils on the low side until the permanent structure is built?

http://www.PeirceEngineering.com