How would you design this storm Junction box
How would you design this storm Junction box
(OP)
Me and my colleague had an interesting conversation. We are designing the junction box highlighted in pink. All the way almost on the top of the photo is the FEMA 100 year flood elevation. My question is, how would you design the soil/water lateral force? How do you design the buoyancy (whether or not you need extended base). Where do you put the ground water elevation? I want to see what everyone's thought. The left pipe is existing, ther right pipe is new. The box inside dimension is roughly 8 ft x 12 ft x 21 ft tall.

RE: How would you design this storm Junction box
For the lateral forces we use PCA's Circular Concrete Tanks without Prestressing handbook. There is also a PCA rectangular tank manual, which would apply to you BUT, the rectangular manual has mostly tables in it. For a discussion of methodology, you want to refer to the Circular manual.
Both these manuals are getting a little old....I think the newest one is from the mid 1990s, but they are the only ones I am aware of.
Finally, we also design our reinforcement to ACI 350 standards, which makes the designs super-conservative.
RE: How would you design this storm Junction box
RE: How would you design this storm Junction box
I find that on these lift stations, and other civil structures people are very hesitant to change designs or methodologies. I think some things are just done because that's the way they have always been done.
In Houston and Southeast Texas, our clays are so wet, and the water tables are so shallow; that assuming the entire well/junction box is submerged is not an unreasonable assumption.
If you are in Denver, that might be an excessively conservative assumption though. Does the water table move up and down? If you do not have to worry about that, then you definitely have a valid point on the design being too conservative.
RE: How would you design this storm Junction box
RE: How would you design this storm Junction box
A lot of our roadway and land people do junction box designs. I'll ask them what elevations they run water to..
RE: How would you design this storm Junction box
RE: How would you design this storm Junction box