Concrete valve box

[LearnerN]

What are some good resources for designing a concrete valve box that would have normal traffic loads driving over it? OR how would you approach designing one? Thank you.

 

[BUGGAR]

There's an ASTM spec which covers pressures on underground vaults. I'll look it up tonight.

 

[LearnerN]

Would the best analysis approach to the design be the following? (1) Determine soil and traffic loads on top of box, and treat the top of box as a beam with end reactions on 2 walls of the box (conservative and simplified for calculations). (2) Design walls and base of box as a retaining-wall/footing of sorts. Moment and vertical loads on the top of the walls, active earth pressure against the box walls. And then base determined by shear, soil pressure, etc. And then use the same wall reinforcement all around, making sure development length is adequate. Does that sound like a reasonable approach?

 

[LearnerN]

BUGGAR: thank you for checking on that ASTM spec.

 

[BUGGAR]

I think it's ASTM C857
I couldn't find my copy of it.
Let a precaster buy you a copy.

 

[LearnerN]

"Let a precaster buy you a copy." Could you explain what you mean?

 

[BUGGAR]

I always write in our specs that suppliers have to furnish the engineer with shop drawings as well as all ASTM documents covering their product. This includes ACI 301. These projects are usually large enough that the cost of these codes is relatively small. I haven't bought a code book or ASTM spec in years.

 

[jayrod12]

Buggar,

That might be the best engineer life hack I've seen in a long time.

 

[BUGGAR]

Not only that, the last time the Contractor "erred", the Contract required that we analyze his proposal for repair using "such engineering tools as necessary for this work" per the Contract. With that phrase, the Contractor bought us the latest Risa 3d so we could analyze his scheme. It pays to write your own Contract Conditions.

 

[bridgebuster]

I can't get to my ASTM specs until Monday, but pretty much, it's just a slab supported by 4 walls. Check your state DOT publications. There should be guidance on manholes and underground structures. If not, go to the NYSDOT highway Design Manual.