My guess is that the 1807.3 provisions are included in IBC because, as you said, they are simpler and more conservative.
I am not familiar with the ASABE method, but I have used the P-y analysis described in a paper entitled "Lateral Load Analysis of Single Piles and Drilled Shafts," by Duncan...
It sounds like you are talking about the overburden above the footing, outside of the arch culvert. I would consider that load, as it will not be balanced by soil on the inside of the culvert.
DaveAtkins
Water pressure should definitely be included in the design. But is the box buried? If so, the external soil pressure on the box will probably control during construction, when the box is empty.
DaveAtkins
I would think the deflection of a pile would be unacceptable long before the pile failed. So I think the service deflection controls, not the ultimate strength of the pile or soil.
DaveAtkins
Subparagraph d clearly prohibits the reduction for hooked bars. This got me to thinking how I could have missed that. I have ACI 318-14, and that exception is not in there! So it previously was allowed (although I don't disagree with KootK that an argument can be made to the contrary).
It...
I think it can be, although subparagraph (a) gives me pause. It says reduction is prohibited "At noncontinuous supports." To be honest, I have never noticed that exception before. Was it added in more recent versions of ACI?
That being said, I don't think a retaining wall stem is...
I think it will be OK. If the pipe begins to deform, the footing will carry the load to either side of the pipe. And as you implied, the footing is oversized for downward bearing pressure.
DaveAtkins
You're not referring to KootK, are you[wink]
My opinion is that if the straight bar gets the moment from the stem wall into the footing, and the horizontal footing reinforcing is developed on both sides of the stem wall, then all should be well.
HOWEVER--I learned from KootK that there is full...
No, the moment arm is to the centroid of the resisting soil pressure (shown as R1 on the diagram), not where the soil pressure is zero. My original post is correct.
DaveAtkins
NBRY1,
I do not understand your question about uncertainties in soil behavior. I thought you were asking about the factor of safety against uplift, which has nothing to do with soil behavior. Just dead load versus wind load uplift.
DaveAtkins
The 0.6D load combination uses a reduced dead load which automatically results in a factor of safety of 1/0.6 = 1.67. No additional checks of factor of safety against uplift are required.
DaveAtkins
The ASCE load combinations include a combination with 0.6D. This load combination automatically gives you a factor of safety > 1.5 for wind load uplift.
DaveAtkins
I have always used service loads to check bearing pressure, because this is what geotechnical engineers use to predict settlement.
I only use LRFD (or USD) to design the concrete.
DaveAtkins