able 1607.1 sidewalk 8,000 lb point load

huangyhg

table 1607.1 sidewalk 8,000 lb point load
i have a simple 4' wall in the row of a typical 36' street, the curb is 7' from the back of wall.  gonna do a keystone wall.  i used the rankine method of analysis, not ncma (conservative).
ibc table 1607.1, "sidewalk etc. ..."   specifies that a 8,000 lb. point load on 20 sq. inches is required.  this loading is required for the city of "la la land"'s retaining wall next to a city street per the design manual.
i pointed out that the city sidewalk couldn't handle that kind of point load let alone the soil 1' from the wall. first i showed them that the standard 4" thick city sidewalk couldn't be shown to support an 8k load over 20 inches square. i then pointed out that the necessary soil bearing strength calcs out to be 58 ksf, and that no soil i know can do this.
i am at a loss here.  i have succombed to the city and provided for 1000 psf ll.  i don't know the reasoning nor the impetus behind this requirement.  do you?
thank you.
e.j.
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trucks drive up onto sidewalks.
i dont know how many times i see semis drive over a side walk to make the tight turn.  city worker trucks drive over side walk all the time, almost like cops that think they can park anywhere.
to quote an architect i used to know:
arguing with a building official is like getting into a mud pit wrestling match with a pig. you will get muddy, mad and frustrated unless you realize one thing: the pig likes to wrestle.
a bousinesque (spelling suspect here) analysis will help you deal with the local lateral surcharge pressures due to wheel point loading.  it's not hard and i would probably "push" the numbers (unconservatively) for the transient vehicular load.  
i would also research whether they also want a guardrail for a 4' drop. guardrail forces will govern the design of most any retaining wall structure.  
the pig does not like to wrestle, the pig is used arguing with people wanting the code to be ignored without going through the appeal process.  the building official has no authority to deviate from the code.
don phillips