D-Load calculation

[cvg]

I am working on D-Load calculations, using the older Marston formula and not the newer methodology. Standard says to use a "Dead Load Factor of 1.9", however I can't find any reference to this factor in any of the equations. It seems very conservative to multiply earth loads by 1.9, but this seems to be the requirement. I wonder if maybe it is a "bedding factor" which could be assumed to be 1.9. Any thoughts?

 

[civilperson]

Is live load traffic/surcharge considered separately?

 

[cvg]

yes and the other loads are fill or embankment loads (sometimes may be referred to as dead loads) no "dead load factor" shows up in the literature I have reviewed. For instance, City of Los Angeles Design Manual does not show a dead load factor - see link below.

http://eng.lacity.org/techdocs/str-man/h-300.pdf