Vertical Component of Equivalent Fluid Pressure on Footing

[dabbler101]

I'm currently working on an abutment design for a bridge out in Lee, MA. In a couple of my load conditions the water table is above the top of footing.

Basically, the abutment footing is 3' thick; there is 5' of saturated soil above the footing, then 2' of dry soil above that.

The geotech report gives a single soil density of 120#/CF

I had planned on taking the (density of the soil in the dry times its respective area above the footing) and adding it to ((density of the soil minus the density of the water) times its respective area above the footing)...

Am I missing something? A coworker seems to think I have to account for the weight of water when it's surrounded by water???

Please advise…

 

[MotorCity]

If you are using the saturated unit weight, the weight of the water is already included in the soil and there is no need to account for the water separately. Verify the saturated unit weight w/ your geotech.