westergaard slab on grade soil bearing pressure
 

westergaard slab on grade soil bearing pressure
can anyone verify with a 3,000 pound wheel load in the center of a 5 inch slab on grade that it transmits a maximum soil bearing pressure of just 150 psf. westergaards formula is based on a radius of relative stiffness and a soil modulus. the soil k value i used was 300pci. any tips will be greatly appreciated.
running a quick elastic layer analysis, i get about 400 psf, considering a concrete modulus of 3,000 ksi and a soil modulus 20 ksi.
your k value of 300 pci is relatively high. what type of subbase soil do you have?
i know there is a difference between the two formulas. i used a conc. modulus of 3500 ksi and a 12 inch compacted gravel sub-base. the distance that the load transmits laterally on the soil varies from 2 to 3 times the radius of relative stiffness or around 3 to 4 feet. i think its similar to soils whereby the internal friction angle decays the original load. in this case its on the order of 10x to 20x less. close enough.