Re: Amazing facts

[Dave Simmons <SMTC45@UOFT02.UTOLEDO.EDU>]

> I once heard an engineer claim that (at least for northern climes) that if
> we could keep heavy trucks off the roads for three weeks after the spring
> 'thaw' we could eliminate the vast majority of road damage.  

In Ohio anyway much road damage is due to movement of the material 
underlying the actual pavement. One of the actions is called 
"pumping." Wet sand, clay, etc is squeezed out from under the pavement 
as a vehicle passes and this leaves a void. When pressure is again 
applied more material is "pumped out." Eventually the pavement gives 
way and a pothole forms. There are of course other mechanisms.

Have we answered the question of trucks vs cars though? If we can keep 
our pressures and forces straight, we should be able to calculate 
which tires exert more pressure. I would guess this is most damaging 
to a road surface. But, if we are talking about damage to a bridge or 
culvert perhaps total force (weight) is the culprit.

Any highway engineers listening?

Dave

*   				St. John's Jesuit High School          *
*  	 David A. Simmons	      5901 Airport Highway             *
*   <smtc45@uoft02.utoledo.edu>  	Toledo OH 43615                *