chapter 3 rigid pavement - DOT On-Line Publications - Department ...

tn considering the poterttial benefits from the us< oi zx:er.ced ?aveme2: jiakj,
their effec: on pavement deterioration should be recognized. In rhis secnon, jiab
stress, strain, deflection, and moist=lre infiltration are considered as they are :e!ated :o
extended KC slabs.
Stress and accumulated pavement fatigue are two parameters used to calc;ia:e
the damage done to a KC pavement by appiied loads. It is widely accepted that
“the most critical pavement stresses occur when the truck wheels are placed at or
near the pavement edge and midway between the joints.“‘” Since the critical stress
OCCWI at the mid-point of the panel, load transfer devices at transverse joints do not
have a great influence on the load stresses at the mid-panel. The effect of trucks
running at the pavement edge can be shown by the stress-fatigue analysis in figure
7.‘” The fatigue was calculated at various locations on the KC slab, inward from the
slab edge, for different truck wheel load placements. “This factor, when multiplied
by edge load stress, gives the same degree of fatigue consumption that would result
from a given truck piacement distribution.“n As the lateral truck wheel distribution
moves away from the PCC slab edge and inward on the slab, the total number of
’ load repetitions increases, but the damage due to stress decreases. As illustrated by
figure 7, the fatigue stress decreases as the percent trucks at the edge decreases:”
Equivalent Edge Stress Fac!or Versus
Percent of Trucks at Edge
?V,. “”
Reference #S
,i j
/
_ 1
Tafaqn 4 :x0 0.03 I
t
I Taragm 2 !ar3 0.6
Efery rpavec snfxicer) 5 CO 8
70 0 1 2 3’ 4 5 5 7 7.9
PEXEM TRUCKS AT EXE
S&l6