Deflections, Stresses, and Strains

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Deflections, Stresses, and Strains
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Schematic of Load Deflection
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FWD Load Plate Sensors
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Hogg Subgrade Modulus
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Composite Pavement Modulus
Eo (1.5 a ?o) / do
Eo composite modulus of the entire
pavement system beneath the load plate
a radius of FWD load plate ?o
(peak) pressure of FWD load under the plate
do (peak) center FWD deflection reading
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36 AREA
A36 6 ? 1 2(d12/d0) 2(d24/d0) (d36/d0)
A36 36 if perfectly rigid (E1
infinity) A36 11.04 if E1 E2 (assuming no
bedrock) For forwardcalculation purposes,
only works well for rigid pavements
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12 AREA
A12 2 ? 2 3(d8/d0) (d12/d0) A12 12 if
perfectly rigid (E1 infinity) A12 6.85 if E1
E2 (assuming bedrock) For
forwardcalculation purposes, only works well for
flexible pavements
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Forwardcalculated Modulus of PCC Layer
EPCC Eo ? AFPCC ? k3(1/AFpcc) / k32.38 where
AFPCC function of A36 and k3 constant
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Forwardcalculated Modulus of AC Layer
EAC Eo ? AFAC ? k3(1/AFac) / k32 where AFAC
function of A12 and k3 constant
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LTPP Section 04-1003 Lane F1, Sta. 475, Drop
Height 4
 
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LTPP Section 04-1003 Lane F1, Sta. 75, Drop
Height 4
 
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LTPP Section 13-4111 Lane F1, Sta. 250, Drop
Height 4
 
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LTPP Section 36-1011 Lane F3, Sta. 250, Drop
Height 4
 
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LTPP Section 20-1005 Lane F3, Sta. 400, Drop
Height 4
 
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LTPP Section 20-1005 Lane F3, Sta. 500, Drop
Height 4
 
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Asphalt Layer Moduli for 15 LTPP Test Sections
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Statistics for back- and forward-calculated
asphalt moduli for 15 LTPP flexible sections (all
test points)
 
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Subgrade Moduli for 15 LTPP Test Sections (AC)
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Statistics for back- and forward-calculated
subgrade moduli for 15 LTPP flexible sections
(all test points)
 
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Statistics for back- and forward-calculated
intermediate layer moduli for 15 LTPP flexible
sections