FAA Pavement Design: AC 150/5320-6E – FAARFIELD

109 Pages·2009·3.38 MB·English

FAA Pavement Design: AC
150/5320-6E – FAARFIELD
2009 PCC Workshop
Indiana Chapter – American
Concrete Pavement Association
January 27, 2009
Gary L. Mitchell, P.E.
Director of Airports and Pavement Technology
American Concrete Pavement Association
FAA Pavement Design
AC 150/5320-6E, Airport Pavement Design and
Evaluation
Completely revised in 2008
–
New design methodologies for Rigid and Flexible
–
pavements
Software dependent design procedures
–
Addresses modern airplane parameters
–
Chapter 2
Soil Investigations and
Evaluation
Chapter 2
Soil Investigations and Evaluation
Very few significant changes
Still uses Unified Soil Classification (USC) system
Reference to ASTM 2487
60
GW CL
GP ML 50
)
I
GM OL P
(
X 40
GC CH E
D
N
SW MH Y I 30
T
I
SP OH C
I
T
S 20
SM PT A
L
P
SC MH - OH
10
CL - ML ML - OH
0
0 10 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT (LL)
Chapter 2
Soil Investigations and Evaluation
Same minimum subsurface boring recommendations
Same soil testing recommendations
AREA Minimum spacing Minimum depth
RWY/TWY 200 ft interval 10 ft
Other areas 1 per 10,000 sq ft 10 ft
Borrow areas As necessary As necessary
Chapter 2
Soil Investigations and Evaluation
Continues to split soil compaction requirements
based upon 60,000 lb gross weight airplane
< 60,000 ASTM D 698 Standard Proctor
> 60,000 ASTM D 1557 Modified Proctor
Chapter 2
Soil Investigations and Evaluation
Soil Strength Parameter for RIGID pavement
Resilient Modulus E (psi) or
Modulus of Subgrade Reaction – k-value (pci)
Design value – “conservative selection”
K-value can be estimated from CBR
0.7788
⎡1500× CBR ⎤
k =
⎢ ⎥
26 (k in pci)
⎣ ⎦
Chapter 2
Soil Investigations and Evaluation
Modulus of Subgrade Reaction – k-value (pci)
Removed the statement:
•
“Rigid pavement is not too sensitive to k-value and an error in
estimating k will not have a large impact on rigid pavement
thickness”
Design comparisons show that FAAFIELD thickness design is
more sensitive to k-value (converted to E) than the previous
Westergaard-based procedure.
Chapter 2
Soil Investigations and Evaluation
Soil Strength Parameter for RIGID pavement
k-value (pci)
With the 3D finite element design procedure
the sensitivity of k-value to rigid design is
increased. Errors in selection of k-value can
generate noticeable changes in the required
pavement thickness.
24
) 22
n
i K = 200
(
s 20
PCC = 16.14
s
e
18
n
k
c 16
i
h
t 14 K = 150
C
C
12 PCC = 17.38
P
10
0 50 100 150 200 250 300 350 400
Example not indicative of all situations
k-value
Chapter 2
Soil Investigations and Evaluation
Seasonal Frost
Same Frost Groups (FG-1, FG-2, FG-3 & FG-4)
Determination of Depth of Frost Penetration
Based on local Engineering experience
i.e. local construction practice, building codes, etc.
No nomographs or programs provided