introducing federal aviation faarfield 1 1_4 examples...pavement design procedures flexible pavement...

Presented to:

By:

Date:

Federal AviationAdministration

Introducing

FAARFIELD 1.42: Latest Updates to FAA Airport

Pavement Design Procedures

Flexible Pavement Examples

IX ALACPA Seminar on Airport Pavements

Quito, Ecuador

David R. Brill, P.E., Ph.D.

30 May 2018


Starting Screen – No Job Files Created

May 30, 2018 FAARFIELD Design Examples 2

Click on “New Job”


Creating/Naming a Job File


Enter Job Title

Click OK


Copy Basic Section/Pavement

Type from Samples


Click on “Samples”


7 Basic Starting Structures in FAARFIELD

Section Name Pavement Type

ACAggregate New flexible on aggregate base

AConFlex HMA overlay on flexible pavement

AConRigid HMA overlay on rigid pavement

NewFlexible New flexible on stabilized base

New Rigid New rigid on stabilized base

PCConFlex PCC Overlay on flexible

PCConRigid Unbonded PCC on rigid


Select the pavement type that most correctly represents your design

requirements.


New Flexible Example Set-Up


Create a new section

in job PROJECT by

dragging section

NewFlexible in

Samples to PROJECT.


Select Metric Option



New Flexible Pavement Design Example

• Initial Pavement Structure:

– HMA Surface, P-401, 100 mm thick

– HMA Stabilized Base, P-403, 150 mmthick

– Crushed Aggregate Base, P-209 (design layer)

– Subgrade CBR = 5

• Traffic Mix:

– 5-Aircraft Mix includes B777, A340, A380

– Use the traffic mix on the next slide.



Traffic Mix for This Example

No. Name

Gross Wt.,

tonnes.

Annual

Departures

Annual

Growth, %

1 A320-100 68.400 600 0.00

2 A340-600 std 366.200 1,000 0.00

3 A380 562.000 300 0.00

4 B737-800 79.243 2,000 0.00

5 B777-300 ER 352.441 1,000 0.00



Changing the Pavement Structure


Click on Structure

button to bring up

the Structure screen.


Change Pavement Structure


In Structure window,

click on Modify

Structure




Change HMA Surface

thickness to 100 mm.

Change base layer


Change subgrade

CBR to 5


Layer Type Selection Box


Aggregate

Materials

HMA

Materials

PCC

Materials

Rigid Base

Materials

Flexible Base

Materials

Materials Identified by FAA Specification Item No.




Click “End Modify”




Click “Save Structure”


Enter Traffic Mixture


Click on “Airplane”

in section

NewFlexible.




FAARFIELD

displays the default

aircraft list.

Clear the list by

clicking “Clear

List” then “Yes”




Add airplanes to

this list one by one

by selecting from

the library at left.

Click “Add” to add

the selected

airplane.




Certain airplanes

appear in the list

twice. This is to

address the

presence of wing

gears and belly

gears.

FAARFIELD treats

these as two

airplanes.

However, the weight

and departures are

interlocked.


Adjusting Airplane Information


Gross Taxi Weight, Annual Departures and % Annual Growth

may be modified.

Allowable Ranges:

• Gross Taxi Weight: Default Weight -40% to +25%

• Annual Departures: 0 to 100,000

• % Annual Growth: +/- 10% (default is zero)


Annual Departures in FAARFIELD

• In general, annual departures means

takeoffs.

• Arrivals are ignored.

• For design purposes, FAARFIELD uses the

total annual departures, multiplied by the

design period in years:

– e.g., 1200 annual departures 20 years = 24,000

departures.



Viewing Airplane Information


Values in CDF and

P/C ratio columns

will be zero when

airplanes are first

entered.

Save the list when

finished, then click

the Back button.


Run the Design


Click “Design

Structure”


Running the Design


During the design

process, the

“Design Running”

clock will appear.


Automatic Base Thickness Design


FAARFIELD

automatically

designed the HMA

base layer.

Minimum thickness

is 5 in. (127 mm) for

stabilized base on

P-209 subbase.

No additional base

thickness required

provided high-

quality P-209

subbase is used.


Asphalt CDF Check


In the Options

screen, check the

box for “HMA CDF”

Uncheck the box

“Enable Automatic

Base Design”

Check the box

“Compute

Compaction

Requirements”

Click “OK”


Asphalt CDF Check


Re-run the design.


Final Design


HMA CDF is < 1.0.

Therefore,

subgrade strain

controls the design

thickness.

Computed subbase

thickness is 843.6

mm.

(Round to 85 cm.)


Compaction Calculation


Click the

“Life/Compaction”

button to compute

subgrade

compaction

requirements for

the completed

design.


Compute Compaction - Notes


Scroll down until the

heading “Subgrade

Compaction

Requirements”

is displayed.

Two tables display

the compaction

requirements for

non-cohesive and

cohesive soils,

respectively.

Compaction depths

here given in inches.


Compaction Tables


Percent of Max.

Dry Density

Depth from

SurfaceDepth from Top

of Subgrade

Critical Airplane

for Compaction

Modified Proctor (Heavy Load)


Design Output


Open file PROJECT_NewFlexible.pdf in the working directory.

FAARFIELD automatically creates a PDF design report.

Presented to:

By:

Date:


Introducing



Rigid Pavement Design


Quito, Ecuador

David R. Brill, P.E., Ph.D.

30 May 2018


New Rigid Example Set-Up


Create a new section

in job PROJECT by

dragging section

NewRigid in Samples

to PROJECT.


New Rigid Pavement Design Example

• Pavement Structure:

– PCC Slab, P-501, R = 4.85 MPa

– Cement-Treated Base, P-304, 150 mm thick

– Crushed Aggregate Base, P-209, 200 mm thick

– Subgrade k = 27 MPa/m

• Traffic Mix:

– 5-Aircraft Mix includes B777, A340, A380

– Use the same traffic mix as the previous example.



Changing the Pavement Structure


Click on Structure

button to bring up

the Structure screen.




In Structure window,

click on Modify

Structure




Change base layer to

150 mm CTB, P-304

Change P-209 layer


Change subgrade k to

27 MPa/m

Change R to 4.85 MPa




Click “End Modify”




Click “Save Structure”


Converting Subgrade k-Value to E

• FAARFIELD automatically

converts k to E, and vice-

versa.

• The new conversion formula

used in FAARFIELD 1.4 is:

k = 28.6926 × CBR0.7788

where: CBR = E / 1500

(E in psi, and k in psi/inch).

• Improved agreement with

field correlations.

• Less conservative than

previous formula when

converting from CBR data.


0

50

100

150

200

250

300

0 5 10 15 20

k, p

ciCBR

Linear Regression NAPTF

ERDC Proposed update

k, FAARFIELD conversion k, PCA Conversion

New conversion formula

(FAARFIELD 1.4)

Old formula

(FAARFIELD 1.3)




Use the “Float

Aircraft” function to

repeat the traffic

mix.

Go to NewFlexible

section.

Click on “Airplane”

in NewFlexible

section.


Aircraft Float List


Click on “Save to

Float.”

This copies the

aircraft list to the

clipboard.




Return to the

NewRigid section.

Go to the Airplane

screen.

FAARFIELD

displays the default

aircraft list.

Clear the list by

clicking “Clear

List” then “Yes.”

Then click “Add

Float” to add the

float aircraft list.




The screen should

look like this.

Click “Save List”

and “Back” to

return to Structure.


Run the Design


Click “Design

Structure”


Running the Design


During the design

process, the

“Design Running”

clock will appear.

For rigid designs,

the design will

normally take a few

minutes. Don’t

interrupt the

process.

The screen display

will change with

each iteration.


Final Design


Thickness should be

rounded to nearest

cm (49 cm)


PCC Stresses for Rigid Design

• FAARFIELD 1.4 compares maximum edge

stress and interior stress for all airplanes.

• The larger value is used in design.

• Output file NikePCC.out lists stress values:


B737-800:

Design Stress = Edge Stress

B777-300ER:

Design Stress = Interior Stress


Design Output


Open file PROJECT_NewRigid.pdf in the working directory.


Additional Aircraft Information

No. NameCDF

Contribution

CDF Max

for Airplane

P/C

Ratio

1 A320-100 0.00 0.00 3.84

2 A340-600 std 0.13 0.13 1.83

3 A340-600 std Belly 0.00 0.00 1.97

4 A380 0.00 0.00 3.82

5 A380 Belly 0.00 0.01 4.24

6 B737-800 0.00 0.00 3.52

7 B777-300 ER 0.87 0.87 3.87


In this example, the B777-300ER

contributes the majority of

damage on the critical strip.

Presented to:

By:

Date:


Introducing



HMA Overlay Design Example


Quito, Ecuador

David R. Brill. P.E., Ph.D.

30 May 2018


Copy an Overlay Section


In the SAMPLES job,

copy the section

AConRigid to

PROJECT.

(drag and drop)


Modify the Section


In job PROJECT, select

Section AConRigid.

Click on Modify.

Modify the section

until it appears like the

image at right:

Overlay: 300 mm P-401

PCC Surface: 400 mm P-501

(R = 4.50 MPa)

Base: 125 mm P-403

Subbase: 300 mm P-209

Subgrade: E = 27 MPa/m

Existing PCC: SCI = 80

Click “End Modify.”


Airplane Screen


Click on “Airplane.”

Note that the B747-

200B consists of 2

lines, for the Wing and

Belly gears. These

lines are interlinked.

Changing the gross

weight or annual

departures on either

line affects the other.

This is a change from

version 1.305 (for

B747 or A380 series).

For this example, use

the default traffic

mixture.


Run Overlay Design


Click Back to return

to Structure Screen.

Click Design

Structure to execute

design.


Final Overlay Design


Final HMA overlay

thickness = 82.8 mm

Design would specify

90 mm

Now, what if the

HMA overlay is very

thick relative to the

existing concrete

slab?


Thick HMA on Rigid Overlays

• Refer to AC 150/5320-6F, 4.10.5:

• When the overlay thickness exceeds the existing

slab thickness, the alternate flexible design option

may be more economical.

• FAARFIELD 1.42 will make this determination

automatically, if the option is selected.



FAARFIELD Options Screen


Allow Flexible

Computation for Thick

Overlays on PCC

This option is “ON” by

default.


Modify the Section


Click on Modify.

Change the PCC

thickness from 400 in.

to 140 mm.

All other inputs are the

same.

Click “End Modify.”


Run Overlay Design


Click Design

Structure to execute

the design.


Alternate Overlay Thickness


Final HMA overlay

thickness = 168.2 mm

Click on “Back” and

then “Notes” to see

the design output.


Design Information


“Overlay thickness

was determined

using a flexible

design procedure,

considering the

existing PCC as a

high-stiffness base

layer. CDF is

determined for the

top of the

subgrade.”


Standard Overlay Design


If you deselect the

“Allow Flexible

Computation” option,

then the required

HMA overlay

thickness increases

to 514 mm.

Try it yourself!


Thank You!

65

http://www.airporttech.tc.faa.gov/[email protected]

May 30, 2018 FAARFIELD Design Examples

Acknowledgments:

FAA Airport Technology R&D Branch:

Dr. Michel Hovan, Branch Manager;

Jeff Gagnon, Airport Pavement Section Manager;

Dr. Navneet Garg; Dr. Richard Ji; Al Larkin; Murphy Flynn; Ryan Rutter; Quinn Jia, Wilfredo Villafane

FAA Airport Engineering Division:

Doug Johnson; Greg Cline

SRA International:

Michael Collins; Dr. Izydor Kawa; Dr. Qiang Wang; Dr. Yuanguo Chen; Dr. Kairat Tuleubekov; Shawn

Hershman

Gemini:

Dr. Hao Yin

http://www.airporttech.tc.faa.gov/

mailto:[email protected]

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