WVDOH IMPLEMENTATION 2006 AASHTO LRFD … Virginia DOT Experience... · IMPLEMENTATION 2006 AASHTO...

WVDOHWVDOHIMPLEMENTATIONIMPLEMENTATION

2006 AASHTO LRFD SECTION 10 INTERIMS

Benjamin Beerman, PE

BackgroundBackground

• Mid 2005– Comprehensive LRFD foundation policy– Specific to Section 10

• Spread Footers• Drilled Shafts• Piling

• 80-90% Complete

• Recent ’06 interims– NCHRP 24-17, aka NCHRP 507

Current Policy/General SiteCurrent Policy/General Site

• State Policy: – “All bridge foundations shall bear on competent rock”

70 t 80% f th t t k ithi th fi t 15’ 20’• 70 to 80% of the state, rock within the first 15’-20’ • 20 to 30%, 30’-50’ of overburden

• Sedimentary Rock• shale• siltstone• claystone • sandstone• sandstone

HighlightsHighlights

• RMR 83• Uniform and comprehensive approach to characterize rock • RMR parameters latter used in the resistance equations• RMR parameters latter used in the resistance equations

• Characterization Criteria for Rock• Methods used to check Limit States• Design equationsDesign equations• Design examples• dBase tracking systemdBase tracking system

RMR 83RMR 83• Transition from Uc/RQD/Presumptive methodsTransition from Uc/RQD/Presumptive methods

and go towards RMR 83• Uniform and comprehensive approach to characterize rock • RMR values are latter used in the resistance equations

• Correlated previously developed geotechnical• Correlated previously developed geotechnical data and AASHTO presumptive values

• Taking a “three tier” approach w/ RMR• RMR>50RMR 50• 20<RMR<50• RMR<20 (soil)

1000)e

(ksf

RMR 83, C & φf, G E

RMR 83, m & s, AASHTO 2006e

(KSF

)

100

stan

ce Gen. Eq.B’ = 15’

24stan

ce

10g R

esis

WV data usingm & s method(AASHTO 2006)

24

g R

esi

10

Bea

ring (AASHTO 2006)

PresumptiveBearing

Approx. Upper Limit for SoilDesign

S ilBea

rin

1

B BearingResistance

Limit for Soilas SoilB

0 20 40 60 80 100RMR

Spread FootingsSpread FootingsStrength Limit State: nominal bearing resistance

• Nominal Bearing Resistance (q )• Nominal Bearing Resistance (qn)[RMR > 50]

( )⎤⎡ eqn. 10.8.3.5.4c-2

m & s: use RMR value with Table 10.4.6.4-4

( ) cn Ussmsq ⎥⎦⎤

⎢⎣⎡ ++=

[20 < RMR < 50]

eqn. 10.6.3.1.2a-1

104 RMRc ×

mcmn BNgcNq γγ5.+=

25

104RMRRMRc

f +=

×=

φ

Spread FootingsSpread FootingsStrength Limit State: nominal bearing resistance

• Nominal Bearing Capacity cont• Nominal Bearing Capacity cont…

[RMR > 50]V

[RMR > 50]• (qn) compared to the applied Strength Limit

bearing stress from triangular/trapezoidal distribution

[20 < RMR < 50]V

• Water table correction factors not required• Generally, surcharge won’t be used• (q ) compared to the applied Strength Limit bearing• (qn) compared to the applied Strength Limit bearing

stress using equivalent B’

Spread FootingsSpread FootingsStrength Limit State: sliding 10.6.3.4

• Sliding• Sliding

– Generally δ = 30-35o

–– Resistance Factor Resistance Factor ϕϕ = 0.90= 0.90DL/LL > 3 0• DL/LL > 3.0

Spread FootingsSpread FootingsService Limit State: Vertical Movement

• Vertical Movement• Vertical Movement• Per 10.6.2.4.4 to calculate settlement, • Use 10.4.6.5 to calculate Em

( ) p

EIB

q144'

1 20 υρ −=

mE144

⎟⎞

⎜⎛ −

4010

10145)(RMR

k iE ⎟⎟⎠

⎜⎜⎝

= 4010145)(m ksiE

Spread FootingsSpread FootingsService Limit State: Rotational Movement

• Rotational Movement• Rotational Movement

1. Compute displacement at the center of footing assuming a concentric loading (uniform load over entire footing area)

2. Compute displacement at the center of the effective footing area.

3. Compute rotation in each direction independently

Eccentric Displacement -V

e Eccentric Displacement

( ) ⎟⎞

⎜⎛ −− LeBV )2(*1 2νθ ( )

⎟⎟⎠

⎞⎜⎜⎝

⎛

−−

=LeBLeB

EV

b

b

zmze )2(

)2(1β

νρρz ρzeθ

Center Displacement -(AASHTO 10.6.2.4.2-1)

Footing Rotation -

⎞⎛

( ) ⎟⎞

⎜⎛− BLVν *1 2 ⎟⎟

⎠

⎞⎜⎜⎝

⎛ −= −

b

zze

eρρθ 1tan

( )⎟⎟⎠

⎜⎜⎝

=BLBL

EV

zmz β

νρ 1 ⎠⎝ b

Spread FootingsSpread FootingsService Limit State: Horizontal Movement

B’xx

B

Horizontal displacement (Δx) at the

• Horizontal Movement

q (load/area)

Horizontal displacement (Δx) at the center (B/2) of the rectangular loaded area is given by the following equation (Giroud 1969)

yy zz

⎤⎡ 2222 '''''''1 LBBLLBL

following equation (Giroud, 1969)

⎥⎥⎦

⎤

⎢⎢⎣

⎡

++−

+++

++−

+=Δ

22

2222

''''''ln

''

''''ln)1(2'1

LBBLBB

BL

BLBLqB

Ex

m

υπυ

Elastic modulus of rock mass

Drilled ShaftsDrilled Shafts

Drilled ShaftsDrilled ShaftsStrength Limit State

• Combine both end bearing and side resistanceresistance

• Use soil-interaction for lateral resistance• Use soil-interaction for lateral resistance when site conditions permit

Drilled ShaftsDrilled ShaftsStrength Limit State: nominal side resistance

• AASHTO LRFD 10.8.3.5.4b-1

⎟⎠⎞⎜

⎝⎛≤⎟

⎠⎞⎜

⎝⎛= c

au

aEs pfpp

qpq '8.765.0 α⎠⎝⎠⎝ aa pp

Side Resistance Correlation

7080

(ksf KR-1

KR-2

506070

tanc

e (

Data PointsLoad Test Data

304050

e re

sist Load Test Data

PM Upper limit for f’Upper limit for f’cc = 5 ksi= 5 ksi

102030

Ult.

Sid

e

KR-1

PM

010

0 20 40 60 80 100

U

0 20 40 60 80 100RMR

Drilled ShaftsDrilled ShaftsStrength Limit State: nominal bearing resistance

• Nominal End Bearing Resistance (q )• Nominal End Bearing Resistance (qn)[RMR > 50]

( )⎤⎡ eqn. 10.8.3.5.4c-2

m & s: use RMR value with Table 10.4.6.4-4

( ) cn Ussmsq ⎥⎦⎤

⎢⎣⎡ ++=

[20 < RMR < 50]

eqn. 10.6.3.1.2a-1

104 RMRc ×

mcmn BNgcNq γγ5.+=

25

104RMRRMRc

f +=

×=

φ

RMR 83 C & φ1000

ce (k

sf RMR 83, C & φf, Gen. Eq.D = 5’

KR1

KR2 PM2

e (k

sf)

100esis

tanc

RMR 83, m & s, AASHTO 2006

PM1stan

ce

100

ring

Re

WV data using m & s24

PM1

g R

esis

10

Bea

r method (AASHTO 2006)Presumptive BearingResistanceL d T t D tApprox UpperB

earin

g

1

Load Test DataApprox. Upper Limit for Soil

Design as Soil

B

0 20 40 60 80 100RMR 1983

Drilled ShaftsDrilled ShaftsStrength Limit State: combined side and end

• 80:20 70:30 “rules of thumb”• 80:20, 70:30 rules of thumb• FHWA-IF-99-025 (O’Neil & Reese) Appendix C

Recommendation for T-z plotsSide Resistance Ec/Em =1 Side Resistance Ec/Em=10Side Resistance Ec/Em 1

0.8

1

/Tm

ax

L/B = 5

L/B = 3L/B = 2

Side Resistance Ec/Em=10

0.81

/Tm

ax

L/B = 5 3 2 1

0

0.2

0.4

0.6

Tmob

ilize

d L/B 2L/B = 1

00.2

0.4

0.6

Tmob

ilize

d

00.0000 0.0005 0.0010

z/L

00.0000 0.0005 0.0010

z/L

Sid R i t E /E 100Side Resistance Ec/Em=50

0.81

Tmax

L/B = 5 3 2 1

Side Resistance Ec/Em=100

0.81

Tmax

L/B = 5 3 2 1

0.2

0.40.6

mob

ilize

d/T

0.20.4

0.6

Tmob

ilize

d/T

00.0000 0.0020 0.0040

z/L

T 00.0000 0.0050 0.0100

z/L

T

Recommendation for Q-z plotsEnd Bearing Ec/Em=1

0.81

/Qm

ax. L/B = 1 5

End Bearing Ec/Em =10

0.81

Qm

ax

L/B = 1 5

00.2

0.40.6

Qm

obiliz

ed/

0.20.40.6

Qm

obiliz

ed/

00 0.005 0.01

z/B

00 0.005 0.01

z/B

End Bearing Ec/Em=50 End Bearing Ec/Em=100End Bearing Ec/Em=50

0.60.8

1

ed/Q

max

.

End Bearing Ec/Em=100

0.60.8

1

ed/Q

max

.L/B = 1 5 L/B = 1 5

00.20.40.6

Qm

obiliz

e

00.20.4

Qm

obiliz

e

0 0.005 0.01z/B

0 0.005 0.01z/B

Drilled ShaftsStrength Limit State: combined side and end

3000

3500 Base Resistance

Resistance

2000

2500

nce

(Kip

s

Side Resistance

Resistance &

Displacement Relation (4.5’ dia. x 10’ long rock socket)

500

1000

1500

Res

ista

n

Combination 2 – Base Failure

Combination 1 – First Slip

(4.5 dia. x 10 long rock socket)

Side Control Rs = 2784Rp = 1200

0

500

0 0.05 0.1 0.15 0.2

Displacement (in)

Rp 1200 RT = 3984 kips

End Control Rs = 1600 Rp = 3180RT = 4780 kips

P y curvesP-y curvesStrength Limit State: nominal bearing resistance

Service Limit State: lateral

P i il• P-y in soil

P i k• P-y in rock – P-y relationship proposed by Liang

Correlation if applicable to WV foundation material– Correlation if applicable to WV foundation material

P-y curvesNCHRP Synthesis 360 (2006)NCHRP Synthesis 360 (2006)

Methods of AnalysisMethods of Analysis

PP--y analysis = 29y analysis = 29COM624 = 17 COM624 = 17 FBFB--Pier = 8Pier = 8

LL--Pile = 23Pile = 23Reese 1997 criteria = 25Reese 1997 criteria = 25States Responding = 33States Responding = 33p gp g

P-y response curves for Rock19781978 Vuggy LimestoneVuggy Limestone Nyman ReeseNyman Reese 0.0004 B0.0004 B19781978 Vuggy LimestoneVuggy Limestone Nyman ReeseNyman Reese

19871987 Sandstone & ShaleSandstone & ShaleKDOTKDOT 0.007 B0.007 B

1997 1997 Weak Rock Weak Rock ReeseReese

2002 2002 RockRock Gabr (NC)Gabr (NC)

2004 2004 Florida Limestone Florida Limestone McVayMcVay

20062006 R kR k Li (OH)Li (OH)

0.004 B0.004 B

2006 2006 Rock Rock Liang (OH)Liang (OH)

20062006 BasaltBasalt WAWA 0 01 B0 01 B2006 2006 Basalt Basalt WAWA

20062006 AllAll Vu (WY)Vu (WY)

0.01 B0.01 B

P-y Resultsy

0-10000 0 10000 20000

Moment (kips-in)

-150 -100 -50 0 50 100 150

Shear (kips)

100

Mcr0

100

200

n)

200

300

Dep

th (i

n

300

Dep

th (i

n)

400

500

400

500

Mmax Vmax

600 600

P-y Resultsy

High Shear Strut and Tie Model for Structural Strut and Tie Model for Structural Design of Shaft (AASTHO 5 6 3)Design of Shaft (AASTHO 5 6 3)

400-150 -100 -50 0 50

Shear (kips)

Design of Shaft (AASTHO 5.6.3)Design of Shaft (AASTHO 5.6.3)

400

420Top of Rock

440

460

R1

480

500

Dept

h (in

)

10' 6.7'

Rock Reaction

520R2

540

5604.5'

Dayton Load test at 3’ depth

300000

350000

400000 Input Rock PropertiesReese & Vuggy LS

200000

250000

P -

lbs/

inch

qu = 5668 psiEm = 38142 psi

0 038 i

50000

100000

150000P γr = 0.038 pciRQD = 8Li 2006

00 0.05 0.1 0.15 0.2

y - inches

Liang 2006qu = 5668 psiEi = 590000 psi

Vuggy Limestone Reese Soft RockKDOT SS Stiff clay (Reese and Welch)Mcvay 2004 Liang 2006Actual

Ei 590000 psiγr = 0.038 pciRMR/GSI = 40mi = 6

Dayton Load test at 3’ depthInput Rock PropertiesInput Rock PropertiesReese & Vuggy LSq = 5668 psi x 0 0240000

45000

50000

qu = 5668 psi x 0.02Em = 38142 psi x 0.02γ = 0 038 pci

25000

30000

35000

P -

lbs/

inch

γr 0.038 pciRQD = 8Liang 20065000

10000

15000

20000P

Liang 2006qu = 5668 psiEi = 590000 psi

0

5000

0 0.05 0.1 0.15 0.2y - inches

γr = 0.038 pciRMR/GSI = 40

6

Vuggy Limestone Reese Soft RockKDOT SS Stiff clay (Reese and Welch)Mcvay 2004 Liang 2006Actual

mi = 6

Dayton Load test at 11’ depthDayton Load test at 11 depthInput Rock PropertiesReese & Vuggy LS

350000

400000

ggyqu = 5668 psi Em = 98102 psi250000

300000

350000

/inch m p

γr = 0.038 pciRQD = 8100000

150000

200000

P -

lbs/

Liang 2006qu = 5668 psi

0

50000

0 0.05 0.1 0.15 0.2

y - inches

Ei = 590000 psiγr = 0.038 pciRMR/GSI = 61

Vuggy Limestone Reese Soft RockKDOT SS Stiff clay (Reese and Welch)Mcvay 2004 Liang 2006Actual RMR/GSI = 61

mi = 6

Dayton Load test at 11’ depth

Input Rock PropertiesReese & Vuggy LS

40000

45000

50000

ggyqu = 5668 psi x 0.02Em = 98102 psi x 0.0225000

30000

35000

40000

bs/in

ch

m pγr = 0.038 pciRQD = 810000

15000

20000

25000

P -

lb

Liang 2006qu = 5668 psi0

5000

0 0.05 0.1 0.15 0.2i h Ei = 590000 psi

γr = 0.038 pciRMR/GSI = 61

y - inches

Vuggy Limestone Reese Soft RockKDOT SS Stiff clay (Reese and Welch)Mcvay 2004 Liang 2006 RMR/GSI = 61

mi = 6Actual

Pomeroy Mason #2 at 0.5’ depth

Input Rock PropertiesReese & Vuggy LS300000

350000

400000

ggyqu = 3797 psi Em = 23885 psi 200000

250000

300000

P -

lbs/

inch

m pγr = 0.059 pciRQD = 4450000

100000

150000P


00 0.05 0.1 0.15 0.2

y - inches


Vuggy Limestone Reese Soft RockKDOT SS Stiff clay (Reese and Welch)McVay 2004 Liang 2006Actual RMR/GSI = 42

mi = 6

Pomeroy Mason #2 at 0.5’ depthInput Rock PropertiesReese & Vuggy LS40000

45000

50000


30000

35000

P -

lbs/

inch

m pγr = 0.059 pciRQD = 44

5000

10000

15000

20000P


0

5000

0 0.05 0.1 0.15 0.2y - inches



mi = 6



350000

400000

ggyqu = 3797 psi Em = 23885 psi 200000

250000

300000

P -

lbs/

inch

m pγr = 0.059 pciRQD = 4450000

100000

150000P


00 0.05 0.1 0.15 0.2

y - inches



mi = 6



45000

50000


30000

35000

P -

lbs/

inch


5000

10000

15000

20000P


0

5000

0 0.05 0.1 0.15 0.2y - inches



mi = 6



350000

400000

ggyqu = 3797 psi Em = 23885 psi 200000

250000

300000

P -

lbs/

inch

m pγr = 0.059 pciRQD = 4450000

100000

150000P


00 0.05 0.1 0.15 0.2

y - inches



mi = 6



45000

50000


30000

35000

- lbs

/inch


5000

10000

15000

20000P


0

5000

0 0.05 0.1 0.15 0.2y - inches



mi = 6

ContCont….• Pile Policy

– Wave Equation analysis• Preliminary analysis, assumed driving equipment• Verification analysis, contractor’s actual equipmentVerification analysis, contractor s actual equipment

WVDOH IMPLEMENTATION 2006 AASHTO LRFD … Virginia DOT Experience... · IMPLEMENTATION 2006 AASHTO...

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