Box Culverts Design (LRFD Approach)

7/28/2019 Box Culverts Design (LRFD Approach)

1/93

TheU

seofAA

SHTOLRFD

TheU

seofAA

SHTOLRFD

Bridg

eDesign

Specifica

tionswith

Bridg

eDesign

Specifica

tionswith

JoshBeakley

JoshBeakley

Novembe

r,2010

Novembe

r,2010


2/93

2

LRFD

isRequ

ired

June28th,2000FHWAMemo


3/93

AAS

HTO

AAS

HTO

Design

Design


4/93

forHighwayBr

idges

Section3

Section3Loads

Loads

Section8

Section8ReinforcedConcrete

ReinforcedConcrete

econ

econ

oo

--orrugae

ea

orrugae

ea

Struc

tureInteractionSystems

Struc


Section16

Section16SoilSoil

--Reinforced

Concrete

Reinforced

Concrete

Struc


Struc


Section17

Section17SoilSoil

--ThermoplasticPipe

ThermoplasticPipe

InteractionSystems

InteractionSystems


5/93

Specifications

Section3

Section3LoadsandLoadFactors

LoadsandLoadFactors

Evaluation

Evaluation

Section12

Section12BuriedStructuresandTunnel

BuriedStructuresandTunnel

ners

ners


6/93

StructuresDesignedPerSection12

Section12.7

Section12.7--MetalPipe,PipeArch,and

MetalPipe,PipeArch,and

Arch

Structures

Arch

Structures

Section12.8

Section12.8--Lo

ng

Lo

ng--SpanStr

ucturalPlate

SpanStr

ucturalPlate

Section12.9

Section12.9--StructuralPlateBox

StructuralPlateBox

Section12.12

Section12.12T

hermoplasticPipes

T

hermoplasticPipes

Section12.13

Section12.13S

teelTunnel

LinerPlate

S

teelTunnel

LinerPlate


7/93

Sectio

n12

Section12.10

Section12.10R

einforcedC

oncretePip

e

R

einforcedC

oncretePip

e

--

--

..

,

,

inin--placeBoxCulverts,Cast

placeBoxCulverts,Cast--inin--placeArches

placeArches

..--

--

Struc

tures

Struc

tures


8/93

What

WeWillDiscuss

Loads

Loads

Load

Modifiers

Load

Modifiers

apacy

acua

ons

apacy

acua

ons


9/93


10/93

LiveLoad

3.6.1.2DesignVehicularLiv

eLoad

3.6.1.2DesignVehicularLiv

eLoad

.

...

.

...

V

ehicularliveloadingon

theroadways

V

ehicularliveloadingon

theroadways

,

,

designatedHL

designatedHL

--93,shallco

nsistofa

93,shallco

nsistofa

Designtruckordesigntandem,and

Designtruckordesigntandem,and

Designlane

load

Designlane

load


11/93

LiveLoadSpa

cingH

L-93

400

0lb.

12,500

lb.

12,500lb

.

1

4t.

6t.

12,500lb.12,500lb

.

1600

0lb.

16000lb.

AASHTO

A

ASHTO

(12,0

0lbperSTD)

H

S20LOAD

ALTER

NATELOA

D


12/93

AppliedLive

loadsNoLane

Load .

...

,

.

...

,

Systems,andtheTopSlabsofBoxCulverts

Systems,andtheTopSlabsofBoxCulverts

Wherethesla

bspansprima

rilyinthe

Wherethesla

bspansprima

rilyinthe

Fortopslabsofboxculvertsofallspans

and

Fortopslabsofboxculvertsofallspans

and

forallothercases,includingslab

forallothercases,includingslab--type

type

.

.

ft,onlytheax

leloadsofthedesigntruck

or

ft,onlytheax

leloadsofthedesigntruck

or

designtandem

ofArticles3

.6.1.2.2and

designtandem

ofArticles3

.6.1.2.2and

....,

,

.

....,

,

.


13/93

AppliedLive

loadsNoLane

Load .

...

esgn

oasor

ecs,ec

.

...

esgn

oasor

ecs,ec

Sy

stems,andtheTopSlab

sofBox

Sy

stems,andtheTopSlab

sofBox

Wheretheslabspansprimarilyinth

e

Wheretheslabspansprimarilyinth

e

transversed

irection,onlytheaxlesof

transversed

irection,onlytheaxlesof

thedesigntruckofArticle3.6.1.2.2

or

thedesigntruckofArticle3.6.1.2.2

or

designtandemofArticle3.6.1.2.3

designtandemofArticle3.6.1.2.3

topofboxc

ulverts.

topofboxc

ulverts.


14/93

LaneLoad3

.6.1.3

64

lbsacrossa

10ftwidth

64

lbsacrossa

10ftwidth

LRFDLRFD

2005

2005T

ruckonly

T

ruckonly

an

ar

pecc

aon

an

ar

pecc

aon..

.

..

.

Eithertruckor

LaneLoad

Eithertruckor

LaneLoad

Truckgoverns

forshorterspans

Truckgoverns

forshorterspans


15/93

PipeCulverts

Lane

Loadsnota

ppliedtopipe

Lane

Loadsnota

ppliedtopipe

For

topslabsofboxculvertsofallspansand

For

topslabsofboxculvertsofallspansandforall

forall

othercases,includingslab

othercases,includingslab--typebridgeswherethespan

typebridgeswherethespan

doe

snotexceed15.0ft,

doe

snotexceed15.0ft,onlytheax

leloadsofthe

onlytheax

leloadsofthe

....

....

3.6.1.2.3,respectively,shallbeapp

lied.

3.6.1.2.3,respectively,shallbeapp

lied.

Histor

Histor


16/93

TireF

ootprint

LRFD

LRFD3.6.1.2.6

3.6.1.2.6

==

.

.

l=

10in.

l=

10in.

an

ar

pec

caon

an

ar

pec

caon....

C

oncentrated

Load

C

oncentrated

Load


17/93

DistributionW

idth


18/93

DistributionW

idth

LRFD(4.6.2.10)

LRFD(4.6.2.10)

=

+

=

+

.

.

EininchesandSinfeet

EininchesandSinfeet

an

ar

...

an

ar

...

E=4+0.06S(forwheel)

E=4+0.06S(forwheel)

EinfeetandS

infeet

EinfeetandS

infeet


19/93

DistributionSteel


20/93

LiveLoadDis

tribution

Parallel

to

BoxC

ulvertSpanunde

rShallow


21/93

LiveLoadDis

tribution

*

*

.

LRFDSpreada=a+1.15*H

.

LRFDSpreadb=b+1.15

*H


22/93


23/93

PipeUnderSh

allowFill


24/93

LiveLoadAre

aforDepths2ft.

LRFD(3.6.1.2.6)

LRFD(3.6.1.2.6)

=

+

=

+

++

.

.

.

.

1.15aboveshouldbereplacedwith

1.0

1.15aboveshouldbereplacedwith

1.0

Stand

ard(6.4.1)

Stand

ard(6.4.1)

AALL=(1.75D

=(1.75DEE))

22


25/93

LiveLoadSpr

ead


26/93

DynamicLoad

Allowance

LRFD

LRFDDynamicLoadAllowance(3.6.2.2)

DynamicLoadAllowance(3.6.2.2)

==

--

.

.

.

.

..

Stand

ard

Stand

ardImpactFactor(3.8.2.3)

ImpactFactor(3.8.2.3)

=

.

=

.--

oo

--

.

.

IM

=0.2

IM

=0.211--1to2

1to2--0INCL.

0INCL.

IM

=0.1

IM

=0.122--1to2

1to2--11

INCL.

11

INCL.


27/93

TwoTrucksPassing


28/93

PipeandSoil


29/93

Lanes

AASHTO

AASH

TO

CHB

DC

STD

LRF

D

1

1.0

1.2

1.0

2

1.0

1.0

0.9

0

3

0.90

0.8

5

0.8

0

.

.

.


30/93

BoxC

ulvertsShallow

Fill

Design

UsingSingleL

ane


31/93

SoilL

oad

Frictional

Soil

Frictional

Soil

Forces

rsm

Forces

rsm

atura

roun

atura

roun


32/93

SoilL

oad

WWEE==

FFeeJJssBBccHH

Bo

xes

Bo

xesSectio

n12.11.2.2.1

Sectio

n12.11.2.2.1

Pipe

PipeSection

12.10.2.1

Section

12.10.2.1


33/93

-

Boxes

WWEE==

FFeeJJssBBccHH

FF=1+0.20H/

=1+0.20H/BB

FFeeshallnotexceed1.15

forinstallations

shallnotexceed1.15

forinstallations

withcomactedfillalon

thesidesof

withcomactedfillalon

thesidesof

theboxsection,or1.40

forinstallations

theboxsection,or1.40

forinstallations

with

withuncompacted

uncompactedfillfill


34/93

-

Pipe

Stan

dardinstallationsforbo

th

Stan

dardinstallationsforbo

th

emba

nkmentsandtrenchesshallbe

emba

nkmentsandtrenchesshallbe

desig

nedforpositiveprojection,

desig

nedforpositiveprojection,

emba

nkmentloadinconditionswhereF

emba

nkmentloadinconditionswhereF

shall

betakenas

theverticalarchingfactor,

shall

betakenas

theverticalarchingfactor,

VAF,specifiedinTable12.1

0.2.1

VAF,specifiedinTable12.1

0.2.1--3for3for

each

typeofstandardinstalla

tion.

each

typeofstandardinstalla

tion.

www.concrete-p

ipe.org


35/93

.

..


36/93

VerticalPressuresandReaction

s


37/93

Vertic

alSoilL

oad

0.8

1.2

1.62

VAFi

1

2

3

4

5

6

7

8

00.4

li

BeddingandFillHeigh

tsforConcreteRoadwayPipe

AndBox

CulvertsC.

Yoo,F.Parker,andJ.Kang,

AuburnUniversity,June

2005


38/93

Loads


39/93

LRFD

(C12.11.2.3)

Whiletypicaldesignsassum

eauniform

Whiletypicaldesignsassum

eauniform

ressuredistributionacrossthebottomslab,

ressuredistributionacrossthebottomslab,

arefi

nedanalysisthatconsid

erstheactual

arefi

nedanalysisthatconsid

erstheactual

soils

tiffnessunderboxsectionswillresu

lt

soils

tiffnessunderboxsectionswillresu

lt

inpressuredistributionsthat

reducebotto

m

inpressuredistributionsthat

reducebotto

m

slabshearandmomentforces(McGrathet

slabshearandmomentforces(McGrathet

al.20

04.

al.20

04.


40/93

LRFD

C12.11.2.3

Suchananalysisrequireskn

owledgeof

in

Suchananalysisrequireskn

owledgeof

in--

situs

oilroertie

stoselectthea

roria

te

situs

oilroertie

stoselectthea

roria

te

stiffn

essforthes

upportingsoil.Arefine

d

stiffn

essforthes

upportingsoil.Arefine

d

anal

sistakinth

isintoaccountmabe

anal

sistakinth

isintoaccountmabe

beneficialwhenanalyzingex

isting

beneficialwhenanalyzingex

isting

culve

rts.

culve

rts.


41/93

PipePressureDistribut

ion


42/93

LateralLiveL

oad

LRFD(3.11.6.2)

LRFD(3.11.6.2)

pp

,

,

wa

llresultingfromapointloadmaybe

wa

llresultingfromapointloadmaybe

2

'ph

=SR2

R3

-R+Z


43/93

oussnesq

sr

uon


44/93

LiveL

oadLateralUnifor

mPressure

LRFD

LRFD3.11.6.4

3.11.6.4

=K=K

hh

HH


45/93

LateralUnifor

mLiveL

oad


46/93

Ingeneral,LRFDprodu

cesgreaterlive

loadsurcharge

pressures

thanStandardf

ordepthsoffill

of5ftorlessan

d

.

,

surchargepressuresfrom

AASHTOM259andM273ar

e

muchgre

aterthanthosefromLRFDfordepthsoffillfrom

to

ta

nesstan

orgreater

egts.n

spiteofthesignificantdifferencesinlive

loadsurcharge

pressures

,theirimpacton

reinforcementareasisrelatively

minor

ComparisonofAASH

TOStandardandLRFD

CodeProvisionsforBuriedConcreteB

ox

uvers

.un

.

cra,

,

2000,ConcretePipefo

rtheNewMillenium


47/93

LateralEarthPressure


48/93

LateralEarthLoad-LRFD

3.11.5.5

3.11.5.5EquivalentFluidM

ethod

EquivalentFluidM

ethod

==

De

nseSandor

Gravel=45

pcf

De

nseSandor

Gravel=45

pcf

..

.

..

.

es

ressure

es

ressure

kkoo=1=1--sinsinII

II=30

=30,k,koo=

0.5,press=60pcf

=

0.5,press=60pcf


49/93

Other

Loads

Alwa

ysConsidered

Alwa

ysConsidered

InternalFluidLoad

InternalFluidLoad

omemes

ons

ere

omemes

ons

ere

Co

nstructionL

oads

Co

nstructionL

oads

Ex

ternalHydrostaticLoads

Ex

ternalHydrostaticLoads


50/93


51/93

Load

Factors

Load

LoadFactor

Standard

LRFD

Dead

1.3

0.90

1.25

Water

1.3

1.0

1.0

EartVert

ca

1.3

0.90

1.30

Earth-Horizontal

1.3

0.90*

1.35

Live

1.3x1.67=

2.17

0.0

1.75**

*Per3.11

.7,a50%reduc

tioninloadmay

beusedinlieu

of

.

**Amultiplepresencefa

ctorisincluded

inthetotalload.


52/93

LRFD

Design


53/93

PhiFactors

Stren

gthReductionFactors

Stren

gthReductionFactors

==

..

IIvv

=0.9

=0.9

....

--

Standard

Standard16.7.4.6

16.7.4.6


54/93


55/93

BasisofLRF

DMetho

dology

66iiJJiiQQii


56/93

Load

Modifier-Culverts

LRFD12.5.4

LRFD12.5.4

buriedstructur

esandtunnellinersas

buriedstructur

esandtunnellinersas

.,

.,

loa

dmodifiers

forconstructionloads

loa

dmodifiers

forconstructionloads

.

.


57/93

Load

Modifiers

LRFDC1.3.2.1

LRFDC1.3.2.1

,

,

,

,

importanceare

significant

aspects

importanceare

significant

aspects

.

.


58/93

ForCulverts

Stand

ard=N/A

Stand

ard=N/A

..

..

Du

ctility=

Du

ctility=DD

=1.0

=1.0

e

unancy=

e

unancy=

RR=

.or.

=

.or.

Im

portance=

Im

portance=II=1.0or1.05

=1.0or1.05


59/93

Load

ModifierCulverts

LRFD1.3.3

LRFD1.3.3Du

ctility

Du

ctility

be

proportione

danddetailedtoensure

the

be

proportione

danddetailedtoensure

the

ine

lasticdeformationsatth

estrengtha

nd

ine

lasticdeformationsatth

estrengtha

nd

.

.


60/93

Load

Modifier-Culverts

LRFD12.5.4

LRFD12.5.4--Redundancy

Redundancy

,

,

structuresshallbeconsidered

structuresshallbeconsidered

.

.

red

undant

red

undant(1.0)

(1.0)underlive

loadand

underlive

loadand

.

.


61/93

Load

Modifier-Culverts

LRFD12.5.4

LRFD12.5.4--Im

portance

Im

portance

determinedon

thebasisof

continued

determinedon

thebasisof

continued

.

.


62/93


63/93

Desig

nfor:

Flexure

Flexure

SteelReinforc

ement

SteelReinforc

ement

Co

ncreteCom

pression

Co

ncreteCom

pression

Shea

r

Shea

r

RadialTension(forpipeonly)

RadialTension(forpipeonly)

Fatig

ue(notrequ

iredforbox

culvertsor

Fatig

ue(notrequ

iredforbox

culvertsor

pipe

perLRFD)

pipe

perLRFD)


64/93

BoxC

ulvertsan

dPipe

Section12.10

Section12.10R

einforcedC

oncretePip

e

R

einforcedC

oncretePip

e

Section12.10.4.2

Section12.10.4.2DirectDesin

DirectDesinAA=?=?

Section12.10.4.3

Section12.10.4.3IndirectDesign

IndirectDesignClass

=?

Class

=?

--

..


65/93

Flexu

re

Asi

gIf

d

Nu

ggIfd

2

Nu2

If

d

t

2Mu

y

quaon

....a-

or

rec

es

gno

pe

Section5.7.2AssumptionsforStrength

andExtremeEv

ent

LimitSta

testakesabroaderviewofflexuraldesign


66/93

LRFD-

12.11.4.3.2:S

TD-16.7.4.8

AsAsminmin=0.002bh

=0.002bh

==

h=

thicknesso

fmemberininches

h=

thicknesso

fmemberininches

...

.

...

.

Stand

ard(16.7.4.8)

Stand

ard(16.7.4.8)


67/93

-


68/93


69/93

Flexu

re(maximumsteel)

Boxculvertwallsandslabsa

redesigned

as

Boxculvertwallsandslabsa

redesigned

as

tensioncontrolledmembers,witha

tensioncontrolledmembers,witha

maximumsteelareaof75%ofthebalanced

maximumsteelareaof75%ofthebalanced

condition(steelw

illalwas

ieldbefore

condition(steelw

illalwas

ieldbefore

concretecrushes)

concretecrushes)

withotherconcre

testructuresaslongasa

withotherconcre

testructuresaslongasa

.

.


70/93

TensionContr

olled-D

uctile


71/93

Crack

Control

(LRFD5.7.3.4)

s

700Je

2dc

d

s

s

LRF

DConcernsitselfwith

steelspacing

LRF

DConcernsitselfwith

steelspacing

stressinthesteel(maximum

of0.6fy?)

stressinthesteel(maximum

of0.6fy?)


72/93

ServiceLoadStress

h

f

s

s

2

Asj

id

..

-


73/93

Factorsaffecti

ngcrack

control


74/93

ExposureConditions


75/93


76/93

Shear

...

...

'

As

Vude

c

.

.bde

Mu

e

Vc

0.0948

f'c

b

de

EquivalenttoE=3


77/93

Shear

...:

....

Slabswithlessthantw

ofeetofcove

r, '

c

.

v

v

Eisbased

onthedimensionsoftheeleme

ntandthestrain

inthesteel


78/93

Shear

...:

....

Slabswithlessthantw

ofeetofcove

r,andsidewalls

orsectonswtanovera

ept

esstan

nces,

andnoten

sion,Ecanbeassumedequalto

2


79/93

TopSlab


80/93

Side

Wall

12X12

20


81/93

DistributionSteel


82/93

DistributionSteel

Inbo

ttomoftopslab(LRFD

9.7.3.2)

Inbo

ttomoftopslab(LRFD

9.7.3.2)

reinforcement

=100/S

reinforcement

=100/S1/21/2

Ne

ednotbem

orethan50percent

Ne

ednotbem

orethan50percent

Intopoftopslab

Intopoftopslab

AsAs

=0.002xAg

=0.002xAg


83/93


84/93

Concre

tePipeInd

irectDesign12.10.4.3

D-LoadEquation

www.concrete-p

ipe.org


85/93

www.concrete-p

ipe.org


86/93

ar

oa

e

ngac

or


87/93

Extra

SafetyFac

torforType1

www.concrete-p

ipe.org


88/93

Liv

eLoadBed

dingFactor


89/93

PipeIndirectDesign

D

-LoadEquation

www.concrete-p

ipe.org


90/93

Class

VPipe(

C76/M1

70)


91/93

Conc

retePipe

12.10

.4.2

Flexu

re

Flexu

re12.10.4

.2.4.a&b

12.10.4

.2.4.a&b

....

....

CrackControl

CrackControl12.10.4.2.4d

12.10.4.2.4d

earear

...

.

...

.


92/93

FLEXURE

CRACKC

ONTROL

RADIALTEN

SION

SHEAR


93/93

TheEnd

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Documents

Box Culverts Design (LRFD Approach)