bridge deck evaluation manual

8/10/2019 Bridge Deck Evaluation Manual

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BRI DGE DECK

EV LU TI ON

M NU L

NEWYORK ST TE

DEP RTMENT OF TR NSPORT TI ON

STRUCTURES

DESIGN

ND CONSTRUCTION DVI SI ON


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BRI DGE

DECK EVALUATION

MANUAL

NEWYORK STATE

DEPARTMENT

OF

TRANSPORTATI ON

STRUCTURES

DESIGN AND

CONSTRUCTI ON

DVI SI ON

MAY 992


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I I NTRODUCTI ON

BRI DGE DECK

EVALUATI ONMANUAL

CONTENTS

I I EVALUATI ON

METHODS

A

V sual Deck Examnati on

B Sounding

C

Potenti al Survey

D Cori ng

1 Procedure

Core Tests

E

Chl ori de

Measurement

F Thermography

G

Radar and I mpact

Echo

I I I

DECK TREATMENTS

A Treatments

l Non Protecti ve Treatments

2 Protecti ve Treatments

3 Deck Repl acement

B Deck Rehabi l i tati on Tasks

C

Performance

Esti mates

D

Treatment Costs

E

Li fe Cycl e

Cost Anal ysi s

I V TREATMENT

SELECTI ON

Deck

Rehabi l i tati on

Deck Replacement

C Treatment Sel ecti on Pol i cy

D

Examples

V

REPORTI NG

REQU REMENTS

APPENDCES

A

Formul as

for

Economc Ana

B Examples

of

Deck

Eval uati on

Treatment Sel ecti on Process

C Bri dge Deck Eval uati on Reports

D

Bri dge

Deck Core

Record

E

Deck Core Eval uati on Form


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I NTRODUCTI ON

Bri dge deck

rehabi l i tati on i s

a

major

component

of the

Department s

bri dge preservati on program An array

of

deck treatments are

avai l abl e

whi ch,

when matched to deck condi ti on

and

age,

can

provi de cost-ef fecti ve strategi es for thei r preservati on These

i nclude

asphal t and

concrete

overl ays,

as

wel l

as

compl ete deck

repl acement

Sel ecti on

of

appropri ate treatments

requi res

that the

Desi gn

Engi neer

know the process

of

eval uati ng

and

i nterpreti ng

deck condi ti on,

be

faml i ar wth the treatments avai l abl e, and

be

abl e

to i ntegrate condi ti on data, treatment type, and

cost i nto

sel ecti on of

a

cost-ef fecti ve rehabi l i tati on strategy

The

purpose

of thi s Manual i s to provi de a si ngl e document

that

the

Desi gner

can use

to sel ect

deck eval uati on methods,

i nterpret

the

f i ndi ngs, and sel ect treatment strategi es Requi rements for

reporti ng deck

eval uati on

resul ts are i ncluded

I t

does not

provi de

ful l

detai l s on howthe vari ous eval uati ons are performed

Thi s

i nformati on

i s

contai ned

i n

the

Materi al s

Bureau publ i cati on

ti tl ed Fi el d Survey

Manual for Bri dge Deck Overl ay

Proj ects

(March

1989)

The contents

of thi s Manual are appl i cabl e to monol i thi c

decks,

two-course decks, and asphal t overl ai d decks For the

l ast

two

deck

types, the

pri mary di f ference i n appl ying

the

Manual s

techni ques

i s i n

methods used

to

eval uate condi ti on An asphal t

overl ay,

i n

parti cul ar, masks condi ti on

of the

underl yi ng concrete

deck and

prevents di rect observati on of spal l s, as wel l as

soundi ngs

to

detect del amnati ons Hal f -cel l potenti al

measurements

to detect corrosi on acti vi ti es cannot be performed

through the asphal t

Chapter

descri bes

currentl y avai l abl e deck eval uati on

methods

Each

method s

purpose i s descri bed,

al ong

wth detai l s of the

i nformati on obtai ned Cri teri a are establ i shed for sel ecti ng

eval uati on methods Fi nal l y, techni ques for

i nterpreti ng

the

data

i n

descri bi ng

deck

condi ti on are reviewed

Chapter

I I I

l i sts vari ous deck treatments i n use

i n New

York

Each

method i s expl ai ned and cri teri a for i ts use are establ i shed

Current i nformati on

on

servi ce l i fe and statewde average

cost

are

i ncl uded

A procedure for cal cul ati ng present worth

of

each

treatment

i s

al so

descri bed


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Chapter I V outl i nes

cri teri a

for

treatment sel ecti on

Age and

current condi ti on of

the deck,

together wth

esti mates

of

treatment

servi ce l i ves, are

used

to

sel ect treatments

provi di ng

cost-

ef fecti ve

rehabi l i tati on Total cost of each treatment,

i ncludi ng

cost

of

constructi on, mai ntenance and protecti on

of

traf f i c (M PT),

protecti on

o

workers

f rom fal l s

and

other hazards,

and

envi ronmental

protecti on s

used to

esti mate

i ts

present

worth The

addi ti onal M PT cost

and

worker protecti on makes the treatment

sel ecti on process hi ghl y dependent on si te condi ti ons and traf f i c

vol ume

For very hi gh traf f i c

si tes,

user costs

resul ti ng

from

constructi on del ays may al so

be

consi dered These addi ti onal costs

tend

to shi f t treatment sel ecti on toward more-complete

rehabi l i tati ons at

such

si tes

Chapter

di scusses

reporti ng requi rements Report format

has

been

standardi zed

to

permt easi er preparati on and revi ew

An

Appendi x of

case studi es

i s

al so i ncluded These case studi es

w l l provi de the reader

wth

speci f i c appl i cati ons of the

procedures

descri bed


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Thorough

bri dge

deck eval uati on

i s

requi red to

sel ect the

best

method

of

rehabi l i tati on

.

Thi s Chapter descri bes eval uati on

techni ques

for

both monol i thi c and two-course decks

The

l atter

wth ei ther a concrete

or

asphal t weari ng course are eval uated

essenti al l y the

same

techni ques Eval uati on methods

currentl y avai l abl e,

al ong wth a bri ef

descri pti on

of thei r

purpose, l i mtati ons, and

the

i nformati on obtai ned, are descri bed

here

.

The

methods

and

thei r purposes

are

summari zed

i n

Tabl e

Each method' s appl i cabi l i ty

i s di scussed as i t

rel ates

to

both

monol i thi c and

two-course bri dge decks . For the l atter,

potenti al

soundi ng eval uati on techni ques

are

ei ther restri cted or

l i mted

thei r

use at

the desi gn

stage

The weari ng course must

be

removed

i f

thi s techni que

i s

to provi de

meani ngful and

compl ete

i nformati on,

maki ng

i t di f f i cul t

for

the Desi gner

to

est i mate

removal

quanti ti es accuratel y on two-course decks

The Desi gner

shoul d use vi sual , cori ng, chl ori de, and possi bl y l i mted soundi ng

data, and past experi ence to est i mate repai r quanti ti es and

l ocati ons .

A potenti al

and soundi ng

survey

shoul d

be

i ncorporated

i nto the bri dge deck

rehabi l i tati on

contract,

af ter

weari ng

course

removal ,

so

that areas requi ri ng rei nforci ng

bar

exposure can

be

accuratel y i denti f i ed Two-course decks

programmed

for total deck

repl acement or

100%

rei nforcement bar exposure do

not

requi re

potenti al or soundi ng eval uati on. Si ml arl y, these eval uati ons are

not needed

i f

an asphal t overl ay

i s

chosen

as

a

short-term

repai r

Speci f i c

i nstructi ons

for

performng and i nterpreti ng vari ety

of

monol i thi c deck

survey procedures are gi ven

i n

the Fi el d Survey

Manual

For

Bri dge Deck Overl ay Proj ects prepared by the

Materi al s

Bureau

These

detai l s are not repeated here. For brevi ty, thi s

document wl l be referred

to

as

the

Fi el d Survey Manual

.

The work shoul d begi n wth

a

vi sual

examnati on

of

the

top and

bottom

deck

surfaces

Safe

access to

the undersi de of the deck must

be

arranged

for

thi s examnati on

Thi s examnati on i denti f i es such

form of surface

di stress as cracks, spal l i ng, scal i ng,

ef f l orescence, rust

on

stay-i n-pl ace

form,

and concrete

di scol orati on.

Each type

of di stress shoul d be documented on

a

scal ed map of the

deck, as

descri bed

i n

Chapter V ( Reporti ng

)

vi sual examnati on wl l i denti fy

the

need

for

methods

.

For exampl e, i f

i t

reveal s extremel y

or

concrete

deteri orati on, there

i s l i ttl e

wth other eval uati on procedures because the deck

on i ndi cates

I I

. EVALUATION METHODS

V sual Deck Examnati on

Requ

other eval ua

severe deck

need

to cant

must

be repl aced By contrast, i f

vi sual


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rel ati vel y sound concrete wth onl y

i sol ated

di stress, such as

spal l i ng

due to

rei nforcement corrosi on, then

addi ti onal eval uati on

procedures must

be

used to

determne l ocati ons for

rei nforci ng

bar

exposure

i f

vi sual examnati on reveal s questi onable deck

bottom

areas, then a more extensi ve eval uati on

wl l

be

needed to determne

the

extent

of

ful l -depth deck

repai rs

V sual

eval uati on

i s

an essenti al task that must

be

completed

for

both monol i thi c and two-course

decks,

usi ng

the

same eval uati on

methods

B

Sounding

Thi s

techni que i s descri bed

i n

the Fiel d Survey

Manual

I t

i s used

to l ocate areas

of

del amnated

concrete by

draggi ng a chai n across

the concrete surface

or

hi tti ng

i t

wth

a

hammer

and

l i steni ng

to

the sound

I f possi bl e, both the

top

and bottomsi de

of

the deck

shoul d be sounded to i denti fy del amnated concrete Sounds

from

del amnated

or hol l ow

areas wl l

be obvi ous Soundi ng

usual l y

i denti f i es del amnated

concrete that

resul ts

from

expansi ve forces

caused by rei nforci ng steel corrosi on

These hol l ow

or

del amnated

areas shoul d

be

studi ed

i n conj uncti on

wth potenti al survey

resul ts Both i denti fy di stress rel ated to rei nforci ng steel

corrosi on (See Chapter

I V

Secti on A Deck Rehabi l i tati on ,

for

further

i nformati on

on

i denti fyi ng

areas for concrete removal

Soundi ng

i s

used

pri mari l y on monol i thi c

decks

On

two-course

decks (wth both

concrete and asphal t

concrete

weari ng courses)

i t

i s di ff i cul t but possibl e to detect del amnati ons

i n

the structural

sl ab by poundi ng

a

hammer

on the

weari ng course

i f

background

noi se

i s l ow

but the chai n drag i s not sensi ti ve enough for thi s

appl i cati on

Del amnati ons detected

by

a

hammer

i n

two-course

decks

shoul d

be

confi rmed by

cori ng before

performng

an extensi ve

survey Experi mental methods

(radar and

i mpact echo)

for l ocati ng

del amnati ons

i n

two-course decks are descri bed

at

the end

of

thi s

Chapter

For two-course decks,

soundi ng shoul d be repeated wth

the

weari ng

course removed The contract documents shoul d provi de

for

thi s secondary soundi ng

C Potenti al Survev

Thi s

method

l ocates areas of acti ve rei nforci ng steel corrosi on

I ts

use i s

l i mted to

monol i thi c

bri dge

decks

and i s detai l ed

i n

the

Fi el d

Survey

Manual

Potenti al

surveys

cannot

be

used

to

eval uate two-course decks unti l

the weari ng course,

protecti ve membrane,

i s

removed By pl otti ng el ectri cal

po

measurements on

a

gri d map, areas

of hi gh

and l owpotenti al can

l ocated

As

j ust stated

regardi ng soundi ng,

hi gh potenti al s

together wth areas

of

spal l s

and

del amnati ons

are

used

to


11/88

determne the extent of rei nforci ng bar exposure Because concrete

del amnati on

i s a progressi ve

form

of fai l ure,

there

wl l

general l y

be

substanti al

i ncreases i n removal

quanti ti es f rom those

i denti f i ed

i n

desi gn

To

account

for

thi s, the Desi gner may want

to i ncrease removal

quanti ti es

by about

20 percent per

year

for

each

year

l apsed

pri or to pl aned constructi on

i . e

.

40%

would

become 48% for a one-year l apse between deck

evaluati on and

constructi on)

On

two-course

decks,

the

contract documents

shoul d provi de

for

compl eti on

of a

potenti al survey af ter the

Contractor removes

the

weari ng

course

Thi s

enabl es the Engi neer

to i denti fy

areas for

rei nforci ng bar exposure more

accuratel y

Procedure

D

Cori nq

cori ng

i s an i mportant

tool

i n

determni ng structural

condi ti on

of

concrete and rei nforci ng

steel ,

and the extent

of

repai r

I t i s

used

i n

eval uati ng both

monol i thi c

and two-

course decks

I ts

i mportance

i s

greater

i n eval uati ng

two-

course decks because

i t

uncovers di stress that

may

otherwse

go undetected

The

pri mary functi on

of cores i s

to veri fy

f i ndi ngs of other

eval uati on

methods, determne extent

of the di stress, and

determne

i ts

l i mts

and depth

They

are

also used

to

eval uate concrete condi ti on through l aboratory testi ng

Avai l abl e

tests i ncl ude

compressi on,

ai r

content,

f reeze-thaw

and chl ori de determnati on Each of these l aboratory tests i s

descri bed

l ater

Vi sual

anal ysi s i s

suf f i ci ent

for

most cores

Onl y

a few

representati ve ones shoul d

be

sel ected

for

l aboratory testi ng

Concrete that l ooks

good general l y i s good

Cores exhi bi ti ng

di stress

throughout

thei r ful l depth (rubbl e) shoul d not be

sel ected

for

l aboratory testi ng One

of

the best

tests

avai l abl e

i s

i n-servi ce performance

of

the

concrete

deck

Cores

having

no vi si bl e si gns of di stress have met the test

of

ti me

Before establ i shi ng

a

cori ng pattern,

the

deck shoul d

be

cl osel y

i nspected,

on both

i ts

top

and bottom sides, as

descri bed

i n

the

Vi sual Deck

Examnati on secti on

of

thi s

Chapter Deck condi ti on shoul d be documented on scal ed

drawngs and representati ve photographs taken,

as

descri bed i n

Chapter V

( Reporti ng Requi rements

for a

Bri dge Deck

Condi ti on Report )

Deck condi ti on

i s

of ten repeti ti ve f rom

as

curb

l i nes,

pan-to-span and

i n

speci f i c

l ocati ons,


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transverse j oi nts,

etc

.

Vari ous

typi cal

condi ti ons shoul d

be

i denti f i ed Deck

l ocati ons

exhi bi ti ng each type

and extent of

di stress shoul d be sel ected

for

core anal ysi s

I t may not be

necessary

to core each span

of

mul ti pl e-span

structure

unl ess di fferi ng condi ti ons

exi st,

but the Desi gner must be

sati sfi ed that al l these condi ti ons are eval uated The cori ng

Engi neer, based

on

resul ts

for

cores

as

they are

extracted,

w l l

resul t

i n

the

most

eff i ci ent use

of

cori ng

and

el i mnate

the possi bi l i ty of msi nterpreti ng di stress observed

i n the

core

. Cores can become damaged due to i mproper cori ng

excessi ve down pressure, worn bi t, rei nforcement wedgi ng

i n

the

core

bi t,

etc

.

The

i nteri or

of

the core

hol e shoul d

always

be

i nspected

to confi rmthe condi ti on

of

broken

core

.

By

i nspecti ng

the i nteri or of the

core,

the

ori entati on of

the

rei nforci ng bars, cover on the transverse and l ongi tudi nal

rei nforcement,

and

the depth of

the

core

and of

del amnati ons

can be determned . Compari son

of

the core to the core hole

l i ni ng can

determne i f

cracks

i n the core represent

the

deck

condi ti on

or

damage caused by

the dri l l i ng

operati on

Cores shoul d

be

taken

wth maneuverabl e pavement core

dri l l

for

access

to

curb

l i ne or

other restri cted

areas,

usi ng

4-

di ameter,

thi n-wal l ,

di amond-bi t

core barrel s They

shoul d i deal l y be taken compl etel y through the deck to permt

ful l -depth

concrete

and

l ower-mat

rei nforci ng

steel

eval uati on

However,

when

core

retri eval

i s

not possi bl e

from

the

deck undersi de,

the

core

may be

broken

off

j ust bel ow

the

l evel

of the

bottomsteel

mat . I n any

case, the core

bi t

shoul d progress wel l i nto the

structural

sl ab . When taki ng

them on spans

havi ng corrugated-steel stay-i n-pl ace

form,

cori ng

shoul d

be di sconti nued when

water

i s l ost through the

perforati on made i n the corrugati ons by

the

dri l l

.

Cori ng

compl etel y through a rubbl e structural deck can cause surface

whi ch may

be

hazardous

to

traff i c

and requi re

mai ntenance I f thi s condi ti on i s encountered,

cores may be

broken off

short

to l eave

base to

core hol e patch

On mul ti pl e-course decks,

i t i s

general l y

best

to

core through

i ndi vi dual courses

and retri

these before conti nui ng

i nto

the structural sl ab . Cori ng

through cold-patch materi al shoul d

be

avoided

as

thi s may gum

up the cori ng equipment and contamnate the

structural

concrete core

.

cave-

conti nu

su

hol d

pattern

shoul d

be

sel ected

so

that

an

esti mate

of

repai r

can

be

made

I f

after

the

i ni ti al i nspecti on

i t

i s

obvi ous

that

compl ete

deck repl acement i s warranted, then

no

cores

are

necessary

When cori ng, qual i f i ed Engi neer preferabl y the Desi gner

responsi bl e

for the

bri dge

rehabi l i tati on,

must

be present .

Modi f i cati on of

the

ori gi nal cori ng pattern by

qual i f i ed


13/88

When cori ng top

sl abs over prestressed concrete box-beam and

prestressed concrete sl abs the bi t shoul d not be

al l owed

to

penetrate through the slab i nto

the

structural

member

Core

Tests

The fol l ow

of

both mono

re tests are equal l y

appl i cabl e

to eval uati on

i s

and

two-course

bri dge decks

Vi sual Anal ysi s

Of

Cores

Because the pri mary reason for taking concrete deck cores

i s

to veri fy apparent surface condi ti on

such

as

rei nforci ng bar

corrosi on most cores

shoul d

be taken for

vi sual anal ysi s onl y

When eval uati ng top

rei nforcement

the

core need onl y

be

taken to

the

top rei nforci ng

mat

When core

i s

taken to eval uate

vi si bl e di stress of

the

deck undersi de ful l -depth

core

shoul d

be

obtai ned

where possi bl e

Vi sual examnati on

of

deck cores i s the pri mary means

of

determni ng the soundness

of

deck

concrete

Cores

shoul d be

physi cal l y

tested onl y

to

resol ve questi ons

that cannot

be

answered

by

vi sual examnati on

Vi sual examnati on must i ncl ude wri tten documentati on to

detai l general condi ti on

of

each core

The examnati on

shoul d

be

compl eted by

qual i f i ed

Engi neer

and i ncl ude

depth

of

cori ng rebars encountered and thei r posi ti on

wthi n the

core and f i el d data and

notes

to

hel p

di fferenti ate between cori ng

damage and

concrete

deteri orati on

Vi sual

examnati on

shoul d

i ncl ude

usi ng

magni fyi ng

gl ass

cl ean broken face examned under magni f i cati on

wl l show

hi dden

detai l s such

as

f i ne cracki ng and/or

the

presence of entrai ned ai r

Vi sual

examnati on

and

documentati on of each core

shoul d

i nclude the

fol l owng

:

Deck Condi ti on Deck surface and undersi de condi ti on i n

the area of the

core

should be noted to record the

purpose of the core

Note core

depth and

whether

i t i s


14/88

Laver

Thi ckness .

f

al l

concrete l ayers are i ntact,

t i s

wl l onl y entai l measurement

of

the core

. I f

rubbl e or

broken

l ayers are

encountered,

thi ckness and

ori gi nal

posi ti on

i n the deck must be

determned by measuri ng

i nsi de

the core

hol e

.

Thi ckness, type, and

condi ti on of

al l

materi al s, i ncludi ng

bi tumnous

overl ays

or

patches,

shoul d

be

noted Where a

membrane

i s

present,

i ts

thi ckness, type,

and condi ti on shoul d

al so be recorded .

Rei nforci ng

Si ze

l ocati on,

and

condi ti on shoul d be

noted .

The rebar may have

to be

broken

out of

the core

to

veri f y potenti al measurements

by observi ng

corrosi on

deposi ts on both

the rei nforcement and

adj oi ni ng concrete

surfaces

Concrete Condi ti on

Thi s coul d range f rom

sound to

rubbl e

Smooth and dense

mortar

i n the

core

ci rcumerence

i ndi cates

sound concrete

Rough,

porous

mortar

i ndi cates

poor-qual i ty concrete

Poor concrete

consol i dati on duri ng

placement

can

resul t

i n

excessi ve

entrapped

ai r

honeycombi ng, bughol es),

resul ti ng i n poor

concrete

strength and

durabi l i ty

Cracki ng

descri pti on shoul d

i ncl ude

whether i t

i s

hori zontal , l ayered

seri es

of

hori zontal cracks),

or

verti cal ,

and

whether

i t

goes through or

around the

coarse aggregate

Cracks

through coarse

aggregate

i ndi cate

that they

occurred af ter the

concrete

devel oped

strength . Cracks

goi ng around

coarse aggregate i ndi cate

shri nkage or a one-ti me

overstressi ng very earl y i n l i fe

of the deck, before

concrete coul d

devel op strength

needed to resi st the l oadi ng condi ti on

Core Photographs

C oseup

photographs

of

each core

shoul d be

taken

for

permanent vi sual

documentati on

Cracks whi ch are a resul t

of

the

cori ng operati on

shoul d

be

i denti f i ed

b

Laboratory Core Testi ng

cores submtted

to

the Materi al s

Bureau for testi

be

properl y marked wth Core

I D

Number and tests to

be

performed usi ng

a

permanent

marker) A

memorandum

descri bi ng test

i nstructi ons, where the resul ts

shoul d

be

sent,

and

who

shoul d be contacted

i f

questi ons ari se,

must

accompany

the

cores

.

Do

not

send

weari ng course

segments or other

porti ons

of

a core unl ess they

are to

be tested

.

No

test can

be

performed

on

rubbl e

.

f there

are segments,

each

shoul d

be

marked wth Core

I D

Number

and

test to

be

performed

. Mul ti pl e testi ng on the

same


15/88

concrete speci men resul ts i n erroneous resul ts,

and

thus

must

not be

requested

Chl ori de

testi ng,

however,

can

be

performed on a

speci men

before a f reeze-thaw or ai r

content test

wthout

affecti ng l ater resul ts I f

more

than

one

test

i s

desi red

on

a

whol e

core,

i t

may be

segmented

to

al l ow

for

mul ti pl e

testi ng The core shoul d

be

marked to l ocate each

cut

avoi d cuts through

rei nforci ng steel Resul tant segments shoul d have Core

I D

number

and

test

to

be

performed marked

on

them as

fol l ows :

d= 4

Compressi ve

Strength

Testi ng

Thi s quanti f i es

the degree of concrete

soundness

Concrete wth no deteri orati on or vi si bl e cracki ng

i s

proved strong

and

sound usi ng thi s test

I t

i s

not

necessary

or

desi rabl e to test

al l

cores

for

compressi on

Onl y a

few careful l y sel ected

cores shoul d

be

tested

Cores shoul d be i n good condi ti on I deal l y, they shoul d

be at

l east

8

i n l ong, but l engths as short as

4

i n may

be tested

They shoul d

not

have rei nforci ng

steel

i n

thei r sides ; steel through the core mdpoi nt

i s

okay

Concrete

strengths

of

3,500

wthstand the ri gors of re

hi gh-pressure water bl asters

eval uati on shoul d be made before a

appropri ate

deck treatment i s made

There

concrete strength bel ow whi ch rehabi l i tati on woul d be

prohi bi ted

wthout addi ti onal study

ess

may be unabl e

to

j ack hammers and

i onal cores and

i si on

on the

o

mni mum

C

C

CORE O O

COMPRESSI ON h=

4

mn R R

E

E

2 2

CORE

F&T

HPA

F&T


16/88

( 2 )

Ai r Content of Concrete Cores

The

hi gh

pressure

ai r

( HPA)

test

measures total ai r

content

of

hardened

concrete

About

1

to

2 of

thi s

total

i s

entrapped

ai r,

and the

rest entrai ned

ai r Ai r

entrainment, wth

ai r

bubbl es

of the

proper size

and

di spersi on, provi des concrete wth

resi stance to water

f reeze-thawdamage As wth compressi on testi ng, onl y a

fewsel ect cores shoul d be tested for ai r

Thi s does

not

requi re

a

whol e core

; a i n or

l arger

pi ece of concrete

can be used

Usual l y,

ai r

testi ng

i s not

even necessary

Concrete

that has resi sted

f reeze-thaw

di stress for years has

wthstood the

test

of

ti me

Exi sti ng deck concrete

sti l l

i n repai rabl e condi ti on, whether ai r entrai ned or not,

wl l be

protected

by

an overl ay

system

Total

ai r

contents rangi ng from

4

to

9

assure

good

durabi l i ty

Concrete wth l ess than 4

entrained

ai r

usual l y has poor resi stance to f reeze-thaw damage and

must be protected i f retai ned Concrete wth hi gh total

ai r

(greater than 9

may be invest i gated for strength,

as

compressi ve strength decreases wth i ncreased

ai r

content

However,

i f the

deck

i s

st i l l

i n

good

condi ti on

then compressi ve strength shoul d

be

okay

Concrete f rom ol der structures (bui l t before 1950)

probabl y

wl l

not contai n

i ntenti onal l y

entrai ned ai r and

testi ng

shoul d not

be necessary

Between

1950

and

1960,

natural cements

were

used

wth

dry

powdered ai r-agent

admxtures,

and

special

speci f i cati ons cal l i ng

for

separate ai r entrai ni ng admxtures Al l thi s provided

some

entrained ai r and varyi ng protecti on ;

these

structures

may be tested for ai r content Monol i thi c

decks showng di stress such

as

scal i ng shoul d

be

tested

for ai r

content

Freeze-ThawTesti ncl

O

Concrete

Thi s complements

the ai r

content test

Adequate

ai r

yi el ds

l i ttl e or no

f reeze-thaw

l oss of

concrete

but l ow

uces hi gh l oss The test measures percent l oss

(by

wei ght)

of

a

concrete

sample

compl etel y

submerged

i n

a

sal t (NaC )

sol uti on and subj ected to cycl i c f reezi ng

and thawng

Freeze-thaw

l osses of

l ess

than

1

at

25

cycl es usual l y

i ndi cate

good durabi l i ty

Those

greater

than

1

i ndi cate poor durabi l i ty

O der (before 1950)


17/88

non-ai r-entrai ned concrete

wl l general l y show hi gh

or

100

l oss, but

properl y

ai r-entrai ned concrete wl l have

l ow

l oss

or

none

These resul ts are an i ndi cator of concrete durabi l i ty .

Concrete wth

no

f reeze-thaw

l oss

wl l

performwel l

when

wet i n wnter, but

that

wth f reeze-thaw l oss wl l sl owy

di si ntegrate

Test l osses

of l ess

than

100

but more

than

1t

i ndi cate

concrete

that

wl l conti nue to

deteri orate

when exposed

to

addi ti onal cycles

Thi s test

wl l not predi ct

ti me

to deteri orati on, because

exposure condi ti ons

i n the f i el d are di f ferent and more

vari abl e than l aboratory condi ti ons

Concrete wth hi gh

l osses wl l

perform

wel l

i n

servi ce

i f i t

i s protected

and kept dry. As wth

ai r

content testi ng,

i f

f reeze-

thaw l oss is to be eval uated, onl y

a

l i mted

representati ve

number of

cores

shoul d

be

sel ected for

testi ng

Thi s cannot

be

run on

cores tested

for

hi gh

pressure ai r

or

compressi on, unl ess the core

i s segmented

as previ ousl y

descri bed .

E Chl ori de Measurement

Thi s techni que consi sts of

obtai ni ng

and testi ng powdered concrete

sampl es,

and i s descri bed i n the

Fiel d Survey Manual

Samples can

be

obtai ned di rectl y f romthe structural sl ab

or

cores taken f rom

i t Chl ori de testi ng

shoul d be conf i ned onl y to sound deck areas

that are to remain after rehabi l i tati on. H gh l evel s of chl ori de

>_

1 3

l b/c

y

of

concrete), when

moisture and

ai r are

present,

cause

accel erated

rates

of

steel corrosi on

Because overl ay

materi al s prevent

or

mni mze

moi sture and

ai r f romreachi ng the

underl yi ng concrete,

Department pol i cy

i s to

l eave hi gh chl ori de-

contamnated

concrete

i n pl ace

Thi s

testi ng

thus i s

not requi red

for monol i thi c decks because i t has no beari ng on the type

of

repai r .

Chl ori de testi ng

on two-course

decks

may

hel p a Desi gner

est i mate

concrete removal quanti ti es

for the

underl yi ng structural slab

Structural sl abs wth l owchl ori des have been ef fecti vel y protected

over

ti me,

and thus wl l probabl y

requi re l i ttl e i f

any

concrete

removal resul ti ng

f romcorrodi ng

rei nforci ng steel

Thi s

testi ng

i s

used onl y

for

esti mati ng

removal

quanti ti es

.

Fi nal deci si ons

on

removal shoul d

be

based

on

del amnati on

and

potenti al

surveys made

af ter

the weari ng

course

has

been removed


18/88

Thermography

Thi s method i s used

to

detect del amnati ons wth an

el ectroni c

thermometer devi ce mounted

i n

a

movi ng

vehi cle

I t

i s

effecti ve

onl y on

monol i thi c

bri dge decks

and thus i s

i nappropri ate

for

two-

course decks

Because

data

are

col l ected from

a

movi ng

vehi cl e,

M PT requi rements are mni mal

I ts

use shoul d be l i mted

to

hi gh-

traff i c l ocati ons where safety and

cost

are pri me

consi derati ons

The

Structures

Dvi si on or the Fi el d

Engi neeri ng

Secti on of the

Materi al s Bureau

shoul d be

contacted before usi ng thermography

to

assure i ts proper use

Thermography

data

pl otted

on

a

gri d

map

i denti fy

areas

for concrete removal

G

Radar And

I mpact

Echo

These

are

methods that have been used experi mental l y on

several

smal l bri dge

decks, and are not

yet perfected

for detecti ng

del amnati ons

A though they

can

be

used

on

monol i thi c

decks,

they

are most advantageous on two-course decks

Resul ts

of the

i mpact

echo are

very

promsi ng The Materi al s Bureau

i s

sti l l devel opi ng

these eval uati on

procedures

I f i nterested i n

usi ng these methods

contact the

Fi el d

Engi neeri ng I Secti on

of the Materi al s

Bureau

(518-457-5956)


19/88

Tabl e

. -

DeckEval uati on Methods

Evaluati orl Method Purpose

Output

Vi sual Examnation Locate

cracks

spal l s

patches Dstress Map

and

other

obvious signs of

di stress

Sounding Locate delamnated

areas not

Delamnati on

vi sual l y

evident Map

Potenti al Survey Locate areas of acti vel y Potenti al

corroding reinforcing steel

Map

Coring Investi gate

areas

where deck Core Data

structural

i ntegri ty

i s

suspect or

where depth of

deteri oration i s unknown

Use in any

questionabl e

areas

not

adequately def i ned

by

other

techniques and to

veri fy

accuracy of sounding

and

potenti al surveys

Chlori de Measurement Determne quanti ty of chl ori de Chl ori de

i on

concentrati on t

the

rebars

Data

Thermography

Locate delamnated areas

Delamnati on

through

measurement

of deck Map

temperature di f ferences

Radar

and I mpact

Echo

Experi mental

methods o

Delamnati on

l ocating deck del amnati ons

Map

May

be

especi al l y usefu

on

two-course

decks


20/88


21/88

I I I .

DECK TREATMENTS

Thi s chapter defi nes

vari ous deck treatment opti ons

and descri bes

thei r

advantages

and

l i mtati ons

. I nformati on

i s

provided

on

rehabi l i tati on

tasks i ncl uded

i n

the treatments, expected

servi ce

l i fe

and treatment

cost, and

a

procedure

for

economc anal ysi s

of

the al ternati ves

.

A Deck Treatments

1

.

Non-Protecti ve Treatments

Mai ntenance

of the exi sti ng surface

or appl yi ng

an

asphal t

overl ay

wthout a waterproof

membrane are consi dered

non-

protecti ve .

Under these treatments,

the deck conti nues

to

deteri orate,

resul ti ng

i n

further structural

damage . Thi s

damage

i n

turn

i ncreases the

cost

of subsequent

treatments

whether those

are

protecti ve

or

non-protecti ve

. Thus,

al though

thei r i ni ti al cost

i s l ow

the l ong-termpenal ty

must

be

recogni zed

.

Because

deteri orati on

conti nues under

non-protecti ve

treatments,

thei r

use

shoul d

be l i mted to

short-term

appl i cati ons

.

Asphal t

overl ays or mai ntenance

treatments

are

effecti ve

for

keepi ng a deck

i n servi ce unti l

i t

can be

repl aced .

Mai ntenance

fi l l i ng of

i sol ated

pothol es duri ng

the

peri od

between eval uati on and

desi gn

of

a deck

rehabi l i tati on

and i ts constructi on

i s al so an appropri ate

use

of

asphal t

concrete

2

.

Protecti ve Treatments

Asphal t overl ays

wth

waterproof

membranes and

concrete

overl ays

are al l

protecti ve

treatments,

extendi ng deck servi ce

l i f e

Asphal t overl ays

wth protecti ve

membranes have shorter

servi ce

l i ves than ri gi d

concrete overl ays .

Gven

favorabl e

roadway

geometri cs and traff i c,

the overl ays

average

up

to

11

years of servi ce . The

protecti ve

membrane

has an

est i mated

l i fe

of

22

years .

Asphal t concrete,

especi al l y

i n

combi nati on

wth

a

protecti ve

membrane, i s very

sensi ti ve to

pl asti c deformati on

(shovi ng/ sl i ppage) fai l ure .

The

asphal t /membrane systemthus

shoul d not be

used

on

hi gh-traff i c

roadways > 5,000

AADT),

steep

grades

>

4 ,

sharp curves

i e

.

ramps) ,

and maj or

i nterchanges wth

on/off ramps, which subj ect the

pavement to

severe

accel erati on and

decel erati on forces .

I n

such

si tuati ons, asphal t

concrete

servi ce l i fe

w l l

be

overl ay system


22/88

shoul d be sel ected Asphal t

concrete/membrane

system are

best sui ted

to rural ,

through-traff i c

structures where l onger

servi ce

l i ves are

desi red

For both

protecti ve treatments, the extent

of

deep

removal i s

the

maj or

factor

i n

servi ce

l i fe and

cost

It is not possi bl e

to determne rel i abl y

the

i nf l uence

of

vari ati ons

i n

amount

of

deep

removal on servi ce l i f e Accordi ngl y,

sel ecti on

of the

appropri ate amount

of

deep

removal

must be based

on techni cal

rather than economc

factors Del amnated

areas and those

experi enci ng

acti ve corrosi on

are

the

i ni ti al

i ndi cators

i n

determning how much concrete

to remove Smal l

i sl ands and

narrow

peni nsul as

of

concrete surrounded

by

areas

of

hi gh

hal f-cel l

potenti al readi ngs shoul d

al so

be

cleared

These

areas

may deteri orate rapi dl y

after uncontamnated

concrete

i s

pl aced

adj oi ni ng

them

I n

general ,

i sl ands

and peni nsul as

shoul d

be

removed when there area

i s l ess

than 100 sq

ft

or

the smal l est di mensi on i s

l ess than

ft

I n

addi ti on,

the

percentage

of

removal shoul d

be consi dered

I f

onl y a

smal l

area

requi res repai r

the

work shoul d

be

confi ned to that

area,

but where the

percentage i s hi gh i t

may

be desi rabl e to

remove

100 percent

These

i ssues are

di scussed

further i n

Chapter I V

Deck Repl acement

Deck repl acement

i s

the treatment

opti on wth

the hi ghest

fi rst

cost

and shoul d be consi dered to be a

l ast resort Deck

mai ntenance

and

rehabi l i tati on must be

careful l y managed to

delay

repl acement

for the l ongest

possi bl e ti me

A deck may

have onl y l ocal i zed areas

of

deteri orati on

through

i ts

ful l

thi ckness

Ful l -depth repai r shoul d

be

l i mted

to those

areas

ss economc

anal ysi s shows compl ete repl acement

to be

i f

i ed

Deck

Rehabi l i tati on Tasks

Regardl ess

of the deck treatment

sel ected,

constructi on

tasks

may be performed

:

Weari nq Course Removal

Removal of asphal t

or

concrete overl ay

Structural

Sl ab

Scari f i cati on

several

common

Deck concrete

i s

removed by

mechani cal

scari f i cati on

Unl ess a greater depth i s

i ndi cated on the pl ans, the

concrete i s removed to

a

mni mum

of

l j 4

i n

and

a maxi mum

of 1/2

i n

When 100 deep removal

i s

speci f i ed,

thi s

pay

i tem

i s

not

used


23/88

Rei nforci ng Bar Exposure

I n

thi s

operati on,

commonl y

referred

to as

deep removal ,

structural

concrete

i s removed fromthe peri phery

of

the

uppermat rei nforci ng bars to provide a

mnimum

1-i n

cl earance between the rei nforci ng bar

surface

and

remaini ng concrete surface Deeper concrete

removal may

be needed to reach sound concrete

Rei nforci ng

Bar

C eani ng

Bl ast cleani ng

to

remove

al l

grease, di rt, concrete,

mortar, and i nj uri ous rust from rei nforci ng bars

I nj uri ous

rust i ncludes

al l scal e,

l oose rust

deposi ts,

or al l

rust not

f i rmy bonded to the steel

Bar

cl eani ng

i s paid under

the payment

i tem

for

concrete

overl ays

5 Sl ab Reconstructi on

Pl acement

of

concrete

around exposed rei nforci ng

bars

to the

l evel of

the surroundi ng concrete or

to

1 2 i n

above the rei nforci ng

steel

Bondi ng grout

i s pl aced

on al l surfaces recei vi ng

sl ab reconstructi on

concrete,

whi ch may be ei ther C ass D

or

one

of the

speci al i zed

concretes used

for

overl ays

6

waterp

r

oof

M

embra

n

e

Ano

i cati

Protecti ve membranes

appl i ed

to the

concrete

deck

An

asphal t

overl ay i s pl aced over

the

membrane

7

overl ays

Asphal t

and concrete overl ays are

used

Asphal t overl ays

are the

same

materi al and

i nstal l ed

by the

same

procedures

as highway

pavement top

courses

Special i zed

concrete materi al s

are

used

for

concrete overl ays C ass

E

Concrete

i s

used when

the f i nal overl ay

thi ckness wl l

be greater than

3 i n

One of the special i zed concretes,

at

the

Contractor s opti on,

i s

used

for overl ays

3 i n

l ess i n thi ckness

The speci al i zed

concretes

ncl ude :

H gh Densi ty Concrete

cement concrete

of

very hi gh densi ty

from standard concreti ng materi al s, wth a

requi red sl ump between

1/2

and

i n

The m

thi ckness

of

overl ay concrete i s 2

i n


24/88

b

c

.

Transverse

texturi ng .

Latex Modi f i ed Concrete

A portl and cement concrete

wth styrene-butadi ene

l atex

admxture The mni mumthi ckness

of

overl ay

concrete

i s

1-1/2 i n

Mcrosi l i c

Concrete

A portl and cement

concrete

wth mcrosi l i ca

admxture

. The mni mum thi ckness

of

overl ay

concrete

i s

1-1/2 i n

Saw

Cut

Gri ndi ng Requi red

to

achi eve

macro-

Appl i cati on

of these tasks

to

the vari ous rehabi l i tati on

treatments

i s gi ven

i n Tabl e 2

C

Servi ce Esti mates

Servi ce l i fe has been esti mated

for

each treatment . Servi ce Li fe

means l ength

of

ti me

that parti cul ar treatment wl l l ast before

addi ti onal deck work

i s needed The

formal

def i ni ti on

i s the age

at whi ch

50% of

decks devel op del amnati ons

over

40% of thei r

surface areas . The ori gi nal

esti mates

(1986) were based on

i nterpretati on

and

eval uati on

of

deck deteri orati on

data by

the

Techni cal

Servi ces D vi sion More recent studi es

have not i mproved

those

esti mates,

but

suggest

that

amount of deep removal

and

qual i ty

of

the

removal

and reconstructi on speci f i cati ons

strongl y

i nf l uence

the

servi ce l i fe obtai ned

. Thus, there

i s

evidence that

servi ce l i fe depends on

the amount

of

deep removal , but

i ci ent data

to

rel i abl y

predi ct

the

magni tude

of

thi s

ef fect

.

recogni zed

that

l ocal

condi ti ons

and

experi ence may support

use of

di f ferent val ues for servi ce

l i f e

. Tabl e i ndi cates

servi ce

l i ves

for

each treatment

Tabl e

2

Deck Rehabi l i tati on Tasks

Asphal t Concrete

Concrete

Wth

After

Sel ect

After

100%

Task

Asphal t Membrane

Deep Removal Deep

Removal

i ng

Course Removal As Needed

As Needed As Needed As Needed

Scari f i cati on

Not

Requi red

Not Regd

Requi red

Not Reqd

Rebar Exposure

As Needed As Needed As Needed

Requi red

Rebar C eani ng As Needed

As

Needed

As

Needed Requi red

Sl ab Reconstructi on As

Needed

As Needed As

Needed

Requi red

Wterproof

Membrane Not Requi red Requi red

Not

Reqd

Not Reqd

overl ay

Requi red Requi red

Requi red Requi red


25/88

Tabl e 3 - Performance

Esti mates

The asphal t overl ay wth waterproof

membrane

treatment

requi res resurfacing after

11

years

Treatment

Costs

Determnati on

of

treatment costs

i s di f f i cul t

because of

the

many

vari abl es invol ved For speci f i c proj ects costs shoul d

be

esti mated usi ng

regi onal

val ues The bri dge rehabi l i tati on modul e

of the

Prel i mnary Esti mate Program

PEP) shoul d

be used

for

thi s

purpose

Ai . ' ysi s

of 1989

weighted average bi d pri ces

produced

the statewde

ave

e

values shown i n Tabl e 4 I t must be emphasi zed that these

val ues

and al l cost val ues shown i n thi s Manual are for

i l l ustr

ve purpose

onl y,

and shoul d

not be taken to

represent

actual cc :

:

experi enced

i n

any

regi on

I n

addi ti on,

concl usi ons

resul ti ng

from

appl yi ng

these costs

are

not

i ntended

to

be

absol ute

Onl y costs speci f i c

to

a proj ect shoul d be used

i n

selecti ng deck treatments

Treatment

Mai ntenance Onl y

Servi ce

Li fe,

Years

- -

Asphal t

Overl ay 4

Asphal t

Wth Membrane

22*

Concrete Overl ay (Sel ect Deep Removal ) 25

Concrete Overl ay

(100

Deep

Removal )

35

Repl acement

Deck

40


26/88

Tabl e

4

Statewde 1989 average

weighted

bi d

pri ces

Descri pti on

Asphal t W

C Removal

Scari f i cati on

Rebar Exposure

Waterproof Membrane

Type 6F Top

Course

Type 3 Bi nder Course

Concrete

Overl ay*

Concrete Removal

Concrete Pl acement

Steel

Reinforcement

Transverse

Saw

Cut

Groovi ng

Composi te

of

speci al i zed concrete overl ay

materi al s

These costs are combined as necessary to esti mate

expense of

a

treatment

on

a speci f i c proj ect For exampl e:

cost

1 . 34/Sq

. Ft

. 99/Sq

. Ft

12

. 61/Sq. Ft

. 07/Sq. Ft

39. 49/Ton

36

. 50/Ton

4

. 89/Sq

. Ft

12 . 30, / Sq

. Ft

22. 34/Sq. Ft

. 0 . 78/Lb

0

. 64/Sq

. Ft

Sel ect deep concrete removal i s assumed

to i nvol ve 50%of the

deck

area Cost of deep removal

i s l arge wth respect to the other

i tem compri si ng a deck rehabi l i tati on I t i s thus appropri ate

for

the speci f i c

deck

bei ng i nvesti gated here

I t i s

i mportant

to

remember that amount

of

deep

removal

i s

a functi on of

deck

condi ti on,

not i nfl uenced

by the

type

of overl ay to be

used

Usi ng

pay i temdata, cost

of

the treatment

can be

expressed

as

a

functi on

of percent

deep

removal

Treatment

Cost/Sa. Ft

Asphal t Wth Membrane

11

. 52

Concrete (Sel ect Deep Removal )

15

. 27

Concrete

(100% Deep Removal )

23

. 03

Replacement Deck

39

. 60


27/88


28/88

Except for

non-protecti ve treatments,

bri dge deck rehabi l i tati on

al ternati ves have servi ce

l i ves over

20

years Because

of

these

l ong

l i ves,

there

has been no

experi ence

wth retreatment . Lacki ng

such

experi ence, i t

may be

assumed that the same

sequence

of

acti ons

w l l

be

repeated, except when the present

treatment

i s

non-

protecti ve

Thus,

the possi bl e

treatment

sequences

are 1)

a

non-

protecti ve treatment

fol l owed at

the

end of i ts

servi ce

l i fe

by

repeated

appl i cati ons

of

a protecti ve

treatment, 2)

deck

repl acement fol l owed by repeated

appl i cati ons

of

one

of

the

protecti ve

treatments, or

3) one of the protecti ve

treatments

repeated as

needed

As an

exampl e

of

l i fe-cycl e-cost

anal ysi s,

assume

the fol l ow

treatment costs

and

servi ce l i ves :

Two

treatment sequences

have been determned to provi de

techni cal l y

appropri ate

sol uti ons for a deteri orated

deck

Sequence A i nvol ves

an

i mmedi ate asphal t overl ay wth

a

deck repl acement i n 4

years

Sequence B i nvol ves

sel ect deep

removal

and overl ayi ng

at 25-year

i nterval s .

Compare

the

l i fe cycl e costs

of

these treatments

usi ng

a

di scount rate of

4%

Sequence

A =

1

. 92

+

39

. 60 x SPPWF = 35. 77fsq

f t

For

Sequence B,

two

appl i cati ons

provi de

50

years of servi ce

compared to

the

44

years

provi ded

by

Sequence A

Accordi ngl y,

Sequence

B

costs must be

adj usted

to a pl anni ng

hori zon

of 44

years :

Sequence

B = 15

. 27

+ 15. 27

x CRF

x

USPWF1 9

x

SPPWF

20. 09J sq

ft

Sequence B cl earl y has the l ower

l i fe-cycl e cost

-22-

Treatment

Cost Servi ce

Li fe Years

Asphal t Overl ay

1 . 92

4

Sel ect

Deep

Removal

15

. 27

25

Replacement

39

. 60

40


29/88

ECTION

Vari ous

treatments

and techni cal

recommendati ons

for

sel ecti ng

sui tabl e appl i cati ons have been descri bed

i n

Chapter I I I Based

on

techni cal consi derati ons,

cri teri a

can

be

establ i shed

that

el i mnate parti cul ar

treatments

f romfurther considerati on

Havi ng

narrowed the f i el d

of

possibl e sel ecti ons, a f i nal choi ce can

be

based on economc compari sons

C earl y, such compari sons shoul d

not be performed

on

treatments that do

not

sati sfy

the

proj ect' s

techni cal needs

Deck Rehabi l i tati on

A

fundamental

consi derati on

i n

i denti fying sui tabl e treatments i s

determni ng whether protecti ve

or

non-protecti ve acti on i s

appropri ate

I n

general , non-protecti ve treatments shoul d not

be

used

except

where

the

deck

must be kept

n

servi ce rel ati vel y

bri ef l y unti l repl acement Use

of

non-protecti ve treatments to

provi de servi ce unti l a protecti ve treatment

can

be

appl i ed

shoul d

be di scouraged

Deck deteri orati on devel ops

gradual l y and

onl y

rarel y can appropri ate

protecti ve

treatments not be normal l y

programmed Under a non-protecti ve treatment deck deteri orati on

may accel erate, resul ti ng

i n

i ncreased cost for future protecti ve

treatments

For protecti ve

treatments, two

i ndependent deci si ons

are

needed

area

of

concrete deep removal f romaround the top rebar

mat and

type

of overl ay materi al Deep removal area i s the more i mportant

and di f f i cul t deci si on Both techni cal and economc consi derati ons

shoul d be examned to resol ve

thi s

i ssue Appropri ate area of deep

removal

does

not

depend

on

type

of

overl ay materi al

The

fol l owng di scussi on

i s

di rectl y

appl i cabl e to both two-course

and monol i thi c bri dge decks For two-course decks,

whether

the top

course

i s concrete or asphal t,

deck

condi ti on eval uati on methods

di f fer

as

di scussed i n Chapter

I I

Except for condi ti on

eval uati on,

however,

there shoul d

be

no

di f ference

i n

the

way

rehabi l i tati on

treatments

are

sel ected

The

obj ecti ves

of

a

condi ti on eval uati on

are to

determne i f the deck can

be

rehabi l i tated, and i f so the

mni mum

amount of rebar exposure

requi red

Wth

thi s

mnimumdetermned, the appropri ate treatment

i s

sel ected

i ndependent

of

exi sti ng deck type

Three i ndi cators

of

monol i thi c deck condi ti on

are

used i n

determni ng

the

need

for

deep

concrete removal

and i ts

extent

--

spal l s,

del amnati ons, and

hal f -cel l potenti al

measurements

greater

than

. 35

v

pal l s are

the

pri mary

i ndi cator because wthout thi s

vi si bl e i ndi cati on

of

deck

fai l ure further

deck eval uati on

i s

2 3


30/88

unnecessary

Del amnati on

and

hal f -cel l potenti al woul d not

ordi nari l y be measured unl ess

such evi dence

of

deteri orati on were

apparent

Deck deteri orati on

i s

conveni entl y

reported

i n

two ways -- as area

of

spal l s,

or as

total

damaged area,

both

expressed as

percent

of

deck

area

Total

damaged

area i s

taken as the sum of

non-

overl appi ng area

of

spal l s,

del amnati ons,

and hal f-cel l potenti al s

greater than

0

. 35 v

These

i ndi cators

provi de

a

quanti tati ve measure of deck condi ti on

and

i denti fy deck

areas

that are

currentl y damaged or acti vel y

corrodi ng

The total

damaged concrete

area, as

a

mnimum

must be

removed to a l evel

at

l east

1 i n

bel ow

the top

mat

of

rei nforcement There are addi ti onal ,

l ess

obj ecti ve

reasons

for

i ncreasi ng

the

area

of

deep concrete removal Hal f-cel l potenti al

measurements on recentl y repai red

decks i ndi cate

that corrosi on

acti vi ty often

i ncreases

dramati cal l y

i n concrete

that i s l eft

i n

pl ace

Thus,

concrete that

di d

not warrant

removal

because

of

hal f-cel l

potenti al

readi ngs before repai r may show val ues that

woul d

j usti fy removal

after repai r

Thi s concrete general l y has

medi umpotenti al 0

. 15

to

0

. 34) before removal

and

represents a

deck area

l ess

than the total damaged area

To

el i mnate the

possi bi l i ty of premature fai l ure of the rehabi l i tated deck, these

areas shoul d

be

removed

accordi ng to the

fol l owng

cri teri a

;

1 I f the sumof al l

medi umpotenti al areas equal s

or

i s

l ess

than total

damaged

area, then they shoul d be

removed Thi s compari son shoul d be on a span basi s

2

I f any medi umpotenti al

area

i s

l ess than

100

sq

f t

or

has

a

mni mumdi mensi on equal i ng or l ess

than

5

f t

. ,

i t

shoul d be

removed

The total area

to

be removed i s defi ned as the

sumof

total damaged

area and the areas j ust

i denti f i ed

by Cri teri a

1

and

2

The total removal

area

i s based sol el y on techni cal

consi derati ons

and

represents that necessary to assure that

at

l east hal f

of the

repai red deck achi eve the servi ce l i ves gi ven

i n

Chapter

I I I

At

some l ocati ons, condi ti ons

may

exi st requi ri ng greater confi dence

i n l ongevi ty of the rehabi l i tati on Speci f i cal l y, 100 deep

concrete removal

may

be

j usti f i ed

on

bri dges

i n

urban

areas

wth

hi gh-traff i c densi ty whenever

one or

more

of

the

fol l owng

condi ti ons are met

:

2

Area of spal l s exceeds

2

i on exceeds

30

-24-


31/88


32/88

Al though cost

of

a

deck

repl acement i s substanti al l y greater

than

that

of a deck rehabi l i tati on, the deci si on to repl ace

i s

pri mari l y

techni cal I ndi cati ons

of

deck undersi de

dampness or

ef f l orescence

strongl y

suggest need

for

repl acement Presence

of

del amnati ons

or

spal l s

on

the undersi de

of the

deck

necessi tate repl acement

These

condi ti ons may be l ocal , and part i al ful l -depth repai r may be

al l that

i s

necessary

to restore the deck

Neverthel ess, M & PT

cost and user del ays may j usti fy

complete repl acement

Cost esti mat

mni

requi

determ

shoul d

eval uati on

Deck Replacement

Treatment Sel ecti on Consi derati ons

Usi ng the methods expl ai ned i n Chapter I I I , total present worth of

each deck treatment that

wl l remedy the deck' s techni cal

def i ci enci es

can be est i mated

Al though thi s est i mate i s a

representati ve

val ue

for

true cost

of

deck

rehabi l i tati on, i t i s

not

appropri ate si mpl y to sel ect the treatment wth l owest present

worth

Cost

esti mati ng

i s

not

an

exact sci ence

and

even

bi d pri ces

w l l

not

necessari l y ref l ect actual cost to

performthe work

Treatment

sel ecti on

shoul d favor the treatment wth l ongest

expected servi ce

l i f e

Thus, smal l premum

for

addi ti onal servi ce

l i fe are warranted

The si ze

of an

acceptabl e premum

i s

sensi ti ve

to

l ocal

condi ti ons

and concerns

and

i s

thus lef t

to the

di screti on

of

the i ndi vi dual

regi ons

D

Examples

Two examples o cost esti mati ng and proj ect sel ecti on

are

gi ven

i n

Appendi x

B

I n the fi rst, a 6,400 sq f t

deck, the di f ference

i n

present

worth between

100%

deep removal

(35-year

l i fe)

and 50%

deep

removal

(25-year l i fe)

i s

onl y

5,850

(l ess

than

3

Total

i ni ti al

cost

of

the

treatment wth l onger

l i fe i s 23% l arger

( 51,600) than the

50%

removal

opti on Deck treatment costs are 56%

of total proj ect cost

I n

the

second exampl e,

two

i nterstate

bri dges

wth

a

total area

of

12,960 sq f t are

bei ng

rehabi l i tated Present worth o Al ternati ve

2

wth the l onger l i fe exceeds the 50% removal opti on

by

20,426

( 5

The

di f ference i n i ni ti al cost i s

104,593

(25 greater

than

the 50% opti on Deck treatment costs are 58%

of the

total cost

eral l y i nvol ves

compari son between cost

of the

of

deck removal

that

wl l sati sfy

techni cal

of

the

j ob

and that

of 100%

deep

removal

I n

the

techni cal l y acceptabl e

removal quanti ty,

care

to fol l ow

al l

provi si ons

of

thi s Manual

for

deck

Questi onabl e deck

areas shoul d al ways be removed

- 2 6 -


33/88

REPORTI NG REQU REMENTS

Thi s

Chapter expl ai ns how to document

f i ndi ngs of

the deck

eval uati on and present

them i n a manner

consi stent wth the

eval uati on

methods outl i ned

i n Chapter I I

It is

i mportant

that

al l

secti ons

of

thi s Chapter

be

compl etel y

sati sf i ed

to

document

deck condi ti on

properl y

and to support the

recommendati on

to repai r or repl ace the deck

Content

of the

secti ons

may

vary because

of

the severi ty of

deck

deteri orati on

or

extensi veness

of the

proposed

rehabi l i tati on

Appendix

C shows a

sampl e Bri d

ge

Deck Eval uati on Report

A

TI TLE : BRI DGE DECK EVALUATI ON

REPORT

I denti fy Structure

BIN Number

-

County

- Town C ty Vi l l age

-

Regi on

- Feature Carri ed

-

Feature Crossed

I NTRODUCTION

Bri dge H story

Year Bui l t

Bri dge

Type

- Structure Length

and

Out-To-Out Wdth

Previ ous

Work

Done

parti cul arl y on the deck

Planned Future

Work

H ghway Cl assi f i cati on

Traff i c

Vol umes

Pl an for

Mai ntenance and Protecti on

of

Traff i c

C

DECK INSPECTI ON

FI NDNGS

Thi s i ncl udes data

col l ected and devel oped duri ng deck

eval uati on f i el d work

A l survey work must

be recorded

by

span for

both

the top and

bottom

of

the deck

The fol l owng

shoul d

be

provi ded

for

revi ew

SKETCH OF DECK UNDERSI DE:

a

b

c

d

e

f

g

system

Crac

Damp

areas

Areas

of eff l orescence

Rusted

stay-i n-pl ace Form

Spal l s and ex

Other i ndi cati ons

of

deteri orati on

z7


34/88

Al l

deteri orati on shoul d

be

quanti f i ed

based on percentage of

the deck exhi bi ti ng the respecti ve

type of deteri orati on

2 COLOR PHOTO OF UNDERDECK

a)

Typi cal

good

areas

b) Areas

of

deteri orati on

i n

each

span,

showng

any

of

the seven types

of

deteri orati on

j ust l i sted

SKETCH OF DECK SURFACE :

a) Spal l s

b)

Cracks

c)

J oi nt probl em

d)

Patches

e) Other

i ndi cati ons

of deteri orati on

f ) Core

l ocati ons

g)

Areas

of

hi gh potenti al 0

. 35v), as

appropri ate

h)

Areas

of del amnati on, as

appropri ate

Al l deteri orati on shoul d

be

quanti f i ed on

percentage of

deck

exhi bi ti ng

the

parti cul ar type

of

deteri orati on

COLOR

PHOTOS

OF DECK

SURFACE :

a)

Typi cal good areas

b)

Areas

of

deteri orati on

i n

each span,

showng any of

the seven types

of

deteri orati on

5 Col or photos of the bri dge

i n

el evati on, approaches,

substructures,

and

any

probl emareas

6

Photo l ayout sheets

i ndi cati ng l ocati on

of

photographer

and camera ori entati on

7

I nspecti on

Form :

Copi es

of

Form TP349 and TP350 from

the

most-recent bi enni al i nspecti on

shoul d

be

revi ewed

for

comments pri or to

the

start of

the

deck

i nspecti on

These form shoul d be attached

to

the

deck report wth

addi ti onal comments

added, as

appropri ate

DECK CORE EVALUATI ON AND TEST RESULTS

DETAI LED

VI SUAL

EXAMNATION

General descri pti on

of

core s)

and

any

defects

Examnati on compl emented

by

f i el d data

and

notes to

hel p

di fferenti ate

between

any

cori ng damage and concrete

deteri orati on Examnati on shoul d al so determne

depth

and l ocati on

of

materi al s encountered

i n

the core

28


35/88

For each

core

or ser

a

Expl ai n

why thi s core l ocati on was sel ected

b Depth

of Cori ng Note whether core i s ful l -depth

or parti al -depth

and i f

appropri ate

the

reason

for

parti al -depth cori ng

Al so

note deck surface

and

undersi de condi ti on

i n the

core vi ci ni ty

c Note the thi ckness

of

l ayers

maki ng up the

core

I f

al l concrete

l ayers are i ntact

thi s wl l

onl y

entai l

measurements I f

rubbl e or broken

l ayers are

encountered thei r thi ckness

and

ori gi nal posi ti on

i n

the deck

shoul d

be

determned duri ng cori ng by

measuri ng

i nsi de

the core hol e Thi cknesses type

and

condi ti on

of

bi tumnous

overl ays or

patches

shoul d be

noted

d

Presence

of a

membrane

an

condi ti on

cores

report the f ol l owng :

thi ckness

type and

e

Rei nforci ng

steel l ocati on size and condi ti on

e g

1-1/

2

i n

cover

No 5 bar no rust A rebar wl l

of ten

have to be broken out of the core af ter

compl eti ng

i ts

examnati on

to

check

for

corrosi on

f Concrete

:

Condi ti on of the concrete may

range

f romsoundto rubbl e

kThi s di scussi on shoul d i ncl ude

al l observati ons resul ti ng f rom

the eval uati on

techni ques

suggested i n Chapter I I .

1

Concrete

Mortar

Qual i ty: type

depth and

amounts

of

deteri orati on shoul d

be

noted

a

Concrete mortar scaled

away

due to moi sture

f reezi ng

and thawng

b Concrete

spal l i ng

caused

by

i nternal

pressures such

as expansi ve

corrosi on

c A smooth dense

mortar on the core

ference i ndi cates

sound concrete

d

A

rough

porous core ci rcumerence i ndi cates

possi bl e

deteri orati on Cori ng may wash away

poor-qual i ty

mortar

l eavi ng

a

rough

i rregul ar surface

2

Any voi ds

and

honeycombi ng

due

to

l ack

of

consol i dati on

or

excess entrapped

ai r

voi ds

shoul d

be

noted


36/88

3) Cracki ng

(whether hori zontal , l ayered,

or

vert i cal )

shoul d be descri bed .

ormati on can be summari zed

i n

the Bri dge Deck Core Record

(Appendi x D)

C ose-up photos

of

each core

wth

proper i denti f i cati on

(i ncl udi ng

BI N Number)

on a

card

i n the

photos . They shoul d be

taken strai ght-on, wth

a

scal e used as a reference i n each shot .

I n

addi ti on

to

the photos, each

core

shoul d be documented as

fol l ows :

SAMPLE BRI DG

E

DECK CORE

RECORD

Core

No

.

:

1

Depth:

18

ful l

depth, depressi on i n asphal t

overl ay,

undersi de

normal

Overl ay

:

5

total , two

1

l ayers

of

top

course

over

a 3

bi nder

Weari ng

4 ,

total

deteri orati on,

steel mesh 1/2 f rom

Course : bottom

Membrane : None

Structural

0

total ,

sl i ght 1/8 scal i ng at top, l ayered

Sl ab :

l ayered cracking through

mortar around

crushed stone, coarse aggregate i n top 3 ,

No

5

bar top

rebar

1-1/2

down shows

heavy

corrosi on ;

remaini ng

6

of

concrete

appears

sound, no

excess

voi ds,

good

consol i dati on,

no corrosi on on

bottom

steel ,

no

stai ni ng

on bottomof

core .

Tests

:

(As

Appropri ate) Compressi on

:

5000

psi ,

structural sl ab .

( I t

not

necessary

to

test each core

Thi s w l l be determned by

the Engi neer .

Freeze-Thaw NaCl Sol uti on:

3

secti on

of

structural

sl ab,

100% l oss i n 20

cycl es .

Ai r

Content : Structural sl ab

1

. 2% entrapped,

0

. 17%

entrai ned

.

NOTE :

See Appendix

E for

form

to

mount

core photo al ong

wth appropri ate

documentati on

descri pti on

- 3 0 -


37/88

RECOMMEND T OL S

recommendati on for

scope

of

work shoul d

be i ncl uded

based

on

the engi neeri ng eval uati on l recommended repai rs

shoul d

be

descri bed wth sketches provided

for

other than

routi ne recommendati ons


38/88


39/88

Gven

a

future expendi ture of 1,

f i nd

i ts val ue today, n peri ods

earl i er at compound i nterest i

Thi s i s

the si ngl e-payment present

worth factor

:

SPPWF

=

n

APPENDX A FORMULAS

FOR

ECONOMC ANALYSI S

The capi tal

recovery factor

CRF

i s

the

val ue

of

future

payments that wl l recover a present amount

of

1 over

wth

compound i nterest

i

n

i ( 1

+

i

CRF

=

n n

( 1

+ i ) -

1

Thi s

i s

the rel ati onshi p

used

to

determne

si ze

of

l oan repayments

For exampl e, a l 0-year l oan

of

10, 000

at 12%

woul d requi re annual

payments

of

10

( 0

. 12)(1

+ 0 . 12)

10,000

x = 1, 769. 84 Per Year

10

USPWF =

n

Thi s amount

can

be consi dered the

annual

cost

of

a

10,000

l oan

The uni form

seri es present worth

factor

i s

the

i nverse

of

the

capi tal recovery

factor I t provi des the present val ue of

a

uni form

seri es of payments of

1

for

n

peri ods at compound i nterest

i

CRF

n

The capi tal

recovery factor and un

are used to adj ust present worth

f rame

(the

pl anni ng

hori zon)

Thi s

annual

cost

of the

treatment over

cost

i s mul ti pl i ed by the uni form

computed for

the

desi red ti me

peri od

present worth of

a

deck treatment that costs

year

servi ce

l i fe

i f

the pl anni ng hori zon

i

rate

4%

A

n

peri odi c

peri od

n

present worth factor

ent to a common ti me

i shed by

cal cul ati ng

l i f e

Thi s annual

present worth factor

exampl e,

what

i s the

20

/ sq ft wth

a

25-

>

20

years?

(Dscount


40/88

Step

Step 2

Annual cost

20 X CRF

25

25

( 0 . 04) ( 1

+

0

. 04)

20 X

25

( 1

+

0

. 04)

-

1

. 28

Per

Year

esent worth of 20 years of annual

payments

of

1

. 28

1

. 28 X

USPW

=

20

20

i

. 28

X

[(1 + 0

. 04) -

1 ]

( 0 . 04) ( 1

+

0 . 04)

20

17 . 40 Per Year


41/88

The

fol l owng

exampl es

i l l ustrate

sui tabl e rehabi l i tati on al ternat

average bi d pri ces and

are

for

practi ce, pri ces speci f i c to the

used

The cost compari son shoul d i nclude al l costs associ ated wth

deck

rehabi l i tati on, i ncl udi ng roadway work, M&PT,

and

mobi l i zati on

User

costs

have not been

i ncl uded i n

these exampl es, al though they

may

be si gni f i cant

at

hi gh-traff i c l ocati ons

Exampl e

APPENDX

B

EXAMPLE

OF

DECK EVAL

SELECTI ON

PROCESS

Assume a 200' l ong by 32

deck

i s a

candi date

for

a

three possi bi l i ti es are

:

wde

(curb-to-curb)

two-course

bri dge

protecti ve

overl ay

of

some type

The

1

Asphal t concrete wth membrane

2 Concrete wth sel ect deep removal

3 Concrete wth 100%deep removal

I t

has been determned that 50%

of

the

deck

area

needs deep

removal

To accompl i sh

the

work, an al ternati ng

one-way traff i c scheme has

been sel ected as

the

appropri ate method to mai ntai n traff i c

Mni mal approach work

i s

requi red

Costs

of

onl y the

overl ays

or

bri dge work are

as fol l ows

:

1 Asphal t_Concr

ete

Wth Membrane

B2

ON/TREATMENT

compari son

of

techni cal l y

Costs used

are

based

on

i ve

purposes

onl y

I n

ob being esti mated shoul d

be

A

Asphal t

Weari ng Course Removal

(200' )(32' )(1

. 34/sq

yd)

_ 8,576

B

Rebar Exposure

(6400)(50%(12

.61/sq

yd) _

40,352

C

Sl ab

Reconstructi on

(6400)(50 )( 4 . 89/sq

yd) _

15,

648


42/88

Mobi l i zati on

$155,968

-

$24

. 37/sq

f t

6400

Sq f t

Cost

of

al l roadway work requi red

to

adj ust the

h~

t i

s

approach

i s

$30,000

. I ncl uded

are

such i tem as survey and stakeout, Engi neer' s

off i ce,

tel ephone-answeri ng

devi ce,

mcrocomputer,

permanent

stri pi ng, pavi ng,

and pavement ml l i ng .

Roadway Costs Common To Al l Overl ays

I t

shoul d be noted that durati on

of

the Contract

for

each

al ternati ve

i n

thi s

i nstance

di d

not

signi f i cantl y al ter

assessment

of I tem

619

. 01 at $20,000 .

B2

Contract .

Membrane

(6400 sq yd)(2

.01/sq

yd) _

13,248

Top Course (2-1/2 )

( 2

. 5)(6400 sq

yd)

1

Ton

($40/Ton)

( 9 SF/Sq yd )

19 Sq yd)

_

3,743

TOTAL

=

81,567

81

. 567

=

$12

. 74/sq

yd

6400

Sq f t

Concrete Wth

50%

Deep

Removal

A Asphal t Weari ng Course Removal =

8,576

B .

Scari f i cati on = 6,400

C Rebar Exposure = 40,352

D Overl ay

6400 ( 1

.5)($4

. 89) = 46,944

E . Transverse

Saw

Cut Grooving

bridge deck evaluation manual

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