bridge deck evaluation manual
TRANSCRIPT
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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
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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
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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
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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
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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
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( 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)
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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
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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)
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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