jap an’s first technique f for box culvert to increase the ... · this is a single layer 3 span...
TRANSCRIPT
Jap
(Constr
1. Intr
Tok
of 1envinteexisthe
The
Narenvnorm
pan’s First T
ruction Proj
roduction
kyo Outer Ri15 km fromvironment in ersects the JRsting viaductground to in
e JR Sobu Lirita Express vironment, thmal national
Outer Ring
Technique f
ject of a New
ing Road (hem the city cenn the center R Sobu Linet on the JR Sntersect (Fig.
ine is an impthat connect
he railway vl road were c
Road
for Box Culv
w Railway BMotoyawat
ereafter referrnter is beingof Tokyo. In
e (between Icobu Line, th1).
Fig. 1 C
portant railwats the city ceviaduct and tconstructed w
Chiba Prefectureconstruction sectio
- 1 -
vert to IncreRC Viaduc
Bridge on thta on the JR
red to as “Oug constructedn the sectionchikawa and
he Outer Ring
Construction
ay line with aenter with Nathe 2 layer r
without hinde
JR S(bet
e on
Ichik
ease the Spat
he Outer RinR Sobu Line)
uter Ring Rod with the on in Chiba Pd Motoyawatg Road below
location
an extremelyarita Airport road space oering operatio
Sobu Line intersectiontween Ichikawa and
Motoyawata)
kawa Station
an and Repla
ng Road betw)
oad”) that linkobjective of iPrefecture, thta). This projw ground, an
y high frequealso runs on
of the Outeron of the trai
JR Sobu Line Ichikawa Minam
Norm
To Matsudo
To Kaigan Dori
JR Sobu Li
ace an Exist
tween Ichika
nks the area aimproving tthe Outer Rioject was to nd the norma
ency of trainsn this line. Ur Ring Roadins (Fig. 2, F
mi IC
mal road
Expressway (Outer Ring Road)
ri
Motoyawata Station
Line
ting
awa and
at a radius the traffic ing Road allow the al road on
s, and the Under this d and the Fig. 3).
2. Out The
RC Outconchaordespannorm
In th
beatracwithwheprob
F
tline of the P
e Sobu Line moment res
ter Ring Roansideration thanged to an uer to achieven beam formmal national
the past this tams directly cks by the cuhin the railwen the trains blems of de
To T
North
Box c
Fig. 2 Outline
Fig. 3
Project
was elevatedsisting viaduad passing ovhe span divisiundergrounde this grade s
mat, to ensurel road.
type of constbelow the t
ut and cover mway lines, and
were stoppeegradation o
Tokyo
Nor
ExpresswayRo
Support beam
side
culvert
Box culv
e of the proje
Outline of th
d in the 1970uct and singlever the railwions of the vi
d scheme dueseparated intee the space fo
truction was tracks of themethod. Howd would be cd, and the w
of the surrou
rmal road
y (Outer Ring oad)
m under the railway lin
vert B1
- 2 -
ect (perspecti
he structure (
0s, during whe T beams. I
way, so the spviaduct. Theree to considerersection, it wor the underg
frequently ce railway, anwever, this cocarried out o
work would bunding envi
JR Sobu Line
ne
Box culvert B2
ive view whe
(normal to th
hich this inteInitially the Opace of the ieafter the schrations of thewas necessarground road
carried out bynd large-scaonstruction m
over a period be carried outironment, le
e
2
en completed
he road)
ersection wasOuter Ring Rintersecting rheme of the Oe surroundinry to modifybox culvert a
y a combinatle excavatiomethod woulof several h
t in a narrow engthening th
To
SRC portal frame m
Box culvert
Box culvert B3
d)
s constructedRoad schemroad did not Outer Ring Rng environmy the viaduct and the abov
tion of instalon directly bld require mu
hours during w space, whicthe construct
Chiba
moment resisting bridge
South side
t
d from an me had the
take into Road was ent, so in to a long
ve ground
lling steel below the uch work the night
ch had the tion, and
e pier
incrtechtechinveloca
F
Before chan
After chang
reasing the chnique to rehnique for cestigated (Fiation of the in
Fig. 5 Increas
nge
ge
cost. In ordereplace the bconstructing ig. 4). Fig. 5 ntersection. T
sing the span
■ Technique RC viaduct
■ Technfoundaspan b
r to deal withbeams in ord
the undergrsummarizes
The structure
Fig. 4
n of the viadu
for increasing tht and replacing
nique for construations for the br
beams
- 3 -
h these problder to increaround box cs the changee consists of
Techniques a
uct (above: b
the span of the ethe beams
ucting box culvridge piers supp
lems, in this ase the span
culvert to sue in the divisf the followin
applied
efore change
existing
vert that form thporting the long
project a men of the exiupport the loion of spans
ng parts (1) to
e, below: afte
he g
ethod of comisting viaducong span bes of the viaduo (3).
er completio
mbining a ct, and a
eams was uct at the
n)
- 4 -
(1) Box culvert structure This is a single layer 3 span box culvert 35.5 m wide, and about 12 m high (internal height about
8.6 m). Three box culverts were constructed: Box culvert B1 (L = 20 m) on the north side of the viaduct, Box culvert B2 (L = 20 m) directly below the viaduct, and Box culvert B3 (L = 20 m) on the south side.
(2) Supporting beam below the railway line This was installed to replace the beam and slab of the viaduct, which was removed as it was an
obstruction to the national road at ground level. This was a continuous beam with a total length of about 50 m formed in a lattice shape. The main beams are arranged in three rows, north, center, and south, made from a PRC structure.
(3) Portal frame type bridge piers
Four of these were constructed to support the supporting beams below the railway line. Of the
four sets of bridge piers, the set on the Tokyo side was an RC type with in situ driven piles as the foundations. The 3 sets on the Chiba side were SRC structure portal frame type moment resisting piers, supported by Box culvert B1 and Box culvert B3 via anchor frames.
3. Construction steps
The main construction steps in this project were as follows.
(1) Construct the box culverts on both sides of the existing viaduct, the inside of which is to be used as the Outer Ring Road and which form the support structure for replacement of the existing viaduct, (hereafter referred to as Box culvert B1 and Box culvert B3) (Fig. 6). The pneumatic caisson method was adopted as the method of construction of Box culverts B1 and B3, in order to minimize any large-scale temporary works and measures against groundwater.
(2) Afrasuloinwpopothco
Ththcovire
(1
After the caissame type bupporting beongitudinal bnstallation powas lifted up ortal frame tyortal frame tyhe viaduct usoncrete was p
hen the oute
hen the transvonstructed. Tiaduct on botemoving core
1) Caisson sink
(1) Caisson sin
sons were cobridge piers eams under beams and sosition. Therand installed
ype bridge piype bridge psing a 500 t poured inside
er main beamverse beams
The transversth sides in thes, inserting P
king
nking
Fig. 6 Ste
ompleted, thewere constrthe railway
slab of the refore, after cd in its final iers were con
piers was divcrane from
e and around
ms of the sups that connecse beams wehe axial direcPC steel, and
- 5 -
tep 1 (caisson
he supportingructed (Fig. y line was existing viaconstructingl position. Anstructed witvided, and era cradle on
d the structur
pport beams ct the outer ere installed ction of the bd tensioning.
n sinking)
g beams belo7, Fig. 8).installed in
aduct, so it wg it directly bAfter installati
th an SRC strected by thea caisson b
ral steel.
under the ramain beamssandwiching
bridge, and in
ow the railwaThe center
n a positionwas difficultbelow the inion of the cetructure. The e method of pox culvert, a
ailway line ws and the ceng the bridge ntegrated wit
ay line and tr main beam
n surroundedlt to construnstallation poenter main b
e structural stpulling it upand after ere
were construnter main bee piers of theith the bridge
the portal m of the d by the uct at the osition, it beam, the teel of the p to under ection the
ucted, and eam were e existing e piers by
(3) Aw(Ffrasp
(2) Ere
(1) Erepier
(3) Ererail
(1) Eli
Fig
After completwas taken by Fig. 9) In thisame type mopace for the r
ection of new brid
ction of new bridrs
ection of support lway line
Erection of supporine
Fig.
g. 8 Step 3: C
tion of the suthe new brid
s operation, toment resistinroad on the g
dge piers
dge
beams under
rt beams under ra
7 Step 2: Co
Construction
upport beamdge piers. (Hthe positionsng bridge pie
ground. This
ailway
- 6 -
onstruction of
n of support b
ms under the Hereafter this of the beamers were dispwas accomp
f new bridge
beams under
railway lines operation i
ms of the exiplaced relativplished using
e piers
the railway l
e, the load ofis referred toisting viaducve to each othg a “top sur
line
f the existingo as “underpct and the SRher, in order rface jack”
g viaduct pinning”.) RC portal to ensure installed
be“bfrapire
(4) Ainredi
(5) A
coBcodi
4. Tec
(1) Co
(F To
mthHof
(4) Tran(5) Cut
(1) Tr
etween the bbottom surfacame type briiers by underemoved.
After removalnstalled undeemoved. Theirections with
After replaceonstructed by1 and B3 duompleted by istribution rei
chniques use
onstruction oFig. 10).
o construct tmain beams ohereby constrHere, in order f the membe
nsfer load using hexisting columns
ransfer load using
beams of the ce jack” instidge piers. Arpinning, the
l of the coluer the main be top surfaceh non-shrink
ment of thy the cut and ue to this ex
y inverted coinforcement
ed in constru
of the lattice
the long spanon both sideructing the lto construct
ers in accord
hydraulic jacks s
g hydraulic jacks
existing viatalled betweeAfter transfere columns of
Fig. 9 S
umns the beabeams and njacks were
k mortar.
e viaduct, Bcover metho
xcavation, thonstruction m
using mecha
uction
PC beams to
n beams, firses and finalllattice PC bet the new PCdance with th
- 7 -
aduct and theen the supporring the loadf the existing
Step 4: Under
aring structunon-shrink mfixed, the hy
Box culvertod. In order t
he top deck omethod. The anical joints.
o integrate w
rst the centerly the transveams below
C beams, it whe design, an
e support beaort beams undd of the exisg viaduct (24
rpinning
ure was instamortar pouredydraulic pres
t B2 directto minimize of Box culvbox culvert
.
with the beam
r main beamverse beamsthe beams
was necessarynd integrate
(2) Cut existin
ams under thder the railwsting viaduct4 No.) were
alled. After rd, the bottomssure remov
ly underneaany displaceert B2 was cts were integ
ms and slab o
m was construs were constand slab of
y to introducethe existing
ng columns
he railway liway line and tt onto the necut by wire
rubber bearinm surface ja
ved, and jack
ath the viadement of Boxconstructed grated by co
of the existin
ucted. Next tructed in th
f the existinge the prestresviaduct and
ine, and a the portal ew bridge e saw and
ngs were acks were keted in 3
duct was x culverts first, and
onnecting
ng viaduct
the outer hat order, g viaduct. ss in each d the new
bestaexfo
(2) Tr
Insustainexthmlone
eams with thages, and thexisting viaduorm.
ransfer of loa
n order to miurface jacks aages to the
nstalled at thexisting bridghe tracks durimm) of the moad was comew structure.
■ Integrationaccomplis
he tension foe tensioning
uct into a long
ad to the new
inimize any and bottom snew bridge
e bearing loce piers wereing construct
maintenance mpleted witho
n of the existingshed by constru
orce. Therefooperation wag span. Also
Fig. 10 La
w bridge piers
displacemensurface hydrpiers. After
cations, and ae cut, therebytion due to trstandard valout generatin
g viaduct beamsucting the memb
- 8 -
fore, the conswas carried ouo, the weight
attice PC beam
rs using jacks
nt of the tracraulic jacks wr transferringafter complety smoothly ransfer of loalue to enableng unaccept
ms and slab with bers in stages an
struction of ut in stages inof the beam
am structure
s (Fig. 11)
cks on the vwere installedg the load, tion of the bcompleting t
ad to the beame the trains ttable crackin
the PC beams wnd prestressing
each memben 7 steps, to
ms was reduce
viaduct, a totad, and the lorubber shoeeam structurthe transfer. ms was mainto operate.
ng in the lon
was
er was carrirationally coed with this
tal of 52 of toad was transes and stoppre, the columThe displac
ntained withiAlso, transf
ng span beam
ed out in onvert the structural
the upper sferred in pers were mns of the cement of in 20% (3 fer of the ms of the
(3) M
InvifocaBHinjacpoca
Minimization
n this projectiaduct. As a rorce would baisson, whichH columns
ncrease the cacks was adoossible to maisson to with
of deformati
t, the caissonresult of FEMbe produced h would causwas installeaisson sinkinopted for co
maintain the hin 15% (2 m
Fig.
ion to existin
n box culverM analysis caon the found
se displacemd to isolate ng accuracy,ontrol of thedisplacemen
mm) of the tr
- 9 -
11 Underpin
ng structures
rts were sunkarried out in
ndation soil oment of the via
the existing, a hydraulice caisson attint of the viarack mainten
■
nning
when sinkin
k at positionadvance, it w
of the viaducaduct. There
g viaduct froc system usinitude. As a
aduct due tonance standar
Using 52 hydratransferred to th
ng the caisson
ns extremely was anticipatct due to the efore, a wall fom the caissong ground anresult of thesinking the
rd value.
aulic jacks, loadhe new bridge p
n (Fig. 12)
y close to theted that a larg
e effect of sinformed fromon. Also, in
anchors and hese measuree cutting edg
d was smoothlypiers
e existing ge pull-in nking the
m a row of n order to hydraulic es, it was ge of the
y
5. Res
TheBy posconmonconsafe
By
elevto rcontechcha
Durinfrictio
PrAtachhy
sults and Ou
e following icarrying ou
ssible to grenstruction pernths and re
nstruction wiety of operati
using this tevated railwayrealize the intntrol standardhnique can banging existin
ng sinking, a largeon
ressure sinking system ttitude control of the ca
chieved with ground anydraulic jacks
Fig. 1
utlook for th
is a compariut underpinnieatly reduce riod and econeduce the coithout any stion of the tra
echnique, it wy in an area wtersection ofd values for dbe widely usng spatial usa
e inward force is
aisson was nchors and
IsolatiMinimforces
12 Minimizin
he Future
son of the ming and effecthe environnomics, it wost by aboutoppage or sains.
was possible with high denf new plannedisplacementsed to greatlage.
generated on the
on with a wall formed mize the effect on the vi
produced during caiss
- 10 -
ng the effect
method used ctively using
nmental loadwas possible tut 15%. In slowing of tr
to rationallynsity of train
ed roads and t and deformly change th
e foundation soils
from a row BH columiaduct of the skin frictioson sinking
of caisson si
in this projeg the structud due to theto shorten the
addition, itrains during
y increase thens. In additionthe Shinkan
mation duringhe form of in
by skin
mnson
inking
ect with the cure of the exie constructioe constructiot was possibconstruction
e width of then, it can be a
nsen (bullet trg operation. Intersecting in
Hydraulic jack
Ground anchor
conventionalxisting viaducon. Also, it on period by ible to compn, and to inc
he road intersapplied as a train), which It is expectednfrastructure
l method. ct, it was terms of about 14
mplete the crease the
secting an technique has strict
d that this e, without