Ａｓａｋｅｇａｗａ Ｂｒｉｄｇｅ

The Asakegawa Bridge, in Yokkaichi City, Mie Prefecture, is a part of the Shin-Meishin Expressway Project. The expressway operator, Central Nippon Expressway Co., awarded a single contract for the design and construction of both the superstructure and sub-structure of the bridge.

Fig. 1 Overview of the Asakegawa Bridge

The bridge is a 325m-long three-span steel and pre-stressed concrete composite continuous box girder bridge stiffened with an arch rib. The overall design was dictated by site conditions: the bridge spans busy national Road No. 365 at the point where it crosses the Asakegawa River. The approach to the east of Abutment 1 is an embankment, while to the west of Pier 3 the bridge links to a viaduct. The center span is 225 m. The launch erection method was chosen for erecting the steel girder, since it could be accomplished during one night of full closure of national Road No. 365. To reduce the length of the span to be launched, a V-shaped structure was adopted for Pier 1. Further, a pre-stressed concrete box girder cantilevered over the road on the west bank of the river. The design is illustrated in Fig. 2.

A number of new techniques were employed in constructing this bridge. These are outlined in the text that follows.

High proof strength joints fabricated from checkered steel pipe were adopted for Pier 1 to reduce the thickness of the steel pipe sheet pile (Fig. 4).

Fig. 4: Pier 1 (left) and high proof strength joints (right)

水

E

As

信

信

標

As

信信

E

T

BOX300

U250

37.4037.70

31.70

37.25

33.15

32.40

31.09

E

31.30

As

30.00

30.72

29.90

29.90

29.80

30.00

29.90

29.85

30.40

信

信

信

Gr

S

S

S

S

S

信

28.92

29.82

30.74

H

H

H

H

S

S S

X:-105800

水水

Ｍ

ＭＥ

Ｅ

φ100

φ100

U300 U240

U300

U240

U700

As

橋面

As

U450

U450

37.44

30.87

30.87

29.82

30.21

31.17

29.98

30.01

30.0029.99

30.01 30.06

30.06

31.25

30.72

30.04

30.04 29.97

30.62

30.14

30.11

31.07

32.45

30.69

30.78

30.7732.48

32.75

30.23

30.74

28.9229.40

34.59

32.4632.11

33.89

37.25

32.47

29.86

29.86

32.42

32.49

32.33

32.51

30.04

32.53

32.44

29.73

29.98

30.00

29.92

29.97

30.93

29.98

30.47

Y:52700

Y3

32.67 31.92

30.00

P3

60.0m

P2 A1P1

40.0m

Asakegawa bridge 325.0m

225.0m

22500

Steel girder stiffened with arch rib 181.5ｍ

ER

F

PC box girder 63.5m

21.5m

PC box girder 80.0m

E

638

772

F

F

Fig. 2: General view of the bridge

Fig. 3: Cross section of the bridge3075 5955 3500 5955 3075

Outbound line Inbound line

3500

1200

3000

23910

Outbound line Inbound line

2500

Asake river

Yamahana diversion weir

Asakegawa bridge

Right bank Left bank

National road No. 365 To the east To the west

Steel girder stiffened with an Arch rib

Pre-stressed Concrete box girder

The use of cast-in-place river-water contaminationenvironmental reasons screw with toe wings were adopted 5), which also served to reduce construction noise.

Seismic safety was confirmed design seismic waveformJapanese specifications for highway bridges. It was also confirmed that the bridge would be safe against collapse in long-period ground motion the Tonankai and Nankai (which are anticipated within the next years).

The launched span was a launch nose of about 100consisting of the steel box girder to be constructed nearby (Fig. 6)of a girder meant less steel was used, with consequently lower CO2 emissionsof the launched span was consisting of 4,508tf for the 544tf for the launching nose, 61tf launching equipment, and equipment used to set the girder downshorten the launching span, ‘one-night’ bent was prepared Located in the river bed (Fig. 8)was able to take a maximum reaction force4,082tf and incorporated undertaken in Japan.

Fig. 5: Screw steel pipe

Fig. 7: The ‘one

Fig. 8: Bent positioned

Fig. 6: The launching nose

place piles can lead to water contamination, so for

crew steel pipe piles were adopted at Pier 3 (Fig.

served to reduce construction

was confirmed using the form given in the

specifications for highway bridges. confirmed that the bridge would

in the case of the ground motion associated with

Tonankai and Nankai earthquakes within the next 100

was 134m long, with about 100m partially

the steel box girder for a bridge (Fig. 6). This re-use

less steel was used, with emissions. The mass

span was 5,015tf in total, for the bridge itself,

the launching nose, 61tf for the and 102tf for the

used to set the girder down. To shorten the launching span, a temporary

was prepared (Fig. 7). (Fig. 8), this bent

maximum reaction force of 12 endless sliders. The launch operation was the largest ever

ipe piles with toe wings

‘one-night’ bent

positioned in the river

operation was the largest ever