INVESTIGATIONS TARGETING THE APPLICATION OF ULTRA-HIGH DURABLE SLAB IN A HIGHWAY BRIDGEINVESTIGATIONS TARGETING THE APPLICATION OFULTRA-HIGH DURABLE SLAB IN A HIGHWAY BRIDGE
超高耐久床版の実橋への適用に向けた実験的検討
R＆D センター

ランコス

構造開発技術室

内堀裕之

HIROYUKI UCHIBORI

R＆D センター

篠崎

裕生

HIROO SHINOZAKI

橋梁構造設計部狩野武

TAKESHI KARINO

チャミラ

CHAMILA RANKOTH

道路橋床版の維持管理費用の削減を目的に，超高耐久床版を開発した。超高耐久床版は腐食する可能性のある鉄筋や PC 鋼材を一切使用しないプレキャスト PC 床版である。本稿は超高耐久床版について，疲労性能を含む基本開発を完了後に，中国自動車道蓼野第二橋下り線における床版取替工事への初適用に先立ち，施工性と品質の確保を目的に実施した実験的検討を報告するものである。具体的には，１）長さ 11m の実証橋を施工し供用中の性能をモニタリングした結果および２）これまでの実績を超える長さ 100m のアラミド緊張材の挿入，緊張およびグラウト注入の実験結果についてまとめたものである。
キーワード：超高耐久，繊維補強コンクリート，アラミドＦＲＰロッド，床版更新

Targeting to reduce future maintenance of bridge deck slabs, Ultra-high durable slab was developed. It does
not utilize any corrosion prone steel members such as reinforcements or prestressing strands. After thebasic development, to utilize it in a real highway bridge, additional experiments were done. A 11 m longmodel bridge was constructed and used for 3 months to investigate the constructability and the structural
performance. 100 m long Aramid tendon tensioning and grouting experiment was carried out as well.
Developed deck slab was utilized in deck renewal project in Tadeno No.2 bridge in Chugoku expressway.
Key Words: Ultra-high durable, Fiber reinforced concrete, Aramid FRP rods, Deck renewal

1. BACKGROUD

1.1 DURA-SLAB STRUCTURAL CONFIGURATIONAs shown in Fig. 1., Dura-Slab is a ribbed slab made of

There is an increment of slab deck replacement projects inhigh strength fiber reinforced (polyvinyl alcohol fiber-PVA)

Japan to secure the serviceability of deteriorated bridges.

concrete with 80 N/mm2 design compressive strength.

Ultra-high durable slab (Dura-Slab), a pre-stressed concrete

Prestressing tendons made of multiple AFRP rods are utilized

bridge deck slab system, was developed to overcome theinstead of steel tendons. Dura-Slab is made as pre-tensioned

corrosion damage of concrete deck slabs aiming to utilize inprecast panels. Longitudinal prestressing tendons aredeck replacements in plate girder bridges. It is made of fiber

installed and post-tensioned at the site to integrate the precast

reinforced concrete, Aramid Fiber Reinforced Polymer

panels in the longitudinal direction.

(AFRP) rods as prestressing tendons and does not contain any

Dura-Slab features a fully non-metal structure by removing

steel components. By eliminating corrosion damage, Dura-all corrosion prone elements. Longitudinal AFRP tendons are

Slab is expected to be requiring very little maintenancebond anchored eliminating the conventional steel anchorage

during the service life which will lead to low carbon emission

components2). Reinforcement near the anchor, consists ofand lifecycle cost. The new structure is estimated to reduce

GFRP (Glass Fiber Reinforced Polymer) rods.

the carbon emission nearly 40%1).

The precast slab panel joint in Dura-Slab is shown in Fig.1.

1

三井住友建設技術研究開発報告第 20 号

Stud openings
slab-girder joint

Pre-cast slab panel joint

Dura-Slab(3 slab panels)

Dura-SlabPVA Fiber

Shear studs
MortaroutletMortar inlet
Transverse prestressing【pre-tensioned
Aramid FRP rods】

Mteel shear studs
High strength noshrinkage mortar Steel girderLongitudinal prestressing[post-tensioned
Slab-Girder joint
Aramid FRP rods]

An Aramid FRP rod

Fig. 1. Components of Ultra-high durable slab and structural arrangement in a slab deck renewal project

By introducing longitudinal prestressing with a transverse

targeting the application of the Dura-Slab is explained next.

ribbed structure, the panel joint was made smaller compared
to a conventional joint. Elimination of reinforcement allows
significant time and labour saving in joint construction.
Conventionally, precast concrete panels are connected to the

2.1 CONSTRUCTION AND LOAD TEST OF A REALSCALE MODEL BRIDGE
2.1.1 OBJECTIVES

steel girders using shear studs. Stud openings which penetrate

A real scale model bridge was constructed at an entrance

the full slab thickness are provided. In addition, bolt openings

to a pre-cast concrete factory to verify the constructability ofare provided to adjust slab level during placement. Steelthe Dura-Slab as well as structural performance.

anchors are used in the top slab surface for panel lifting.

Three major constructability related objectives were

Girder-slab joint of Dura-Slab shown in Fig. 1. is constructedinvestigated. First, the construction of precast slab panel joint.

by injecting high strength low shrinkage mortar from bottom

The deck slab panel joint is only about 30 mm as shown inof the slab avoiding slab penetrating openings. Level

Fig. 1. However, it is necessary to provide the longitudinal

adjustment bolt holes were not provided, and ceramic inserts

tendon sheath couplers at each panel joint. Constructability

were set in the sides next to slab keys for panel lifting.

of the joint including the sheath coupler was investigated.

This paper summarizes the experimental studies which

Second, Panel level adjustment method without deck

were carried out targeting the application of the Dura-Slab inpentrating level adjustment bolts. And the third was theTadeno No.2 bridge located in Shimane prefecture.

mortar injection method to the slab-girder joint form thebottom side of the slab as shown slab-girder joint in Fig. 1.

2. DEVELOPMENT OF DURA-SLAB

To confirm the structural safety, static load tests werecarried out just after construction and after putting the bridge

After designing the main structural form of the slab,

to service for 3 months. During the service, continous

overall slab performance including the panel joint wasmonitoring of the structre was carried out targeting slab

verified with a real scale wheel load running test3). Thereafter,

deformation, strain and so on.

the stud connection of the slab with steel plate girders was

2.1.2 CONSTRUCTION OF THE MODEL BRIDGE

investigated with a series of stud pushout

tests4).

It wasModel bridge dimensions are shown in Fig. 2. Typicalverified that the stud connection without additional

panel transvesrse tendons consisted of 4 AFRP rods withreinforcement around the slab-girder joint was possible to bediameter 7.4 mm. Each precast deck panel consisted of 6

utilized. Additional experiments that were carried outtransverse pre-tensioned AFRP tendons or equal. longitudinal

2

INVESTIGATIONS TARGETING THE APPLICATION OF ULTRA-HIGH DURABLE SLAB IN A HIGHWAY BRIDGE

10960mm

10960
30

2470

30

2470

30

2965

D1

V5

120

300

180

2965

500

30

2470

2470

30

D2

2965

Strain
gauge

V4

500

500

2965

10000
11000
10960
30

V2

V1

V7

D4

V9

V6
A

V8

A

V3

T
D5

D3

2500

D6

2500

6000

Section A-A

Girder-slab joint

120

500

180

K1
300

Fig. 2. Model bridge dimensions
New panel
STEP1: Placement of deck panel
placement

K2

C1 slab strain
K1,K2 girder strain

S1

S2

S3

S4

S1 S3
Stud strain gauges

V2 displacement

Existing panel

Fig. 5. Model bridge sensor locations
STEP2: Sliding the panel to the final position

Studs

Slidi

Fig. 3. Slab panel joint construction

Fig. 6. Loading locations in static load test
Contrary to the conventional method of providing slab(a) Panel placement

Mortar injection hoses(b) Joint mortar injection

penetrating bolt holes, level adjustment of Dura-Slab wasdone from bottom side of the slab utilzing plasitc plates.
Construction could be done without any major difficulties.
Mortar injection to the slab-girder joint is shown in Fig.
4.(b). It could be successfully done with a mortar injection
hand pump from bottom side of the slab. Completed model
bridge is shown in Fig. 4.(c).
2.1.3 STATIC LOAD TEST OF THE MODEL BRIDGE
Major structural measurement locations during the load(c) Completed model bridge during load test
Fig. 4. Construction of the model bridge

test are shown in Fig. 5. Measurements included verticaldisplacement of middle steel girder (V1~V3), verticaldisplacement of the slab at the center of the girders (V4~V9),

prestressing consisted of 14 tendons where each tendon

relative displacement of the deck slab and the steel griders inconsisted of 9 AFRP rods with diameter 7.4 mm.

the bridge axial direction(D1~D6), stud strain at the end ofConstruction method of the precast slab panel joint is

the middle girder (S1~S4) and the longitudinal strains atshown in Fig. 3. To make the longitudinal sheath joint, thesection A-A which includes the slab top surface strain (C1),

new panel should be placed on the girder and slide towards

girder top and bottom flange strains(K1,K2).

the panel placed before. Studs are welded in advance to theStatic load tests were carried out utilizing a 65 t roughpanel placement and the stud opening size was decided

terrain crane (front wheel load 19,710 kg, rear wheel loadconsidering the sliding length. Panel placement is shown in

19,885 kg). During the service time of 3 months, the number

Fig. 4.(a).

of vehicles pass across the model bridge was calculated to be3三井住友建設技術研究開発報告第 20 号(a) Slab vertical deformation(a) Slab-Girder relative deformation(b) Bridge cross sectional strain distribution
Fig. 7. Static load test results (loading at span center)(b) Stud strain
Fig. 8. Static load test results after in service for 3 months

1170 where most were dump trucks. The crane was placed in
the center line at the width of the bridge and in thelongitudinal direction, 10 loading points were defined basedon the rear wheel location of the crane in such a way toinclude the top of the transverse rib, panel joint and normal
slab section as shown in Fig. 6. The behaviour of the bridge
during the static load test was estimated using three-(a) Vertical displacement of girder and temperature

dimensional liner finite element analysis in advance.
The static load test results are shown in Fig. 7. when thecrane in the middle of the bridge span. The verticaldeformation of the slab matched the FEM analysis output asshown in Fig. 7.(a). Moreover, the experimental difference ofthe deformations before and after the model bridge was put
to use was not significant. The strain variation in the verticaldirection of section A-A is shown in Fig.7.(b). From(b) Stud strain variation
Fig.9. Model bridge structural monitoring dataexperimenal strain varitaion in the vertical direction, it canbe thought that the grider-slab system behaves as a composite

to be sufficient.

system. The strain variation was not significantly different
for two loading tests as well.

2.2 MODEL BRIDGE MONITORING

The girder-slab relative displacements measured byContinous measurements of all the installed senors was

D1~D6 and the stud strain in the second loading test is shown

done once every hour during the model bridge was in service.

in Fig. 8. The relative displacement affects the performance

The purpose of the monitoring was to observe whether anyof the girder-slab joint. The maximum relative displacement

unexpected, abnormal structrual behaviours occur during thewas 0.13 mm at D5 while the maximum stud strain was 284

continous use.

μ. However, the relative displacment and stud yield strain

Structural monitorng data of the model bridge is shown inobserved at the joint yeilding during the stud pushout

Fig. 9. The vertical displacement of the middle steel grider isexperiment4) was 0.59 mm and 1,390 μ respctively.

Withshown in Fig. 9.(a). The measurement is largely affected bysaftety factor above 4.5 with respcitive to the relative

the ambiant temperature variation. Besides that, there was nodisplacement and yield strain, the joint safety was consideredout of ordinary variations of the girder displacement. Stud

4

INVESTIGATIONS TARGETING THE APPLICATION OF ULTRA-HIGH DURABLE SLAB IN A HIGHWAY BRIDGE

strain variation is shown in Fig. 9.(b), at the initial stage an

Friction during the tensioning was not significant.

increment of compressive strain was observed. This was

Therefore, tendon tensioning was carried out similar to an

thought to be due to the effect of the plasitc plates used forexternal tendon based on the load and the tendon extension

panel levelling as shown in Fig.10. Initially the dead load oflength. Tendon tensioning is shown in Fig. 11.(c). Tensioned

the deck is supported by the plastic plates, however, graduallytendon was kept a day in tensioned condition and de-with the vehicular loading, the load might tranfer to joint

tensioned to observe the tendon condition. The tendons weremortar excertin a compressive force on the studs. Both the

not damaged due to the friction or due to the horizontal

grider displacement and stud strain measurements variation

curvature of the specimen.

is increased gradually, this was due to the gradualtemperature variation increment as shown in Fig. 9.(a).

To facilitate the bond anchoring of tendons, a bond lengthof 2 m from the slab end was sheath-free (Fig. 13.). Highstrength mortar was injected at the bond length and normal

2.3 REALLENGTHTENDON

INSERTION

AND

CONSTRUCTION EXPERIMENT

tendon-grout was injected in the rest. In the experiment, firstbond mortar was injected in the lower end of (lower height)

Tadeno No.2 bridge, where the Dura-Slab was first applied,

the specimen, then tendon grout was injected in middle andis nearly a 100 m long bridge. One of the issues at the time

finally mortar was injected at the second end. The inlet outlet

was the lack of experience of using aramid AFRP internal

hose arrangement and mortar injection procedure at the lasttendons in a 100 m long structure. A 100 m long specimen

end is shown in Fig. 12. The mortar injected in the middle

was created as shown in Fig. 11.(a) and experimented

was flown to the bond segment as shown in top part of Fig.

targeting the tendon insertion, tensioning, and grouting.

12. When the mortar is injected, the weight of the out flowing

The specimen was constructed using 2.4 m long blocks asmortar was measured to verify that the grout is fully removed

in the precast panel width of the actual bridge. In addition,from the duct. The specimen was cut in longitudinal direction

the horizontal curvature of the actual bridge was also

after strength gain to observe the injection condition. It wasconsidered.

observed that the grout has remained in the bond section.

Longitudinal AFRP tendons consisted of 9 AFRP rods with

Mortar and grout injection was improved as in Fig. 13.

diameter 7.4 mm. As the 100 m long tendon was only 56.7kg

First, tendon was inserted, and temporary anchor used forin total, insertion could be done with manpower as shown intensioning was attached. Then, tensioning was carried out.

Fig. 11.(b).

As in step 2, a mortar barrier was created with high viscous
mortar. And then, high strength low shrinkage mortar was
injected into the bond zone followed by normal grout
injection to the opposite side. After leaving for enough time
Slab
Plastic plate
for levellingto gain the mortar strength, the excess AFRP was cut off and
Low shrinkage
mortarthe temporary anchor was removed as shown in step 4.

Fig.10. Slab panel levelling
Insertion point

Jack ramRam chair

AFRP tendon

AFRP tendon(c) Tendon tensioning(a) 100 m long specimen(b) AFRP tendon insertion by manpower
Fig. 11. 100m long tendon insertion, grouting, and tensioning experiment5三井住友建設技術研究開発報告

1.Grout injection
Grout outlet
Grout injection
Tendon Duct
(From lower end)

第 20 号

did not differ confirming the sound structural performance.
AFRP rods

Continuous monitoring was carried out of the model bridge
during the service. Monitoring data including girder
deformation and stud strain was largely affected by the

2.Mortar injection

Grout outlet is sealed
Advance flow of grout

ambient temperature. However, no abnormal structural
phenomenon was observed.

Mortar injection

High strength low
shrinkage mortar

Fig. 12. Mortar injection at the high end of the specimen

A real scale longitudinal tendon insertion, tensioning, andgrouting experiment were carried out. Tendons did not
damage during construction. Mortar and grout injection
methodwas

improved

based

on

the

experimental

observations.
Based on the experimental results, Dura-Slab was appliedin Tadeno No.2 bridge successfully and in service from
November 2021.
Acknowledgement: The development of Ultra-high durable
slab (Dura-Slab) was carried out as a joint research between
NEXCO west and Sumitomo Mitsui Construction Co., Ltd.
Authors express their sincere gratitude to everyone who
supported in the development.
References
1) Uchibori H., Rankoth C.K., Matsuo Y., Kido Y.:“Development and Applicationof Ultra-High Durable
Slab for Deck Slab Renewal”, Proceedings of the fib
Fig. 13. Mortar and grout injection for longitudinal tendons

symposium, (2022)
2) Matsuo Y., Wada, Y., Fujioka T., Nagamoto N.,:

3. CONCLUSIONS“Construction of Non-Metal Bridge”, Proceedings of the
fib symposium (2021)

Targeting a lower lifecycle cost by reduced maintenance,3) Fukuda M., Ashizuka K., Karino T., Kasuga A.:

Ultra-high durable deck slab was developed. In addition to“Experimental study on fatigue durability of ultra highthe major structural development, additional experiments

durable slab”, Proceedings of the fib symposium,

were conducted targeting the application of the structure in areal highway bridge.

Melbourne (2018)4) Rankoth

C.K,

Karino

T.,

Wada,

Y.,

Fujii

Y.:

A model bridge was constructed to investigate the“Experimental study on ultrahigh durable slab to girder

constructability of the dura-slab. Construction of the deck

joint in steel plate girder bridges”, The 29th Symposium

panel joint was successfully done by panel sliding afteron Developments in Prestressed Concrete，pp347-350

placing on the girder to make the longitudinal sheath(2020.10)

coupling. Panel levelling was done with plastic plates put on5) Shinozaki H., Wada Y., Matsuo Y., Uchibori H.:

the steel girder. finally, the high strength low shrinkage“Experimental construction of 100m long AFRP rod for

mortar injection for the girder-slab joint could be completed

Ultra-high durable slab”,

adequately.

Developments

To investigate the structural performance of the model
bridge, two static load tests were carried out just after
construction and after using the bridge for 3 months. The
difference of slab deformations and strains before and after

6(2021.10)

in

The 30th Symposium on

Prestressed

Concrete，pp639-642