Next Stage : Space‫ اﻟﻔﻀﺎء‬: ‫اﻟﻤﺮﺣﻠﺔ اﻟﺘﺎﻟﯿﺔ‬KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Road maintenance andmanagement improvement technique~ Upgrading of Existing Bridge Decks Using Ultra High Strength Fiber Reinforced Concrete ~‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫~ ﺗﺤﺴﯿﻦ أﺳﻄﺢ اﻟﺠﺴﻮر اﻟﺤﺎﻟﯿﺔ ﺑﺎﺳﺘﻌﻤﺎل اﻟﺨﺮﺳﺎﻧﺔ اﻟﻤﺴﻠﺤﺔ ﺑﺎﻷﻟﯿﺎف ﻋﺎﻟﯿﺔ اﻟﺼﻼﺑﺔ‬Jointly developed by Central Nippon Expressway andKajima CorporationRepair and reinforcement technique to improve the load bearing capacityand durability of the road bridge floor baseUltra-high-strength Fiber-reinforced Concrete (UFC) offers excellent durability and strengthcharacteristics to allow the top of the existing floor base of a road bridge to be replaced in athin layer. The technique drastically improves floor base loading bearing capacity and durability,
contributing to a long-term maintenance cost reduction.
Current

Asphalt paving

Adding thickness with an
SFRC overlay

This technique

Conventional techniqueFloor base durability
improvement

Asphalt paving

40

Reinforcement steel

75
Cracking
Scaling
Broken togravel-sizedfragments
Potholes

10075

Floor base durability
improvement (SFRC)

50~80

Floor base concrete

Floor base concrete

Asphalt paving
Ultra-high-strength Fiberreinforced Concrete (UFC)

Floor base concrete

Cut face

Reinforcing steel fiber

Paving renewal with UFCFeatures
Sophisticated UFC technique allows
reinforcement without changing thedesign cross section

Load bearing capacity and fatigue
resistance evaluation of UFCrepaired/reinforced floor base by dynamic
wheel loading test

High material density drastically improves
floor base durability

150 Mpa class ultra-high strengthachieved without special heat curing on
the site
Fluidity is flexibly adjustable according toreinforcement bar arrangement and lateraland longitudinal inclinations of theexisting floor base

Dynamic wheel loading test

Construction test
Test construction with a dedicatedfinisher
UFC cast over a simulated existing floorbase and cured on site

Mixing steel fiber into theconcrete mix

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Construction by machine

Road maintenance andmanagement improvement technique～ Prestressed Concrete Tendon Tension Monitoring System with Optical Fiber Sensor ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫~ ﻧﻈﺎم ﻣﺮاﻗﺒﺔ ﺷﺪ اﻟﺨﺮﺳﺎﻧﺔ ﻣﺴﺒﻘﺔ اﻹﺟﮫﺎد اﻟﻤﺰود ﺑﻤﺴﺘﺸﻌﺮ اﻷﻟﯿﺎف اﻟﺒﺼﺮﻳﺔ‬~Optical fiber-embedded steel strand in prestressed concrete can monitor distributed tension
force along the whole length of strand. This technique does not only assists construction
management of prestressed concrete structures, but also improves effectiveness and efficiencyof road maintenance after construction.
Directions of vehicle travel

Optical fiber

Strain distribution ismeasured and converted
into tension

Connecting
fiber-optic
cableJack

Concreteprestressing

Side view of a bridge pierOptical fiber-embedded steel strand

Measurement unit

■ Strain distribution can be measured along the whole length of strand when prestressing.
■ Re-measurement can be made any time afterward, thus the technique is also helpful formaintenance.
■ Optical fibers’ chemical stability contribute to long-term durability. The technique has an over
20 years of successful implementation record in other industries.
■ Optical fibers are embedded in the factory so that the strand can be handled in the same way
as normal strand wires on the construction site.
■ Use of typical communication optical fiber.

1

Optical fiber-embedded strand

2

Prestressing

3

Measurement

4

Optical connectors for re-measurement(in the girder)

Measured tension force (kN)

It has been verified that the technique is capable ofsupporting greater tension force than designed force andalso allows re-measurement.

Optical fibersa) Bare wire type
Glued along the gap of the strand

Final stressing
After anchoring
200 days after tensioning
Designedb) ECF type
Optical fiber embedded in epoxy coating(along the gap of the strand)

Measurement position (m)This system has been jointly developed by Sumitomo Electric Industries, Hien Electric Industries and Kajima Corporation.

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Road maintenance andmanagement improvement technique～ Ground Anchor Tension Monitoring System with Optical Fiber Sensor ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫~ ﻧﻈﺎم ﻣﺮاﻗﺒﺔ ﺷﺪ اﻟﻤﺮﺗﻜﺰ اﻷرﺿﻲ اﻟﻤﺰود ﺑﻤﺴﺘﺸﻌﺮ اﻷﻟﯿﺎف اﻟﺒﺼﺮﻳﺔ‬Optical fibers are embedded along the ground anchor for tension force distribution
measurement. This technique is effective not only for tension force variation detection, but for
identification of the cause of force variation. Thus, it is gratefully useful for maintenance ofground-anchor-reinforced-slope.

Tension force variation along the ground anchor can be detected, locatedand identified.
Optical fiber cable can be routed into
Optical fibers forindoor areas away from the slope.

measurement

Connector for longterm measurement

Optical fiber-embedded strand for groundanchor (ECF type)

Applicability to long-term
measurement capability① Increase or decrease due to external
force such as movement of the soil

Anchor head Free length section 12.0 m

Tension distribution variation due to ②

Tension force② Insufficient adhesion inside the anchor body
Reduction of circumferential friction against thesoil

Anchor body 4 m

Tension distribution variation due to ①

Measurement position (m)■ Tension force distribution can be measured along the whole length of ground anchor
including the inside of the anchor body.
■ Re-measurement can be made any time afterward, thus the technique is also helpful formaintenance. No need for elaborate measurement setup such as that for lift-off tests.
■ Use of durable optical fiber cabling allows us to monitor the slope any time from a safe
location.

Example of ground anchor measurement resultAnchor headFree length section 12.0 m

Anchor body 4 m① 0.4 Td prestressing② 0.8 Td prestressing

Measured tension
force [kN]

③ Tp prestressing④ Tension released⑤ Final stressing (Td)
⑥ After anchoring⑦ Approximately after
one month
Td: Final stressing tension
Tp: Planned maximum loading

Cable measurement position (m)This system has been jointly developed by Sumitomo Electric Industries, Hien Electric Industries, SE and Kajima Corporation.

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Road maintenance andmanagement improvement technique～ UHPFRC Deck Slab for Highway Bridge ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫ ﻟﺠﺴﺮ اﻟﻄﺮﻳﻖ اﻟﺴﺮﻳﻊ‬UHPFRC ‫~ ﻟﻮﺣﺔ ﺳﻄﺢ‬Development of UHPFRC Deck SlabKajima Corporation has partnered with Hanshin
Expressway to jointly develop a deck slab for
highway bridges made of ultra-highperformance fiber-reinforced concrete, namely,“UHPFRC Deck Slab”.
UHPFRC Deck Slab has a thin and lightweight
structure yet provides excellent durability andfatigue resistance.
The UHPFRC Deck Slab can be produced in twotypes, “waffle type” and “flat type”. The ultralightweight waffle type has been developed
mainly as a substitute for steel orthotropic deckslab. The flat type has been developed toreplace aged concrete deck slab.
With established performance through various
testing and analysis, the technology has beencertified by the Japan Society of Civil Engineers
Technology Assessment System in 2015.

Waffle type UHPFRC Deck Slab

Flat type UHPFRC Deck SlabWheel Running Fatigue Test
Wheel running fatigue tests have proven thatUHPFRC Deck Slab has a fatigue resistance offar longer than 100 years.
Flat-type UHPFRC Deck Slab did not exhibit any
fracture-triggering damage even after thenumber of loading cycles where ordinaryprestressed concrete deck slabs would collapse
has been exceeded, giving evidence to asuperior fatigue resistance to that of prestressed
concrete deck slab.

Weight Reduction of Deck Slab
Waffle-type
The waffle-type UHPFRC Deck Slab can be made1.0
UHPFRCequally lightweight as steel orthotropic deck slab.
The weight of a flat-type UHPFRC Deck Slab canFlat-type
2.1
be reduced to approximately 60% of prestressed
UHPFRC
concrete deck slab.
In the past, concrete deck slabs have often been
0.98
Steel Orthotropic
designed and built for the vehicle load which
was lighter than that of recent vehicles andPrestressed
3.4
without sufficient consideration for fatigue. Many
concretesuch aged deck slabs are now rapidly
deteriorating. The flat-type UHPFRC Deck SlabReinforced
4.5
concretecan successfully replace such concrete deckslabs with weight reduction benefit.
With the base of waffle-type UHPFRC Deck Slab weight as 1.0

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Road maintenance andmanagement improvement technique～ Replacement of aged reinforced concrete floor base with flat-type UFC floor base ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫ اﻟﻤﺴﺘﻮﻳﺔ‬UFC ‫ اﻟﻤﺘﻘﺎدﻣﺔ ﺑﺎﺳﺘﺨﺪام أﻟﻮاح أرﺿﯿﺎت‬RC ‫~ ﺗﺠﺪﻳﺪ أﻟﻮاح أرﺿﯿﺎت‬Replacement with flat-type UHPFRC Deck SlabThe reinforced concrete deck slab of an oldhighway bridge which was constructed in 1970
has been replaced with our flat-type UHPFRCDeck Slab.
Without adequate technical knowledge at thetime of construction, the bridge has beenplanned and built with little consideration for
fatigue.
Flat-type UHPFRC Existing reinforced
In addition, the deck slab was designed for theconcrete
deckslab
DeckSlabweight of vehicles at the time, which was muchlighter than that of recent vehicles. As a result,the deck slab was only 180 mm thick, which
would not satisfy the current design standards.
Precast prestressed
128.4
concretedeckslab
The thickness of the UHPFRC deck slab that
replaced the old concrete slab is 150 mm, thus
Existing reinforced
successfully reducing the slab weight by
100.0
concrete deck slab
approximately 20%.
With the lighter deck slab, the total bridge girder
Flat-type UHPFRC
78.7
loading did not increase even with the greater
Deck Slabweight of recent vehicles taken into
02550
75
100125150
consideration.
Weight ratio (%)

Durability improvement by eliminating cast-in-situ portion
The flat-type UHPFRC Deck Slab is longitudinallyprestressed by post-tensioning.
Longitudinal post-tensioning work normallyrequires a jack operation space to be provided
at the end of the deck slab, which must then becast in place after tensioning. With this, thedeck slab end portion cannot be prestressedlongitudinally.
On the other hand, our flat-type UHPFRC Deck
Slab technology and its superior material
characteristics allow downsizing the anchors of
post-tensioning tendons, enabling the jack to beplaced and operated under the deck slab at thecenter of the span and thus realizing a fully
precast deck slab construction through to theends.
With the entire deck slab prestressedlongitudinally, durability has further drastically
improved.

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Cast-in-place portion
at the end

JackE nd p anelStandarpanels d(5)Intermediatepanel

Standarpanels d(5)E nd p anel

Road maintenance andmanagement improvement technique～ Replacement of aged reinforced concrete floor base with flat-type UFC floor base ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫ اﻟﻤﺴﺘﻮﻳﺔ‬UFC ‫ اﻟﻤﺘﻘﺎدﻣﺔ ﺑﺎﺳﺘﺨﺪام أﻟﻮاح أرﺿﯿﺎت‬RC ‫~ ﺗﺠﺪﻳﺪ أﻟﻮاح أرﺿﯿﺎت‬Fabrication of flat-type UHPFRC Deck Slab components in exiting
production plants
The flat-type UHPFRC Deck Slab is prestressedtransversally by the pre-tensioning. Therefore, the flattype UHPFRC Deck Slab components can be fabricatedusing existing plant equipment for prestressed
concrete products.
The flat-type UHPFRC Deck Slab has a simple,
constant-thickness geometry and therefore can beproduced with simple formwork. In addition, absenceof reinforcement steel inside the concrete reduces
work steps in production.
Internal structure of a flat-typeUHPFRC Deck Slab without
reinforcement steel

Use of an exclusive erection machine to allow installation work tobe completed within the width of the road
We have developed and implemented an exclusive
lightweight erection machine for the handling of thelightweight flat-type UHPFRC Deck Slab components.
The special machine weighs only approximately 1/3 ofa mobile crane unit commonly used for precast deckslab installation. With this, the installation of flat-type
UHPFRC Deck Slab can be started with minimum
amount of bridge girder strengthening.
The lightweight special machine can travel over theinstalled deck slab section and carry deck slab
components right up to the intended installation
position. It has been demonstrated that all installation
work can be done within the width of the road,indicating the feasibility of single-lane deck slab
replacements in the future.

KAJIMA CORPORATION
https://www.kajima.co.jp/english/

Road maintenance andmanagement improvement technique～ Waffle-type UFC floor base for new ramp bridge construction ～‫ﺗﻜﻨﻮﻟﻮﺟﯿﺎ ﺗﺠﺪﻳﺪ إدارة ﺻﯿﺎﻧﺔ اﻟﻄﺮق‬~ ‫ اﻟﻤﻨﻘﻮﺷﺔ ﻓﻲ ﺟﺴﻮر اﻟﻄﺮق اﻟﺠﺪﻳﺪة‬UFC ‫~ اﺳﺘﻌﻤﺎل أﻟﻮاح أرﺿﯿﺎت‬Weight reduction achieved
with the use of waffle-type UHPFRC Deck SlabOur waffle-type UHPFRC Deck Slab has beenused as the deck slab of a new bridge as partof the Hanshin Expressway Nishisemba
Junction Renovation Project.
The original plan had a cast-in-situ reinforced
concrete deck slab which has later been
replaced with our waffle-type UHPFRC DeckSlab. This design change resulted in more than
50% reduction in the deck slab weight,
reducing the number of girders from three totwo. The total bridge weight has been reducedby more than 40%.
Girder section withUFC floor baseGirder section withreinforced concretefloor base

Deck slab component jointing for easy replacement
In this project, adjacent waffle-type UHPFRCDeck Slab components were secured andjoined by post-tensioning bars.
The jointing feature has been designed andbuilt for consideration for easy removal andrepositioning of post-tensioning bars after thestart of bridge service. With this, single deckslab panels can be swiftly replaced should it
become damaged due to heavy objects
dropped.

Perfobond rib
Post-tensioning bars

Cast-in-situ
UHPFRCsheathing
Post-tensioningbars

Cast-in-situ UHPFRC

Perfobond rib

End rib
Lateral beam

High-strength fiber-reinforced mortar for gap filling
A fluidity-enhanced UHPFRC has been used tofill gaps between the waffle-type UHPFRC Deck
Slab and the steel girder for composite. Gapfilling with UHPFRC has improved thehorizontal shear resistance of the structure byapproximately 40%, making it a highly hopefultechnique to be applied to long span bridges inthe future.

KAJIMA CORPORATION
https://www.kajima.co.jp/english/Gap filling
test withfluidityenhanced
UHPFRC