23rd, August ,2024
Central Japan Railway Company

Development of new construction methods for large-scale renovation work
As we look forward to celebrating the 60th Anniversary of the Tokaido Shinkansen at thestart of October, we must ensure the civil engineering structures remain in good condition
for the future. We have therefore been carrying out large-scale preventive maintenancework since fiscal year 2013.
Concrete bridges are among the structures targeted in our large-scale renovation work, andwe have been using a method that covers the cantilever slabs with highly corrosion-resistantplated steel plates (hereafter referred to as steel plates) to prevent cracks and other
deterioration due to the ageing of the concrete.
In order to steadily carry out large-scale renovation works on concrete bridges in thefuture, we have been developing technologies to improve conventional construction
methods that use heavy steel plates. Based on various verification tests at our research
centre in Komaki, Aichi prefecture, we have now developed a new construction method
using light, high-strength carbon fibre materials.
1. Overview
・ The surface of the cantilever slab is covered with a carbon fibre sheet and a surface
protection material is applied. (Appendix 1)・ It is able to prevent cracks caused by deterioration of concrete over time, to thesame extent or better than conventional construction methods.
Carbon fibre sheet (Top and bottom are one piece)※ImageCarbon fibre sheet
2. Impact of introducing a new productBased on the verification tests conducted during the development stage, the following
effects can be expected:

・ Improved safety and work efficiency
The weight of a single carbon fibre sheet is less than
1/60 of that of a steel plate (maximum 60 kg/sheet),making them easy to handle. As a result, the burden on
workers is significantly reduced and the safety of thecovering work is greatly improved. In addition,
construction can be done by one person, which
improves work efficiency compared to the conventional
method (photo on the right), which required three orWork using conventional methods

more people to complete the work.
・ Cost reduction
The new method requires less labour for coating work, and since it requires fewer
components and is cheaper than steel plates, it is expected to reduce costs by about
30% compared to conventional methods.
・ Shortening of construction period
The new construction method can shorten the construction period because it does
not require large-scale removal and restoration even if there is a building under theviaduct. (Appendix 2)
3. When to introduce
The new construction method will be sequentially used from September 2024.

Appendix 1 Comparison of construction methods in large-scale renovation work

【Conventional Method】••

Covering the surface of “Cantilever slab” of concrete bridges with steel plates. （Fixed with anchors）Maximum weight of steel plate is 60kg/sheet.
Soundproofwall

Steel Plate(Blue:Top , Red: Bottom)
鋼板（青：上面、赤：下面）

Cantileverslab

Covered withsteel plate

Anchor for
fixing steel
plate

Concrete bridges【New Construction Method】 （Patent pending）••

The surface of the "Cantilever slab" is covered with a carbon
fibre sheet (fixed with adhesive), and a surface protection
material is applied to the surface of the carbon fibre sheet.
The weight of a carbon fibre sheet is 1/60 or less compared
to a steel sheet of the same area.
Adhesive

Concrete※Image
Carbon fibre sheet

O2

H2O

CO2

Surfaceprotection
material

Anchor for fixing
soundproof wall

Carbon fibre sheet(Top and bottom are one piece)

Appendix 2

Comparison of construction methods for buildings located under viaduct【Conventional Method】••

In order to install the steel plates, the obstructing
exterior walls must be removed and restored.
In some cases, relocation and restoration of buildings
may be necessary.

Steel plate on
top surface

Steel plate on
bottom surface
Buildingexteriorwalls

Building exterior walls

Under-viaduct equipment【New Construction Method】 （Patented）••••

Dividing carbon fibre sheet and cover the inside andoutside of building walls.
Carbon fibre sheets inside and outside the building
walls are integrated by “Carbon fibre anchors”.
This can be installed by simply drilling small holes inthe external wall to allow the anchors to passthrough, while ensuring that the system is effective
in reducing cracking.
Shortening construction times, as large-scale
removal and restoration of buildings is not required.

※ImageCarbon fibre anchor

Carbon fibre sheets(Inside building walls)

The exterior wall
is obstructing
the structureand needs to beremoved andrestored.
Carbon fibre sheets(Outside building walls)

Building walls