Volume 4, Issue 4 December 2019

Special Contribution

Technology Developments in Japanese Construction Industry
Kenichi Horikoshi
General Manager, Technology Planning Department
Taisei Advanced Center of Technology, Taisei Corporation
ABSTRACT: The major Japanese construction companies have their own research and development (R&D) institutes aswell as the design and engineering divisions, which is very different from the construction contractors outside Japan andone of the unique characteristics of the construction business in Japan. Such in-house research capability allows them tomeet a wide variety of technical, social demands, and customer requirements in the world. It is also very important for
their research institutes to develop new technologies in view of future trends in the business markets in the world. This
report will introduce the recent activities of technology developments in such research institutes of one of Japanesecontractors, i.e., Taisei Corporation which the author belongs to, with much focus on the technologies using recent ICT &AI technologies.
Key Words: Construction industry, Technology Development, Research Institute, Robot, ICT
1.

INTRODUCTION

Major Japanese construction contractors have their own research institutes to enhance and expand their businessmarkets. The topics of their research fields are significantly varied to cover the social and technical demands raised byour social lives and business activities of clients, as well as global trends. Selections and prioritizations of research anddevelopment topics are one of the major important duties of the author.
Major topics of research and development currently arei) Technologies to cope with major future earthquakes and other natural disasters,ii) Renovation and replacement of old existing infrastructures and buildings, especially in urban areas such as Tokyo,iii) Environment-friendly construction to meet corporate social responsibility,iv) Application of advanced technology such as use of ICT and AI to enhance productivity,andv) New construction technologies required for major projects in Japan.
Sustainable Development Goals (SDGs) which was proposed by the United Nations in 2015 are also important issues
which we surely need to follow as the current and future global trends. Among the topics of the above, the recent
advanced technologies which use ICT are introduced in this report after the brief introduction of the recent trends inJapanese construction industry.
2.

RECENT TRENDS IN JAPANESE CONSTRUCTION INDUSTRY

600

120500

100

400

80

3006020040

GDP
Investment in Construction

10001980

2001985

1990

1995

2000

2005

2010

2015

Year

Fig. 1. Investment in construction in Japan(Data from JFCC handbook)3

Investment in Construction(Trillion Yen)

Fig. 1 shows the overall trend in Japanese Gross Domestic
Product (GDP) alongside investment in the construction
market. It is revealed that GDP has remained almost
unchanged for the past twenty years, with a slightincrease up to about JPY 550 trillion (equivalent to USD
5.1 trillion at the latest exchange rate of 108 JPY/USD). At
the same time, despite the unchanged trends in JapaneseGDP, the investment in construction had halved by 2010
from a peak value of JPY 84 trillion in 1992 after thecollapse of the Japanese bubble economy in 1989. Afterthe investment hit the bottom value, the investment inconstruction has crept upward by 1.5 times to about JPY

GDP (Trillion Yen)

It is necessary to first give an outline of overall trends in the Japanese construction industry. The Japan Federation ofConstruction Contractors (JFCC) publishes an annual handbook giving the latest data on the Japanese constructionindustry (JFCC, 2019). The author combines the data by referring the past issues of the handbooks.

700

650

650

600

600

550

550

500

500

Number of Companies
Number of Employees

4504001980

450

Number of Employees(x 10,000)

Fig. 2 shows the overall trend in the numberof construction companies operating in Japanand employees in the industry. The numberof construction companies has decreased by
22% from the peak of 601,000 in 1999, while
employment has fallen by 25% from the 1997
peak of 6.85 million. Although theinvestment has increased by about 1.5 times
in the last five years, the number ofconstruction companies as well as thenumber of employees have not increased atall, which means that a significant lack oflabor in the construction industry has beenexperienced. Fig.2 clearly shows that once
left the industry, it is not easy to return.
Owing to the lack of labor, the construction
workers have been busier and busier, whichleads to the work of the construction industry
less attractive for young engineers.

700400
1985

1990

1995

2000

2005

2010

2015

YearFig. 2. Number of construction companies & employees inconstruction industry
40

Percentage of workers in differentage (%)

60 trillion in 2018, which increase is thought
to be attributed to rehabilitation andreconstruction work following the 2011
Tohoku Earthquake and a construction boom
related to the upcoming 2020 Tokyo Olympicand Paralympic Games, and other big
projects in Japan.

Number of Construction
Companies (x 1,000)

Volume 4, Issue 4 December 2019

35
30
2520
15

Construction industry(>=55 years old)
All industries(>=55 years old)
All industries (<=29 years old)
Construction industry (<=29 years old)

1050Fig. 3 shows the percentage of workers in19901995
2000
2005
2010
2015Yeardifferent age in the construction industry
compared with that for all industries in Japan.
Fig. 3. Percentage of workers in different age in construction industry
It shows the significance of rapid aging in thecompared with that for all industries
construction industry compared with otherindustries in Japan. At present, more than
one third of employees in the industry exceed
55 years old, with only about 10% being less than 29 years old. Attracting young engineers to the construction industry is avery urgent issue.
Considering the above situations in the construction industry, it is very important for us to develop new technologies tocope with the shortage of labor and skilled workers in construction, as well as more advanced technologies using ICT andAI which are attractive to young engineers, and which will change the negative image of ‘3D’ in the industry, i.e., Difficult,Dangerous, and Dirty. Improving productivity in the industry will surely be one of the solutions.
3.

IMPROVING PRODUCTIVITY IN CONSTRUCTION INDUSTRY

Unmanned construction system
In 1991 one of Japan’s most active volcanoes erupted and generated an enormous pyroclastic flow that killed 43 people(Fig. 4). The site at Mt. Unzen remained in dangerous conditions, but the disaster recovery efforts had to go on, so thegovernment decided to use unmanned construction systems for the work. Following the successful application of
unmanned construction system at the Mt. Unzen site, the technology has been improved and used for many other naturaldisasters. These include the sites of landslides resulting from earthquakes, heavy rains and other natural occurrences. It
is worth noting, also, that unmanned construction systems played an important role when the Fukushima nuclear power
plant was severely damaged in the 2011 Tohoku Earthquake (Fig. 5). The unmanned machines removed rubble and debris
immediately after the accident to allow rapid and problem-free commencement of other recovery work. Initially, theunmanned machines were controlled from a site house located at the nearest safe place for the work. Remote control ofconstruction machinery requires particular skills that differ from those needed to operate the machines directly. Work
was carried out step by step under manual control, using many monitors set up in the site house to observe the operation.
4Volume 4, Issue 4 December 2019

Fig. 5. Unmanned construction systems at
Fukushima nuclear power plant
https://www.nikkei.com/article/DGXNASFK110
34_R11C13A2000000/

Fig. 4. Pyroclastic flow occurred at Mt. Unzen in 1991
(https://en.wikipedia.org/wiki/Mount_Unzen)

More than 25 years have passed since the first application of unmanned construction. Advanced technologies related toreal-time positioning systems, monitoring systems, highly accurate sensor systems, communications, and other recent
ICT and AI techniques ensure more accurate work with more automatic and autonomous control. Unmanned
construction technology also contributes to reduce demand for workers. Two autonomous unmanned construction
machines have been developed, a vibration roller system and a breaker system (Katayama and Ishii, 2016, Katayama etal., 2015). These machines can complete an assigned task without further human control once the initial conditions andtarget results are entered.
Fig. 6 shows the autonomous unmanned vibration roller named as ‘T-iROBO Roller’. It is fitted with a number of sensors
needed for autonomous operations. Fig. 7 shows the machine undergoing verification tests. After an operator enters data
specifying the area requiring compaction, themachine completes the work, autonomously
keeping track of the number of compactions. Since
the machine accurately tracks its own position,
construction work can continue even in poor
visibility, such as with fog, and at night. Operational
data can be linked with data from Building
Information Modeling (BIM) or Construction
Information Modeling (CIM) systems and linked toquality control data. An autonomous unmanned
breaker machine (Fig. 8) named as ‘T-iROBO Breaker’
is able to detect a target object, such as a mass ofrock, from a distance, approach the target, and break
Fig. 6. Autonomous unmanned vibration roller
the up target while determining the best breakingposition.

Fig. 7. Verification test of autonomous unmannedvibration roller

Fig. 8. Autonomous unmanned breaker5Volume 4, Issue 4 December 2019

Automatic concrete slab finisher and cleaner
Manual slab finishing just after casting is hard work for a construction worker as shown in Fig. 9. It is slow work in adifficult posture that places a heavy burden on the body. An automatic finishing machine was then developed for concrete
floors. An attempt was made to improve work
conditions and efficiency in this concrete finishingwork by developing a light-weight construction robot
named as ‘T-iROBO Slab Finisher’ (Nakamura, 2016),
as shown in Fig. 10. The machine does the work of
three construction workers. Operation is done by asingle worker with a controller like the one used forcomputer games, leading to a reduced workforce andeasier work. The machine is battery-operated andweighs 90kg, of which 25kg is a battery weight.
Continuous operation for 3.5 hours is possible. Batteryperformance and weight still leave room for
improvement. In addition to the types of automatic
machine described above, an automatic cleaningmachine for construction sites has been developed(Kato, 2016) named as ‘T-iROBO Cleaner‘ as shown in
Fig. 11. It can recognize safety cones and barriers Fig. 9. Finishing cast concrete is hard & time-consuming work
marking off-limits areas.

Fig. 10. Automatic concrete slab finisher

Barriers marking off-limits
areas
Safety coneFig. 11. Automatic cleaner for construction sites6Volume 4, Issue 4 December 2019Advanced positioning system for pile installation
Work of accurately marking the specified locations
for piles generally requires at least two people,
one stationed by the measuring system (totalstation theodolite) and the other moving aroundinto the exact pile positions. An advanced
positioning method named ‘T-Mark Navi’ that canbe operated by just one person has beendeveloped (Tanaka and Sueda, 2016). The
operator wears a pair of wearable (smart) glasses
that include a display system. Fig. 12 compares theoperation of the system with the conventional
method. A specially designed measurement
device is used instead of the conventional total
station theodolite. The operator carries a smart
phone that communicates with the measurement
device via wireless LAN and uses voice control
technology to determine precise pile positions.
Positioning data is visible on the display of thesmart glasses, as shown in Fig. 13. This system
reduces the number of workers required for pile
positioning by half.

Heretofore

Loud Voice

Display on
Smart glasses

Developed System
Measured Value

Setting Operationby Smartphone
Voice Control
on Smart glasses

Fig. 12. Precise positioning system operated by only one person

Far from TargetNear Target(less than 100mm)

Just onTarget Position

Fig. 13. Display of positioning data via smart glasses

Systems developed for safer tunnel construction
Tunneling in complicated geotechnical conditions is one of the difficult constructions. Safe and secure tunneling is always
desired. A technology used projecting mapping was developed for tunnel construction (Fig. 14) (Tani et al., 2019, Nikkei
Construction, 2019). Once drilling was finished at the tunnel face, the face is covered with shotcrete quickly for safetyand protection. Therefore, it is important to share the information on the face with all workers and operators. The systemprojects the necessary information directly on the runnel face so that all workers and operators can share the technicalinformation easily. Examples of the projected information are shown in Fig. 15.
Example of Projected Information on Tunnel Face

Weak Rock Area

Hard Rock

Projector

Drilling Machine

Fig. 14. Projection mapping system on tunnel face

7Fig. 15. Examples of the projections

Volume 4, Issue 4 December 2019
4.

SUMMARY

Some of the research and development activities at Taisei Advanced Center of Technology (TAC.T) was briefly introducedwith focus on technologies to cope with the shortage of labor and skilled workers in the construction industry. Most
technologies use advanced ICTs, and more AI technologies in the future. Implementation of ICT and AI in construction
technologies will enhance the productivity of the construction industry as well as attract more young engineers to theindustry. Please note that the contents described in this report are only a small part of the results. Further information
can be available on the website of Taisei Corporation, and Report of Taisei Advanced Center of Technology, or pleasecontact the author.
‘Open innovation’ has become a major keyword in the recent research and development activities. Collaborative workon a global scale with a wide variety of fields beyond the scope of construction is more necessary for further developmentof the construction industry in near future.
5.

REFERENCES

Japan Federation of Construction Contractors, JFCC, Construction industry handbook 2019 (in Japanese), published everyyear.
Horikoshi, K., 2017. Recent technology development trends in the Japanese construction industry, Proceedings of design
and analysis of piled raft foundations 2017, chapter 19, pp. 259-274.
Katayama, S. and Ishii, T., 2016. Evaluation of rolling compaction performance with autonomous control vibration roller“T-iROBO® Roller” - On site inspection of robots for the next generation social infrastructure- (in Japanese), Report ofTaisei Technology Center, Vol. 49, Paper #54.
Katayama, S., Miyazaki, H. and Aoki, H., 2015. Demonstration of the autonomy rock crash work by the excavator with abreaker - Development of the next-generation unmanned construction System - (in Japanese), Report of Taisei
Technology Center, Vol. 48, Paper #50.
Kato, T., 2016. Development of the autonomic cleaning robot “T-iROBO® Cleaner” (in Japanese), Report of TaiseiTechnology Center, Vol. 49, Paper #53.
Ministry of Land, Infrastructure, Transport and Tourism, 2016. Reference on current situation and change in constructionindustry Public announcement by Japanese Ministry of Land, Infrastructure (in Japanese), Transport and Tourism onMarch, 2016.
Nakamura, Y., 2016. Development of concrete slab finishing robot “T-iROBO® Slab Finisher” - Improvements of work
environment and efficiency in concrete slab finishing work - (in Japanese), Report of Taisei Technology Center, Vol. 49,Paper #52.
Nikkei Construction (in Japanese), pp. 8-13, issue of February 25, 2019.
Tani, T., Koga, Y., Miyamoto, S., and Aoki, T., 2019. Visualization of geotechnical information by projection mapping
technique on the tunnel face (in Japanese), Annual Convention of JGS, Omiya, No. 699, July.
Tanaka, Y. and Sueda, T., 2016. Development of position measurement system by using a smart glasses (in Japanese),
Architectural Design, No. 799, pp.52-59, August.

◆ A brief CV of Dr. Kenichi Horikoshi
Kenichi Horikoshi is the general manager at Taisei Advanced Center of Technology, Taisei
Corporation, Japan. After completing the Master's degree from Kyoto University in 1987, hejoined Taisei Corporation. In 1996, he received PhD degree from the University of Western
Australia for the thesis of ‘Optimum Design of Piled Raft Foundations’. Since then he has
engaged in a number of research projects and consulting works on a wide variety ofgeotechnical engineering fields. Currently, he is responsible for technology development
strategy in Taisei Corporation. He is also the Secretary General of Asian Civil Engineering
Coordinating Council (ACECC), as well as the vice president of Japanese Geotechnical Society.

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