50
CONSTRUCTION WORLD
OCTOBER
2014
ROADS AND BRIDGES
The new airport, opened last year
in the east part of Ishigaki Island
of Okinawa prefecture, and was
designed to accommodate the
most modern planes on its 2 000 m runway.
The existing airport was not able to accom-
modate the midsized planes that are neces-
sary to link with capital regions, because of
its short runway.
Project responsibility was given to the
Asphalt Business Association, which consists
of four local paving and grading contractors
– Toyo Kogyo, Nansei Doken, Yaejima Kogyo
and Sakihara Construction.
The association used Topcon’s LPS 3D
machine control system on their graders,
pavers and asphalt paver. The project
included surface preparation work and
paving of the runway and taxiways, in all a
construction area of 187 500 m
2
.
The 3D-MC system used a QS robotic
total station which locates and tracks for
the 360° prism mounted on the machinery
and measures the precise position of the
machine in real time. The system then auto-
matically controls the blade and screed
height of the grader and paver by verifying
the position and 3D design data. The results
are extremely accurate.
Seiken Haemori, president of Nansei
Doken, said, “The paving plan for the new
airport was first announced in 2009, at that
Unlike conventional paving or
tiling on a concrete surface in
which the pavers or tiles are
attached directly onto a concrete
base layer using grout or some other binding
agent to create an impervious watertight
surface, in suspended paving the pavers are
mounted on small polythene sandbags (see
picture) without the use of any adhesive or
binding agent. All that is needed to keep the
pavers firmly in place is their weight. More-
over, they are laid 10-12 mm apart which
creates a water permeable surface.
These and other advantages are why
suspended paving is finding increasing
favour among some of the country’s leading
architectural practices. And the process has
already been used on some major construc-
tion projects using pavers supplied by Cape–
based Concrete Manufacturers Association
NPC (CMA) member, Revelstone. Recent
projects include: Cape Peninsula-based
projects such as Liberty Life’s headquarter
premises in Century City; Bloemhof in Tyger
Valley; Wembley Square in Gardens; and
some student residences in Stellenbosch.
Suspended paving has also been used
at Dainfern Square in Johannesburg and
Liberty Life’s Umhlanga offices in KwaZu-
lu-Natal, among other high-profile projects.
According to Johnny Schwartz a partner
of Louis Karol Architects – a suspend-
ed-paving pioneer – the process offers
some distinct advantages over conventional
roof-top or terrace paving.
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Outstanding results in
Topcon 3D-MC system yields outstanding productivity in runway
paving project at the Japanese Ishigaki Airport completed in just
five months instead of the usual 12 months.
RUNWAY PAVING
time we began discussing the project with
local contractors.”
Yoichi Shii-uezato, president of Toyo
Kogyo, said, “We were invited to a construc-
tion site to see a demonstration with the
Topcon 3D-MC system and we realised
immediately it was the perfect solution. It
was apparent that work could be done at the
rate of 6 000 m
2
per day. This was about four
times the speed of conventional methods.”
Regarding the asphalt paver, Shii-uezato
said, “Though the accepted range of accu-
racy for ordinary paving is ±15 mm, target
accuracy for this particular project was
±5 mm. We could reach the specified accu-
racy perfectly.” Satoshi Taira, president of
Yaejima Kogyo, said, “We successfully hit all
the designed grades along with the runway.
With the co-operation of the four companies
and utilising 3D-MC systems, we were able to
accomplish the paving in just five months,
less than half of the expected twelve months
for the project.” The contractors received
the highest evaluation points after project
completion from governmental authorities.
Hirotaka Sakihara, a member of the senior
staff of Sakihara Construction, said, “We
will utilise the auto-tracking total stations
not only for projects requiring 3D machine
control, but also for general surveying tasks.
We will also apply the instrument in the
projects requiring as-built checks.”
How does one convert a dull
bitumen-coated flat roof or
terrace into an attractive
paved surface without the
use of grout or any other
form of binding agent? One
answer is to be found in
suspended paving, a process
which uses concrete flagstone
pavers without the use of any
binding agent.
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