November 16, 2000
Building-Moving Base Isolation Improvement Method
Implemented on a Laboratory Building of Kansai University
Base isolation system installed after moving the whole building
eight meters
while maintaining a workable environment inside the building
At the Senriyama Campus of Kansai University
located in Suita City, Takenaka Corporation (Head office: Osaka, President:
Toichi Takenaka) moved the Faculty of Engineering's No. 1 Laboratory Building,
an existing structure (a reinforced concrete four-story structure with
a total weight of approximately 2,000 tons, dimensions of 16.4 x 29.1
meters, and height of 13.6 meters), approximately eight meters to the west,
to install a base isolation system. This is called the building-moving
base isolation improvement method. Using this method it is possible to
achieve base isolation improvements while maintaining the building in a
normal state that allows the building to function normally while work
is being carried out.
This No. 1 Laboratory of the Faculty of Engineering was completed in
1973, and was built according to old building standards, so the decision
was made to improve earthquake resistance, thereby improving the standard
of safety in the campus. The method chosen to do so was to move the building.
The moving of the building is to be carried out in 15 hours over two
days on November 16 and 17. The installation of the base isolation system
is to be carried out from mid-December to mid-January.
In the installation of base isolation systems for existing buildings
in the past there has been a number of cases where moving of buildings
has been carried out, but this is the first case in Japan where a building
has been moved as far as eight meters while the building continues to be
used.
Construction procedure for the Building-Moving Base
Isolation Improvement Method
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(1) Earth retaining and pile work
Earth retaining H-shaped steel piles will be put in place to prevent
collapse of the ground surrounding the site where the building is to be
moved. Some 44 new piles will be put in place where the building is to
be moved.
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(2) Excavation work
The earthen floor slab of the first floor
will be broken up, and a new structural slab laid, strengthened with beams.
Excavation will be carried out while strengthening existing piles on the
base under the existing building and the new site of the building. |
(3) Cut existing piles and construct foundations
Foundations in areas except around existing
piles will be constructed.
A temporary base will be installed, the existing piles cut, and then
new foundations constructed around existing piles. |
(4) Building-moving work
A roller-lift device will be installed,
and the temporary base removed. The building will then be moved approximately
eight meters by eight 50-ton propelled hydraulic jacks on the transfer
roadbed. The stroke of the jacks is 20 centimeters, and they require approximately
five minutes to extend. After the building moves 20
centimeters, the jacks
will be reset, and this
process repeated. |
(5) Base isolation work
After installing a temporary base and removing
the rolling device, the base isolation system - rubber bearings (diameter
600 millimeters, seven locations), sliding bearings (diameter 450 to 30
millimeters, 11 locations) and oil dampers (four locations) will be installed
under the existing foundations, with the gap to be filled in with concrete,
and the temporary base removed. |
(6) Completion
The remaining retaining walls will be completed,
and the surrounds of the building closed off with expanding metal plates. |
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Current state of methods to improve earthquake resistance
'With the Great Hanshin-Awaji Earthquake in 1995
as a turning point, the Earthquake-Resistance Improvement Promotion Law
was enacted to promote improvements to existing buildings which do not
meet current earthquake-resistance standards. This law makes it mandatory
to carry out earthquake-resistance diagnosis and earthquake-resistance
improvements on existing buildings of a given size and greater which do
not meet standards. In addition, for school facilities under the jurisdiction
of the Ministry of Education, in addition to diagnosing earthquake resistance,
a system has been established to subsidize improvements to strengthen earthquake
resistance. Methods of improving the earthquake resistance of reinforced
concrete buildings include strengthening columns and walls, installing
additional earthquake-resistant studs and diagonal bracing, and installing
base isolation systems.
Base isolation involves using base isolation systems installed underneath
buildings to hinder the transfer of seismic force from the ground to the
building. The base isolation system installed in this case comprises rubber
lamina of rubber and steel plate laid alternately, sliding bearings which
allows the building to slide freely on the support surface, and dampers
which perform a damping function.
There are two techniques to improve the earthquake resistance of buildings
to enable them to withstand major earthquakes, without stopping the function
of the building: quake-resistance/structural control improvements and
base isolation improvements. When carrying out either type of improvements,
Takenaka adopts low vibration, low-noise and low-dust methods to minimize
the impact on the living and working environments of building users.
Takenaka's track record of installing base isolators while existing
buildings are being used includes the Head Office of Himeji Shinkin Bank
(Himeji), and Tokyo Dia Building, which is currently in progress. This
is the first time that Takenaka has used this building-moving base isolation
improvement method.
Overview of No.1 Laboratory of Faculty of Engineering,
Kansai University
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| Location |
3-874 Senriyama-Higashi, Suita City |
| Client |
Kansai University |
| Number of floors |
4 Fl. Above ground (maximum height 13.6 m) |
| Structure |
Reinforced concrete |
| Total floor space |
1,271.1 m2 |
| Building area |
384.5 m2 |
| Work period |
June 2000 to April 2001 |
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