Construction Revolution

Implant Bridge
Solution for Bridge Reconstruction in Urban Area

General Outline
Introduction
In the early 20th century, the first automobile was introduced in Japan. Since then, the number of automobile hasgrown drastically throughout the world. Automobile has become substantial and compulsory in our life.
Popularisation of automobile plays a substantial role in economical and cultural developments, and it has affectedvarious associated industries. More road networks are required to cope with the rapid increase of vehicles on road.
Unfortunately, the road networks are inadequate and its function is limited. For example, bridges which were built
earlier are too old to serve its function effectively causes massive traffic jams at the junction. Thus, it is critical forthe society to respond to the current traffic problems and new construction approach shall be implemented as soon
as possible in urban city.

Outline of Implant Bridge
Giken's Proposal to Bridge Reconstruction“Implant Bridge” is another form of “Implant Structure”. Implant Structure is made of modular prefabricatedstructural elements and installed into the ground using the Press-in Method. It functions both as a foundation
pile and act ultimately as the body of a structure. During the construction, no extensive temporary work isnecessary. It is a structural revolution which changes the current footing type of structures into the concept of“Implant Structures”. Giken has successfully established a new construction method to eliminate all negative
aspects of conventional construction works.
This new concept of construction method further adds engineering value to the overall construction. It reinforces
the existing structures with minimum rectification works required. The procedure of works is systematic which
imposes less environmental problem to the surrounding (e.g. minimum disturbance to the existing traffics andpedestrians). Even if any existing structures obstruct the construction of a new structure, it can still be solved bydemolishing only a small affected part of the existing structure. With such, the “Implant Structure” will extend thelife of the existing structure by re-creating a new function to it. This concept fits well on the idea of re-cycling fora sustainable society.
[ Footing Structure ]New StructureNewStructure1[ Implant Structure ]ExistingStructure

NewStructureImplant Bridge

Features of Structure
Substructure
Modular structural elements (made of prefabricated piles) are continuously being pressed-in to the required
depth without removing the existing abutment and embankment. These piles will function as the bridge
abutment, so called the “Implant Abutment”.
Construction activities are neither affected by the variations in water level nor any seasonal restrictions.
Hence, the total construction period and cost can be remarkably reduced.
Foundation and structural parts can be completed in one-step by penetrating through the existing structureseven at hard ground condition.
By selecting the most appropriate pile materials, structure which shows high resistance against earthquake
can be constructed economically.

Superstructure
The concept of this design is to transfer the horizontal force to superstructures through the pre-tensionedgirders. Cushioning materials are inserted between the parapets of abutments and at both ends of thegirders, allowing the transfer of horizontal force instead of bending moment. In the design, simple beam
concept is applied since the fulcrums are at the pile tops. As the result, stresses and deformations are smaller
than those induced in the cantilever beam action, which eliminate the need for a massive substructure to beconstructed.
Reduction of construction period can be achieved by employing pre-tensioned pre-cast simple slab or T
shape pre-cast girder.

[ Prop Structure Sample Illustration ][ Detail Bearing A1 &A2 ]Cushioning
Material
Rubber Bearing
Anchor Bar(Limit Displacement)

H : Horizontal Force
V : Vertical Force
M : Bending Moment
Kv : Axial Spring
Kh : Lateral Spring

2General Outline
Features of Gyropress Method
Press-in operation is carried out on completed piles and repeated based on a simple standard procedure.
Therefore, construction can be carried out under any site restrictions with minimum space and no temporary
work is necessary.
Pile material with the required strength and dimension will be selected to satisfy with the design requirement.
The construction can be achieved with good accuracy by the superiority of press-in principle.
Machines used for the construction of functional structure are free from noise and vibration with minimum
emission of exhaust gas. The use of bio-degradable oil further adds to the environmental friendliness of thesystem.
Systemized machines are self-standing by gripping the pre-installed piles. Thus, the machines are safe
against the toppling possibility. The small and compact machine further eliminates the negative impact to thesurrounding environment.
Highly advanced IT technologies are equipped with systemized machines which enable the work to be carriedout safely and efficiently at a longer time.

Gyro Piler

Penetration into a Reinforced Concrete Structure
Penetration through reinforced concrete by Gyropress method; Thickness 80 cm, D16@250 x 3 layers.

3Implant Bridge

General Application[ Plan ]A1

RiverRiver

Design Outline
1) Superstructure
Pre-tensioned System PC Simple Deck Bridge2) Substructure
Implant Abutment
3) Foundation
Tubular Piles (Baring Piles)
4) Pile LengthSemi-infinite ( ȕLe ≧ 3 )5) Earthquake Resistant Design Standard
The Traditional Elastic Static Seismic Method

A2[ Superstructure Elevation ][ Cross Section ]Asphalt paving
Bridge Length (New)Bridge Length (Existing)

Implant
Abutment

Parapet Wall to be removed
Pretension Girder[ Substructure Elevation ]Implant
Abutment

H.W.L

H.W.L

River Bed
Level
ExistingAbutment A1

Existing
Abutment A2

Tubular Pile
Existing Bearing Piles

Tubular Pile4

Construction Method Comparison
Bridge Reconstruction by Implant Bridge
The “Implant Bridge” is a method to construct the “Functional Structure” without the demolition of existing abutment.
Construction can be carried out without disrupting the existing traffic and affecting the comfort of pedestrians. It
maximises the use of existing structures as the working area and eliminates the massive temporary works which arerequired based on the conventional methods. This method can also prevent from secondary disaster during floodseasons considering that there is no obstruction to the river flow during construction. With the effective use of thesuperiority of press-in principle, construction will be carried out with minimum temporary works and complied with theFive Construction Principles.

During Tubular Pile Installation[ Plan ][ Cross Section ]Gyro Piler

Implant Abutment
GyroPiler

Power
Unit

H.W.LRiver

Tubular Pile

Tubular Pile

GyroPiler

5

Crane

Tubular Pile
River
Existing
Abutment A1

PowerUnit

Existing
Abutment A2

Implant Bridge

Conventional Bridge Reconstruction
The construction starts from the removal of massive existing structures. In order to remove the existing structures, massive
temporary works are carried out (e.g. temporary enclosure by sheet piles, excavation, dewatering, strutting and waling,demolition of existing abutment and foundation including disposal of excavated materials and demolished concrete etc).
Majority of the works involves huge temporary works, causing traffic obstruction and discomfort to pedestrians duringconstruction. Furthermore, extensive temporary enclosure and working platform will be required in the river which affects thesmooth river flow and draws the risk of the occurrence of secondary disaster during heavy rain and flood seasons. Footing typestructure is common for this conventional structure and the construction works are difficult to comply with the Five Construction
Principles. Consequently, it prolongs the construction period and causes detrimental effects to the surrounding environment.

During Existing Abutment Demolition Work

[ Plan ][ Cross Section ]Road Closed

Road Closed

Large Breaker

Sandbags

RiverSandbags

RiverH.W.LDemolition
ExistingAbutment A2

Existing Pile
RemovalGround Anchor

Sheet Pile IV6Construction Solutions Company
GIKEN LTD.

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Ver 1.0EN05 / 27 Feb 2014