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Jackets (for piers)

In this method, piles are driven into the legs of a three-dimensional truss structure assembled from steel pipes and fixed to the seabed ground, and the piles and legs are welded or grouted together.
The piles are covered with a jacket, which is called a 'jacket' in the sense that it is worn over the piles.

Features of the method

  1. Advantageous in deep water and soft ground
  2. Rapid on-site construction
  3. High earthquake resistance
  4. Environmentally friendly

jacketed pier (construction method overview)

1.Overview

A jacket pier is a pier consisting of a foundation pile covered with a truss constructed of steel pipes.
(It is called a "jacket" in the sense of wearing.)

jacketed pier (construction method overview)

2.Characteristics

  1. High horizontal rigidity (three-dimensional truss structure)
  2. Pile spacing can be extended (fewer piles)
    ⇒ Suitable for deep water, earthquake resistance, soft ground, and rapid construction

jackets with other functions

jacketed pier (construction method overview)

3.jackets with other functions

Jacket with wave barriers
Arc sheet pile jackets
Installed jackets
Gravity-type (installed without piles on a seabed with good soil)
Airport runways and taxiways
Long-term durability corrosion protection
(Lined with super stainless steel)
Earth-loading jetties (jacketed foundations)
Jacketed substructure

Method of improving existing piers with jackets

Existing wharves can be improved economically and in a short construction period by using a rigid jacket as a method of improving, seismically strengthening and renewing the superstructure.

  1. Economic and seismic strengthening is possible by utilising existing piles.
  2. Easy and rapid on-site construction

Jacket replacement method (reinforcement of existing piers)

4.Reinforcement method for existing pier (Jackets substitution)

About jackets for work jetties

Jackets are also used for temporary structures such as temporary jetties for offshore construction work.

  1. More economical than other types when water depths are large.
  2. Fewer piles need to be driven than with piled piers, etc., enabling rapid construction on site.
  3. High rigidity makes it strong against horizontal forces during construction, improving safety.
  4. Can be used as a buffer after construction.

Jacket for Work Platforms

Example of application of jackets for work platforms in pneumatic caisson construction

Construction examples

Name of construction work Yokohama Port Honmoku Area Quay (-16 m) (earthquake resistant) construction work
Client Kanto Regional Development Bureau, Ministry of Land, Infrastructure and Transport
Purpose and function Quay (-16 m)
Year of construction 2020
Dimensions L40×B38.0×H15.3
Number of units 2 units
Weight
Steel weight 650 t/unit
Concrete volume
Design overview Design depth (-16 m)
Features/functions Container berths
Name of construction work Emergency rehabilitation of the Yokohama Harbour Road (Hama Road)
Client Kanto Regional Development Bureau
Purpose and function Impact prevention works
Year of construction 2020
Dimensions L6*B6*H7.5
Number of units 10 unit
Weight
Steel weight 15 t/unit
Concrete volume
Design overview
Features/functions Impact protection for piers and bridge girders (especially PC sections)
Name of construction work Motobu Port (Honbu area) Quay (-10.5 m) maintenance work (H 30-1)
Client Okinawa Prefecture
Purpose and function Quay (-10.5 m)
Year of construction 2019
Dimensions ①L50.0*B20.0*H12.0
②L50.0*B20.0*H12.0
Number of units 2 unit
Weight
Steel weight ①510 t/unit
②625 t/unit
Concrete volume
Design overview Design depth (-10.5 m)
Features/functions Cruise ship berths
Name of construction work Mizushima Port Tamashima Area Quay (-12 m) Construction (Part 4)
Client Chugoku Regional Development Bureau, Ministry of Land, Infrastructure and Transport
Purpose and function Quay wall (-12 m)
Year of construction 2018
Dimensions L64.0*B20.0*H14
Number of units 2 units
Weight
Steel weight 380 t/unit
Concrete volume
Design overview Design depth -12 m
Features/functions Container berths
Name of construction work Construction of new passenger boat wharf quay at Lot 13 in 2017 (Part 1)
Client Tokyo Metropolitan Government
Purpose and function Quay (-11.5 m)
Year of construction 2017
Dimensions L60.0*B30.0*H13.85
Number of units 4 units
Weight
Steel weight approx.810 t/unit
Concrete volume
Design overview Design depth -11.5 m
Features/functions Cruise ship berths
Name of construction work Shinko Wharf No. 9 quay improvement works (No. 3, main body fabrication and substructure)
Client Yokohama City
Purpose and function Quay (-9 m)
Year of construction 2017
Dimensions ①L45.0*B20.0*H12.45
②L44.0*B20.0*H5.0
③L38.0*B20.0*H5.0
Number of units ①2 units
②1 unit
③1 unit
Weight
Steel weight ①330 t/unit
②260 t/unit
③245 t/unit
Concrete volume
Design overview Design depth - 11.3 m
Features/functions Cruise ship berths
Name of construction work Port of Kushiro West Port - 14 m quay B section upper part construction work
Client Hokkaido Development Bureau, Ministry of Land, Infrastructure and Transport
Purpose and function Quay (-14 m)
Year of construction 2016
Dimensions L25*B20*H14
Number of units 3 units
Weight
Steel weight 160 t/unit
Concrete volume
Design overview Design depth -14 m
Features/functions Berths for Panamax vessels
Name of construction work Toyama Shinko Thermal Power Station LNG Unit 1 Jetty
Client Hokuriku Electric Power Company
Purpose and function LNG working platform
Year of construction 2014
Dimensions Length 32.5 x width 37.0 x height 19.0 m (number of legs 12)
Number of units 1 unit
Weight
Steel weight 840 t/unit
Concrete volume Grout 47 m3/unit
Design overview Design seismic load L1
Features/functions Diagonal pile type
Name of construction work Ishinomaki Fishing Port - 7.0 m jetty outside disaster restoration (Part 2)
Client Miyagi Prefecture
Purpose and function Quay (-7 m)
Year of construction 2012
Dimensions L40*B38.0*H5.5
Number of units 12 units
Weight
Steel weight 140 t/unit
Concrete volume
Design overview Design depth -7 m
Features/functions Rehabilitation of a damaged (sunken) pier by raising it
Name of construction work Sakaide LNG Terminal Impulse Protection Jacket Fabrication
Client Sakaide LNG Company, Incorporated
Purpose and function Protective construction
Year of construction 2007
Dimensions L8.2 x W8.2 x H7.0 m (number of legs 4)
Number of units 4 units
Weight
Steel weight 30 t/unit
Concrete volume Grout 7 m3/unit
Design overview Design seismic intensity 0.18
Features/functions Impact protection for the foundations of the pipeline connection bridge
Name of construction work Fushiki Toyama Port (Shin-Minato Area) Road (East-West Line) Work Jetty Construction
Client Hokuriku Regional Development Bureau, Ministry of Land, Infrastructure and Transport
Purpose and function Work pier
Year of construction 2003
Dimensions L18.0 x W10.0 x H8.0 m
Number of units 2 units
Weight
Steel weight 87 t/unit
Concrete volume
Design overview Installation depth - 7.0 m, design seismic intensity 0.16
Features/functions
Name of construction work New construction of the Hitachinaka Thermal Power Plant Lifting coal jetty
Client Electric Power Development Co.,Ltd.
Purpose and function Quay (-19 m)
Year of construction 2000
Dimensions Length 25.0 x width 32.0 x height 25.0 m (number of legs 12)
Number of units 12 units
Weight
Steel weight 2560 t/unit
Concrete volume
Design overview Installation depth -20.5 m
Features/functions Installation type (gravity type)
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