1.0
CONTENT
C O N T E N T
1.0
CONTENT
2.0 DOCUMENT STATUS
3.0 INTRODUCTION
3.1 Purpose
3.2 Project Description
4.0 MARINE CONSTRUCTION NOISE SOURCES
4.1 Bored Piling Work
4.2 Working Vessels and Platforms
5.0 ACOUSTIC DECOUPLING MEASURES
5.1 Bored Piling Work – Bubble Curtain
5.2 Working Vessels and Platforms –
Isolation Pad
Appendix A: Proposed
Isolation Pad Details
2.0
DOCUMENT STATUS
2.1 Details of Revision:
Rev. |
Rev. Date |
Sections |
Amendment Source and/or
Details |
A |
8/10/2012 |
All |
For the first submission to the SOR. |
B |
12/10/2012 |
All |
Incorporated the SOR/IEC/ENPO’s comments and
amended text where necessary. |
C |
26/11/2012 |
Section 4.0 |
Incorporated the EPD and IEC’s comments and amended text where necessary. |
3.0 INTRODUCTION
3.1 Purpose
The Acoustic Decoupling Measures Plan
(the Plan) has been prepared in accordance with Condition 2.6 of the
Environmental Permit (EP-352/2009/A) for the Highways Department Contract
namely Contract No. HY/2011/09 – Hong Kong-Zhuhai-Macao Bridge Hong Kong Link
Road – Section between HKSAR Boundary and Scenic Hill.
The
Plan shall describe the measures to be taken to minimize impacts to
marine ecological environment, and mainly for the Chinese White Dolphins (CWD)
when carrying out bored piling, dredging and reclamation.
3.2 Project
Description
Highways Department commissioned the project
“Hong Kong Link Road- Section between HKSAR Boundary and Scenic Hill” (hereinafter
called the Contract) with Contract No: HY/2011/09. Dragages
-China Harbour-VSL Joint Venture (DCVJV) is awarded the Contract. The scope of
the works comprises the following major item:
(i)
a
dual 3-lane carriageway in the form of viaduct from the HKSAR boundary
(connecting with the HZMB Main Bridge) to the Scenic Hill (connecting with the
tunnel under separate Contract No. HY/2011/03), of approximately 9.4km in
length with a hard shoulder for each bound of carriageway and a utilities
trough on the outer edge of each bound of viaducts;
(ii)
a
grade-separated turnaround facility located near San Shek Wan, composed of slip
roads in the form of viaduct with single-lane carriageway bifurcated from the
HKLR mainline with an elevated junction above the mainline;
(iii) provision of
ancillary facilities including, but not limited to, meteorological enhancement
measures including the provisioning of anemometers and modification of the wind
profiler station at hillside of Sha Lo Wan, provisioning of a compensatory
marine radar, and provisioning of security systems; and
(iv) associated civil,
structural, geotechnical, marine, environmental protection, landscaping,
drainage and highways electrical and mechanical (E&M) works, street
lightings, traffic aids and sign gantries, marine navigational aids, ship
impact protection system, water mains and fire hydrants, lightning protection
system, structural health monitoring and maintenance management system
(SHM&MMS), supervisory control and data acquisition (SCADA) system, as well
as operation and maintenance provisions of viaducts, provisioning of facilities
for installation of traffic control and surveillance system (TCSS),
provisioning of facilities for installation of telecommunication
cables/equipments and re provisioning works of affected existing
facilities/utilities.
Cinotech Consultants Limited was
commissioned by the DCVJV to undertake the EM&A works for the Contract
and was appointed as the Environmental Team (ET).
The location of the Contract is illustrates in Figure 4.1.
Hong Kong Link Road under
Contract No: HY/2011/09
Figure
4.1: The location of the Contract
4.0
MARINE CONSTRUCTION
NOISE SOURCES
4.1 Bored
Piling Work
Bored piling, instead
of percussive piling, will be undertaken with permanent steel casing for
construction of the substructures of piers. Low-vibration hammers will be used
to install the casings into the seabed following the alignment control guides
set on the platform.
4.2 Working
Vessels and Platforms
Stationary powered
mechanical equipments mounted on boards of working vessels or platforms, when
operating, may generate vibration or noise through the hull
if they are directly placed on the deck without proper isolation. These common
equipments on board include,
·
Generators,
·
Winch
generators,
·
Air compressors.
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Generator on vessel board |
Winch system on vessel board |
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Air compressors on vessel board |
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In order to minimize the noise transmission to the sea, acoustic
decoupling measures for the stationary equipment mounted on boards will be
adopted.
5.0 ACOUSTIC DECOUPLING MEASURES
5.1 Working
Vessels and Platforms – Isolation Pad
Noise isolation pad is
proposed to separate the stationary equipments from the decks or hulls in order
to reduce noise transmission to the sea via the working vessels or platforms.
The proposed isolation pad details are given in Appendix A.
Instead of directly mount
on decks, noisy equipments will be fixed on noise isolation pad. Prior to
installation, DCVJV will ensure the foundation of equipments is flat and level.
Adequate clearance all around the noisy equipment will be kept to avoid direct
vibration transmission to other materials and machineries.
It is estimated that common generators to be operated on board are about
1m x 2m in plan dimension and they will easily fit to sit on the proposed
isolation pads formed by individual units with dimension 1m x 1m. An installation sketch is attached in the
Appendix A to show the design scheme.
5.2 General
Notes to Install the Measures
·
To
forbid direct vibration transmission, adequate plinth clearance shall be kept
all around.
·
Close
all panels or doors of generators when in use.
·
To
avoid noise breakout and the undesirable sound paths through gaps, the
foundation where the equipment to be placed shall be flat and level.
·
To
further eliminated the sound generation from noisy parts, flexible bellows
silencers, mufflers shall be applied when necessary.
END OF TEXT
Appendix A – Proposed Isolation Pad Details
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