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

N

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.

Generator on vessel board	Winch system on vessel board
Air compressors on vessel board

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