Method Statement
detailing the
Protective Measures on Declared Monument
Buildings
at
Former Marine Police Headquarters, KIL 11161
Conditions Imposed under Section 5(12) of
Environmental Impact Assessment (EIA) Ordinance, Cap.499
Application for Permission to Apply Directly for Environmental Permit
Application No.: DIR-094/2003
Project Proponent: Flying Snow Limited
Prepared By: All Arts Architectural Design and Research Limited
March 2004
Method Statement detailing the Protective Measures on Declared Monument Buildings
1.
Background Information
1.1
The Submission
1.1.1
This Method Statement (MS) detailing the protective measures on the Declared
Monument Buildings at Former Marine Police Headquarter (FMPHQ), KIL
11161(the Subject Site) is prepared and submitted under the condition imposed under
the Environmental Impact Assessment (EIA) Ordinance, Cap. 499, regarding
application for permission to apply directly for Environmental Permit [Application
No.: DIR-094/2003] and the Permit Condition 2.4 of Environmental Permit No.
EP-184/2004 (the Permit).
1.1.2
This MS outlines the objectives, standards, scope and implementation schedule of the
protection measures for:
„
„
„
„
the Main Building of Former Marine Police Headquarters,
the Stable Block,
the Signal Tower and
the Accommodation Block of the Former Fire Station
during the earthworks and building works stage within this site of cultural
heritage.
Main Building of FMPHQ
Stable Block
Accommodation Block of Former
Fire Station
Signal Tower
All Arts Architectural Design and Research Limited
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Method Statement detailing the Protective Measures on Declared Monument Buildings
1.2
The Declared Monument Buildings
1.2.1
The buildings of historic significance highlighted in Item 1.1.2 of this section are
regarded as the “Declared Monument Buildings”(DMB) referred in the Permit
Conditions. The location plan of the DMB is shown in Appendix I-1. The FMPHQ
and its compound, including the DMB have been declared as monuments under the
Antiquities and Monuments Ordinance (Cap. 53) on 23 December 1994.
1.2.2
The Main Building of FMPHQ, Stable Block and Signal Tower are located at the
central and northern portion of the Subject Site at an elevation of about 14.5 mPD
whereas the Accommodation Block of Former Fire Station is located at about 4 mPD
at the same level of Salisbury Road.
1.3
Other Applicable Ordinances
1.3.1
The MS involves protective measures that are in themselves defined as “building
works” under the Buildings Ordinance. The Buildings Ordinance is considered the
applicable ordinance in this regard. Before commencement of these works, approval
and consent have to be issued by the Buildings Authority.
1.3.2
Under Section-6 of Antiquities and Monuments Ordinance (Cap.53), no person shall„
excavate, carry on building or other works, plant or fell trees or deposits earth or
refuse on or in a proposed monument or monument; or
„
demolish, remove, obstruct, deface or interfere with a proposed monument or
monument,
except in accordance with a permit granted by the Authority (the Antiquities
Authority). This permit is referred as “Section-6 Permit” in this MS.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
2.
Objectives and Standards
2.1
Objectives
2.1.1
This MS of protective measures forms part of the overall conservation scheme of the
project.
2.1.2
The objectives of the MS shall follow that of the overall conservation scheme, which
are:
„
to produce a restoration of a complete Victorian-Colonial complex to an
international standard that will be acknowledged as one of the best of its kind in
the Asia-Pacific region;
„
to produce an economically viable reuse of the Lot, while preserving the setting
and the fabric of the Historic Buildings;
„
to make limited and controlled intervention to the Lot and the Historic Buildings
in order that their future heritage value are not diminished by inappropriate and
non-Reversible alterations or additions.
2.1.3 Down to the construction level, the protection measures aim to preserve the DMB at
their existing locations and elevations and protect them from adverse ground movement and
other potential impacts by physical and management measures.
2.2 Standards
2.2.1
The conservation aspects of the project would be carried out to an international
standard, reference should be made to established international principles; Charters to
be respected, in particular:
„
1964 – Venice Charter (ICOMOS)
„
1978 – Burra Charter (Australia ICOMOS)
2.2.2
Involvement of conservation experts in preparation of conservation schemes, method
statement for protection and project supervision through out the project. The
Technical Schedule and Conservation Guidelines established by the relevant
Authority are followed.
2.2.3
The standard of works mentioned in the MS will follow that of Permit Condition
issued under the Antiquities and Monuments Ordinance, Approval and Consent
Conditions under the Buildings Ordinance as well as the TM–EIAO.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
3.
Descriptions of Earthworks and Building Works
3.1
General
3.1.1
The MS of protective measures for the DMB are prepared in relation to the protection
of the site of cultural heritage during the earthworks and building works stages.
3.1.2
The earthworks and building works are elaborated according to the stages of
construction in Item 3.2 of this Section while their potential impacts and proposed
protective measures are described in Section 4.
3.2
Stages of Construction
Site Formation [Involving earthworks]
3.2.1 Site formation includes bulk excavation, demolition of existing temporary structure
and construction of retaining walls. The Main Building of FMPHQ, Stable Block and
Signal Tower will be protected and preserved in-situ by means of construction of
retaining walls.
3.2.2
Subject to the result of the site investigation and detail design, a preliminary proposal
of using pile wall /concrete ring /steel ring as the retaining wall to retain the DMB is
considered feasible.
3.2.3
After the construction of the retaining walls for DMB, the earth will be removed in
phases by open cut excavation until the level of the hill was brought down to the
existing pedestrian level.
Building Foundation [Involving earthworks and building works]
3.2.4 The construction of building foundation involves shallow foundation work and
installation of piles to support the future new buildings. Replacement pile or / and
shallow foundation on reliable stratum appears to be suitable to support the future
buildings composed of retail facilities.
3.2.5
The earthwork involves localized excavation and piling work. To facilitate the
excavation process, backhoe with breakers shall be employed to excavate the ground
to the founding levels.
3.2.6
A system of shallow foundation and some piles is proposed for the new building
subject to current available information. No new foundation would be employed for
the monument buildings for the aim of minimum intervention according to current
information. The proposal shall be reviewed from time to time.
Superstructure Works [Involving building works]
3.2.7 Conventional reinforced concrete structure will be adopted for the new building.
Structural system adopting a beam/slab or flat slab arrangement with column frames
and shear walls appears to be feasible. The works will involve erection of formwork
and falsework, fixing of reinforcement and concreting.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
4.
Potential Impacts and Proposed Protective Measures
4.1
Pre-Construction Phase
Impacts
4.1.1
There are protective measures at the pre-construction phase that will be carried
through stages of work for the purpose of protection of the DMB.
4.1.2
During this phase, there are site mobilization, the preparation of site equipment,
delivery of construction materials and construction of site hoarding. There will be site
vehicles and construction plants in the site.
4.1.3
The potential impact will be the accidental damage of the DMB during the
mobilization, the transportation of the construction plants, demolition of temporary
structures and during the subsequent foreseeable work stages.
Proposed Protective Measures
Chain Link Fence
4.1.4 In order to keep an effective distance between the
construction vehicles and heavy machinery from
the Main Building of FMPHQ and Stable Block, a
chain link fence was constructed along the
periphery of the two monument buildings and the
vehicular access road.
4.1.5 The chain link fence is of 3000mm in height and at
a minimum distance of 2000mm from the Main
Building and Stable Block. It is constructed of steel
and has three access doors. It is connected to the
existing chain link fence at both ends in order to
provide a complete separation.
4.1.6 The construction material, details, alignment,
location of access doors of the chain link fence
were approved by the issuance of Section-6 Permit
under Antiquities and Monument Ordinance (Cap.
53) on 26 September, 2003. The approval letter and
the layout plan of the chain link fence are shown in
Appendix II-1 and Appendix II-2 respectively.
4.1.7
The chain link fence will be removed to give way
for piling works associated with the retaining wall
around Main Building of FMPHQ and Stable
House. The protection measures will be replaced
by other temporary fence-off structures to be
described in the earthwork section.
All Arts Architectural Design and Research Limited
Chain Link Fence at around Main
Building (View 1)
Chain Link Fence at around Main
Building (View 2)
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Method Statement detailing the Protective Measures on Declared Monument Buildings
Proposed Protective Measures (cont.)
Steel Hoardings
4.1.8 A steel hoarding and covered walkway is
constructed around the project site. There are two
portions of the steel hoarding that locate within the
Declared Monument Boundary which are:
(A) constructed at the space between the
Accommodation Block of Former Fire
Station and the existing slope.
(B) Constructed at the space between the Main
Building of FMPHQ and the northern site
boundary.
Steel Hoardings (A) constructed next
to the Accommodation Block of the
Former Fire Station
4.1.9 There will be machinery for bulk excavation and
transportation of the excavated materials in the site
formation or earthwork phase. The proposed gantry
of the site will be located next to the
Accommodation block of Former Fire Station. In
this connection, a steel hoarding is proposed to
screen off the site of earthwork and the
Accommodation Block of Former Fire Station and
to keep a physical separation.
4.1.10 The hoarding between Main Building and northern
site boundary is to maintain a clear physical
separation and to outline a definitive heritage
protective zone for the subsequent construction
stages.
Steel Hoardings (B) constructed
between the Main Building of
FMPHQ and the northern site
boundary
4.1.11 The steel hoarding for Item 4.1.8 (A) is of
4500mm in height and constructed of steel beams
on concrete base. The steel hoarding for Item 4.1.8
(B) is of 2400mm in height and constructed of
steel channels with corrugated sheets on concrete
base. The layout, construction details and
materials of these portions of steel hoarding were
approved by Buildings Department on 13
November 2003 and by the issuance of Section-6
Permit under Antiquities and Monument
Ordinance (Cap. 53) on 17 January 2004. The
Section-6 Permit approval letter and the location
plan of the portion of steel hoarding are shown in
Appendix III-1 and Appendix III-2 respectively.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
Scaffolding and tarpaulins around existing barracks during demolition
4.1.12 The existing barracks at the foreground of FMPHQ Main Building have to be
demolished under Lease Conditions. In order to screen off the demolition site from
the DMB, scaffolding and tarpaulins are employed around each of the barracks.
4.1.13 The scaffolding should be at least 3500mm high and firmly related to each other and
the ground. The scaffolding also includes the protection for the demolition of an
existing water tank and pylon. The layout plan of the scaffolding is shown in
Appendix IV-2.
4.1.14 The layout, construction details, materials and other technical requirement of the
scaffolding were approved by Buildings Department on 10 October 2003 under the
demolition plan submission and by the issuance of Section-6 Permit under Antiquities
and Monuments Ordinance (Cap.53) on 8 December 2003. This letter of approval for
Section-6 Permit is shown in Appendix IV-1.
4.1.15 The scaffolding and tarpaulins will be removed upon completion of the demolition
work for the barracks.
Establishment of a Control Zone for the construction crane
4.1.16 During the Building Construction stage, there will be tower crane for mobilization
and delivery of materials around site. The exact height of tower crane will be
designed by the building contractor.
4.1.17 During the delivery process, there may be risk of accidental damage of DMB due to
fall of materials when such materials are carried across the buildings by the tower
cranes.
4.1.18 A Control Zone demarcating the overhead space of DMB to be restricted from the
entry of the tower cranes will be established during the subsequent building stages.
Appendix V-1 shows the layout and alignment of such Control Zone.
4.1.19 No overhead entry of the tower crane into the Control Zone will be allowed except by
written request by the building contractor. In such circumstances, the duration,
reasons and enhanced protective measures during such process of the entry will be
assessed by the project team including project architect, engineer and conservation
consultant. Technical Competent Person from the contractor should be present
monitoring the whole process of entry of the tower cranes.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
4.2
During Earthworks and Building Works
Impacts
4.2.1
The ground condition of the site of cultural heritage is prone to certain degree of
effect due to the substantial earthworks to be carried out in the site. The monument
buildings within the site will be subject to geotechnical and structural effect such as:
„
Ground Settlement
„
Building Settlement
„
Tilting
„
Deformation
4.2.2
The above geotechnical impacts and consequences will also be causative of the piling,
installation of soil nails and construction of the retaining pipe-pile wall. The work
procedures and methodology employed are critical to the mitigation for such adverse
effects.
4.2.3
As the stability of the DMB relies heavily on the soil capacity of the site, it would be
potent to ensure the integrity of such existing soil mass during the process of its
eventual removal in the stage of bulk excavation. The protection of the soil mass is
the protection for the DMB.
4.2.4
The impact to DMB during the building work stage is expected to be of similar
nature to that of the earthworks stage, that is the vibration effect and ground
movement.
Proposed Protective Measures
Prohibition of Percussive Piling
4.2.5 For the protection works to the DMB, replacement piling method is considered more
suitable than the displacement piling or percussive piling for it would induce less
vibration due to driving force and in turn generates less adverse impact on the
monuments as well as the surroundings. Based on the available ground investigation
information, the proposal of the protection works are shown in Appendix VI-1.
4.2.6 This proposal of piling work has been vetted by Buildings Department and Civil
Engineering Department and has been approved on 13 February 2004. The proposal is
also under Section-6 Permit approval.
Prohibition of Blasting
4.2.7 Local open cut excavation with a safe slope angle in front of the Main Buildings of
FMPHQ, Stable Block and Signal Tower will be carried out during the bulk
excavation period. According to the geotechnical assessment result, the site is mainly
composed of fill and in-situ materials with small percentage of rock at lower level
near to the junction of Canton road with Salisbury Road. In this connection, no
blasting is anticipated.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
Avoidance of concurrent pipe pile driving
4.2.8 In order to avoid the generation of cumulative ground vibration impact on the DMB,
the concurrent pipe pile driving for tree ring retaining structure and retaining walls for
Main Building of FMPHQ, Stable Block and Signal Tower less than specified distance
when the pipes are about to penetrate the bedrock will be prohibited.
4.2.9
The prohibition of concurrent pipe pile driving less than specified distance is also
subject to the control under the relevant subsidiary regulations under the Buildings
Ordinance.
Sufficient temporary support for the Monument Buildings
4.2.10 There will be no additional foundation system for the monument buildings. In this
connection, their stability relies on the integrity and capacity of the originally existing
ground soil mass. During the bulk excavation period when the existing soil is
removed in stages, temporary structures have to be installed following the stages of
work. They included:
„
Shoring System
„
Temporary Soil Nails
„
Ground Anchors
4.2.11 These protective measures are geotechnical works. They have been vetted by
Buildings Department and Civil Engineering Department and has been approved on
13 February 2004 under the site formation plan submission. The site formation plan
submission is also under Section-6 Permit application process.
4.2.12 These temporary supporting structures are installed to achieve a conjunctive effect for
the overall lateral support. As there may be unforeseen ground condition during the
course of excavation. The layout will be subject to amendment when such problem
occurs. The layout plan of these supporting structures is shown in Appendix VII-1.
Installation of monitoring system and checkpoints
4.2.13 The performance of the protective measures have
to be checked by a monitoring system in which
checkpoints on settlement and ground movement
will be assigned.
4.2.14 The installation for the checkpoints such as ground
settlement markers, building settlement markers,
tilting markers, piezometers, inclinometers, load
cells, crack tell-tales, strain gauges, etc. All
monitoring records include graphical plots and
tables should be kept on site for inspection during
Qualified Site Supervision as if required under the
Buildings Ordinance.
An installed telltale for an existing
crack at FMPHQ
4.2.15 In case of contingent geotechnical situations,
actions should follow that advised and designed by
qualified site supervisor or other professional
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Method Statement detailing the Protective Measures on Declared Monument Buildings
consultants responsible for the works.
Enhanced protection during heavy rainfall
4.2.16
There should be enhanced protective measures of earthwork during heavy rainfall.
All earth works for the Declared Monument Buildings shall be graded and sealed to
„
„
Ensure run-off and to avoid ponding
Prevention of collection of rainwater at around Declared Monument Buildings
by devising proper temporary surface channel and discharge points during the
construction period.
4.2.17
These associated protective works are included in the site formation plan
submission and has been approved by Buildings Department on 13 February 2004.
The submission is also under approval process of Section-6 Permit application.
4.2.18
In any case of occurrence of adverse effects due to heavy rainfall on the Declared
Monument Buildings, immediate reporting to Architect and Engineer should be
taken by the contractor.
Good Site Practice and Management
4.2.19
To submit to Architect, Engineer and Conservation Consultant for approval on use
of heavy machinery, method statement and programme intended to be carried out
on site during the earth work and building work stages.
4.2.20
To provide the appropriate frequency of supervision by technically competent
persons (TCPs) during the whole process of earth work and building works within
the declared monument boundary as if required under the Buildings Ordinance.
4.2.21
To site cranes, mobile plants and heavy machinery as far away from the Declared
Monument Buildings as possible. In all cases of transportation of heavy machinery
and materials to and away from the DMB, the operation should be over-looked by
the resident competent person provided by the building contractor. The
construction site setting has to be monitored by the professional personnel from the
contractor, architect and engineer streams.
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Method Statement detailing the Protective Measures on Declared Monument Buildings
5.
Ref:
Implementation Schedule of the Proposed Protective Measures
Proposed Protective
Measures
Location of the
Who
Measure
implement
Around the
To construct chain
Declared
link fence of
Monument
3000mm high and at
Building of
a minimum distance
FMPHQ
of 2000mm from the
Main Building &
stable Block
4.1.8(A) To erect steel
Besides
hoardings of
Accommodati
4500mm high
on Block of
Former Fire
Station and
4.1.8(B) To erect steel
Along
hoardings of
northern
2400mm high
boundary of
FMPHQ site
Surrounding
4.1.13 Scaffolding and
existing
tarpaulins around
barracks,
existing barracks
water tank and
during demolition
pylon to be
demolished
4.1.5
When to
implement
*Applicable
Objectives of the
Ordinances recommended measures
or
& main concern to be
Regulations
addressed
Contractor
Before
construction
was
commenced
A&MO
To keep away the
construction vehicle
and heavy machinery
from the Monument
Buildings
Contractor
Before
construction
was
commenced
A&MO
&
BO
Before
construction
was
commenced
Contractor
Before
Demolition
A&MO
&
BO
To protect the DMB
from the proposed earth
work and excavation
work by clear physical
separation
To maintain a clear
separation and outline a
definitive heritage
protection zone
To enclose the barracks
during demolition to
prevent any adverse
impact and damage to
the adjoining
Monument Buildings
Contractor
A&MO
&
BO
4.1.18 Establishment of a
Control Zone to limit
the entry of
overhanging tower
cranes
Site
Contractor
During
Building
Work Stage
A&MO
To prevent the
accidental falling of
materials during
delivery by the tower
cranes
4.2.5
Prohibition of
percussive piling
Site
Contractor
All Phases
A&MO
&
BO
To eliminate possibility
of generating any
significant ground
vibration impact on the
DMB
4.2.7
Prohibition of
blasting
Site
Contractor
All Phases
A&MO
&
BO
To eliminate possibility
of generating any
significant ground
vibration impact on the
DMB
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Method Statement detailing the Protective Measures on Declared Monument Buildings
Ref:
Proposed Protective
Measures
4.2.8
Location of the
Who
Measure
implement
When to
implement
*Applicable
Objectives of the
Ordinances recommended measures
or
& main concern to be
Regulations
addressed
Avoidance of
concurrent pipe pile
driving near the tree
ring and the Main
Building of FMPHQ
when the piles to
about to penetrate the
bedrock.
4.2.10 Installation of
temporary supporting
structures
Site
Contractor
During
earthwork
stage
A&MO
&
BO
To minimize the
generation of
cumulative ground
vibration impact on the
DMB
Site
Contractor
During
Earthwork
and building
work stage
A&MO
&
BO
4.2.14 Installation of
checkpoints
including ground and
building settlement
markers, tilting
markers,
piezometers,
inclinometers, load
cells, crack tell-tales
and strain gauges
4.2.16 Construction of
enhanced measures
to protect the open
earthwork during
heavy rainfall
Site
Contractor
During
earthwork
and building
work stage
A&MO
&
BO
To provide lateral
support to the DMB
during process of bulk
excavation and building
work stage and to
ensure the stability of
the excavated soil mass
To provide a
continuous monitoring
system on the DMB
during the earthwork
and building work
stage.
Site
Contractor
During
earthwork
stage
A&MO
&
BO
Site
Contractor
During
4.2.21 To ensure site cranes,
earthwork
mobile plants and
and building
heavy machinery to
work stage
be placed far from
the DMB and site
work to be
supervised by
competent personnel
Abbreviation
A&MO
– Antiquities and Monuments Ordinance
BO
– Buildings Ordinance
Notes
* Reference should be made to Section. 1.3.3
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A&MO
&
BO
To mitigate any adverse
impacts due to heavy
rainfall during the
earthwork and building
work period on the
stability of DMB
To minimize the
possibility of any
adverse effect or
damage to the DMB in
the process of site
mobilization or due to
poor construction site
management
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Method Statement detailing the Protective Measures on Declared Monument Buildings
Appendices
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