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No. S 250

Building Control Act

(Chapter 29)

Building Control (Amendment No. 2) Regulations 2008

In exercise of the powers conferred by section 49 of the Building Control Act, the Minister for National Development hereby makes the following Regulations:

Citation and commencement

1. These Regulations may be cited as the Building Control (Amendment No. 2) Regulations 2008 and shall come into operation on 1st October 2008.

Amendment of regulation 2

2. Regulation 2 of the Building Control Regulations 2003 (G.N. No. S 666/2003) (referred to in these Regulations as the principal Regulations) is amended by inserting, immediately after the definition of “fresh air”, the following definition:

“ “geotechnical report” means calculations, plans or report prepared in respect of underground building works by a qualified person who is a geotechnical engineer showing —

(a)	the results of the findings, evaluation and interpretation of the site investigation and laboratory tests;
(b)	assessment of and recommendations on the geotechnical aspects for the design and construction of the underground building works; and
(c)	plans showing those elements of building works designed by the person who is a geotechnical engineer;”.

New regulation 2A

3. The principal Regulations are amended by inserting, immediately after regulation 2, the following regulation:

“Underground building works

2A. For the purposes of paragraph (c) in the definition of “underground building works” in the Act, all types of foundation works for buildings of 30 or more storeys are prescribed as underground building works.”.

Amendment of regulation 4

4. Regulation 4(1) of the principal Regulations is amended —

(a)

by deleting the word “and” at the end of sub-paragraph (a)(iii);

(b)

by inserting, at the end of sub-paragraph (a)(iv), the word “and”; and

(c)

by inserting, immediately after sub-paragraph (iv) of sub-paragraph (a), the following sub-paragraph:

“(v) where applicable, underground building works plans;”.

New regulation 10A

5. The principal Regulations are amended by inserting, immediately after regulation 10, the following regulation:

“Particulars to be shown in underground building works plans

10A.—(1) The underground building works plans referred to in regulation 4(1)(a) shall consist of or contain the following, where applicable:

(a)	plans of any tunnelling support system;
(b)	plans of any excavation and earth retaining structures;
(c)	plans of the foundation;
(d)	instrumentation and monitoring plans.

(2) Without prejudice to regulations 6, 7 and 8, all underground building works plans shall —

(a)

be in accordance with the provisions of the Act and these Regulations and any other requirement of the Commissioner of Building Control;

(b)

be signed and endorsed by the qualified person who prepared the plans and calculations, and by the appropriate accredited checker;

(c)

bear a certificate by the qualified person who prepared the plans on the first and last sheets of the calculations stating that, to the best of his knowledge and belief, the design calculations have been prepared in accordance with these Regulations and that he is the person who prepared the design calculations;

(d)

state on the first page of the certificate of the qualified person referred to in sub-paragraph (c) the number of pages per book and a numbering of every page in the book;

(e)

be accompanied by an Information Sheet giving a summary of the key design and construction information including, where applicable, load conditions, codes of practice, assumptions, earth-retaining system, tunnel support system, foundation system, and other information relevant to the design and construction in question;

(f)

be accompanied by an impact assessment report on neighbouring structures and a site investigation report;

(g)

be accompanied by a geotechnical report which shall contain —

(i)	a summary to highlight the key elements of the design and the issues addressed;
(ii)	evaluation and interpretation of existing information and investigation and monitoring results;
(iii)	assessment of geotechnical parameters and groundwater conditions;
(iv)	geotechnical assumptions, analysis, design and calculations;
(v)	geotechnical requirements relating to the design and construction of the underground building works including testing, validating, controlling, inspecting and monitoring;
(vi)	geotechnical reviews; and
(vii)	any other details as the Commissioner of Building Control may require; and

(h)

be accompanied by such other reports as the Commissioner of Building Control may require.

(3) The plans of a tunnel support system for the design and construction of any tunnel with diameter, width or height of more than 2 metres shall contain, where applicable —

(a)

layout, sections and details of all excavation and tunnel support works showing —

(i)	subsurface information including plan showing layout of investigation boreholes and subsurface profile along each tunnel axis;
(ii)	maximum depth, and extent of excavation at each stage including heading, bench and invert;
(iii)	face pressure and other key performance indicators for ensuring stability of tunnel during construction;
(iv)	location of planned stoppages and necessary ground improvement and monitoring details; and
(v)	profile and the nature of the site and its surrounds including ground topography, neighbouring structures, subsurface geological and geotechnical data, and groundwater conditions;

(b)

layout, sections, details and material specifications of tunnel support elements and structures, tunnel face support system and overall tunnel support system and other structural elements showing types, sizes and material specifications of members to be used and the connection details;

(c)

layout, sections and details of earth or ground strengthening, improvement or protection works including layout, sections and sizes of all elements, material specifications, details of inspections and tests to be carried out;

(d)

method and sequence of construction including duration and spatial limits of critical activities;

(e)

details of inspections and tests to be carried out;

(f)

details of any special precautions, groundwater control measures, control and protective measures required during excavation, installation and removal of any tunnel support element;

(g)

other specifications and relevant particulars; and

(h)

such other details as the Commissioner of Building Control may require.

(4) The excavation and earth retaining system plans for any excavation or any building works for constructing, altering or repairing any earth retaining structure (including slope) in or for a caisson, cofferdam, trench, ditch, shaft or well for supporting earth which has a depth of more than 6 metres shall contain, where applicable —

(a)

layout, sections and details of all excavation and earth retaining works showing —

(i)	subsurface information including plan showing layout of investigation boreholes and surface profile along and across the excavation boundary;
(ii)	maximum depth, and extent of excavation at each stage; and
(iii)	profile and the nature of the site and its surrounds including ground topography, neighbouring structures, subsurface geological and geotechnical data, and groundwater conditions;

(b)

layout, sections, details and material specifications of earth retaining elements and structures, wall elevation showing the wall founding depth or penetration depth or minimum wall embedment requirement, and overall retaining system;

(c)

layout, sections and details of struts, anchors, soil nails, walers, king posts, bracings, corbels and other structural elements showing types, sizes and material specifications of members to be used, connection details, and where appropriate, inspections and tests to be carried out;

(d)

layout and sections of earth berms or slope showing type of soils, size and location of berms, internal and external drainage provisions and protection measures including against surface weathering;

(e)

(f)

layout, sections and details of permanent support system to the earth retaining system showing details of lateral bracing element, and connection details;

(g)

method and sequence of construction including duration and spatial limits of critical activities;

(h)

details of inspections and tests to be carried out;

(i)

details of any special precautions, groundwater control measures, control and protective measures required during excavation, and installation and removal of any earth retaining element;

(j)

other specifications and relevant particulars; and

(k)

such other details as the Commissioner of Building Control may require.

(5) The foundation plans for the design and construction of foundation for buildings of 30 or more storeys shall contain, where applicable —

(a)

the layout, sections and details of all foundation works showing —

(i)	types of piles or foundation and specification of material to be used;
(ii)	location of piles or foundation and site investigation boreholes;
(iii)	pile or foundation founding depth or pile minimum embedment into competent stratum for each pile or foundation;
(iv)	unit shaft friction, pile base resistance or foundation bearing pressure;
(v)	allowable foundation capacity before and after accounting for negative skin friction where applicable, allowable tension, and lateral load;
(vi)	details of pile reinforcements, pile joints, connection with pilecap, pile shops;
(vii)	allowable total and differential foundation movement; and
(viii)	allowable vibration limit; and

(b)

the number, type of pile or foundation tests, structural integrity tests and location of preliminary test pile or ultimate load tests and site investigation for the tests.

(6) The instrumentation and monitoring plans shall contain, where applicable —

(a)	layout and location of neighbouring structures in relation to the underground building works;
(b)	numbers, types, locations, details and other particulars of instruments for monitoring forces and movement of structural elements, building and ground movements, and variations in the groundwater or piezometric levels;
(c)	frequency and duration of monitoring;
(d)	allowable ground or building movement limits;
(e)	allowable vibration limits;
(f)	where applicable, long-term instrumentation, monitoring and maintenance requirements;
(g)	other specifications and relevant particulars; and
(h)	such other details as the Commissioner of Building Control may require.”.

New regulation 24A

6. The principal Regulations are amended by inserting, immediately after regulation 24, the following regulation:

“Duties of qualified persons regarding underground building works

24A.—(1) Every qualified person appointed under section 8(1)(a) or 11(1)(d)(i) of the Act to prepare the plans of geotechnical aspects of underground building works shall carry out the tasks set out in Part I of the Eighth Schedule.

(2) Every supervising qualified person appointed in respect of the geotechnical aspects of underground building works shall carry out the tasks set out in Part II of the Eighth Schedule.”.

Amendment of regulation 50

7. Regulation 50 of the principal Regulations is amended by deleting the words “regulation 25” and substituting the words “regulation 24A, 25”.

Amendment of First Schedule

8. Paragraph 1 of the First Schedule to the principal Regulations is amended by deleting sub-paragraph (q) and substituting the following sub-paragraph:

“(q)	any retaining wall or earth retaining structure that is constructed with structural steel or reinforced concrete and with a visible height of not more than 1,500 millimetres, or any other retaining wall or earth retaining structure with a visible height of not more than 1,000 millimetres.”.

Amendment of Sixth Schedule

9. The Sixth Schedule to the principal Regulations is amended by inserting, immediately after the words “for alkali-carbonate reaction” in paragraph (b), the words “or alkali-silica reaction”.

New Eighth Schedule

10. The principal Regulations are amended by inserting, immediately after the Seventh Schedule, the following Schedule:

“EIGHTH SCHEDULE

Regulation 24A

Part I

Duties of Qualified Person Appointed to Prepare the Plans of Geotechnical Aspects of Underground Building Works

1. In the preparation of plans relating to the geotechnical aspects of any excavation or other building works to construct a tunnel with a diameter, width or height of more than 2 metres, the qualified person shall —

(a)	determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the tunnel;
(b)	analyse the site investigation results and determine the geotechnical parameters for the design, taking into consideration onerous water conditions, seepage pressures, and surcharge, earth, water, construction and accidental loadings;
(c)	determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions;
(d)	determine suitability of tunnelling method, sequence of construction, and tunnel support system including face pressures and ground support system;
(e)	determine allowable limits of ground deformation and changes in groundwater and piezometric levels, and measures to control groundwater where required;
(f)	analyse the stability of excavation and determine the ground stabilisation or improvement works as appropriate;
(g)	design soil or rock reinforcement, where applicable, including the consideration of the structural and geotechnical capacity;
(h)	determine the instrumentation and monitoring of geotechnical engineering parameters such as tunnel face pressures, pore pressures, water table level, ground deformation and stresses including the consideration of location, type and number of instruments, and frequency of monitoring and reporting; and
(i)	assess monitoring results and site conditions to ensure that the geotechnical aspects during construction are within design assumptions and parameters at every critical stage of construction, and review or modify the design so as to ensure its adequacy as appropriate.

2. In the preparation of plans relating to the geotechnical aspects of any excavation or any building works for constructing, altering or repairing any earth retaining structure (including slope) in or for a caisson, cofferdam, trench, ditch, shaft or well for supporting earth which has a depth of more than 6 metres, the qualified person shall —

(a)	determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the earth retaining structure including earth slope;
(b)	analyse the site investigation results and determine the geotechnical parameters for the design of the earth retaining structure including consideration of onerous water conditions, seepage pressures, and surcharge, earth, water, construction and accidental loadings;
(c)	determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions;
(d)	determine suitability of earth retaining structure types and scheme, and the method and sequence of construction;
(e)	analyse the stability of the excavation work, taking into consideration groundwater, drainage and seepage conditions, basal heave, hydraulic uplift and piping, and determine the ground stabilisation or improvement works as appropriate;
(f)	determine allowable limits of ground deformation and changes in groundwater and piezometric levels, and measures to control groundwater where required;
(g)	design tie-backs, soil or rock reinforcement, where applicable, including the consideration of the structural and geotechnical capacity;
(h)	ensure that drawings of the earth retaining structure, including earth slopes, are consistent with the calculations relating to the geotechnical aspects;
(i)	determine the instrumentation and monitoring of geotechnical engineering parameters such as pore pressures, water table levels, ground deformation and stresses including the consideration of location, type and number of instruments, and frequency of monitoring and reporting; and
(j)	assess monitoring results and site conditions to ensure that the geotechnical aspects during construction are within design assumptions and parameters at every critical stage of construction, and review or modify the design so as to ensure its adequacy as appropriate.

3. In the preparation of plans relating to the geotechnical aspects of such type of foundation works for buildings of 30 or more storeys, the qualified person shall —

(a)

where a caisson, raft or piled-raft foundation is adopted —

(i)	determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the caisson, raft or piled-raft foundation;
(ii)	analyse the site investigation results and determine the geotechnical parameters, such as soil strength and deformation characteristics, pile shaft friction, downdrag, pile base resistance or bearing pressures and pile lateral geotechnical capacity, for the design of the foundation taking into consideration the onerous water conditions, seepage pressures, and loads from surcharge, earth, water and construction;
(iii)	determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions;
(iv)	determine suitability of the foundation type and the method of construction;
(v)	where applicable, determine and analyse the negative shaft friction;
(vi)	ensure that the drawings of the foundation are consistent with the calculations relating to the geotechnical aspects;
(vii)	analyse the stability of excavation for the caisson or raft during construction taking into consideration groundwater, drainage and seepage conditions, basal heave, hydraulic uplift and piping, and determine the ground stabilisation or improvement works as appropriate;
(viii)	analyse the forces and deformation of the raft or pile-raft foundation and stability of the foundation including the consideration of short-term and long-term conditions;
(ix)	determine the number, location and types of load tests, analyse the results of load tests; or

(b)

where a caisson, raft or piled-raft foundation is adopted —

(i)	determine the site investigation including the extent (which shall include the quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the piled foundation;
(ii)	analyse the site investigation results and determine the geotechnical parameters such as soil strength and deformation characteristics, negative skin friction or downdrag, pile shaft friction, founding depth, pile base resistance, pile group effects, settlement, bearing capacity, and where applicable, lateral geotechnical capacity; and
(iii)	determine the load tests and analyse results of load tests to ensure that the pile shaft friction, founding depth, base resistance, pile movement, and other appropriate geotechnical parameters are within the design, and as appropriate, review or modify the design so as to ensure its adequacy.

Part II

Duties of Supervising Qualified Person for the Geotechnical Aspects of Underground Building Works

1. In the supervision of geotechnical aspects of any excavation or other building works to make a tunnel with a diameter, width or height of more than 2 metres, the supervising qualified person shall —

(a)	supervise the implementation of instrumentation and monitoring of geotechnical parameters in accordance with the instrumentation and monitoring plan; and
(b)	assess the ground conditions at the site and construction of the tunnel in relation to its impact on the geotechnical aspect of the design and review the performance and results of instrumentation and monitoring of the tunnelling works such that the geotechnical aspects are within the design at every critical stage.

2. In the supervision of geotechnical aspects of any excavation or any building works for constructing, altering or repairing any earth retaining structure including slope, in or for a caisson, trench, ditch, shaft or well with a depth or height of more than 6 metres, the supervising qualified person shall —

(a)	supervise the implementation of instrumentation and monitoring of geotechnical engineering parameters in accordance with the instrumentation and monitoring plan;
(b)	determine adequacy of the founding or penetration depth of embedded earth-retaining wall on site; and
(c)	assess the ground conditions at the site and construction of the earth retaining structure (including earth slope) in relation to its impact on the geotechnical aspect of the design and review the performance and results of instrumentation and monitoring of the earth retaining structure including earth slope such that the geotechnical aspects are within the design at every critical stage.

3. In the supervision of geotechnical aspects of such type of foundation works for buildings of 30 or more storeys, the supervising qualified person shall —

(a)

where a caisson, raft or piled-raft foundation is adopted —

(i)

determine the founding or penetration depth of the caisson, raft or piles on site; and

(ii)

assess the ground conditions at the site and construction of the caisson, raft or piled-raft foundation in relation to its impact on the geotechnical aspect of the design, analyse the results of load tests, and review the performance and results of instrumentation and monitoring of the caisson, raft or piled-raft foundation to verify that the geotechnical aspects are within the design at every critical stage; or

(b)

where jacked-in piles or driven piles or bored cast in-place piles or barrettes are adopted —

(i)	determine the founding or penetration depth of the piles on site; and
(ii)	assess the ground conditions at the site, analyse the results of load tests, and review the performance and results of instrumentation and monitoring of the piles to verify that the geotechnical aspects are within the design at every critical stage.”.

Saving

11. Notwithstanding anything in these Regulations, the principal Regulations in force immediately before 1st October 2008 shall continue to apply to underground building works which started before 1st October 2008 as if these Regulations have not been enacted.

Made this 5th day of May 2008.

TAN TEE HOW

Permanent Secretary,
Ministry of National Development,
Singapore.

[eReg; AG/LEG/SL/29/2002/1 Vol. 6]

(To be presented to Parliament under section 52 of the Building Control Act).