2012年6月22日 星期五

Comparison of Jacked and Driven H-pile

Comparison of Jacked and Driven H-pile

Type

Jacked Pile
( ArchSD’s PS(1) and VLA (2011)(2) )
Driven H-Pile
(COP of Foundation(3) and BD’s EM 2.1.13(4) )
1. Design requirement
Working load
(WL = 0.33Ys):
i) 305x305x180kg/m
ii) 305x305x223kg/m
For grade 55C
2950kN
3450kN
For grade 55C
2950kN
3450kN
Pile group reduction for group of 5 piles for spacing 3 times circumscribed rectangles of H-piles
0.85
0.85
Founding of pile
SPT N-value may less than 200
i) SPT N-value ³ 210 for 305´305´223 kg/m H-piles
ii) SPT N-value ³ 180 for other H-piles
(BD EM
Settlement analysis
More than 10 piles
No specify
2. Installation
Maximum jack force
(i) Not exceed 90% of total weight of the pile-jacking machine; and
(ii) 80% of yield stress of H-pile
N/A
Calibration of hydraulic jack
(i) Calibrated by HOKLAS by calibrated load cell;
(ii) Re-calibration at a force of 2.2.WL shall be carried out after jacking every 30 piles or repair.
N/A
Monitoring of jacking force
e.g. Pile Driving Monitor (PDM) developed by Inopiles International Pte Ltd.
N/A
Prevention of pile buckling
Gaps between the H-pile and pile hole shall be kept filled up with sand
N/A
Storage of spliced piles
To avoid idling time, several pieces of piles will be welded and stored into bored hollow shaft vertically
N/A
3. Termination procedures and criteria
Pre-creeping by pre-loading process
(i) Before termination of pile, at least 2.3WL for suitable period determined by contractor
(ii) At 10% of piles (min. 5 piles) to be carried out by pre-loading test: 2.2WL until the settlement rate is less than 5mm per 15 minutes
N/A
4. Verification
Trial pile
Subject to static loading test
(6.11 of PS)
Depend on actual site condition. e.g. for short pile
(BD EM 2.1.4)
not less than 2 testing pile which rest on bedrock
(5.4.11 (4) of COP)
Verification test
The Contractor shall demonstrate with PDA analysis that driving stresses would not exceed 0.9 fy.
(clause 5.18(iv) of GS)
The integrity and capacity of at least 10% of the working piles should be verified by PDA tests.
No of piles for loading test
1% minimum one pile or more
(clause 5.28(ii) to (iv) of GS)
1% & at least 1 no of piles
(BD EM2.1.6 & 2.1.11)
Loading test
(where P = 2WL)
1st cycle: 0->0.25P->0.5P-> 0.25P->0
2nd cycle: 0->0.25P->0.5P-> 0.75P->P (72 hrs)->0.75P-> 0.5P-> 0.25P->0
1st cycle: 0->0.25P->0.5P-> 0.25P->0
2nd cycle: 0->0.25P->0.5P-> 0.75P->P (72 hrs)->0.75P-> 0.5P-> 0.25P->0
Settlement of loading test
(i) Total settlement = P/AE + D/120 + 4 mm
(ii) Residual settlement = D/120 + 4 mm; and
25% of the maximum pile head
settlement during the test,
whichever is the greater.
where:
D = Diameter of circular pile in mm, or = The least lateral dimension of steel 'H' pile section in mm (for driven steel 'H' pile )
P = 2WL Test load
L = Nett length of pile (For piles with rock sockets, L shall be measured to the center of the rock socket.)
A = Cross sectional area of pile
E = Young's modulus of pile given below:
Same as ArchSD’GS
Reference:
4.   Engineering Manual issued by BD;
Other reference:

2012年6月14日 星期四

Building accidents news

Buildings Department

2013.8.22 Buildings Department intends to apply for closure order in respect of 51 Kai Ming Street, August 22, 2013 2011.10.14 Report on the Collapse of the Canopy of a Building at 3 Kin Kwan Street, Tuen Mun - T.M.T.L. 87 on 9 June 2011
2011.10.07 Press release Canopy collapse due to lack of maintenance (with photo) - Thursday, October 6, 2011 2011.8.17 BD responds to Coroner's verdict - Tuesday, August 16, 2011
2011.6.10 Buildings Department organises territory-wide inspection of buildings with cantilevered slab canopies
2011.3.01 Findings of investigation into cause of building vibration at No.18-20 Tai Wong Street East
2010.4.26 Buildings Department report on building collapse in Ma Tau Wai Road and inspection results of buildings aged 50 or above (with photos/video)
2010.2.24 Buildings Department to demolish 45G and 45H Ma Tau Wai Road
2010.1.29 Report on the Collapse of the Building at 45J Ma Tau Wai Road, To Kwa Wan, Kowloon - K.I.L. 8627 on 29 January 2010
Developement Bureau - Studies and Reports1. Buildings Department's Review on Building Safety Enforcement Procedure and Practices :
Buildings Department's Review Report
Professor Ko Jan-ming's Independent Review on the Buildings Department's Report
Mr Daniel Lam's Independent Review on the Buildings Department's Report
Discussion Paper for the Legislative Council on the Independent Experts' and the Buildings Department's Reports
2. Review of Investigation Report on the Flooding in Sha Po Tsai Village, Tai Po on 22 July 2010
Investigation Report on the Flooding in Sha Po Tsai Village, Tai Po on 22 July 2010 - Executive Summary (Relevant Document uploaded in website of Drainage Services Department)
3. Response of the Development Bureau on a Residential Development next to Phase 8 of Mei Foo Sun Chuen (i.e. Remaining Portion of New Kowloon Marine Lot No. 25 (NKML 25 R.P.) and Section B of New Kowloon Marine Lot No. 25 (NKML 25 S.B))
Housing Department 1. The Report of the Investigation Panel on AccountabilityPiling Contract 166/1997 of Shatin Area 14B Phase 22. Select Committee on Building Problems of Public Housing Units

Architectural Services Department 1. Investigation Report on the Incident of Fallen Metal Gate on 5 May 2009 at Hang Ngai Manufacuring & Hostel 3 Hung Ling Street, Hung Hom, Kowloon

Mandatory Building and Window Inspection Schemes

http://www.info.gov.hk/gia/general/201206/13/P201206130430.htm
LCQ18: Mandatory Building and Window Inspection Schemes
*******************************************************
 Following is a question by the Dr Hon Priscilla Leung and a written reply by the Secretary for Development, Mrs Carrie Lam, in the Legislative Council today (June 13):

Question:

 An organisation has earlier on conducted a survey on the Mandatory Building and Window Inspection Schemes (the Schemes) which will be implemented in the second quarter of this year, and found that as many as 70% of the respondents have not heard of the Schemes, and reflected that the details of the Schemes' complementary and support measures have not been announced after a long time, making the owners of the so-called "three nos" buildings (i.e. no management, no owners' corporations (OCs) and no maintenance) feel very much worried.  In this connection, will the Government inform this Council:

(a) of the current channels through which the Schemes are publicised; given that the aforesaid survey has revealed that 70% of the respondents have not heard of the Schemes, whether the authorities have assessed if publicity on the Schemes is adequate, and whether they will consider stepping up publicity;

(b) of the earliest time by which the authorities will inform the OCs or owners of the first batch of target buildings under the Schemes in writing that the Government will make it mandatory for them to inspect their buildings and windows; upon receipt of the notification, the time by which they will be required to start inspecting their buildings and windows; whether the authorities have assessed if under the procedure of the Schemes, OCs or owners have been offered adequate time for preparation;

(c) of the total number of professionals in the architectural or engineering sector who have registered under the Schemes as registered inspectors (RIs) so far; whether the authorities have assessed if the target number of at least 300 or more RIs across the territory can be met before the implementation of the Schemes in the second quarter of this year; if not, of the measures to be put in place to attract more professionals to register as RIs;

(d) of the new subsidy schemes or support and complementary measures the authorities will introduce in respect of the Schemes; among such subsidy schemes and measures, application and implementation details of which have already been announced; regarding those which have not yet announced the details, of the latest time by which such details will be announced;

(e) of the special measures the authorities have put in place to assist the owners of "three nos" old buildings in complying with the statutory notices and inspect their buildings and windows; and

(f) of the means adopted by the Government to specifically penalise those owners who refuse to share and pay for the costs of building and window inspection, and ensure that the owners who are willing to share the costs will not be affected and penalised?

Reply:

President,

 The Buildings (Amendment) Ordinance 2011 (B(A)O), enacted by the Legislative Council (LegCo) on June 29, 2011, provides for the legislative framework of the Mandatory Building Inspection Scheme (MBIS) and the Mandatory Window Inspection Scheme (MWIS). The LegCo also completed the scrutiny of the relevant subsidiary legislation on December 21, 2011.

 The MBIS and the MWIS cover all private buildings aged 30 years or above and 10 years or above respectively, except domestic buildings not exceeding three storeys in height.  Under the MBIS, building owners are required, within a specified timeframe, to appoint a registered inspector (RI) to carry out a prescribed inspection and to appoint a registered contractor to carry out a prescribed repair found necessary of the common parts, external walls, projections and signboards of the building once every 10 years.  Under the MWIS, building owners are required, within a specified timeframe, to appoint a qualified person (QP) to carry out a prescribed inspection and to appoint a registered contractor to carry out a prescribed repair found necessary of the windows in the building once every 5 years.

 Those sections in the B(A)O and subsidiary legislation concerning registration of RIs and other miscellaneous amendments to the Buildings Ordinance (BO) were brought into operation on December 30, 2011.  On May 9, 2012, we tabled at LegCo three commencement notices, which seek to commence the remaining provisions of the B(A)O and the regulations on June 30, 2012 to fully implement the MBIS and the MWIS.

 To dovetail with the implementation of the two schemes, the Buildings Department (BD) has launched a publicity programme in phases to arouse the awareness of the public, owners and the industry of the two schemes.  The Hong Kong Housing Society (HKHS) and the Urban Renewal Authority (URA) will launch a subsidy scheme to subsidise owners of eligible buildings the cost of the first building inspection under the MBIS, and to provide technical support to owners.

 My reply to the six-part question is as follows:

(a) To arouse public awareness of the MBIS and the MWIS, BD has launched a publicity programme in two phases.  In the first phase, an Announcement of Public Interest (API) was launched in mid-February 2012, which mainly served to publicise the registration of RIs.  The API was broadcast on all television and radio stations, as well as public transport vehicles including buses and railways.  Over the past few months, BD has participated in a number of seminars organised by various professional organisations and District Councils to promote the MBIS and the MWIS in the community.   In the second phase, which began in early May 2012, BD launched a dedicated webpage on its website containing detailed information on the inspection schemes for public reference.  A series of newspaper supplements is also being published starting from mid-May 2012.  Other publicity materials including another set of API targeting at the requirements of the inspection schemes, leaflets, posters and outdoor advertisements will be launched in end June 2012 to publicise the full implementation of the schemes.

(b) Each year, BD will arrange to select a total of 2,000 buildings aged 30 years or above and 5,800 buildings aged 10 years or above for the MBIS and the MWIS respectively.  To spread over the workload of building professionals and contractors, the selection of target buildings will be conducted at quarterly intervals, with 500 buildings for the MBIS and 1,450 buildings for the MWIS to be selected in each quarter.  The target buildings selected each year will represent a mix of buildings in different conditions and age profiles in different districts.  Besides, to minimise disturbance to building owners, BD will synchronise the implementation of the MBIS and the MWIS, whereby buildings selected for the MBIS (i.e. the 2,000 buildings each year) will also be selected for the MWIS under the same cycle so that owners can carry out inspection and repair works under both schemes concurrently.  The remaining 3,800 target buildings will carry out the MWIS only.

 After the commencement of the relevant legislative provisions, starting from July 2012, the BD will issue pre-notification letters to the owners/owners' corporation (OC) of the first quarterly batch of target buildings selected for the MBIS and the MWIS concurrently to alert them that their buildings have been so selected so as to give them ample time to get prepared for the inspection that they will be required to arrange.  The statutory notice requiring the owners/OC to carry out the inspection will be issued, at the earliest, six months (i.e. in early 2013) after the issuance of pre-notification letter.  The owners/OC should appoint an RI within three months, and complete the prescribed inspection within 6 months, from the date of the statutory notice.  If repairs works are found necessary according to the inspection, they should be completed within 12 months from the date of the statutory notice.  An extra three months will be allowed for owners of buildings without an OC to organise and arrange for the required inspection and repair works. 

 In respect of buildings selected for the MWIS only, starting from July 2012, the BD will issue a pre-notification letter to the OC or post the letter at a conspicuous part of the target building to alert the owners/OC to get prepared and organised.  One to two months after the issuance or posting of the pre-notification letter, the BD will issue statutory notices to the owners/OC of the target buildings.  The owners/OC should appoint a QP within three months, and complete the prescribed inspection and repair (if necessary) within six months, from the date of the statutory notice.  Same as for buildings selected for the MBIS and the MWIS concurrently, an extra three months will be allowed for owners of buildings without an OC to organise and arrange the required inspection and repair works under the MWIS.

(c) Registration of RIs for the MBIS has commenced since December 30, 2011, and an Inspectors Registration Committee has been established for considering applications for registration.  Over the past few months, BD has been taking active measures to encourage qualified building professionals to register as RIs, including launching an API publicising registration in mid-February 2012, writing to the relevant professional institutes to invite them to disseminate the message to their members and to provide on their websites a hyperlink to BD's website for access to application forms for registration, arranging briefing sessions for members of the professional institutes, and writing to all authorised persons and registered structural engineers inviting them to apply for registration.   Registration is progressing well.  As at June 6, 2012, a total of 311 applications for registration as RI had been received, of which 195 applications had been approved and 27 applications deferred or refused.  The rest of the applications are being processed.  The inspectors' register has been uploaded on BD's website for public inspection.

 As we have mentioned previously, to ensure fair competition, we consider that the market should have a supply of at least 300 RIs initially when the first prescribed inspection under the MBIS is to commence.  Considering the present progress of registration, we are confident that we would be able to achieve this level of supply in the second half of 2012, before the statutory notices for the first batch of target buildings under the MBIS are issued in early 2013.

(d) and (e) HKHS and URA will provide the necessary financial and technical assistance to owners taking part in the MBIS and the MWIS, including "three nil" buildings, i.e. those without OCs, residents' organisations and property management companies. In terms of financial assistance, the two organisations will implement the "Mandatory Building Inspection Subsidy Scheme" (MBISS) to subsidise owners of eligible buildings the full cost of the first building inspection under the MBIS, subject to a cap.  The MBISS will mainly subsidise the cost of first inspection of the common parts of buildings under the MBIS.  The cost of first inspection of windows in the common parts under the MWIS will also be covered under the MBISS provided that the actual cost of inspection of the common parts of the building under MBIS does not exceed the subsidy cap.  The cost of any detailed investigation and subsequent repair works will not be covered by the subsidy scheme.  Under the MBISS, buildings will be categorised into various groups according to the number of units, and each group will have its respective cap limit.  To assist in working out the level of the subsidy cap, HKHS and URA have conducted a market survey early this year.  The two organisations have completed an analysis of the data collected in the survey and are in the process of finalising the proposed level of the cap under the MBISS.  It is estimated that the level of the subsidy cap and application procedures would be announced in the third quarter this year.

 For the sake of convenience and clarity to owners, HKHS and URA will adopt the same eligibility criteria on rateable value of the Integrated Building Maintenance Assistance Scheme (IBMAS) in the MBISS.  In view of the rising trend of rateable values in recent years, HKHS and URA have since April 1, 2012 raised the rateable value limits under the IBMAS to benefit more property owners.  The average rateable value limit of residential units in urban areas (including Tsuen Wan, Kwai Tsing and Shatin) has been lifted from $100,000 to $120,000, and that in the New Territories from $76,000 to $92,000.  About 80% of buildings aged 30 years or above are covered by these revised rateable value limits.  "Three nil" buildings may also apply for the above MBISS if they meet the eligibility criteria on rateable value.

 As for the repair works found necessary according to the inspection, the Government, together with HKHS and URA, will continue to provide financial assistance under the various existing schemes, including the IBMAS jointly administered by HKHS and URA, the Building Safety Loan Scheme administered by BD, and the Building Maintenance Grant Scheme for Elderly Owners administered by HKHS.  In line with the spirit of provision of "one-stop" service, owners can make multiple applications covering various types of grants/loans in the above schemes by simply completing one set of application forms under IBMAS. 

 HKHS and URA will provide technical assistance to owners in need during the various stages of the inspection schemes, including assisting them to organise themselves and offering support on tendering and appointment of RIs and contractors.  BD will, in collaboration with HKHS and URA, provide owners with necessary reference materials and, upon the issuance of pre-notification letters, organise district briefing sessions for owners who have received notification to explain the details of the inspection schemes and assistance packages available.  HKHS and URA will make use of the existing hotline of IBMAS to provide one-stop service to owners.  The various forms of technical assistance mentioned above will be applicable to "three nil" buildings.  In particular, having regard to the needs of this type of buildings, an "OC Formation Subsidy" is established under the IBMAS, whereby each successfully established OC can receive a maximum subsidy of $3,000.  In fact, during the implementation of the Operation Building Bright over the past few years, HKHS and URA have assisted buildings that have difficulties in co-ordinating repair works.  The two supporting organisations will make use of the experience gained in providing assistance to buildings without management organisations under the MBIS and the MWIS.

(f)  Under the MBIS and the MWIS, it is an offence if a person, without reasonable excuse, refuses to pay the relevant share of the cost of inspection, investigation, works or other action for the common parts of the building that are required to be carried out by the OC for compliance with the statutory notice issued by the Building Authority.  Offenders are liable on conviction to a fine at Level 4 (i.e. a maximum fine of $25,000).  This arrangement seeks to deter any person from refusing to contribute financially to the inspection and repair works for the common parts of the building thus resulting in non-compliance with the notices issued under the MBIS and MWIS.  Owners who are willing to share the cost will not be affected.
Ends/Wednesday, June 13, 2012
Issued at HKT 16:41