1. Temporary Works

2. Temporary Works Definition (according to BSI)
Any temporary construction necessary to assist the execution of the permanent works and which will be removed (sometimes not) from the site on completion.

3. Temporary Works
(according to the General Conditions of Contract for Civil Engineering Works, Hong Kong Government 1993 Edition)
All temporary work of every kind required for the construction, completion and maintenance of the Works.

4. Common Temporary Works in construction sites
Hoading & Fencing, Site offices, storage facilities
Excavation supports
Access Scaffolds
Working Platforms

5. Common Temporary Works in construction sites
Falsework
Shoring
Temporary Access Bridges, Ramp
Temporary Structures for Construction Plants
River Diversion Structures

6. Temporary Works and the Conditions of Contract
General Conditions of Contract for Civil Engineering Works, Hong Kong Government 1993 Edition
Clause 10 – Extent of Contract ( General Obligations )

7. Temporary Works and the Conditions of Contract
The Contractor shall, subject to the provisions of the Contract, execute the Works and provide all labor, materials, Construction Plant, Temporary Works, transport to and from the Site or in and about the Works and everything whether of a temporary or permanent nature required in and for such execution so far as necessary for providing the same is specified in or reasonably to be inferred from the Contract

8. Temporary Works & the Common Law
It shall be the duty of any person who designs, manufactures, imports or supplies any article for use at work,
 (a) to ensure, so far as is reasonably practicable, that the article is so designed and constructed as to be safe and without risks to health when properly used;

9. Temporary Works & the Common Law
(b) to carry out or arrange for the carrying out of such testing and examination as may be necessary for the performance of the duty imposed upon him by the above paragraph;

10. Temporary Works & the Common Law
 (c) to take such steps as are necessary to secure that there will be available in connection with the use of the article at work necessary and adequate information about the use for which it is designed and has been tested, and about any conditions necessary to ensure that when put to that use, it will be safe and without risks to health.

11. Temporary Works & Contract Pricing
Requirements of temporary works: labor, plants, materials, construction methods(including safety provisions) and the associated cost need to be established at the tender stage. 

12. Temporary Works & Contract Pricing
Otherwise the tender sum may not allow sufficient budget for the subsequent site activities in the construction phase, hence decreasing the Contractor's profit margin or to the worst incurring a significant loss at the end of the Contract

13. DESIGN OF TEMPORARY WORKS
Standard Solutions
Solutions to temporary works problem by reference to tables/charts previously prepared for the likely variety of loadings that could be met in situations amenable to their use.

14. DESIGN OF TEMPORARY WORKS
Relevant information could be available from :
I.   in-house tabulations showing loads and spacing of materials used on a standardized basis;
II. authoritative guidance documents resulting from research and testing e.g. CIRIA Reports, B.S.

15. DESIGN OF TEMPORARY WORKS
III. documents provided by manufacturers marketing proprietary equipment tested to comply with the relevant local legislation/industrial standards.

16. DESIGN OF TEMPORARY WORKS
Why Standard Solutions ?
Requirements in relation to temporary works can be assessed with good accuracy.
The pricing of various bill items will be more accurate.
Standard solution tables provide site management with the means of checking the work of subcontractors involved in carrying out the temporary works on site.

17. DESIGN OF TEMPORARY WORKS
Designed Solutions
Designed solutions become necessary for situations where the standard solutions are in appropriate. Competent persons should be employed in such particular site situations.

18. SCAFFOLDING Definition:
a crucial item to ensure that workers have a safe place of work and a safe means of access to it.
Related legislation:
Strength and Stability; Platform widths for various purposes; Provision of hand rails, toe boards, prevention of materials falling off scaffolds

19. SCAFFOLDING Codes of Practice:
BS 5973:1990 Code of Practice of scaffolding (design code)
BS 1139:1981 Part 3 Specification for prefabricated access and worker towers
No codes of practice for proprietary systems

20. Terminology in Scaffolding Layout
Standards
Lift
Bay
Ledger/Lacing
Diagonal Brace
Ledger Brace
Plan Brace
Transom

21. Terminology in Scaffolding Layout
Putlog
Coupler
Guardrail
Decking/Boarding
Toeboard
Sole Plate/Board

22. Terminology in Scaffolding Layout
U-head/Fork head
Screw (U-head/Base)Jack
Prop (telescopic)
Tie rod

23. Couplers & Fittings Standard 90 deg coupler Putlog head Reveal pin
Fixed coupler
Swivel coupler
Safety/Check coupler
Putlog head
Reveal pin

24. Types / Configurations of Scaffolds
A. Tube and Fitting Scaffolds
Putlog Scaffolds :
scaffolds are those which have one line of standards to support the outside of the scaffold deck, while the inside edge is supported from the wall being built. The 'putlog' is a transom member with a flattened end to rest on masonry walling. The whole scaffold erection is slightly lean inwards to increase stability.
Limitation - for use on load bearing walls only.

25. Types / Configurations of Scaffolds
Independent Tied Scaffolds :
scaffolds are those have two rows of standards supporting the working deck. The transom members are tied between the two layers of standards and act independent of what is being built. For improving the overall scaffold stability, the structure is tied at some points to the new building.

26. Types / Configurations of Scaffolds
Special Scaffolds for specialised work
Free-standing scaffolds - movable and stable Vs overturning without any attachment to any other structure but occasional guy or raking strut support. (Covered by BS 1139 : Part )
Slung Scaffold - those hanging from a structure overhead but incapable of being moved sideways or raised or lowered. (Covered by 5973:1990)

27. Types / Configurations of Scaffolds
Suspended Scaffolds - working platforms suspended on wire ropes from a suitable structure above, such that they can be raised or lowered, but not moved sideways. (Covered by 5974:1982)

28. Types / Configurations of Scaffolds
B. Proprietary Scaffolding Systems
The specialised systems are designed to avoid the use of loose fittings and are modular in concept. Their load carrying capacity and structural stability work on a deem-to-satisfy basis after extensive testing to validate the performance figures by the respective manufacturers.

29. Comparison between Tube & Fittings Scaffold and Proprietary Scaffold
Tube and Fitting Scaffold
Advantage
more flexible to awkward situations and dimensions which do not fit the modules of proprietary methods.

30. Comparison between Tube & Fittings Scaffold and Proprietary Scaffold
Advantages:
Connection methods provide a rigid connection to standards than conventional tube and fittings
The members are of fixed modules and hence the scaffold set out itself. If dimensions are wrong, the pieces will not fit together.
It is easier and quicker to train scaffolders.

31. Comparison between Tube & Fittings Scaffold and Proprietary Scaffold
Advantages (Cont’d):
Few loose fittings are needed.
Quicker erection due to no coupling to be set out or done up required in the tube methods.
Losses are minimized because of the size of the standard components.

32. Comparison between Tube & Fittings Scaffold and Proprietary Scaffold
Disadvantage:
the capital cost is grater than with tube and fittings.

33. Division between standard and designed solutions
BS 5973 recommends that the design of Tube & Fitting Scaffolds can adopt standard solutions (i.e. without design calculation) up to 50 metres high provided that they do not carry loads nor greater bay lengths than those specified in the document, nor subjected to loading of materials by mechanical means.
The Proprietary Scaffold Systems all come into the standard solutions. Any modified approach need to be supported by designed solutions.

34. Checklist for scaffolding requirements
Preparations for scaffolding specifications will be assisted by having available a checklist similar to one shown below of all possible types of scaffolding that may be needed for both internal and external construction activities.
1. External elevations
2. Scaffold to roof level structures
3. Hoist towers

35. Checklist for scaffolding requirements
4. Rubbish chutes
5. Loading towers
6. Internal wall and partition scaffold
7. Birdcage access scaffold
8. Mobile access towers

36. Checklist for scaffolding requirements
9. Truss-out Access scaffold
10.Handrails and guardrails
11. Lift shafts
12. Protective fans
13. Other specialist requirements
14. Protection requirements

37. Provisions in Scaffolding Contracts
Responsibilities
1. The scaffold owner shall declare the loads that are brought down by each standard. The hirer will be responsible for adequate foundations and this information on loading of standards is necessary for him to provide the necessary support. 
2. The hirer is responsible for the provision of sufficient anchorage points for a positive tie into the structure, in accordance with BS 5973 or as may be agreed between the parties. 

38. Provisions in Scaffolding Contracts
3. Those erecting the scaffold will ensure that the scaffolding is soundly and adequately constructed and complies with appropriate Regulations (esp. in respect of safety) on handing over.
4. The legal requirements calling for regular inspections of the scaffold thereafter rest with site management.

39. Provisions in Scaffolding Contracts
Pricing
1. Provision of scaffolding as described by the main or specialist contractor who is responsible for its provision; 
2. The extra over rate for the hire of the scaffold if the contract period is overrun, as a rate per week; 
3. Hourly labor rates for alterations to the scaffold after the initial erection.

40. Site Safety Regulations for Scaffolding Works
The responsibilities of a contractor in working with scaffolds under the Construction Sites (Safety) Regulations of Hong Kong are :

41. Site Safety Regulations for Scaffolding Works
(I) ensure practicable, suitable and sufficient safe access to and egress from every place on site at which any person at any time works, and maintain it properly,
(ii) ensure every place on the site shall be made and kept safe for any person working there
(iii) ensure that no scaffold is erected on the site or substantially added/altered/dismantled except under the immediate supervision of a competent person and by competent workmen of adequate and appropriate working experience.

42. Site Safety Regulations for Scaffolding Works
(iv) ensure every scaffold is of good construction, made of strong and sound materials and free from patent defect and properly maintained.
(v) ensure every scaffold is kept so fixed, secured or placed in position.
(vi) no part of structure or building is used in support for a scaffold unless it is strong and stable.

43. Site Safety Regulations for Scaffolding Works
(vii) the scaffolds to be inspected by a competent person within the immediately preceding month,
(viii) inspection reports to be made in approved forms by the person who is responsible for inspection which contain the prescribed particulars and delivered to the contractor concerned.

44. Bamboo Scaffolds - Advantages
Flexibility
Bamboo could be cut and lapped through fastening thus tailor-assembled easily to suit the profile and contour for most construction structures even of very complicated geometry and shape.
Bamboo scaffolds could also be erected at any elevation of a multi-storey building, for instance truss-out scaffold structures, which is particularly advantageous in Hong Kong where tall buildings are crowded with limited space for access in general.

45. Bamboo Scaffolds - Advantages
Bamboo when combining with steel brackets as the primary structural supports could be a very safe solution for most scaffolding work.

46. Bamboo Scaffolds - Advantages
Cost effectiveness
·  Abundant supply of bamboo is available from the Southern China areas, thus reducing the cost of transportation for scaffolding work in Hong Kong.
·  Fast growth in bamboo plantation could make it as a cheap and environmental friendly temporary works materials
The cost is usually a few percent of that of steel scaffolding tubes.

47. Bamboo Scaffolds - Advantages
Speediness
·  Bamboo is very light-weighted which can be handled by workers and it requires no machinery and sophisticated hand tools.
This feature is leading bamboo scaffolds could be erected and dismantled much faster than other types of other types of scaffolding.

48. Bamboo Scaffolds - Common Causes of Failure & Limitations
1. A safely erected bamboo scaffold could be put into a dangerous access structure for construction workers if other trade-workers damage it through cutting bamboo elements to suit their own operational needs e.g. plastering work, plumbing.. etc.

49. Bamboo Scaffolds - Common Causes of Failure & Limitations
2. Immature bamboo was imported and used for the scaffolding work, in particular when there is a large over-consumption of bamboo in the times when construction is a blooming business.

50. Bamboo Scaffolds - Common Causes of Failure & Limitations
3. Inadequate of monitoring and maintenance of bamboo scaffold erected are not uncommon in local building sites. Sometimes a bamboo scaffold is left unattended for several months.

51. Bamboo Scaffolds - Common Causes of Failure & Limitations
4. Unskilled scaffolding workers are employed to erect or dismantle bamboo scaffold. Traditional skill and correct code of practice are neither ignored nor carried out by inexperienced workers which eventually produce an unsafe temporary structure.

52. Bamboo Scaffolds - Common Causes of Failure & Limitations
5. Bamboo is a natural material bearing biological defects which are difficult to be characterised assessment in the current engineering practices. Design and construction of bamboo scaffolds depends on skill and experience of the trade. Application to very high-rise and heavy duty structural works should be avoided.