1. 1 Formwork Definition Definition A structure, usually temporary (but sometimes wholly or partly permanent), used to contain poured concrete to mould it to required DIMENSIONS, FINISHES and SUPPORT it until it is able to support itself. A structure, usually temporary (but sometimes wholly or partly permanent), used to contain poured concrete to mould it to required DIMENSIONS, FINISHES and SUPPORT it until it is able to support itself. Formwork consists of contact face material and the bearers which support the face material. Formwork consists of contact face material and the bearers which support the face material.

2. 2 Code of Practice for Formwork Design Concrete Pressure Computation: Concrete Pressure Computation: Concrete Pressures on Formwork, CIRIA Report 108 (Ref.) Concrete Pressures on Formwork, CIRIA Report 108 (Ref.) Design Practice: Design Practice: Formwork – a Guide to Good Practice, published by Concrete Society and IStructE (Ref.) Formwork – a Guide to Good Practice, published by Concrete Society and IStructE (Ref.)

3. 3 Common Types of Formwork Wall Form Wall Form

4. 4 Common Types of Formwork Wall Form Wall Form..\Teaching_Notes\TEMP_ WK\multimedia\Wall form001.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form001.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form001.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form001.jpg

5. 5 Common Types of Formwork Wall Form Form

6. 6 Common Types of Formwork Wall Form Wall Form..\Teaching_Notes\TEMP_ WK\multimedia\Wall form003.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form003.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form003.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form003.jpg

7. 7 Common Types of Formwork Wall Form Wall Form..\Teaching_Notes\TEMP_ WK\multimedia\Wall form004.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form004.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form004.jpg..\Teaching_Notes\TEMP_ WK\multimedia\Wall form004.jpg

8. 8 Common Types of Formwork Column Form Column Form..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnfo rm1003.jpg

9. 9 Common Types of Formwork Soffit Form Soffit Form..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Sof fit Form Frame001.jpg

10. 10 Common Types of Formwork Beam Form Beam Form..\Teaching_Notes\TEMP_WK\multimedia\Beam Form-Edge004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form-Edge004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form-Edge004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form-Edge004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form005.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form005.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form005.jpg..\Teaching_Notes\TEMP_WK\multimedia\Beam Form005.jpg Stair Form Stair Form Permanent Formwork Permanent Formwork

11. 11 Combined formwork and falsework Formwork and falsework can be combined into a single handleable unit Formwork and falsework can be combined into a single handleable unit Time could be saved in erection and stripping and the labor content of the operation thus significantly reduced Time could be saved in erection and stripping and the labor content of the operation thus significantly reduced Large repetition is a must for this method to be effective. Common examples include: Large repetition is a must for this method to be effective. Common examples include: Table Form..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg, Flying Form..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg, Table Form..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg, Flying Form..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg,..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg Travelling Form..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg Travelling Form..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg Usually they are available from specialist suppliers Usually they are available from specialist suppliers

12. 12 Formwork Three general principles govern formwork design and construction: QUALITY QUALITY SAFETY SAFETY ECONOMY ECONOMY

13. 13 Quality of Formwork Relating to the formed faces of the permanent concrete structure and refers to the following two aspects: Accuracy of Concrete Shape Accuracy of Concrete Shape Quality of Concrete Surface Quality of Concrete Surface

14. 14 Quality of Formwork Accuracy is controlled by the deviations permitted (Tolerances) in the : Formwork deflection Formwork deflection Materials Materials Components Components Workmanship Workmanship

15. 15 Quality of Formwork To minimise deviations, all formwork must have adequate means of: Alignment and adjustment both at construction joints and throughout the formwork Alignment and adjustment both at construction joints and throughout the formwork e.g. Simple wedges, screw adjustments on supports, camber adjustments e.g. Simple wedges, screw adjustments on supports, camber adjustments

16. 16 Quality of Formwork Failures in achieving surface quality are often caused by: Lack of formwork stiffness to resist the movement coming from concrete vibrators during concrete placement and the subsequent grout loss at the joints (honey- combing, harder stripping) Lack of formwork stiffness to resist the movement coming from concrete vibrators during concrete placement and the subsequent grout loss at the joints (honey- combing, harder stripping) Concrete shape, disposition of steel bars Concrete shape, disposition of steel bars Efficiency of conc. placement, forms stripping Efficiency of conc. placement, forms stripping

17. 17 Quality of Formwork Classes of Finishes Classes of Finishes Formed Finishes Formed Finishes F1, F2, F3, F4, F5 (CED G.S. Table 14.1) – Class F5 the best F1, F2, F3, F4, F5 (CED G.S. Table 14.1) – Class F5 the best Unformed Finishes Unformed Finishes U1, U2, U3, U4, U5 (CED G.S. Table 14.2) – Class U5 the best U1, U2, U3, U4, U5 (CED G.S. Table 14.2) – Class U5 the best Treated Finishes Treated Finishes T1, T2, T3, T4, T5, T6 (CED G.S. Table 14.3) T1, T2, T3, T4, T5, T6 (CED G.S. Table 14.3)

18. 18 Quality of Formwork Different concrete structures buried underground or exposed to naked eyes require different class finishes specified by the contract document Different concrete structures buried underground or exposed to naked eyes require different class finishes specified by the contract document The formwork design requires appropriate method of construction/treatment, different surface irregularities requirements and types of contact face sheeting materials The formwork design requires appropriate method of construction/treatment, different surface irregularities requirements and types of contact face sheeting materials

19. 19 Quality of Formwork Tolerances Tolerances

20. 20 Safety of Formwork Two major aspects must be covered: Personal Safety of both formworkers and the public Personal Safety of both formworkers and the public Safety of the formwork structure Safety of the formwork structure

21. 21 Safety of Formwork I. Construction phase As a general practice, the erected formwork shall be : Structurally safe Structurally safe Having secured and effective guard rails, toeboards, access ladders and stairs around its periphery Having secured and effective guard rails, toeboards, access ladders and stairs around its periphery Formworkers equipped with safety helmets and boots Formworkers equipped with safety helmets and boots For high work, safety harnesses and security screen are to be installed For high work, safety harnesses and security screen are to be installed

22. 22 Safety of Formwork II.Design phase a)Evaluation of possible Loading Combinations occurred in the following stages: Stage 1: before conc. Placement Stage 1: before conc. Placement Stage 2: during conc. Placement Stage 2: during conc. Placement Stage 3: after conc. Placement Stage 3: after conc. Placement

23. 23 Safety of Formwork b) Structural requirements Three important aspects to be met: STRENGTH (material strength and force equilibrium) STRENGTH (material strength and force equilibrium) STABILITY (Sliding, overturning, uplift and sidesway) STABILITY (Sliding, overturning, uplift and sidesway) STIFFNESS (accuracy and permissible tolerances) STIFFNESS (accuracy and permissible tolerances)

24. 24 Economy of Formwork Where formwork is highly repetitive activity, a small reduction in fabrication/stripping could result a significant overall cost saving. Where formwork is highly repetitive activity, a small reduction in fabrication/stripping could result a significant overall cost saving. Cost involves formwork materials and labor, erection (including hoisting), stripping, repairing and cleaning of formwork after concrete pour. Cost involves formwork materials and labor, erection (including hoisting), stripping, repairing and cleaning of formwork after concrete pour.

25. 25 Economy of Formwork Increase in no. of reuses lower the unit cost of the formwork Increase in no. of reuses lower the unit cost of the formwork More sophisticated design could be economically justifiable esp. when less maintenance will be required. More sophisticated design could be economically justifiable esp. when less maintenance will be required. Good formwork, apart from meeting the technical specifications requirements, means it is easy to fabricate, erect, adjust, dismantle, and within the available crane/man handling. Good formwork, apart from meeting the technical specifications requirements, means it is easy to fabricate, erect, adjust, dismantle, and within the available crane/man handling.

26. 26 Care of Formwork For maximum formwork life, efficient stripping; care in formwork handling, storage, and maintenance are essential For maximum formwork life, efficient stripping; care in formwork handling, storage, and maintenance are essential After stripping, the formwork units for reuse should be moved away from the work area (workers of other trades may damage it as an item of obstruction left there). After stripping, the formwork units for reuse should be moved away from the work area (workers of other trades may damage it as an item of obstruction left there).

27. 27 Care of Formwork They should be stored and protected from weather to avoid surface damage They should be stored and protected from weather to avoid surface damage Large formwork panels should be stacked in racks, facing away from direct sunlight Large formwork panels should be stacked in racks, facing away from direct sunlight Hardened slurry, dirt left from previous pour should be removed from plywood sheeting surfaces before they are getting harder Hardened slurry, dirt left from previous pour should be removed from plywood sheeting surfaces before they are getting harder

28. 28 Care of Formwork Mechanisms, locking devices and fixings should be cleaned and oiled. Mechanisms, locking devices and fixings should be cleaned and oiled. Face sheeting to be given a coat of release agent Face sheeting to be given a coat of release agent Care to be taken not to damage the presealed surface of the plywood sheeting (Use a soft brush in dust removal and a softwood wedge to remove larger concrete particles) Care to be taken not to damage the presealed surface of the plywood sheeting (Use a soft brush in dust removal and a softwood wedge to remove larger concrete particles)

29. 29 Formwork Striking Procedures -RC Slab Form Ease all supports by 1-2 turns for each prop Ease all supports by 1-2 turns for each prop Starting from mid-span, remove the props towards columns or walls Starting from mid-span, remove the props towards columns or walls This will ensure no negative hogging bending moment induced in the concrete slab if the last few supports were left at the mid-span as intended in the original design. This will ensure no negative hogging bending moment induced in the concrete slab if the last few supports were left at the mid-span as intended in the original design. Cracking due to reverse bending will occur otherwise Cracking due to reverse bending will occur otherwise

30. 30 Formwork Striking Procedures -RC Slab on Beam Form Strike the slab soffit form first Strike the slab soffit form first Then strike the beam soffit starting at mid-span towards the columns/walls Then strike the beam soffit starting at mid-span towards the columns/walls This will ensure that all the imposed vertical load will be supported by the slab which is in turn supported by the beam form plus its falsework. By removing propping to the beam form at the mid-span, the beam could then span across the column/wall at both end as intended by the original structural design. This will ensure that all the imposed vertical load will be supported by the slab which is in turn supported by the beam form plus its falsework. By removing propping to the beam form at the mid-span, the beam could then span across the column/wall at both end as intended by the original structural design. Cracking due to reverse bending will occur otherwise. Cracking due to reverse bending will occur otherwise.

31. 31 Formwork Striking Procedures -RC Cantilever Slab Form Start the propping striking from the tip of the cantilever and work towards the column/wall/beam. Start the propping striking from the tip of the cantilever and work towards the column/wall/beam. \Particular care should be observed that any effect of overloading on the adjacent spans temporarily when the propping to cantilever is not properly striken. \Particular care should be observed that any effect of overloading on the adjacent spans temporarily when the propping to cantilever is not properly striken.

32. 32 Formwork – Minimum Period before Striking (BS 8110) Formwork Surface conc. temperature >16 deg C Surface conc. temperature 0 – 10 deg C Column, wall, large beam form 12 h Slab form 4 days Beam & props to slab form 10 days Prop to beam 14 days

33. 33 Backpropping The speed of construction vertically will dictate a number of slab levels acting together to support the total construction loads imposed from the topmost concrete slab casting operation The speed of construction vertically will dictate a number of slab levels acting together to support the total construction loads imposed from the topmost concrete slab casting operation

34. 34 Backpropping To avoid excessive loads building cumulatively in the backprops, backprops are loosened after striking a slab formwork and then repositioned and retightened. The cast floor is thus allowed to take its deflected shape hence the load imposed from the floor(s) above To avoid excessive loads building cumulatively in the backprops, backprops are loosened after striking a slab formwork and then repositioned and retightened. The cast floor is thus allowed to take its deflected shape hence the load imposed from the floor(s) above

35. 35 Formwork Materials Face Contact Materials (features left*) Face Contact Materials (features left*) Sawn board formwork (sawmarks*) Sawn board formwork (sawmarks*) Plywood (fine & smooth surface*) Plywood (fine & smooth surface*) Steel form (variable color*) Steel form (variable color*) Aluminium form (react with cement*) Aluminium form (react with cement*) Glass fibre reinforced plactics (highest quality for sculptured profiles*) Glass fibre reinforced plactics (highest quality for sculptured profiles*) * features/drawback

36. 36 Formwork Materials Waling/Bearer, Soldier/Props Materials Waling/Bearer, Soldier/Props Materials Solid timber Solid timber Steel in lattice configurations or cold formed sections (standard/proprietary) Steel in lattice configurations or cold formed sections (standard/proprietary) Aluminium (Al Alloys) sections Aluminium (Al Alloys) sections

37. 37 Formwork Materials Expanded metal (stopends) Expanded metal (stopends)..\Teaching_Notes\TEMP_WK\multi media\expanded metal formwork.tif..\Teaching_Notes\TEMP_WK\multi media\expanded metal formwork.tif..\Teaching_Notes\TEMP_WK\multi media\expanded metal formwork.tif..\Teaching_Notes\TEMP_WK\multi media\expanded metal formwork.tif

38. 38 Proprietary Formwork System Basic Panel system – generally no walings, but complete with corner panels, access brackets, stabilisers Basic Panel system – generally no walings, but complete with corner panels, access brackets, stabilisers Table forms Table forms..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Tableform2.jpg Flying forms Flying forms..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg..\Teaching_Notes\TEMP_WK\multimedia\FlyingForm2.jpg Slab support system Slab support system..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Modular Frame.jpg Waffle and trough moulds Waffle and trough moulds Composite Floors with Steel Decking Composite Floors with Steel Decking

39. 39 Form Ties Recoverable and non-recoverable types Recoverable and non-recoverable types..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg Tie rods are the most critical parts in the formwork design which will lead to the complete formwork failure if any of them fails Tie rods are the most critical parts in the formwork design which will lead to the complete formwork failure if any of them fails

40. 40 Form Ties Factor of safety in tension capacity Factor of safety in tension capacity 1) 1.5 for HT cold worked steel 2) 2.5 for mild steel Bearing plates/washers to be checked if bearing stresses acting on the timber waling/soldiers are exceeded or not Bearing plates/washers to be checked if bearing stresses acting on the timber waling/soldiers are exceeded or not Limitation on spacing of form ties is also a concern for aesthetic reasons Limitation on spacing of form ties is also a concern for aesthetic reasons

41. 41 Formwork Design – Concrete pressure FactorsIncreasePressureChanges Cement Types/ Mix Composition (C 2 ) Retarder,PFA Rate of Pour (R) Size & Shape of Formwork (C 1 ) Column, Wall Height of Form (H) Concrete Temperature at Placing (T) Unit Weight of Conc. (D)

42. 42 Concrete pressure distribution along a vertical wall form (Trapezoidal) Concrete is still hydrostatic Concrete has been hardening P max

43. 43 Concrete Pressure Formula (CIRIA Report 108) C 2 is coefficient depending on mix ingredients C 2 is coefficient depending on mix ingredients D is unit weight of concrete, kN/m3 D is unit weight of concrete, kN/m3 C 1 is coefficient depending on form size & shape C 1 is coefficient depending on form size & shape H is vertical form height, m H is vertical form height, m K is temperature coefficient K is temperature coefficient R is rate at which conc. rises vertically, m/h R is rate at which conc. rises vertically, m/h

44. 44 Formwork Design - Loading Self-weight of Formwork Self-weight of Formwork Imposed Loads (permanent work loads and construction operation loads) Imposed Loads (permanent work loads and construction operation loads) Concrete Pressure (for wall/column forms) Concrete Pressure (for wall/column forms) Environmental Loads (Wind loads, Snow/Ice Loads) Environmental Loads (Wind loads, Snow/Ice Loads) Horizontal Loads (Imposed plant loads, skip impact loads,.. And minimum horizontal stability force i.e. 10% of the total form self-weight) Horizontal Loads (Imposed plant loads, skip impact loads,.. And minimum horizontal stability force i.e. 10% of the total form self-weight)

45. 45 Formwork Design - Design procedures follow the design of permanent works but: 1) Permissible stress design method are often used; 2) Higher working material stresses 3) Formwork system will include manufacturing and assembly tolerances

46. 46 Formwork Design – Soffit Form Stability Stability of soffit formwork erected at the top of falsework is covered in BS5975 (formwork is considered as an integral part of the falsework)

47. 47 Formwork Design – Wall Form Stability Stability of freestanding wall forms must be checked for the following three scenarios: 1) Maximum Wind and Nominal access Loads on any working platform (W/P) 2) Working Wind and Full Construction Operation Loads on any W/P

48. 48 Formwork Design – Wall Form Stability 3)Minimum Stability Force and Full Construction Operation Loads on any W/P Note: Working wind means the upper wind speed limit below which operations could still be allowed Note: Working wind means the upper wind speed limit below which operations could still be allowed

49. 49 Formwork Design – Design Concepts Single Face Formwork Single Face Formwork Cantilevered Formwork Cantilevered Formwork Discontinuity in Face Sheeting and Soffit Discontinuity in Face Sheeting and Soffit Impact against a fixed face/joint during concreting Impact against a fixed face/joint during concreting Inclined Soffits Inclined Soffits Cantilevered Soffits Cantilevered Soffits

50. 50 Special Formwork Slipforms Slipforms..\Teaching_Notes\TEMP_WK\multimedia\Slipform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Slipform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Slipform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Slipform001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Slipform001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Slipform001.jpg Climbforms. Climbforms...\Teaching_Notes\TEMP_WK\multimedia\ClimbForm.jpg.\Teaching_Notes\TEMP_WK\multimedia\ClimbForm.jpg.\Teaching_Notes\TEMP_WK\multimedia\ClimbForm.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform4.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform4.jpg..\Teaching_Notes\TEMP_WK\multimedia\Climbform4.jpg Travellers Travellers..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Travelform3.jpg

51. 51 Special Formwork Tilt-up Moulds Tilt-up Moulds..\Teaching_Notes\TEMP_WK\multimedia\Tilt-up Mould.tif..\Teaching_Notes\TEMP_WK\multimedia\Tilt-up Mould.tif..\Teaching_Notes\TEMP_WK\multimedia\Tilt-up Mould.tif..\Teaching_Notes\TEMP_WK\multimedia\Tilt-up Mould.tif Gang Forms Gang Forms..\Teaching_Notes\TEMP_WK\multimedia\Gangform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform1.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform2.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform3.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform4.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform4.jpg..\Teaching_Notes\TEMP_WK\multimedia\Gangform4.jpg Moulds for Prestressed Concrete Moulds for Prestressed Concrete Tunnel Form Tunnel Form..\Teaching_Notes\TEMP_WK\multimedia\Tunnel Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Tunnel Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Tunnel Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Tunnel Form.tif

52. 52 Special Formwork Details Kickers for wall form Kickers for wall form..\Teaching_Notes\TEMP_WK\multimedia\Kicker.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Kicker003.jpg Kickers for column form Kickers for column form..\Teaching_Notes\TEMP_WK\multimedia\Column Kicker.tif..\Teaching_Notes\TEMP_WK\multimedia\Column Kicker.tif..\Teaching_Notes\TEMP_WK\multimedia\Column Kicker.tif..\Teaching_Notes\TEMP_WK\multimedia\Column Kicker.tif Stopend forms for wall form Stopend forms for wall form..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Stopend Form004.jpg

53. 53 Special Formwork Details Wall Ties Wall Ties..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall Tie001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg..\Teaching_Notes\TEMP_WK\multimedia\Wall tie004.jpg Props Props..\Teaching_Notes\TEMP_WK\multimedia\Prop.jpg..\Teaching_Notes\TEMP_WK\multimedia\Prop.jpg..\Teaching_Notes\TEMP_WK\multimedia\Prop.jpg..\Teaching_Notes\TEMP_WK\multimedia\Prop001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Prop001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Prop001.jpg U-head U-head..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form U-head.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form U-head.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form U-head.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form U-head.jpg Sloping soffit form Sloping soffit form..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Sloping Details003.jpg

54. 54 Special Formwork Details Bracing for soffit form Bracing for soffit form..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Frame Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Frame Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Frame Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Frame Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Bracing Connector.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Bracing Connector.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Bracing Connector.jpg..\Teaching_Notes\TEMP_WK\multimedia\Soffit Form Bracing Connector.jpg Bracing for beam form Bracing for beam form..\Teaching_Notes\TEMP_WK\multimedia\Beam-Soffit Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Beam-Soffit Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Beam-Soffit Form.tif..\Teaching_Notes\TEMP_WK\multimedia\Beam-Soffit Form.tif Bracing for column form Bracing for column form..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing001.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing002.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing003.jpg..\Teaching_Notes\TEMP_WK\multimedia\Columnform Bracing003.jpg

55. 55 Slipforms – features The system is intended for continuous concreting work for walls of constant section. The system is intended for continuous concreting work for walls of constant section. The shutter rises from 150 to 300 mm per hour depending on the rate of concrete hardening. The shutter rises from 150 to 300 mm per hour depending on the rate of concrete hardening.

56. 56 Slipforms – features The form is about 900-1200 mm deep, fixed to and held apart by timber or steel frame or yokes as shown in the figure on the right. The form is about 900-1200 mm deep, fixed to and held apart by timber or steel frame or yokes as shown in the figure on the right. On top of each yoke is fixed a hydraulic jack which climbs along a steel jacking rod, about 25 mm in diameter, which is cast into the wall. On top of each yoke is fixed a hydraulic jack which climbs along a steel jacking rod, about 25 mm in diameter, which is cast into the wall.

57. 57 Slipforms – Operation Procedures (i) Fix steel reinforcement above the shutter (i) Fix steel reinforcement above the shutter (ii) Pour concrete into the shutter and vibrate it in final position (ii) Pour concrete into the shutter and vibrate it in final position (iii) Operate the jack to work against the lower jaws to raise the yoke and the form with it (iii) Operate the jack to work against the lower jaws to raise the yoke and the form with it

58. 58 Slipforms – Operation Procedures (iv) When the oil pressure is released, the upper jaws grip under the action of a spring (iv) When the oil pressure is released, the upper jaws grip under the action of a spring (v) The jack is operated in cycles (iii) + (iv) and each cycle gives a rise of about 25 mm (v) The jack is operated in cycles (iii) + (iv) and each cycle gives a rise of about 25 mm

59. 59 Slipform – Uses and Limitations Uses The process is used for constructing concrete chimneys, silos, shaft linings, towers and building cores and bridge piers The process is used for constructing concrete chimneys, silos, shaft linings, towers and building cores and bridge piers Possible to vary wall thickness and layout over the height (despite overall cost will be increased) Possible to vary wall thickness and layout over the height (despite overall cost will be increased)

60. 60 Slipform – Uses and Limitations Limitations Steady and continuous concreting must be maintained throughout the process Steady and continuous concreting must be maintained throughout the process Longer duration and sophisticated equipment layout in the initial setup Longer duration and sophisticated equipment layout in the initial setup High capital cost in the plant & equipment High capital cost in the plant & equipment

61. 61 Slipform – Uses and Limitations Limitations Labors working in shifts and hence higher labor costs Labors working in shifts and hence higher labor costs No construction joints No construction joints Working platform to be protected from adverse weather e.g. high wind, heavy pours Working platform to be protected from adverse weather e.g. high wind, heavy pours

62. 62 Slipform – Uses and Limitations Limitations Limitations Standby plant and operatives are needed Standby plant and operatives are needed Openings formed by timber/polystyrene within a film of concrete on each face could avoid displacement of the former during the vertical sliding process Openings formed by timber/polystyrene within a film of concrete on each face could avoid displacement of the former during the vertical sliding process It requires specialist working and supervision operatives It requires specialist working and supervision operatives

63. 63 Tilt-up Moulds The unit mould is cast horizontally and may subsequently be tilted through a designed angle The vertical position of the cast unit on completion of demoulding could facilitate easy and early formwork removal, and the subsequent vertical stacking The vertical position of the cast unit on completion of demoulding could facilitate easy and early formwork removal, and the subsequent vertical stacking Horizontal processing could allow easy tiling works, or composite sandwich/hollow units manufacture Horizontal processing could allow easy tiling works, or composite sandwich/hollow units manufacture

64. 64 Moulds for Prestressed Concrete Sideforms which cannot be removed before prestressing operations commence should be designed to allow vertical and horizontal movement of the cast member during prestressing Sideforms which cannot be removed before prestressing operations commence should be designed to allow vertical and horizontal movement of the cast member during prestressing Safety rules to all personnel concerned must be adhered to during the tendon stressing operation Safety rules to all personnel concerned must be adhered to during the tendon stressing operation

65. 65 Formwork Checklist Design concept in relation to expected concreting rate Design concept in relation to expected concreting rate Material strength, stiffness, condition and dimensions Material strength, stiffness, condition and dimensions Access – adequate space, guardrails, toeboards, ladder/stairs Access – adequate space, guardrails, toeboards, ladder/stairs

66. 66 Formwork Checklist Assembly - layout dimensions, plumb & stability, inserts fixed, ties tightened and thread conditions checked, sealed against kicker, panel joints sealed, waterstop installed, filling over nail holes Assembly - layout dimensions, plumb & stability, inserts fixed, ties tightened and thread conditions checked, sealed against kicker, panel joints sealed, waterstop installed, filling over nail holes Release agent applied Release agent applied Formwork cleaned out Formwork cleaned out Stripping – nails bent/removed, resuable materials separated Stripping – nails bent/removed, resuable materials separated