SPECIFICATION 821

FORMWORK

Copyright MAIN ROADS Western Australia

Specification 821 Formwork – 04/10135 Issued 01/05/2017
REVISION REGISTER
Clause
Number / Description of Revision / Authorised By / Issue Date
Whole document / Reformatted / SCO / 01/05/2017
Clause 821.02 / Redundant AS 2271 removed / A/SDSE / 11/06/2010
Whole document / Complete revision of Issue 1.3 to new format / MCP / 01/08/2006

CONTENTS

ClausePage No

GENERAL

821.01SCOPE

821.02REFERENCES

821.03 – 821.05NOT USED

PRODUCTS AND MATERIALS

821.06GENERAL

821.07OFF-FORM CONCRETE FINISHES

821.08TIMBER FORMWORK

821.09OTHER TEMPORARY FORMWORK

821.10PERMANENT DECK SOFFIT FORMWORK

821.11VOID FORMERS

821.12 – 821.25NOT USED

OPERATIONS

821.26FORMWORK DESIGN

821.27FORMWORK CONSTRUCTION

821.28REMOVAL OF FORMWORK

821.29TOLERANCES FOR CONCRETE CONSTRUCTION

821.30PROVISION FOR THERMAL MOVEMENT

821.31 – 821.70NOT USED

AS BUILT AND HANDOVER REQUIREMENTS

821.71 – 821.90NOT USED

CONTRACT SPECIFIC REQUIREMENTS

821.91 – 821.99NOT USED

ANNEXURE 821A

SPECIFICATION 821

FORMWORK

GENERAL
821.01SCOPE
  1. The work under this specification consists of the design and construction of formwork required for the proper construction of concrete for structures in the permanent Works to the tolerances specified herein.

821.02REFERENCES
  1. Australian Standards, MAIN ROADS Western Australia Standards and MAIN ROADS Western Australia Test Methods are referred to in abbreviated form (e.g. AS 1234, MRS 67-08-43 or WA 123). For convenience, the full titles are given below:

Australian Standards
AS 1761Helical Lock-Seam Corrugated Steel Pipes
AS 3610Formwork for Concrete
Australian/New Zealand Standards
AS/NZS 2271Plywood and Blockboard for Exterior Use
Main Roads Specifications
Specification 820CONCRETE FOR STRUCTURES
821.03 – 821.05NOT USED
PRODUCTS AND MATERIALS
821.06GENERAL
  1. Formed concrete surfaces shall comply with the requirements of Section3 of AS 3610.

821.07OFF-FORM CONCRETE FINISHES
  1. Surface Finishes shall meet the requirements of AS 3610 to the classes designated on the Drawings.

  1. Particular importance is attached to the achievement of good "off-the-form" concrete finishes throughout the Works. Formwork shall be designed and fabricated and erected and dismantled so that all formed concrete surfaces achieve the specified uniform surface finish and texture without patching or plastering or cement washing or any treatment after removal of the formwork.
/ Surface Finish
  1. All formwork made up from separate panels shall be so designed that the pattern of exposed panel joints complements the overall geometry of the structure and does not detract from the final appearance of the structure. The Contractor shall detail proposed soffit and side formwork panel arrangements on the formwork Drawings.
/ Panel Arrangement
  1. In order to minimise the number of joints, formwork panels shall be supplied in the maximum practicable width and length. Plywood when used shall be placed with the grain of the outer plys in the direction of the span.
/ Plywood Panels
821.08TIMBER FORMWORK
  1. Timber for formwork shall be well seasoned and free from loose knots and other defects. Timber which has become warped or unsuitable for use shall be replaced at no cost to the Principal.
/ Timber
  1. Plywood used in formwork lining shall comply with the relevant provisions of AS/NZS2271.
/ Plywood
821.09OTHER TEMPORARY FORMWORK
  1. Forms made from materials other than plywood will be permitted provided that the requirements for strength and rigidity and tightness are met and that all bolts and rivet heads are countersunk and the finished concrete appearance is not inferior to that obtained with good quality plywood. Steel forms shall be suitably treated to prevent rusting of the face to be in contact with the concrete. The minimum thickness required for steel formwork is 4mm.
/ Steel Forms
  1. Polystyrene used as formwork shall be lined with a 3mm thickness of plywood on the face that is to be in contact with the concrete to be poured and such facing shall be glued with a suitable adhesive to the polystyrene.
/ Polystyrene
821.10PERMANENT DECK SOFFIT FORMWORK
  1. Where indicated on the Drawings, permanent deck soffit formwork shall be used between the beams. Such permanent formwork shall be "BONDEK"with thickness as detailed on the Drawings or an equivalent material approved by the Superintendent.
/ Bondek or Similar Approved
  1. Due care shall be exercised in achieving an effective seal at the seating joint between the "BONDEK" and the beams. The minimum width of the seating on the beams shall no be less than that detailed on the Drawings.
/ Seating of Bondek
  1. The Contractor's attention is drawn to the tendency of the "BONDEK" formwork to 'walk' off the beam seating. The Contractor shall ensure it is installed so that it cannot move during any stage of construction. The joining ribs shall be securely fastened together with self tapping screws or equivalent method approved by the Superintendent. The "BONDEK" profiled ends shall be sealed in accordance with the manufacturer’s published recommendations.
/ Securing and Sealing Bondek
  1. The fixing of "BONDEK" formwork to the steel beams, where used, shall be by tack or puddle welding. The fixing of “BONDEK” formwork to timber stringers shall be by spiking.
/ Fixing of Bondek
  1. Care shall be taken to align the “BONDEK” ribs across the bridge section prior to fixing deck reinforcement.
/ Alignment
821.11VOID FORMERS
  1. Non-recoverable void formwork as shown on the Drawings shall be helical lock seam corrugated galvanised steel pipe of 1.6mm minimum sheet thickness. The void former and material shall be in accordance with the relevant sections of AS1761. The Contractor shall ensure that the void former is held rigidly in position until the surrounding concrete has set.
/ Corrugated Steel Pipe Void Formers
821.12 – 821.25NOT USED
OPERATIONS
821.26FORMWORK DESIGN
  1. The design of all formwork shall be in accordance with AS3610.

  1. Formwork shall be so designed and constructed that it can be removed without damage to the concrete. In the case of prestressed concrete the design of the formwork shall permit movement of the members to occur during prestressing without damage to the permanent Works. Formwork shall be set to the profiles and pre-cambers shown on the Drawings and due allowance shall be made in setting the levels of the formwork to compensate for any deflection or deformation due to the weight of the concrete. Formwork shall be designed and constructed to withstand the vibration required during placing of the concrete as specified in Specification 820 CONCRETE FOR STRUCTURES.

  1. Where concrete is poured in more than one operation the Contractor shall take all necessary precautions to hold the formwork tight against the previous pour to avoid any discontinuities in the finished off-form surface.
/ Construction Joints
  1. At least two weeks prior to commencing formwork construction the Contractor shall supply to the Superintendent design details and Drawings checked and certified by a qualified structural engineer that the formwork complies with the Specification.
/ HOLD POINT
821.27FORMWORK CONSTRUCTION
  1. Forms shall be built true to line and level and braced in a substantial and unyielding manner to maintain correct position and shape.

  1. On all exposed concrete surfaces the joints and splices in formwork panels shall be arranged in a manner suitable to the shape and area being formed. Wherever possible, joints in adjoining panels shall be positioned to be either staggered by half panel lengths or placed in line.
/ Joints
  1. Forms shall be mortar tight and the edges of all joints shall be sealed with a suitable type of sealant. Forms subject to external water pressure shall be watertight.
/ Sealing
  1. Forms shall be held in correct alignment and spacing by bolt and rod assemblies designed so that when the forms are removed no metal shall be closer to the surface of the concrete than the minimum cover specified on the Drawings. The rods shall be held in place by devices capable of developing the strength of the rod attached to the walings. Bolt and rod assemblies shall be arranged so that cavities caused by their removal shall form a regular pattern appropriate to the area being formed. All such cavities shall be wetted and carefully packed with colour matched mortars and brought to an even surface.
/ Bolt and Rod Assemblies
  1. The use of wires and/or bolts extending to the surface of the concrete shall not be permitted except where shown on the Drawings. Wires or bolts or fastenings for forms or fixing reinforcement shall have the same concrete cover as specified for reinforcement.
/ Cover
  1. All balustrade and traffic barrier sockets and hole formers and all other fittings shall be accurately located. Bolts, pipes and bars used to form holes in the structure shall be well greased and arranged so that they may be removed from the concrete without excessive jarring or hammering before removal of forms.
/ Fittings
  1. Form lubricants shall be of the non-staining type which do not adversely affect the surface of the concrete. Lubricants shall be used after the fabrication of forms and prior to the placing of any reinforcing steel or other embedded item. The lubricant shall be uniformly applied in a thin film and any surplus shall be removed prior to placing concrete. Care shall be taken that such coatings do not soil the surface of reinforcement.
/ Lubricant
  1. Where the bottom of a panel is inaccessible from within then access panels shall be provided to permit thorough removal of rubbish before placing concrete.
/ Access Panels
  1. Prior to concreting all forms shall be clean and free from sand and shavings and tie wire ends and other debris. Surplus water shall be drained and any temporary openings closed in a proper manner.
/ Cleaning
  1. Forms for re-entrant angles shall be chamfered and forms for corners shall be filleted. The bevel in each case shall have a width of 20mm on each side unless otherwise shown on the Drawings.
/ Chamfers & Fillets
821.28REMOVAL OF FORMWORK
  1. Formwork shall be removed in such a manner to ensure that no damage to the concrete occurs.
/ Removal
  1. Based on average conditions in accordance with AS 3610, formwork support and formwork to reinforced concrete deck soffits and pier cap beams shall not be removed until a minimum of 7 days has elapsed and the concrete has achieved acylinder strength of 30Mpa. For other environmental conditions, AS 3610 Table 5.4.1 shall be used to determine minimum formwork stripping times.
/ Timing
  1. Formwork support and formwork to prestressed concrete deck soffits and pier cap beams shall not be removed until the concrete has achieved the transfer strength specified on the Drawings and the concrete has been prestressed. In addition, the minimum formwork stripping times given in As 3610 Table 5.4.1 shall be met.
/ Timing
  1. Based on average conditions in accordance with AS 3610, for other parts of the structure other than the deck, formwork shall not be removed until a minimum of 48 hours has elapsed and the concrete has attained acylinder strength of 20Mpa. For other environmental conditions, AS 3610 Table 5.4.1 shall be used to determine minimum formwork stripping times.
/ Timing
821.29TOLERANCES FOR CONCRETE CONSTRUCTION
  1. The materials for forms and form arrangements shall be such as to result in finished concrete work complying with the tolerances shown in Table 821.1

TABLE 821.1TOLERANCES FOR CONCRETE CONSTRUCTION

Footings to Piers and Abutments:
  1. Variation of dimensions in plan and elevation
/ - 5mm + 20mm
  1. Misplacement or eccentricity of centreline
/ + 10mm
  1. Variation in specified level
/ + 10mm
Abutment Walls, Columns and Column Cap Beams:
  1. Variation from vertical or specified batter.
/ The lesser of 1:300 or
+ 5mm in full height
  1. Variation in cross sectional dimensions
/ - 5mm+ 10mm
  1. Misplacement or eccentricity of centreline
/ + 5mm
  1. Variations from specified level of surfaces other than bearing surfaces
/ + 5mm
  1. Variation from specified level of all bearing surfaces
/ + 3mm
Bridge Superstructures:
  1. Departure from specified alignment of centreline and edges
/ + 10mm
  1. Departure from specified profile
/ + 10mm
  1. Variation in cross-sectional dimensions
/ - 3mm + 5mm
  1. Variation from specified level of all bearing surfaces
/ + 3mm
821.30PROVISION FOR THERMAL MOVEMENT
  1. The Contractor's attention is drawn to the need for the formwork for all deck diaphragms other than the fixed piers to be supported off the steel beams in a manner that will permit temperature movement of the deck diaphragms relative to the cap beams during construction.

821.31 – 821.70NOT USED
AS BUILT AND HANDOVER REQUIREMENTS
821.71 – 821.90NOT USED
CONTRACT SPECIFIC REQUIREMENTS
821.91 – 821.99NOT USED

ANNEXURE 821A

(Insert as required. Include tables, diagrams, etc as necessary. Delete Annexure page if not required.)

GUIDANCE NOTES

FOR REFERENCE ONLY – DELETE GUIDANCE NOTES FROM FINAL DOCUMENT

  1. All edits to downloaded Specifications shall be made using Track Changes, to clearly show added/deleted text.
  1. If all information relating to a clause is deleted, the clause number should be retained and the words “NOT USED” should be inserted.
  2. The proposed documents with tracked changes shall be submitted to the Project Manager for review, prior to printing the final batch of documents. When this final printing is carried out, the tracked changes option is to be turned off.
  3. Before printing accept all changes in the document, turn off Track Changes and refresh the Table of Contents.
  4. The Custodian of this specification is the Structures Design and Standards Engineer.
  1. PERMANENT DECK SOFFIT FORMWORK (Clause 821.10)

If the design and Drawings nominate the use of “TRANSFLOOR” permanent concrete deck soffit formwork then CONTRACT SPECIFIC REQUIREMENT clause 821.91 should be included and clause 821.10 deleted and replaced with “Not Used”.

CONTRACT SPECIFIC REQUIREMENTS

The following clauses are to be placed under the CONTRACT SPECIFIC REQUIREMENTS, as required. After inserting the clause, change the clause number and heading to style “H2 SP” so it appears in the Table of Contents.

821.91PERMANENT DECK SOFFIT FORMWORK
  1. As indicated on the Drawings, the design has assumed the use of "TRANSFLOOR" precast concrete, permanent formwork for the in situ concrete deck slab.

  1. The Contactor shall be responsible for designing the "TRANSFLOOR" formwork in accordance with the details shown on the Drawings.

  1. Particular care shall be taken in detailing the location of reinforcement in the panels and the beam shear stud layout to avoid clashes.

  1. The Contractor may propose alternative types of permanent formwork. In this case, the Contractor shall provide details of any required modifications to the deck slab. If steel permanent formwork is proposed, it may only be used between the beams, not for the cantilever or parapet.

  1. Tenderers shall provide details of their proposed alternative deck formwork with their Tender.

AMENDMENT CHECKLIST

Specification No. / 821 / Title: / FORMWORK / Revision No:
Project Manager: / Signature: / Date:
Checked by: / Signature: / Date:
Contract No: / Contract Description:
ITEM / DESCRIPTION / SIGN OFF
Note: All changes/amendments must be shown in Tracked Changes mode until approved.
Project Manager has reviewed Specification and identified Additions and Amendments.
CONTRACT SPECIFIC REQUIREMENTS addressed? Contract specific materials, products, clauses added? (Refer Specification Guidance Notes for guidance).
Any unlisted materials/products proposed and approved by the Project Manager? If “Yes” provide details at 16.
Standard clauses amended? MUST SEEK approval from Manager Commercial.
Clause deletes shows as “NOT USED”.
Appropriate INSPECTION AND TESTING parameters included in Spec 201 (Text Methods, Minimum Testing Frequencies verified).
ANNEXURES completed (refer Specification Guidance Notes).
HANDOVER and AS BUILT requirements addressed.
Main Roads QS has approved changes to SMM.
Project Manager certifies completed Specification reflects intent of the design.
Completed Specification – independent verification arranged by Project Manager.
Project Manager’s review completed.
SPECIFICATION GUIDANCE NOTES deleted.
TABLE OF CONTENTS updated.
FOOTER updated with Document No., Contract No. and Contract Name.
Supporting information prepared and submitted to Project Manager.
Further action necessary:
Signed: / (Project Manager) / Date:

Document No: DXX#XXXXPage 1 of 13

Contract No: XXX/XX [Contract Name]