SPECIFICATION 828

PRECAST CONCRETE MEMBERS

Copyright MAIN ROADS Western Australia

Specification 828 Precast Concrete Members – 04/10139 Issued 03/05/2017
REVISION REGISTER
Clause
Number / Description of Revision / Authorised By / Issue Date
Whole document / Reformatted / SCO / 03/05/2017
Clause 828.02 / Redundant AS 1554.3 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

828.01Scope

828.02References

828.03 – 828.05NOT USED

MANUFACTURE

828.06General

828.07Formwork

828.08Reinforcement

828.09Prestress

828.10Concrete

828.11Transfer of Prestress

828.12Records

828.13Member Tolerances

828.14Marking of Members

828.15 – 828.25NOT USED

TRANSPORT, HANDLING AND STORAGE

828.26General

828.27Lifting

828.28Transport

828.29Stacking

828.30 – 828.40NOT USED

INSTALLATION

828.41General

828.42Welding of Positive Moment Connection Reinforcement at Beam Ends

828.43Plank Joints

828.44Deck Concrete Overlay

828.45 – 828.80NOT USED

AS BUILT AND HANDOVER REQUIREMENTS

828.81 – 828.90NOT USED

CONTRACT SPECIFIC REQUIREMENTS

828.91 – 828.99NOT USED

ANNEXURE 828A

Supply of Precast Members by Principal

SPECIFICATION 828

PRECAST CONCRETE MEMBERS

GENERAL
828.01SCOPE
  1. The work under this specification consists of the supply and installation of precast concrete members (beams and planks).

828.02REFERENCES
  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 1349Bourdon Tube Pressure and Vacuum Gauges
AS 5100Bridge Design
Australian/New Zealand Standards
AS/NZS1554.3Structural Steel Welding - Welding of Reinforcing Steel
AS/NZS4680Hot-dip Galvanised (Zinc) Coatings on Fabricated Ferrous Articles
Other Standards
Concrete Institute of AustraliaPrecast Concrete Handbook (2002)
Main Roads Specifications
Specification 820CONCRETE FOR STRUCTURES
Specification 821FORMWORK
Specification 822STEEL REINFORCEMENT
Specification 824PRESTRESSING OF CONCRETE
828.03 – 828.05NOT USED
MANUFACTURE
828.06GENERAL
  1. Manufacture and acceptance shall be in accordance with this Specification and details shown on the Drawings and the Concrete Institute of Australia publication, “Precast Concrete Handbook (2002)”.

  1. Casting methods shall be designed to ensure that no damage occurs to the units. The ends of all units shall be free from any grout loss or honeycombing or cracking or spalling. Units with defects of this nature shall be rejected.

  1. Some beams are required to have holes located in the webs for subsequent attachment of formwork during bridge construction. The location and size of these holes and the number of beams requiring these holes are detailed on the Drawings.

828.07FORMWORK
  1. The provisions of Specification 821 FORMWORK shall apply and in addition:

  1. Formwork shall be fabricated from steel with a minimum thickness of 3mm.

  1. Unformed surfaces shall be roughened and shall be free from laitance and loose material which may be deleterious to the bond with the in situ deck concrete. This shall be achieved after curing by scabbling or any other suitable method.

828.08REINFORCEMENT
  1. The provisions of Specification 822 STEEL REINFORCEMENT shall apply, except that the tolerance on the minimum clear cover specified shall be -0mm + 5mm in all cases. Any lengths of reinforcement which are left exposed after manufacture shall be coated with cement grout to prevent rusting.

828.09PRESTRESS
  1. The provisions of Specification 824 PRESTRESSING OF CONCRETE shall apply with additional provisions as specified below:

  1. The stressing bed shall have the capacity to safely accommodate the forces involved for the pretensioned member being manufactured.

  1. The structural adequacy of a temporary stressing bed shall be certified by an Engineer eligible for Corporate Membership of the Institution of Engineers, Australia. Such certification shall be made available to the Superintendent prior to the commencement of any stressing.

  1. Pressure gauges shall comply with the requirements of AS 1349. The diameter of the gauge shall not be less than 150mm or shall be of such a type which will allow visual reading to the nearest 0.5MPa. The maximum jacking force shall correspond to a gauge pressure between 50 and 90 percent of the gauge capacity. A device shall be fitted to the gauge to protect it against a sudden loss of pressure. Provision shall be made for the attachment of a second gauge.

  1. Calculations to determine the nominated jacking force, nominated elongations, and corresponding gauge pressure shall be carried out for the coils in each lot, using the representative test certificates.

  1. All calculations shall be certified by an Engineer who is eligible for Corporate Membership of the Institution of Engineers, Australia.

  1. Where prestressing strand is to be deflected at tie down points as shown on the Drawings then the steelwork which is cast into the beam to hold the deflected strand shall be hot dipped galvanised in accordance with AS/NZS 4680 and shall be rebated 15mm from the surface of the concrete. The void so formed shall be filled with a compatible colour matching epoxy mortar and brought to a smooth, even finish.

  1. At least one working day prior to the proposed pretensioning of each member or line of members, the Contractor shall submit to the Superintendent stressing calculations, Engineer's certification and the representative test certificates for each member.
/ HOLD POINT
  1. The Superintendent will consider the submitted documents for compliance with the Specification, prior to authorising the release of the Hold Point, for each member or line of members.

  1. Strands at the ends of units shall be cut off flush or left protruding as detailed on the drawings. Strands cut off flush shall be coated with epoxy resin to prevent rusting. Strands left protruding shall be coated with cement grout.

828.10CONCRETE
  1. The provisions of Specification 820 CONCRETE FOR STRUCTURES shall apply. In addition:

  1. If the Contractor proposes to use external type vibrators for concrete compaction then evidence shall be provided to show that the same level of compaction can be achieved.
/ Compaction
  1. Where steam curing is proposed to be used then it shall be low pressure wet steaming and in accordance with Specification 820 CONCRETE FOR STRUCTURES. Any other form of accelerated curing will not be permitted. Steaming shall not commence until at least two hours after the last batch of concrete has been placed. Subsequent curing shall be in accordance with Specification 820.
/ Curing
828.11TRANSFER OF PRESTRESS
  1. The Contractor shall use methods that result in a relatively shock free transfer of stress during the release of tendons. Examples of non-complying methods include cutting through with a disk grinder, and severing the tendons directly and quickly with a naked flame.

  1. The transfer of the prestressing force from the stressing bed to the member shall not occur until the concrete has reached the minimum transfer strength specified in the Drawings.

  1. Prior to transfer all tendons shall be checked. All tendons shall be tight.

  1. The slippage of each tendon into the concrete at transfer shall be visually inspected. Localised spalling around fully bonded strands at transfer as a result of excessive slippage shall be identified as a nonconformance.

828.12RECORDS
  1. The Contractor shall enter all transfer information on a record sheet. Information shall include, but not be limited to, concrete compressive strength, verification of the transfer method and order of release of tendons, and any defects in the member.

828.13MEMBER TOLERANCES
  1. The precast pretensioned concrete I beams shall conform to the dimensions and details given on the Drawings.
/ Beams
  1. The precast pretensioned concrete planks shall conform to the dimensions and details given on the Drawings. The overall depth of the plank shall be 380mm ± 5mm.
/ Planks
828.14MARKING OF MEMBERS
  1. Each member shall be clearly marked using distinguishing numbers or letters consistent with those shown on the Drawings.
/ Identification
828.15 – 828.25NOT USED
TRANSPORT, HANDLING AND STORAGE
828.26GENERAL
  1. Temporary storage areas shall be carefully cleared and levelled. The beams and planks shall be supported over their full width at the lifting points only. Temporary supports shall be of timber of a minimum size 150mm wide, 100mm thick and 1m long. The supports shall be on firm foundations and every precaution taken to prevent subsidence from occurring and to prevent the units bearing other than at the specified support positions.

  1. Any units damaged or distorted in excess of the specified tolerances prior to or during installation shall be replaced at no expense to the Principal.

828.27LIFTING
  1. Units shall be kept in the upright position at all times and shall only be lifted from the specified lifting points. Units shall be lifted using either a full length steel lifting beam or two cranes to ensure the force at the lifting points is in accordance with the Drawings.

828.28TRANSPORT
  1. The beams shall be transported to the Site in a manner which does not damage the beams. Beams shall not be transported until they are at least 7 days old and the concrete shall have reached its 28 day nominated strength.

828.29STACKING
  1. Precast concrete members may be stacked on top of each other. Each layer shall be separated from the next layer by at least 75mm, by temporary supports placed in line vertically at the support points. No superimposed loads shall be placed on the units.

  1. Where stacking of girders is required by the Contractor, the design of the stacking arrangement shall be carried out by an Engineer eligible for Corporate Membership of the Institution of Engineers, Australia. A certificate from the Engineer shall be provided to the Superintendent, prior to stacking the girders, stating that the proposed stacking arrangement will not overstress or damage any girder so stacked. Consideration shall be given to the relief of temperature, shrinkage, creep and any other effects on the stacking arrangements.

828.30 – 828.40NOT USED
INSTALLATION
828.41GENERAL
  1. No beam or plank shall be positioned in the Works until the supporting substructure has gained 75% of its design strength. Beams and planks shall be positioned to a tolerance of ±3mm.

828.42WELDING OF POSITIVE MOMENT CONNECTION REINFORCEMENT AT BEAM ENDS
  1. The Contractor shall observe the rules and procedures of welding laid down in AS/NZS1554.3.

828.43PLANK JOINTS
  1. The plank locating dowels shall be fully installed and grouted before placing any shear key concrete.

  1. The shear keys between planks shall be adequately sealed at their lower section as detailed on the Drawings before placing the shear key concrete.

  1. The shear key concrete shall be placed in a continuous operation for each shear key for each plank length. Concrete shall be compacted using a 25mm maximum diameter pencil vibrator in accordance with Specification 820 CONCRETE FOR STRUCTURES.

  1. Joints between plank ends over the piers shall be filled with a cement mortar with a water/cement ratio by mass not exceeding 0.42 and a sand/cement ratio by mass of 3.0. The mortar shall be rodded into the joint to achieve maximum compaction.

828.44DECK CONCRETE OVERLAY
  1. The deck concrete overlay shall not be placed earlier than 3 days after the completion of all plank shear key joints.

  1. Before the deck concrete overlay is placed the top surface of the precast units shall be thoroughly cleaned with a water jet to remove dust and chips and any other foreign matter.

  1. Immediately prior to commencing of concreting the top surface of the precast units shall be thoroughly wetted.

  1. All other works for the deck concrete overlay shall be in accordance with Specification 820 CONCRETE FOR STRUCTURES..

828.45 – 828.80NOT USED
AS BUILT AND HANDOVER REQUIREMENTS
828.81 – 828.90NOT USED
CONTRACT SPECIFIC REQUIREMENTS
828.91 – 828.99NOT USED

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 theStructures Design and Standards Engineer.
  1. SUPPLY BY PRINCIPAL (Clause 828.91)
  2. If the Principal will pre-supply precast concrete members, include Clause 828.91 in the CONTRACT SPECIFIC REQUIREMENTS Section, complete and incorporate Annexure 828A into the Specification document.
  3. Annexure 828A is provided for listing Principal supplied items such as precast concrete beams and planks, in which case any Clauses relating to manufacture should be deleted and marked as “Not Used”. The description to be entered in Annexure 828A should include identification with items shown on the Drawings, and the location for pick-up of precast members.

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.

828.91PRECAST MEMBERS SUPPLIED BY THE PRINCIPAL
828.91.01GENERAL
  1. The number and type of pre-tensioned, pre-stressed concrete beams and planks which will be supplied by the Principal free of charge to the Contractor is given in Annexure 828A. These will conform to the dimensions specified on the Drawings within the tolerances specified in the Concrete Institute of Australia publication, “Precast Concrete Handbook (2002)”. All units have been precast under factory conditions.

  1. Holes are provided on the beam webs for the attachment of falsework. The drilling of other holes in the beam will not be permitted.

828.91.02SUPPLY
  1. The beams and planks will be stored in the Perth metropolitan area and will be available to the Contractor at the times and locations shown in Annexure 828A. The Contractor shall provide all equipment, plant and labour necessary for the transportation of the beams and planks to the Works.

ANNEXURE 828A

SUPPLY OF PRECAST MEMBERS BY PRINCIPAL

Type / Number / Location / Time Of Availability
(Weeks after Commencement of Contract)
Beam Type A
Beam Type B
Plank Type A
Plank Type B

(NOTE:This Annexure is used in conjunction with Clause 828.91 and should be varied as required to suit.)

AMENDMENT CHECKLIST

Specification No. / 828 / Title: / PRECAST CONCRETE MEMBERS / 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]