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Precast Fabrication and Installation

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Precast Fabrication and Installation HYer Standard

Purpose and Scope

The purpose of this procedure is to ensure that precast concrete elements have been fabricated and installed as per the relevant project documentation, Australian Standards, in compliance with other Hansen Yuncken HYer Standards and procedures, and undergo all required quality control verifications.

This procedure is to be read in conjunction with the Precast and Tilt Up Procedure and HYer Standard which document the safety requirements associated with Precast works. A full list of associated documents is available in the Associated Documents at the bottom of this procedure.

Responsibilities

Project Manager

  • Ensuring design changes are assessed for constructability risks.
  • Ensure any design constructability risks are assessed, controlled, and documented in the Project’s Risk Register.
  • Ensuring any constructability risks identified are communicated to workers performing the work and the HY project team.

Hy Project Team

  • Obtaining and reviewing project documentation, drawings, and specifications.
  • Managing workflows to document RFIs and design changes.
  • Managing the project’s document registry and communicating documentation to relevant parties.
  • Communicating requirements for submittals, warranties, and inspection and test plans to Subcontractors and other parties as applicable.
  • Ensure nominated subcontract users are registered in the QA platform and invited to the Project Profile.
  • Ensuring relevant quality control pre-work checks are complete prior to starting works.
  • Ensuring any applicable hold and witness points are in place and adhered to.
  • Receiving and controlling submittals, warranties, and inspection and test plans.

Subcontractor Supervisor

  • Ensure personnel responsible for using the QA platform are registered and have means to access the platform via mobile or desktop devices.
  • Ensuring relevant quality control pre-work checks are complete prior to starting works.
  • Ensuring any applicable hold and witness points are adhered to.
  • Providing any required submittals, warranties, and inspection and test plans.

Quality Verification 

Hansen Yuncken predominantly utilises Autodesk platforms (BIM360 and ACC) to carry out quality control checks and verifications. Subcontractor supervisors or nominated representatives must have a registered Autodesk account and be invited onto the Project Profile by the HY project team. 

The Precast Concrete – Fabrication and Precast Concrete – Erection Checklists in the QA platform are to be completed prior to and throughout the relevant stages of works.  HY representatives are responsible for completing the header and preparation sections. The subcontractor representatives are responsible for completing their respective sections respectively. All hold points must be adhered to and verified by the HY representative to proceed.

Guidance on the use of software for Subcontractor users can be accessed via the Onboarding Induction and Training Procedure.

Note: Defence Projects and select Government Projects may have unique requirements regarding Quality Control and the use of software packages to carry out verifications.  The agreed methods and software packages will be determined at Project Commencement considering the specific project needs and client requirements.

Preparation

Project drawings and specifications will detail the locations and requirements of the precast concrete units and materials to be installed. The latest revisions of drawings and specifications are to be referenced for the works, which are to be provided to the subcontractors carrying out the works.

Approvals 

Submittals, samples, and materials are to be identified, reviewed, and approved by the respective responsible parties in accordance with project specifications prior to works beginning. Any changes are to be captured via appropriate channels for the project (e.g., Aconex Workflow) and communicated to workers. 

The precast concrete and associated fixings are to be verified in accordance with the project drawings and specifications.  Hansen Yuncken also are required to confirm the following items:

  1. Shop drawings have been approved by the Structural Engineer and issued for fabrication.
  2. Each concrete mix design has been reviewed and approved by Engineer. Mix design to comply with specification for strength (MPa), aggregate size (mm), slump (mm) and class of finish required. Refer to the specification for concrete testing frequency of samples.
  3. Test sample panel/s have been approved by the engineer/client.
  4. Precast subcontractor’s fabrication ITP has been reviewed and approved.

Fabrication

Formwork, Reinforcements, and Inserts:

The following items are to be verified prior to the mix being poured into the cast:

  1. Panel size/thickness is as specified.
  2. Penetration and rebate dimensions are correct.
  3. Type and position of lifters are correct.
  4. The pull-out capacity of lifting inserts embedded in concrete has been tested in accordance with AS 3850.
  5. Cast-in fastenings are to be designed in accordance with AS 5216
  6. Size and location of ferrules are correct.
  7. Bar chairs in position and correct cover as specified.
  8. Bars or mesh are of correct size, tied in position, lap length and cover is correct.

Precast Element Fabrication

The following items are to be verified prior to fabrication:

  1. The concrete ordered and used is of the approved mix design.
  2. The concrete slump meets the specification.
  3. Concrete strength reached required design strength (MPa) prior to lifting.
  4. Approved admixtures have been used (if applicable).
  5. Water has not been added to the concrete on site (unless approved by engineer/tester).
  6. The panel surface finish is in accordance with specified class and colour control requirements.
  7. Embedded surface design/pattern is in accordance with requirements.
  8. Panel is flat and not warped/twisted.
  9. Panel edges are straight and any deviation from square is within tolerance.
  10. Delivery dockets are being prepared in order to delivery precast concrete panels to site.

Installation

Safety

The Precast and Tilt Up Procedure and HYer Standard document the safety requirements applicable to lifting and installing precast elements.

The Precast Concrete – Pre/Post Erection Inspection in HammerTech is to be completed to verify the following items prior to the lifting and placement of any precast items.

  1. A SWMS has been developed detailing the risks and controls and has been reviewed by HY.
  2. Lifting equipment is currently certified and SWL and current inspection tags are displayed.
  3. Lifting inserts and clutches are a compatible design (must be proprietary).
  4. Spreader bar and rigging configuration used meet load requirements for type of panel.
  5. Ground conditions are suitable for supporting crane.
  6. Maximum safe wind speed to be determined by crane/rigging crew.
  7. Crane operator, riggers and doggers have appropriate HRCW licenses.
  8. Work will be supervised by a person who holds a rigging license in either Intermediate Rigging or Advanced Rigging.
  9. The transport frame compliance plate/certificate of compliance is current and relevant to the particular transport frame.

The relevant Plant, Equipment, Operators, and SWMS are to be linked to or identified in the HammerTech Inspection.

Pre-Erection:

The following items must be verified prior to installation:

  1. Approved shop drawings are available on site.
  2. Bracing layouts and design have been designed and certified by a structural engineer.
  3. The precast manufacturer’s compliance certificates have been received for each panel which includes confirmation the lifting design strength has been achieved.
  4. Brace footings have been installed in accordance with the engineered design and have reached their required concrete strength.
  5. An erection sequence has been prepared and certified by a qualified engineer.
  6. A lifting plan has been developed for the erection showing crane setup location, underground services, location of obstacles, hazards and existing structures in proximity to the crane (especially temporary braces)

Installation:

During and at completion of the installation of precast items, the following is to be verified:

  1. Panels have not been damaged during transit, handling, or storage.
  2. All bracing or supporting structure fixing points have been installed and fixed as per shop drawings and engineers’ drawings.
  3. Panel connection bolts are installed to correct torque as noted on drawings including 24 hours after installation.
  4. Braces are installed as per design (45-60 deg to horizontal / +or- 5 degrees from perpendicular and 2/3 of the height of the panel unless otherwise specified.
  5. Grout material is in accordance with specific requirements.
  6. The base of the panel is fully grouted in accordance with specific requirements.
  7. Dowel pockets are fully grouted in accordance with specific requirements.
  8. The location of panels are in accordance with the marking plans.
  9. Precast elements have been installed true and plumb.
  10. Penetration and rebate dimensions are correct.
  11. Proposed caulking material (grade, type and colour) is in accordance with the specified requirements.
  12. All joints are of consistent width and caulked as specified.

Specifications and Compliance 

Current Project Specifications are to be used to confirm all approvals, samples, and submittals required for the project. Project Specification requirements are to be entered into the Project’s Compliance Schedule.

Fabrication:

Approvals Required:

  • Subcontractor fabrication ITP.
  • Shop Drawings.
  • Concrete mix design.
  • Sample test panel.

Hold Points:

  • Shop drawings have been approved by the Structural Engineer and issued for fabrication.
  • Test sample panel/s have been approved by the engineer/client.
  • Inspection by engineer prior to pour of first panel (if applicable).

Supporting Documentation:

  • Inspection Report.
  • Concrete delivery dockets.
  • Compressive strength report.
  • Lifting Insert Compliance Certificate.
  • Fabrication ITP.

Installation:

Hold Points:

  • Verify all pre-erection and safety documentation has been provided.
  • Verify all items in the structural engineer’s report have been addressed and signed off.
  • Verify a bracing layout and design has been designed and certified by an engineer.
  • Written approval has been provided by the project design engineer or suitability qualified independent engineer to remove temporary bracing.

Supporting Records:

  • Erection sequence and lifting plan.
  • Approved bracing layout.
  • Lifting equipment certification.
  • Transport frame certificate of compliance.
  • Inspection Report.
  • Erection ITP.

Definitions

ITP – Inspection and Test Plan

SWMS – Safe Work Method Statement

RFI – Request for Information

References

  • AS 1012 – Methods of testing concrete Sampling of concrete.
  • AS 1379 – Specification and supply of concrete.
  • AS 1478.1 – Chemical admixtures for concrete, mortar and grout.
  • AS 2758.1 – Aggregates and rock for engineering purposes Concrete aggregates.
  • AS 3972 – General purpose and blended cements.
  • AS 3600 – Concrete structures.
  • AS 3610 – Formwork for concrete Specifications.
  • AS 3850.1 – Prefabricated concrete elements General requirements.
  • AS 3850.2 – Prefabricated concrete elements, Part 2: Building construction.
  • AS 5216 – Design of post-installed and cast-in fastenings in concrete.
  • AS/NZS 1554.3 – Structural steel welding of reinforcing steel.
  • AS/NZS 2312 – Guide to the protection of structural steel against atmospheric corrosion by the us.
  • AS/NZS 4671 – Steel for the reinforcement of concrete.
  • NP: PCH-2009 Precast Concrete Handbook.

Associated Checklists and Documents

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