1 William Street 'Tower of Power' Crown Roof and Spire

800 Tonne of Complex Architectural Structural Steel

Client: Brookfield Multiplex Construction Limited
Location: Brisbane CBD
1 William Street 'Tower of Power'  Crown Roof and Spire

Scope of Works

  

End to end Project and Site Construction Management  

1 William Street is a completed skyscraper in Brisbane, Queensland, Australia and is the tallest in the city at 267 metres. The modern style office building is located in the Brisbane central business district in close proximity to Parliament House. The building is to be developed for the Queensland Government as part of the government's plan for a renewed Government Administrative Precinct and to meet its accommodation demands.  

Construction cost of the tower is expected to be $538 million, with a total development cost of over $650 million. It is to be completed in September 2016.

Property Developer/ Owners: CBUS Property Group.

Building Tennant: State Government Executive Building and QLD Public Service Central Offices.

Project Delivery Team

Primary Design and Construction Building Contractor: Brookfield Multiplex Construction Limited.

Architects: Woods Bagot.

Design Engineers: Arcadis Engineering (formally Hyder Engineering)

Primary Structural Steel Fabricator and Construction Contractors: Hosken Site Steel Pty Ltd.

Virtual Construction Modellers and Steel Detailers: Steelcad Drafting Pty Ltd.

Steel Erection Subcontractors: Mulherin Cranes and Rigging Pty Ltd.

Surveyors: Bennett and Bennett and AAM Surveyors.

Industrial Applicators and Transport Facilitators : Tranzblast Coating Services and Industrial Galvanisers.  

Work Break Down Structure (WBS)

• Level 40, 41 and 42 Terraces -100 Tonne of Composite Floor Structure, consisting of Fire Protected Fabricated Plate Beams, Secondary Universal Beams, Bondek and Shear Studs

• Vertical Crown Mullions- Level 39, 40,41 and 42- 20 Tonne

• Vertical Steel between the top of Level 42 and underside of Level 44-133 Tonne

• Primary Open Roof Area - 250 Tonne. The Primary Roof consists of extremely complex angular connection geometry given the 46.1◦ Roof Pitch

• Access Walkway to the Perimeter of Primary Roof- 27 Tonne

• Mainatence Stairs and Walkway Bridge Above Level 44 and Building Mainatence Unit-11 Tonne

• Secondary Roof Frame – Louvre Cassettes- 100 Tonne. Louvre Blades were installed into the Cassette Frames at Tranzblast Paint Facility. The Cassettes were installed as completed modules on site by Mulherin Rigging

• Roof Spire- 75 Tonne and 90 meters in length. The top of the Spire is approximately 267 meters above ground level, and projects 50 meters above the BMU Roof.  

Design Development, Virtual Construction Modelling and Steel Detailing Phase

• Selection and engagement of the Virtual Construction Modelling and Steel Detailing Professionals, Steelcad Drafting

• General coordination between the Steel Detailers and Design Consultants during the Virtual Construction Modelling and Steel Detailing phase.

• Steelcad were contracted to Hosken Site Steel and embedded with the Design Consultants on an ‘Early Engagement’ basis. This was primarily due to the status of the design at the time of their engagement and the fact that Steelcad Drafting are experts in this complex workspace. Steelcad became an integral member of the design team and assisted significantly in the design development and completion of all areas of the WBS

• Steelcad's Virtual Construction Modelling and Detailing Software (Tekla) and their skilled Senior Managers were critical to progressing the design to accurate completion. This enabled procurement and fabrication to commence at the earliest stage possible

• The Design Development, Virtual Construction Modelling and Detailing was completed over a seven (7) month period, with weekly meetings required to progress the collaborative nature of the design process

• Steelcad maintained an up to date BIM report weekly that provided an accurate status of the design / detail progress

• These reports included 3d colour coded modelled images of the status of the design and detailing until all shop detail drawings were IFC

• The reports provided the design team a single point of controlled reference to the status of the Modelling and Detailing and enabled critical design items to be elevated, addressed and closed out

• The professionalism and perseverance provided by all parties during the design development phase resulted in a shop detail drawing deliverable that enabled the geometrically complex structural steel work to be fabricated and erected to a very high standard with marginal clashes encountered during construction

• Steelcad Drafting also added their experience and value in terms of Project Engineering support, offering their services to complex lifts studies, temporary works design, numerous As Constructed Survey Interfaces and virtual construability simulations. Steelcad's engineering support during the construction phase was a fundamental factor in progressing the day to day site works with confidence.

The Structural Steel  for the Crown Roof and Spire was actually constructed twice.

The 1st time in the virtual sense with the Integrated Construction Model facilitating the virtual construction simulations and the 2nd time in reality on site.

Click on the following link for information on the benefits of early detailer engagement and the integrated project delivery method.

 http://integratedprojectdelivery.com.au/ipd-benefits/ 

 Fabrication and Protective Coatings Coordination

• Due to the size and scope of the structure the WBS was broken down into manageable phases. This enabled fabrication packaging and the tracking of all components through all stages of production, paint and transport to site

• Hosken Site Steel have implemented Strumis a fully integrated MRP Management System for Project Controls and an advanced CNC beam line for the processing of Hot Rolled Long Products https://www.youtube.com/watch?v=BOJn8VHJ6DE

Strumis was used to its full extent on this project and added significant end to end value in terms of Project Controls

• Weekly Strumis colour coded 3D Progress Images and detailed data base reports were issued to the client. These reports created an accurate dash board for the Project Leaders and enabled practical progress measurement of the Structural Steel throughout all stages of fabrication, painting transport and installation

• Fabrication was managed and controlled accurately by the team at Hosken Site Steel, again with marginal fabrication errors detected during site construction

• Given the complex geometry involved in some of the members, the fabrication QA/QC was executed to a very high standard

• All Structural Steel was defined as Architectural and was either a 3 coat or 4 coat paint system, with a large quantity having a metallic finish

• Tranzblast Coatings completed all protective coatings to a high standard of finish

• Steelink provided their independent NACE 2 Coating Inspector and International Welding Inspector as a secondary control measure to ensure the fabrication, welding and protective coatings were completed in accordance with the Project Specifications and Australian Standards. http://qaqcmanagers.com.au/

Transport and Handling

• High Rise Construction by nature is complex and difficult in terms of logistics management , set down areas, movement around the site and vertically up the Tower

• 1 William Street was extremely constrained for lay down area at ground level and floor plate size within the Tower

• Specially designed steel transport racks were manufactured out of Container Bases. The four (4) certified lifting lugs were rated to have a WLL of 10.5 tonne that included the weight of the rack.

• The Steel Racks were delivered to site and lifted to the specified level within the Tower

• Where racks could not be utilized conventional, over size, piloted and police escorts loads were employed

• Protective foam was placed between steel in racks and on trucks and proved to be an adequate form of mitigating transit damage to the painted steel

• In excess of 130 loads of Structural Steel and associated materials were delivered to site. At times trucks could encounter 4>6 hour delays due to the competing site conditions and weather events.

Programing and Co-ordination

Programing and sequencing the Structural Steel construction activity was a massive undertaking on this Project.

At least 4 critical path major trades were working alongside each other at times all competing for the valuable Tower Crane Hook Time. 

3 weekly Steel Erection look ahead programs were prepared, submitted and workshopped with Brookfield Multiplex on a weekly basis. 

Tower Crane coordination meetings were held daily with all critical path trade Site Supervisors required to attend. 

The most fundamental factors can comprise progressing the planned work on High Rise Towers, such as;

  • Inclement weather events , rain and wind
  • Change of Construction sequence
  • Competing Trades not meeting their programed commitments
  • Design coordination issues
  • Detailing, Fabrication and Construction non conformances
  • Supply Chain constraints
  • Transport co-ordination breakdowns
  • Equipment breakdown and failure.

An extremely high level of site communication, cooperation, perseverance  and upstream co-ordination was critical for progressing the site construction activity as efficiently as possible.

Site Construction

• The most complex, risky and challenging element of the Project

• Mulherin Rigging and Cranes erected 800 tonne of steel safely with significant access and Tower Crane allocation constraints

• The floor plate area per slab level was extremely limited and created significant access constraints for, steel handling access equipment and Steel Riggers

• Due to the nature of the project and program milestones many trades were competing for the Tower Crane Hook time, this is not an unusual challenge on High Rise Construction

• Hosken Site Steel engaged Natform on a Design and Construct basis to design, certify and hire all elements of the Screen System around the complete live edge at Level 44

• Peri Australia were engaged to provide all heavy duty props to support the Natform Screens

• Steelcad Drafting interfaced with Natform’s Engineers and imported the Screen design into the Virtual Construction Model to ensure a clean interface and bolt up to the structural steel was achieved

• A few minor teething issues were encountered during the initial installation. Overall the Screen System proved to be fit for purpose as live edge protection and negated the risks of men, equipment, tools and any other objects falling over the edge of the building

• Mulherin Rigging designed and installed a debris netting catchment system around the perimeter of the building to enable the vertical steel between Level 42 and 44 to be installed and control the risk of falling objects

• The netting proved its value as debris catchment and negated the risk of falling objects during construction

• Eight (8) Modular lifts were designed and executed safely and efficiently by Mulherin Rigging

• The modular lifts were designed practically and significantly mitigated the safety risks associated with working at heights.

 Roof Spire 

  • Length: 90 Meters, end to end
  • Weight: 75 Tonne, including platforms and ladders
  • Top out height from Ground Level:267 Meters. 

The Roof Spire officially enables the 1 William Street Tower to claim the title of tallest Skyscraper in the Brisbane CBD. 

The Spire is bolted back to the tower via Stub connections in two (2) locations. 

Mulherin Cranes and Rigging worked from a specially designed working platform aptly nick named ‘The Shark Cage’ that was temporarily bolted to the Stub section during installation to the Tower and again when the Spire sections were bolted to the Stubs. 

This platform allowed the Riggers full access to the connection for the placement and tensioning of the Structural Bolts. 

Two (2) Riggers travelled inside the Shark Cage when it was lifted up the side of the Tower , 215 meters above ground level at the highest point.  

The spire construction consists of 5 separate lifts with bolted flange splice connections. 

The 3rd lift of the Spire was the most complex of the 5 lifts. 

It has two (2) significant bolted connection points. 

One  (1) connection is bolted to section 2.

The 2nd connection bolts to Secondary Stub that is mounted to the BMU Wall, 215 meters above ground level. 

Prior to this lift detailed ‘As Constructed’ Surveys were carried out on all mating elements that included a trial assembly of section 1,2 and 3 off site. 

The Survey data was interfaced by Steelcad Drafting into the Virtual Integrated Construction Model. This enabled the  mating Secondary Stub Sections to be manufactured to suit the survey data. 

This site Survey data was critical to understanding and workshopping the constructability challenges and safety risks associated with the lift. 

Safety Risk Management  

Safety risk management is always the most important factor on all of the Projects we work on. 

The majority of site construction at 1 William Street was in the extremely high risk category.  

High Rise Construction by nature is fall of safety risks that require robust controls and procedures to be implemented.  

Prior to the  commencement of any work all stages of the WBS required detailed Risk Assessments,  Work Method Statements and associated JSA’s to be prepared and  submitted to the Project Safety Committee for approval.

Construction Workers were required to have lanyards attached between their tool belts and tools to negate the risk of falling objects.   

The Structural Steel was installed without any major safety incidents or Lost Time Injuries to the Construction Workers.   

We are extremely proud of the safety management record on this uniquely challenging project.