Gateway Arterial Bridge Strengthening

Project Overview

The project involved critical remedial works to the Gateway Motorway flyover and pavement upgrades at the Gympie Arterial Road–Bruce Highway interface. JF Hull was the sole invitee for the design constructability phase and appointed principal contractor in 2020 under a TIC-CO (Construct Only) R3/B4/A4 contract.

The works followed 2019 investigations identifying shear cracking in the flyover’s halving joints, risking structural degradation and unplanned closures.

Load restrictions and traffic management were immediately introduced to maintain freight operations and safety. With over 40,000 vehicles daily, restoring the flyover’s capacity was vital for this key corridor. Transport and Main Roads (TMR) committed to removing all restrictions by late 2020, setting an ambitious deadline that required a fast-tracked construction program, bespoke engineering solutions, and close coordination across disciplines.

Despite challenges including working beneath a live bridge, heavy traffic, and COVID-19 impacts on workforce and supply chains, non-negotiable milestone targets were successfully met, and in most cases, exceeded. JF Hull provided early constructability advice and used innovative methods to meet technical and schedule demands. Strong collaboration with TMR, AECOM, Boral, VSL, and Formcon ensured the works were completed safely, efficiently, and was key in the project having such a successful outcome. Scope included road realignments, pavement and drainage upgrades, barrier and guardrail installation, and landscaping. The project demonstrated JF Hull’s ability to deliver complex, time-critical infrastructure under challenging conditions while meeting client and community expectations.

Project Manager: Graham Hull
Project Engineers: Emma Thiele & Reece Reimers
Quality Manager: Barry Story
Supervisors: Paddy O’Shea & Dave Prouten
Date Commenced: May 2020
Date Completed: December 2020
Contract Value: $14.69 million

Project Scope

The project involved strengthening four bridge piers on the Gateway Northbound Flyover of the Gympie Arterial, along with associated civil works to realign the arterial road to suit the modified substructure.

To meet an accelerated completion date, delivery was structured in three phases:

Design Phase: JF Hull was engaged early to provide constructability advice during design development. This minimised construction RFIs and enabled temporary works planning ahead of time, improving delivery efficiency.

Early Works: While design was being finalised, early works commenced to bring forward construction ultimately reducing the overall program by two to three months.

·        Early works included:

·        Site mobilisation

·        Onboarding of project personnel

·        Traffic management design and implementation

·        Formwork and flat-jack procurement

·        Concrete and grout mix design and testing, and

·        Site investigations

Project Works: Strengthening of the existing piers was delivered in two concrete pour stages using custom mix designs, bespoke steel formwork and innovative placement techniques. Intermediate and final load transfers were completed using hydraulic and grout-filled jacks, managed by specialist subcontractor VSL.

Civil works on the Gympie Arterial were mostly completed offline and included:

·        Drainage

·        Soil nailing and shotcreting

·        Shoulder widening

·        Asphalt resurfacing

·        Safety barrier installation, and

Final works carried out under night-time traffic conditions to minimise disruption.

Key Achievements

The successful completion of the construction of the Gateway Arterial Flyover strengthening works has demonstrated JF Hull’s ability to deliver technically challenging projects in compressed timeframes. Key project achievements include:

• Project success was underpinned by a strong, collaborative partnership among all stakeholders including the project teams, client TMR, E&T division, Administrator GHD, AECOM, JF Hull, and key subcontractors Formcom and VSL. The project teams’ close coordination and shared commitment were instrumental throughout delivery

• Accelerated project completion by providing constructability advice during the design phase. A Minor Works contract enabled early mobilisation, implementation of the traffic guidance scheme, formwork design, procurement and testing of flat jacks, and development and testing of concrete and grout mix designs

• Winner of the 2021 Concrete Institute of Australia (QLD) Excellence Award for Repair, Restoration and Retrofitting; shortlisted for CCF (QLD) Earth Awards – Category 4

• Delivered innovative solutions, including TMR’s first use of flat jacks on a bridge project and a custom early-use Envisia® concrete mix designed for early strength, low shrinkage, reduced heat of hydration, and enhanced sustainability

• Delivered on time and under budget despite additional scope through early involvement of JF Hull and key subcontractors, and strong collaboration throughout construction, and

• The project maintained an excellent safety record, with no reported LTIs or injuries. There were also no environmental incidents across the project.

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Project Outcomes and Performance

Social

Exceeding Training Commitments and Delivering Workforce Development

Despite a short six-month construction phase requiring specialised skills, JF Hull exceeded its training commitments. An administrative trainee and a formwork carpenter were engaged for most of the project, with subcontractors adding new entrant hours. Amid COVID-19 challenges, JF Hull delivered strong upskilling outcomes. Two part-time undergraduate/cadet engineers received training in Working at Heights and Chain of Responsibility. Overall, 37 new entrants were engaged, with six completing Certificate III qualifications and 15 receiving upskilling. A total of 8,992 training hours were delivered, including 6,541 for new entrants, well above the targets.

Maximising Local Participation and Strengthening Regional Supply Chains

JF Hull actively leveraged their well established relationships with South East Queensland’s local supply chain throughout the delivery of the project, engaging key local subcontractors Civforce Traffic Management, Formcon Group, VSL Australia, LCR Group, and A1 Highways. This approach reflects JF Hull’s strong commitment to engaging local networks, supporting job creation and contributing to strong, resilient communities throughout project delivery.

Driving Economic Value Through Safer, More Reliable Infrastructure

The project enhanced freight and traffic efficiency, reducing delays and improving transport productivity. Enhanced network reliability and connectivity supported sustained economic activity by facilitating the timely movement of goods and services. In addition, improved road safety lowered accident risk and associated costs, delivering long-term and broader economic benefits.

Achieving Excellence in HSEQ Through Innovation and Responsibility

  • Implemented water management measures – early runoff protection, drainage retention, and flood control to minimise environmental impact and protect surrounding ecosystems
  • Used existing hardstand areas to prevent vegetation clearing and eliminate the need for gravel import and export, reducing environmental disturbance
  • Implemented a comprehensive waste recycling program for steel, concrete, asphalt, and general waste, reducing landfill use and promoting sustainable resource management
  • Effective noise, light, and dust management was maintained, with tailored controls for day and night works. Light impacts were specifically reduced during night operations, and

Replaced polystyrene with insulated foam sprayed onto steel forms, enhancing road safety, and environmental outcomes by eliminating blow-off, while maintaining effective concrete insulation and quality.

Communication and Engagement to Support High-Impact Night Works and Traffic Management

Effective communication was critical to managing travel restrictions during construction, particularly night works required to lift load and travel limits on the flyover. Major structural activities, including concrete pours and jacking operations, took place at night to minimise daytime disruption, requiring lane closures and full Gateway traffic detours. Clear, timely updates helped maintain stakeholder trust and minimise complaints, with only one formal complaint received despite noise and lighting impacts. JF Hull Communications worked closely with TMR to deliver consistent messaging, while early engagement with the heavy vehicle industry ensured their needs were factored into planning and support was maintained.

The Gateway Flyover Strengthening project required bespoke, non-standard design solutions, driven by a tight delivery timeline. This fostered innovation across design, construction, and contracting, including:

Temporary Works and Formwork Solutions

Excavation beside the busy Gympie Arterial was enabled by a soil nail and shotcrete solution beneath the live carriageway, avoiding detours or closures. Space constraints required custom self-bracing steel formwork by Bonacci, featuring internal stiffeners, access windows for staged pours, bolt-together panels, insulation for temperature control, and external form vibrators to ensure concrete quality.

Innovative Pier Construction

For piers over 8m tall with limited access and dense reinforcement, concrete was placed through 2m-spaced windows in the formwork to minimise drop height and ensure control. This approach met all technical requirements and supported safe, efficient construction.

Two-Stage Load Transfer System

To ensure long-term performance, AECOM designed a two-stage load transfer using flat jack technology – rare in bridge works. Initial hydraulic jacking was followed by shrinkage monitoring, then grout filling the jacks and epoxy injection. Validated through full-scale trials with VSL, the method delivered a durable, high-integrity connection.

“The Administrator is satisfied the Contractor has met and at times exceeded the project requirements such as completing early and producing a quality product.”

Adrian Derbyshire, (Administrator – GHD)