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Infrastructure Access Solutions (part of Alimak Group) was engaged to undertake a major inspection and engineering assessment of the powered under-deck gantries operating beneath the Sydney Harbour Bridge.
These permanent access systems enable inspection and maintenance crews to safely access the bridge’s steelwork below the roadway, which is a critical component in maintaining one of Australia’s most iconic pieces of infrastructure.
The project required detailed engineering assessment of complex access plant operating in a highly constrained environment beneath an active transport corridor.
The gantries consist of integrated structural, mechanical, electrical, and control systems that must function reliably while supporting suspended access operations at height.
Working within strict safety and operational requirements, the inspection program needed to verify the integrity and performance of the systems while minimizing disruption to ongoing maintenance activities.
Infrastructure Access Solutions delivered a coordinated major inspection and certification program, combining in-house engineering expertise with specialist testing services.
The scope included comprehensive inspection of structural elements, drive systems, rolling components, electrical and control systems, and operator safety features.
Non-destructive testing of critical components was undertaken through a NATA-accredited laboratory, alongside functional testing of brakes, limit systems, and operational controls.
Infrastructure Access Solutions managed multiple specialist disciplines throughout the project, ensuring a structured inspection methodology and clear engineering documentation to support the certification process.
Through a detailed engineering assessment and coordinated inspection program, the under-deck gantries were verified for safe operation, restoring reliable access to critical areas of the bridge for ongoing inspection and maintenance activities.
The project highlights Infrastructure Access Solutions’ capability in delivering complex inspection and certification programs for permanent access and specialist maintenance equipment operating in demanding infrastructure environments.
The Kangaroo Point Bridge is one of Brisbane’s most innovative transport links. Stretching 460 metres across the Brisbane River, it connects the suburbs of Kangaroo Point with the city center. Designed for pedestrians and cyclists, the bridge supports Brisbane’s goal of creating a more sustainable and connected city.
The project was delivered by Brisbane City Council with design input from Connect Brisbane with Rizzani de Eccher, Dissing + Weitling, ASPECT Studios, Blight Rayner, Right Angle Studios, and Rowland, among others, and constructed by Besix Watpac.
During construction, workers needed to safely access the upper pylon structure of the bridge to install the cable stays. This required a temporary solution that could be removed once the work was complete and would not damage or change the final look of the bridge.
Infrastructure Access Solutions, working under the Manntech brand, was chosen to design and deliver a tailored access system for this purpose.
The team designed a one-of-a-kind custom Manntech BMU system featuring a central mounting platform known as a “crow’s nest” and two specially shaped cradles on elbow jibs.
These cradles allowed workers to move smoothly along the curved surfaces of the bridge structure. As the cradles travelled downward, they adapted to the changing profile of the pylon, providing full and safe coverage throughout the work area.
To avoid any permanent fixing into the facade of the pylon, tensioned cables were used to guide and stabilize the cradles during operation.
The entire system was mounted at the highest point of the bridge structure, offering a secure base for workers to carry out their tasks and later take the system down without leaving a mark.
Installing the system was challenging, as space at the top of the structure was extremely limited. With support from Besix Watpac’s expert crane team, the system was delivered by barge and lifted into place.
Much of the lifting was done at night to meet site requirements and coordinate with other ongoing work. To make the process more efficient, most parts of the system were assembled in advance.
Infrastructure Access Solutions was selected for their smart design approach, in-house installation team, and reliable project management. The access system made it possible to complete the bridge works safely and efficiently while protecting the clean, modern design of this important Brisbane landmark.
The Gordie Howe International Bridge is a landmark infrastructure project connecting Detroit, Michigan, and Windsor, Ontario. Upon opening to traffic, it became the longest cable-stayed bridge in North America and a critical transportation corridor supporting trade and travel between the United States and Canada.
To support the bridge’s long-term inspection and maintenance requirements, Infrastructure Access Solutions (IAS) North America was selected to design and supply two custom Tractel® Under Bridge Maintenance Gantries (UBMGs).
The systems were designed to provide safe and efficient access to critical bridge components throughout the structure’s operational life.
Success required close collaboration between engineering, manufacturing, procurement, and project management teams, as well as strong coordination with the client and project stakeholders.
The team successfully progressed from concept and engineering through manufacturing, testing, and delivery while meeting aggressive project milestones.
The project stands as a testament to IAS’s ability to deliver complex access solutions under challenging conditions while building lasting partnerships through technical excellence, responsiveness, and execution.
Torin Gillen, P.Eng
Technical Sales Manager, Infrastructure Access Solutions
torin.gillen@alimakgroup.com
+1-416-298-8822
The Crown Bridge, designed by Knight Architects and constructed by KREATE and YIT, stands as Finland’s tallest bridge and an iconic structure in Helsinki. The 135-meter-tall diamond-shaped pylon and the 2 x 250-meter cable-stayed spans are key highlights of this landmark, central to the Kruunusillat (Crown Bridge) project connecting the city center to Laajasalo via sustainable public transport.
Tractel™ was selected for its technical expertise and value-engineering solutions to address the client’s need for a cost-effective deck maintenance system. Tractel designed and implemented a rotating underdeck gantry capable of passing through the V-shaped piers, enabling seamless inspection across the bridge’s entire length with a single piece of equipment, improving efficiency and reducing maintenance costs.
Installation: To overcome the challenges of limited on-site space and the absence of a crane, TRACTEL developed an original installation method for the gantry.
Digital: TRACTEL worked with BIM technology, based on bridge’s digital model, to ensure accurate integration of the underdeck gantry in the bridge unique design.
This project enhances Tractel’s ability to deliver innovative, efficient, and sustainable solutions for landmark infrastructure projects.
Point of Contact: Aurélien Guimard
