Fraco innovates for Montreal renovation job
February 13, 2025
At nearly 60 years of age, Montreal’s 620-foot-tall Stock Exchange Tower recently demanded major renovations.
Built in 1964 for Canada’s “Expo 67” fair, the skyscraper was originally constructed in the International Skyscrapers Architectural Style, featuring a bronze-tinted anodized aluminum curtain wall that sharply contrasts with slightly slanted precast concrete columns at each corner. Divided into three sections by mechanical floors with recessed octagonal corners, it allows small open-air spaces behind the columns at these levels.
The precast concrete panels (weighing 3,000 to 7,000 pounds) on the building’s corners, and the anchors that secured those panels to the building, needed to be replaced. Furthermore, repairs were necessary for the nose of the concrete slabs due to its significant degradation.
With a number of challenges that spanned from building shape and location to local weather and material/equipment weight, a custom solution was needed – and Fraco answered the call.
The nitty gritty details
The project’s main challenges were location, building tenants and property values, weather conditions, the weight of the material to be installed and the shape of the building.
Location played a key role in the project’s narrative due to not only the skyscraper’s prime downtown location which bustles with people and businesses, but because of what also occurs beneath the city streets it shares.
Below the Stock Exchange Tower, multiple underground levels house various functions –servers rooms, a shopping mall that connects to a metro station, a parking lot, and much more.
In the complex environment of the multi-leveled underground city, a challenge arose in securing the base of Fraco’s platform. With an anticipated load of 375,000 pounds to be transferred to the ground, placing it directly on the surface risked potential collapse into the underground infrastructure. Finding a solution to this issue was imperative to ensure the stability and safety of the platform.
For the Tower’s tenants, relocation and disturbance to everyday life were not options. Work needed to be scheduled for after-hours and during nights. And with a project duration of approximately 4 years, weather – and the ebb and flow of humidity, snow, sun, rain and wind – had to be taken into consideration.
Fraco’s solutions also had to able to withstand handling panels that weighed as much as 7,000 pounds – a crane could not be used because of the building’s location next to other high rise structures.
And, lastly, the shape of things. The base of the Stock Exchange Tower is slightly wider the top, tapering in at roughly 8 feet. The precast panels at the base were significantly bigger and heavier than those at the top.
So, in order to provide external access to the fully occupied and functioning office building, Fraco engineered, produced and installed three customized, 3-towered mast-climbing platforms, with a self-erecting jib resting on the top of each of the three mast assemblies. Fraco’s standard SEP transport platforms used the 3-mast structure to bring materials and workers on the job.
In order to address the challenges, Fraco established several goals to tackle the access-related obstacles. The first goal was to design an innovative technical solution for a platform that could:
- effectively move up and down the building corner
- support heavy loads
- operate without the need for a crane
- facilitate easy mobility between levels
- ensure worker safety and efficiency of work
- ‘modifiable’’ work deck surface, in order to stay close to the tapered facade
The second goal was to address the base issue, and the third goal was to mitigate weather-related issues.
How Fraco did it
Coming up with a technical solution for the platform:
The initial challenge was to develop a mast-climbing work platform capable of shaping the corners of the building while ensuring stability, safety, and sufficient load-bearing capacity. Fraco addressed this by designing a 3- tower platform, merging 2 FMC-8 platforms with a specialized joint on the floor - a drop-down work area to link both platforms. This solution allowed for the separation of platforms for vertical movement and their subsequent reassembly at desired levels. The joint unit equipped with a modular truss system had a customizable work area to adapt to the changing shape of the building.
The new unit included a comprehensive safety system to prevent falls of people and objects. The platform was equipped with a 2-meter high completely enclosed guard rail to protect workers, and the adjustable floor of the platform came close to the building to avoid objects falling. The safety devices on both units protected the platform from a free fall.
The second challenge involved identifying and incorporating a lifting mechanism suitable for both erecting the towers and hoisting heavy precast panels to desired levels. The general contractor hesitated to use a standard crane due to cost, limited downtown space, and weather constraints. Fraco’s solution came in the form of a self-erecting jib-arm, which was used to install the towers and manipulate precast concrete panels.
Fraco constructed a specialized platform for the self-erecting jib arm, featuring ample space to accommodate a weather-proof booth for the operator. This jib-arm not only facilitated tower erection for mast-climbing platforms but also minimized ground space usage and provided sufficient power to safely lift the 7,000-pound precast panels. The jib arm moves up and down using its hydraulic ratchet system unit also developed by Fraco.
Addressing location-related challenges
Beneath downtown Montreal lies a sprawling underground city, with at least five levels beneath the Stock Exchange tower. This posed a significant challenge in placing the platform without risking ground collapse.
This issue was resolved by strategically installing shoring posts in the underground levels to provide support. Subsequently, several massive steel beams were positioned at ground level to distribute the platform’s weight effectively to the building’s foundation. The beams rested on the fortified concrete foundation of the Stock Exchange Tower. This intricate engineering required precise calculations, given the high stakes involved.
Addressing weather-related challenges
To address the third set of challenges related to weather, Fraco devised access to the sarcophagus that was intended to shield the levels under construction.
Essentially, the building was segmented into multiple “working zones,” each consisting of six stories. The floors under construction were enclosed within a sarcophagus that first, ensured that the weather would not damage the inside of the building, and second, protected the works from extreme cold and heat.
Inside the sarcophagus, the workers demolished the old concrete blocks and transported the debris on the ground using the Fraco SEP transport platform. After, they would replace the steel anchors that attached the panels to the building, and finally, new massive pre-cast panels were fed on the platform by the self-erecting jib arm. Once the precast concrete blocks were replaced, the work platform and jib-arm platform would descend six stories. And the sarcophagus would be lowered too.
Mast climbing work platforms prevail
The customized MCWP was designed and produced explicitly for this project. The platform was a juxtaposition of two FMC-8 platforms which could be joined for safe and efficient work, but could be easily separated during the vertical movement. The adjustable floor allowed for shaping the corners of the building. Multiple security devices were implemented to ensure the safety of individuals and prevent the collapse of the unit.
To avoid using a crane, Fraco placed on the top of the mast a self-erecting jib-arm that could lift the towers of the mast for the erection of the platforms and was powerful enough to raise the 7,000-pound precast panels safely. Fraco SEP construction hoist operating on the same 3-mast structure was also used to safely transport people and materials.
The self-erecting jib-arm positioned on its designated platform not only cut the costs and inconveniences of using a traditional construction crane downtown but also erected towers for mast-climbing and transport platforms. It saved months of work compared to standard scaffolding and weeks compared to using a construction crane because the jib-arm’s proximity to the worker enables direct manipulation of materials, significantly accelerating work. Additionally, its precision significantly contributed to the speed and safety of operations.
The motor system of the platform with the self-erecting jib arm also had to meet certain criteria of weight, location, safety, speed and power.
To address these, Fraco also developed and manufactured a hydraulic ratchet system. This system had a hydraulic component to handle heavy loads, while the mechanical part ensured safety. Moreover, all three motor blocks were equipped with two hydraulic ratchet mechanisms each. One mechanism was dedicated to holding the climbing block in place, while the other served as the moving part. These mechanisms engaged and disengaged alternately, one at a time.
Fraco celebrates winning the 2024 Scaffold & Access Industry Association’s Project of the Year Award for Mast-Driven Hoists and Platforms during the SAIA’s 2024 Annual Convention & Exposition. (Photo: SAIA)
Fraco’s engineers also implemented an additional safety feature. Each independent mechanism included a built-in electrical safety device. This device prevented disengagement until its counterpart was 100 percent engaged, thus preventing operator misuse.
For its work and innovations, Fraco was awarded the 2024 Scaffold & Access Industry Association’s Project of the Year Award for Mast-Driven Hoists and Platforms. For more information on these highly coveted awards, visit www.saiaonline.org.
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