Luffing Jib Tower Crane the Right Fit for Smith Bros. & Wilson
Major metropolitan downtown reconstruction projects offer even more challenges for the lifting contractor. It is a virtual certainty that the site will be surrounded by structures on all sides, making it a tight fit for mobile cranes. Busy streets make it nearly impossible and sometimes cost-prohibitive to block off a road for a significant period of time.
This is precisely the type of demanding project facing contractor, Smith Bros. & Wilson (BC) Ltd. (SBW) of Vancouver, British Columbia, during the demolition and reconstruction of the 8th and 9th floors at the downtown Vancouver Public Library. The tasks included converting the once provincial government office spaces into additional library space, meeting rooms and an urban green space, all while keeping the library open to thousands of visitors daily.
Demolition and construction activities required many materials, large and small, to be moved. “All the demo material had to be removed,” explains Tyler Brown, general superintendent for SBW, “and the library only had service elevators to get material from the top floors to street level. During the tender phase, we saw the need to hoist many items, including large-span escalators to get people up to the green space. It was quite a challenging prospect.”
This is a very high profile project for the city, as the building’s distinct design makes the library a focal point of the downtown area. While the historical look allows it to stand out, it also poses unique challenges that require much preplanning in order to properly bid.
“The library is designed after the Roman Colosseum and surrounded by an elliptical wall on the east side,” comments Dean Arsene, crane rental & sales representative for Leavitt Machinery of Vancouver, an authorized Terex Cranes distributor. “We started discussing the project with SBW in late 2016, and all options were reviewed.”
Like most contractors submitting bids, SBW initially considered mobile cranes to tackle the heavy lifting from street level. Unlike those companies, however, SBW saw several drawbacks that made planners rethink the option.
“The structure’s shape required a minimum of a 500 t capacity class mobile crane to hoist large materials to and from the upper floors because it would be boom bound,” says Tyler Brown. Given the possible set-up locations for a mobile crane at the site, smaller cranes just did not offer the capacity to lift many of the objects at the required boom lengths and working radii. “This meant we would have had to shut down an entire street, and mobilization costs would have been high. By the time we counted everything that needed to be hoisted, it was cost-prohibitive to use a mobile crane.”
The next option for SBW was tower cranes, and they looked at flat top, hammerhead and luffing jib designs. “The job required a 55 m boom radius, and the flat top and hammerhead cranes didn’t offer the capacity we needed for the escalators without breaking them down,” mentions Mr. Brown. Plus, there was a more pressing issue, as the crane would be placed about 15.2 m from an adjacent structure. “Those booms were too long, and they didn’t have the freedom to slew without hitting a structure, so these designs were not an option,” explains Dean Arsene. For SBW, the only option was a luffing jib tower crane, and the Terex® CTL 430-24 offered the reach and capacity for the job.
Throughout the demolition phase, the crane was kept busy daily removing large structural pieces and concrete from the rooftop. Choosing the tower crane for this project gave work crews more flexibility with material removal.
As work transitions to the reconstruction phase, the crane will be used to hoist large building materials and full concrete buckets from street level to the 8th and 9th floors. The largest and heaviest planned lifts will be the 2 escalators weighing 5.4 t each, hoisted into position without disassembly to save time and money.
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