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Ren t Un al Ava its ilab le
ULTRASONICS
Rebarscope Most Advanced Rebar Locator
CORROSION
Mini R-Meter An Economical Rebar Locator for Professionals
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new jobs and almost 2 kilometers (1.2 miles) of cycle ways. It will also conserve the heritage listed Rozelle Tram Depot, which operated on the site from 1904 to the 1960s. The Harold Park Paceway was comprised of an 800-meter (2,624.7foot) track, a 3,000-seat grandstand and administration and parking facilities. CSDA member OzCut Concrete Cutting Services of Penrith, also a member of the Australian association (CSDAA), was contracted by Hassarati & Co. Demolition & Excavation of Greenacre to remove the concrete support struts of the old Paceway track. “The suspended slab beams were constructed over a viaduct and consisted of hard to medium concrete with approximately 84 to 106 stress cables per beam, per cut,” said Steve Hill, operations manager for OzCut. The general contractor had placed a strict timetable on OzCut to keep the building project on schedule and minimize costs associated with employing an 800-ton crane for the job. It was important that the cutting contractor used a method that was fast, efficient and kept operators safe while working on suspended concrete structures. “We do utilize hydraulic systems on some jobsites, but we chose to use a high-frequency wire saw system purely to eliminate the weight factor. There were safety issues regarding working at height and accessibility to the work area by knuckle booms, so we had operators and site workers harnessed almost constantly,” added Hill. By starting with an initial setup of three CS10 wire saws supplied by Husqvarna, two on one beam doing the cutting and one set up ready to cut on the next beam, the team from OzCut was able to reduce transition time between beams and allow operators to keep up a cut rate of six cuts per day. C1000 diamond wire was supplied by Husqvarna with a average length of around 20 meters (65.6 feet). Each of the 2-meter-wide (6.6-foot) and 1.5-meter-thick (4.9-foot) beams required two cuts. Some of the beams also had 900-millimeterdiameter (35.4-inch) support columns attached that also needed to be cut. It took operators an average of one hour to complete one cut, with some taking up to 2.5 hours. Pulleys were used to create angled cuts to lift vertically, and some inverted cuts were performed. Due to the lightweight nature of the wire saw system, the equipment was able to be moved by telehandlers and knuckle-boom excavators. This further reduced the time needed to dismantle and reassemble the system between cuts. Once the beams were cut, an 800-ton crane was positioned on site to lift the sections away from the work area. The average weight of the concrete sections was between 125 and 150 tons. While the cutting work went smoothly, there were some specifications that the contractor had to make sure it met. Harold Park is deemed a heritage-listed site, meaning that all materials used on the site had to be environmentally friendly and have no impact on their surroundings whatsoever. The suspended beam was positioned over a creek bed, which had to be completely protected. The high-frequency wire saw system used was a lightweight conversion, consisting of only a single lead, water hoses and no need for large power packs traditionally associated with hydraulic systems. This eliminated the chances of any oil spilling into the creek, although the contractor did set up tarp covering to prevent any other type of debris entering the water. Aside from the heritage restrictions, the cutting of a suspended concrete structure approximately 6 meters (19.7 feet) in the air was no easy task. All equipment required for the job had to be lifted to the work area and carefully placed. The size of the beams proved to be awkward, as they were not only incredibly large, but also narrow, at only 2 meters (6.6 feet) wide. This environment meant that only one operator could be
Test Well. Build Well.
CSDA Training 2013–2014 Wall Sawing 101
March
Operator Certification
November
Concrete Polishing
November
World of Concrete
January ’14
www.csdatraining.com 24/7 For more information, visit www.csda.org or call 727-577-5004.
The Association of Cutting Professionals
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