This past fall, Saskatoon carbon fiber composites manufacturer SED Research Inc. (SRI), a Calian subsidiary, commissioned Kristian to increase their shop productivity with the design and installation of three new overhead cranes. The cranes were needed by SRI to construct their line of 10M composite carbon fiber antennas for the satellite ground systems industry.
Their custom order included two Demag column-mounted jib cranes, 1 ton each, and a 5 ton Demag top running single girder bridge crane. These overhead cranes were chosen to assist SRI in their day to day production processes of manufacturing their sophisticated, state-of-the-art satellite earth station antennas. SRI provides composite carbon fiber reflectors to Calian SED, a global solution provider of advanced communication systems for over 50 years.
Both jib cranes were selected from a standard Demag construction, ensuring a straightforward and uncomplicated installation consistent with Demag’s quality design. However, the 5 ton bridge crane offered up a few challenges for the Kristian design and production team.
Kristian’s main obstacle designing the bridge for SRI was their specification that the entire crane structure, including the runways, must be completely freestanding and could not be tied back to the building’s structure in any way. Freestanding bridge and workstation cranes are not unusual in any sense, but with a span of 45’ and a runway length of 77’, this was no small freestanding crane. The larger the crane, specifically the span, the less weight the structure is able to support properly without the possibility of the columns pulling in towards each other. In order to stop this from happening, brace support beams must be placed along the crane, crossing from column to column, to reinforce the entire system. But considering the span of this particular crane system, these brace support beams would cause a large additional amount of extra weight to stretch across the entire structure.
In such cases, the Kristian design and production team will utilize a truss bridge beam. Truss beams are comprised of bracket-type rods, straight, or cambered pieces joined together by trussing. Truss beams are significantly lighter and can be less expensive to manufacture as they require less material overall. However, constructing a truss beam properly is complex, and the additional labour hours required can also increase the overall cost of a project.
