5 Tandem Girder Gantry Cranes
Westmont Engineering, in conjunction with Sievert Crane & Hoist, has begun assembly of 5 tandem girder gantry cranes in the Chicagoland area. When complete, each crane will be 100 feet tall 60 feet wide and 250 foot long. Each girder is made up of 3 pieces, approximately 90,000 lbs each for a total of about 270,000 lbs per girder. The rail that runs the length of each girder has +/-3 millimeter alignment tolerance.
To establish and hold these tolerances when assembling the 3-piece girders, Westmont designed and fabricated adjustable supports with cross tube hangers using 2" threaded rods so elevations could be quickly established and easily adjusted. For lateral alignment, the girder end section cross tube supports included teflon pads allowing movement without lifting the piece from the support. These support stands were fabricated using Westmont's new automatic plasma beam line reducing fabrication time and ensuring accuracy. These fixtures were designed to minimize crane time and provide the fine adjustment (up/down and side-to-side) needed to meet the alignment tolerances.