Late last year, Louisville-based Caldwell Tanks, Inc., completed its largest jumpform grain silo: A 160-ft.-tall, 90-ft.-diameter structure at Kokomo Grain Inc.’s Edinburgh, Ind., facility. The entire tank, from foundation start to silo wall completion, took about 110 days to complete, and crews were challenged by extreme summer heat and an early harvest.
Approximately 2,500 yd. of ready mixed with 4-in. slump and 5 percent air was delivered from Shelby Materials' Columbus, Ind. facility. A 2 percent retarder was added to the mix design to counter the placement in hot weather. Caldwell silo crews were able to place two rings per day with 15 men working five hours per level. A typical concrete pour took about 1 hour 15 minutes per level, using cranes with 2-yd. buckets discharging into a 0.5-yd. cart, which then pours into the form.
Caldwell representatives said this jump form method is better suited and more economical to this type of silo erection than slipforming since crews are not required to work 24 hours/day, and the overall construction works faster since there is no wait time for the roof design and material prior to starting wall construction.
Caldwell previously erected two 80-ft.-diameter silos at the site; all three feature bottom discharge onto a below-grade, common conveyor running the length of the structures’ footprint. The three silos also are equipped with Bobcat access doors, allowing a front-end loader in for cleanout.