Forces on monitoring cables during grain bin filling and emptying

Authors: Casada, Mark; THOMPSON, SIDNEY - University Of Georgia; Armstrong, Paul; MCNEILL, SAMUEL - University Of Kentucky; MAGHIRANG, R. - Kansas State University; MONTROSS, MICHAEL - University Of Kentucky; TURNER, AARON - Clemson University

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2019
Publication Date: 6/1/2019
Citation: Casada, M.E., Thompson, S.A., Armstrong, P.R., McNeill, S.G., Maghirang, R.G., Montross, M.D., Turner, A.P. 2019. Forces on monitoring cables during grain bin filling and emptying. Applied Engineering in Agriculture. 35(3):409-415. https://doi.org/10.13031/aea.13147.
DOI: https://doi.org/10.13031/aea.13147

Interpretive Summary: Temperature and moisture content are frequently monitored by stored grain managers as the two most important quality parameters for safe grain storage. Monitoring is usually accomplished with temperature and/or moisture sensors incorporated into cables suspended from the bin roof, where they create a substantial extra load during bin filling and emptying, from forces such as friction on the roof-mounted cables. These forces must be known and accounted for in design of the roof structure. To address these design requirements, we determined forces on five different cable sizes and configurations during filling and emptying of 25-m deep concrete bins of wheat and corn. The average forces during emptying were always higher than during filling, generally by a factor of near or equal to two. The maximum vertical forces recorded for a cable was 1060 lb (4.73 kN) for the largest cable. The forces generally increased with increasing cable size. Cables close to the sidewalls of the bin had higher vertical forces than those in the center. These results can be used by designers to estimate loads on bin roofs and show that cable size and design along with center versus sidewall cable mounting locations are key variables to account for in the force calculations.

Technical Abstract: Monitoring the temperature of stored grain with permanent cables suspended from the bin roof is common practice in commercial grain storage and is sometimes used in on-farm grain storage bins. Knowledge of the forces imparted on the cables by flowing grain is required for proper design of cables, connection hardware, and bin roofs, but there is little data in the literature for full size bins. To determine forces on different cable sizes and configurations, five different cable designs were tested during filling and emptying of wheat and corn. Two concrete storage bins, 4.6-m diameter and 25-m maximum depth, were used with cables suspended from the center of the bin or suspended 0.6 m from the sidewall. The lower end of the cables were weighted but were not fully restrained. Forces on the cables were monitored during filling and emptying of the bins. Forces during emptying usually exhibited slip-stick behavior. The greatest forces were during emptying, where forces were often double those during filling, with vertical forces up to 4.73 kN (1060 lb) for the largest cable. The cables nearer the sidewalls of the bin had higher vertical forces than those located in the bin center. Results showed no effect of grain type, corn or wheat, while cable size had a significant effect on peak load in most cases.