MEASURING MOISTURE-INDUCED LOADS IN A MODEL GRAIN

Tests were conducted to measure moisture-induced lends in a model corr ugated steel bin 0.96 m in diameter and 1.57 m high. Vertical forces o n the bin floor and wall were measured separately with force transduce rs. Lateral and vertical pressures were measured at three depths in th e grain mass using diaphragm pressure sensors. Freshly harvested hard red spring wheat was wetted from 9.1% to 16.0% d.b. (dry basis) by blo wing moist air through the grain bulk. Expansion of wetted grain cause d grain weight to shift from the bin wall to the floor. All up-lift fo rce of 4.07 kN on the bin wall was measured while the floor load was 1 .4 times the total grain weight. Lateral pressure in the grain mass in creased dramatically as grain was wetted. The highest measured value n ear the bin floor was 8.6 times the static lateral pressure. Vertical pressure increased less than lateral pressure, thus the lateral to ver tical pressure ratio increased considerably during grain wetting. The highest measured pressure ratio was 1.60 near the bin floor.