Lateral Pressure in Squat Silos under Eccentric Discharge

The influence of eccentric discharge of stored solids in squat silos has been highly valued by many researchers. However, calculation method of lateral pressure under eccentric flowing still needs to be deeply studied. In particular, the lateral pressure distribution on vertical wall could not be accurately recognized mainly because of its asymmetry. In order to build mechanical model of lateral pressure, flow channel and flow pattern of stored solids in squat silo are studied. In this passage, based on Janssen-s theory, the method for calculating lateral static pressure in squat silos after eccentric discharge is proposed. Calculative formulae are deduced for each of three possible cases. This method is also focusing on unsymmetrical distribution characteristic of silo wall normal pressure. Finite element model is used to analysis and compare the results of lateral pressure and the numerical results illustrate the practicability of the theoretical method.




References:
[1] Pieper, K., and Wagner, K., "The influence of different types of
discharging on side pressures in silo compartments,"
Aufbereitungs-Technik, vol. 10, pp. 542-546, 1969. (in German).
[2] Reimbert, A. M., and Reimbert, M. L., "Pressure and overpressures in
vertical and horizontal silos," Proceedings of the International
Conference on Design of Silos for Strength and Flow, University of
Lancaster, 1980, pp. 364.
[3] Britton, M. G., and Hawthorne, C. R. J., "Dynamic behavior of wheat in
a lamellar bin," Amer. Soc. of Agric. Engrs., vol. 84, pp. 501, 1984.
[4] McLean, A. G., and Bravin, B., "Wall loads in eccentric discharge
silos," Int. J. Bulk Solids Storage in Silos, vol. 1, no. 1, pp. 12-24, 1985.
[5] Ross, I. J., Moore, D. W., Loewer, O. J., and White, G. M., "Model
studies of grain silo failures," Winter Meeting, Amer. Soc. Agric. Engrs.,
Chicago, 1980, pp. 2-264.
[6] Thompson, S. A., Usry, J. L., and Legg, J. A., "Loads in a model grain
bin as affected by various unloading techniques," Trans., Amer. Soc.
Agric. Engrs., vol. 29, no. 2, pp. 556-561, 1986.
[7] Thompson, S. A., Usry, J. L., and Morse, D. D., "Experiments with the
eccentric unloading of a model corrugated grain bin," Canadian Agric.
Engrg., vol. 30, no. 1, pp. 165-171, 1988a.
[8] Jenike, A. W., "Denting of circular bins with eccentric drawpoints,"
ASCE J. Struct. Div., vol. 93, no. 1, pp. 27-35, 1967.
[9] Rotter, J. M, "Buckling under axial compression," Design of Steel Bins
for the Storage of Bulk Solids, J. M. Rotter, ed., Sydney: The Univ. of
Sydney School of Civ. and Mining Engrg., pp. 122-137, 1985.
[10] Safarian, S. S., and Harris, E. C., Design and construction of silos and
bunkers, N.Y.: Van Nostrand Reinhold Co., 1985.
[11] Johnston, F.T. and Hunt, F.A., "Solutions for silo asymmetric flow
problems," Proc., Second Int. Conf. on Design of Silos for Strength and
Flow, Stratford-upon-Avon, 1983, pp. 13.
[12] Wood, J. G. M., "The analysis of silo structures subject to eccentric
discharge," Proc., Second Int. Conf. on Design of Silos for Strength and
Flow, Stratford-upon-Avon, 1983, pp. 44.
[13] Roberts, A. W., and Ooms, M., "Wall loads in large metal and concrete
silos and silos due to eccentric draw-down and other factors," Proc.,
Second Int. Conf. on Design of Silos for Strength and Flow,
Stratford-upon-Avon, 1983, pp. 70.
[14] Emanuel, J. H., Best, J. L., Mahmoud, M. H., and Hasanain, G. S.,
"Parametric study of silo- material interaction," Powder Tech., vol. 36,
pp. 223-33, 1983.
[15] Rotter, J. M., "The analysis of steel bins subject to eccentric discharge,"
Proc., Second Int. Conf. Bulk Materials Storage Handling and
Transportation, Wollongong, 1986, pp. 264-271.
[16] ACI 313-97, Standard practice for design and construction of concrete
silos and stacking tubes for storing granular materials. Detroit: ACI,
1997, pp. 6-8.
[17] Rotter, J. M., "Pressures, stresses and buckling in metal silos containing
eccentrically discharging solids," Festschrift Richard Greiner,
celebration volume for the 60th birthday of Prof. Richard Greiner, TU
Graz, Austria, 2001, pp. 85-104.
[18] EN 1991-4. Eurocode 1: actions on structures, Part 4: silos and tanks.
Brussels: European Committee for Normalisation, 2006, pp. 40-65.
[19] Janssen, H. A., "Versuche uber getreidedruck in silozellen," Zeitschrift
des Verein Deutscher Ingenieure, vol. 39, pp. 1045-1049, 1895. (in
German).
[20] A. J. Sadowski, J. M. Rotter, "Steel silos with different aspect ratios:
IIÔÇö behaviour under eccentric discharge," Journal of Constructional
Steel Research, vol. 67, no. 10, pp. 1545-1553, 2011.
[21] R. A. Bucklin, S. A. Thompson, and I. J. Ross, "Bin-wall failure caused
by eccentric," Journal of Structural Engineering, vol. 116, no. 11, pp.
3175-3190, 1990.
[22] E. Gallego, C. González-Montellano, A. Ramírez, F. Ayuga, "A
simplified analytical procedure for assessing the worst patch load
location on circular steel silos with corrugated walls," Engineering
Structures, vol. 33, pp. 1940-1954, 2011.
[23] P. Vidal, A. Couto, F. Ayuga, and M. Guaita, "Influence of hopper
eccentricity on discharge of cylindrical mass flow silos with rigid walls,"
ASCE Journal of Engineering Mechanics, vol.132, no. 9, pp. 1026-1033,
2006.
[24] F. Ayuga, M. Guaita, P. J. Aguado, and A. Couto, "Discharge and the
eccentricity of the hopper influence on the silo wall pressure," ASCE
Journal of Engineering Mechanics, vol.127, no. 10, pp. 1067-1074,
2001.
[25] M. Guaita, A. Couto, F. Ayuga, "Numerical simulation of wall pressure
during discharge of granular material from cylindrical silos with
eccentric hoppers," Biosystems Engineering, vol. 85, no. 1, pp. 101-109,
2003.