Static Analysis and Design of Laterized Concrete Cylindrical Shells for Farm Storages

ABSTRACT As the prices of building materials in the country continue to increase sharply, there is growing need to source local materials as alternative for farm building constructions. This project investigates the performance of a cylindrical shell built of laterized concrete for storage of foodgrains or water. L In order to optimize the mix ratio of the constituent materials that will produce maximum strength, a mathematical model which relates the strength of laterized concrete and its component ratios was developed using Scheffe's simplex lattice approach. The optimum mix proportion obtained was used to determine the structural characteristics of laterized concrete in the laboratory. The values obtained for the material properties were applied in performing the static analysis of the cylindrical shell structure under the action of hydrostatic and foodgrain pressures using Pasternack's equations formulated on the basis of theory of shell of revolution. The reduced equation of static equilibrium was solved by the Initial-value method. A generalized solution of the cylindrical shell made of laterized concrete was obtained and used to evaluate the performance of the structure through the determination of deflection and stresses. Adequate cross-section of the cylindrical shell was determined. The experimental data are very well fitted to the regression model, which satisfies the student-t and chi-square tests. The optimum strength value " of 27Nld corresponding to an optimum mix proportion of 1 : 1 :2:0.650 of cement, laterite, gravel and water-cement ratio respectively was predicted by the model. For the structural characteristics, the values obtained for the optimum mix ratio were higher than that obtained for the mix ratio of 1 :2:4:0.791. The results of the analysis indicate that the maximum stresses developed due to hydrostatic loading is greater than the strength of the laterized concrete in reservoir thickness of 5Omm, 1 Om in diameter and 5m in height. The wall thickness of 100- was found adequate. The maximum stress developed due to soybean grain loading is greater than the material strength in silo thickness of 100mrn, 20m in diameter and 8m in height. The wall thickness of 150mm was found adequate. Thus, the possibilities of using laterized concrete in constructing cylindrical storage structures were successfully demonstrated.