Stability Analysis of Prefabricated Underground Granary Composite Silo Walls

Abstract

The prefabricated steel plate-concrete composite silos have been recently used for underground granaries. As the buried depth and diameter-thickness ratio of underground silos increase, the calculation of elastic stability, which takes into account the effects of prefabricated joints, becomes a primary consideration in the design of the silo walls. In the present study, the equation to estimate the elastic critical pressure of double-layer heterogeneous cast-in-situ silos under uniform external pressure was proposed first. The theoretical solutions were then compared with the numerical results and the accuracy of the equation was verified. To derive the critical pressure of prefabricated steel plate-concrete silo walls, an equivalent joint design method was proposed and verified by a series of numerical analyses for different models. The results indicate that if the bending stiffness ratio of the joint is larger than the bending stiffness of the composite silo wall section, the prefabricated double-layer composite silo walls are equivalent to cast-in-situ double-layer composite silo walls, and the equation to evaluate the elastic critical pressure of double-layer heterogeneous cast-in-situ silo walls under uniform external pressure could be used to derive the critical pressure of prefabricated steel plate-concrete silo walls. The bending tests of the full-scale steel plate-concrete composite silo wall models with and without joints were conducted and the experimental results indicate that the assumption of a rigid connection between the steel plate and concrete was reasonable, and the equivalence of prefabricated composite silos to cast-in-situ composite silos to obtain the elastic critical pressure is feasible and the result is reliable.