ABSTRACT
ABSTRACT. The paper describes a phenomenon known as stress escalation in circular biological filter bed walls caused by cyclical solar heating. The resulting circumferential tensile forces created by the radial interface stresses from the contained granular material (GM) are studied in ring-tension type filter beds, Three components of loading are identified for design purposes:
1. First filling of the containment with GM; ’at rest’ stress state. 2. Repeated cyclic heating and cooling causing ratcheting strains and stress
escalation to hydrostatic values after several years. 3. Cyclic stress perturbations resulting from daily temperature changes.
