EFFECT OF DAMAGE ON COMPOSITE CYLINDERS SUBJECTED TO EXTERNAL-PRESSURE

This paper describes the effect of damage, in the form of dents and holes, on the behavior and strength of composite (steel-concrete-steel) cylinders when subjected to external pressure. The depth of dent was the main parameter; two thicknesses of steel skin were used, and in ten of the twenty tests the filler material was a lightweight aggregate concrete. The results are compared with theory and clearly show the integrity and lack of sensitivity to initial imperfections of this form of construction. Dents up to one-eighth of the wall thickness, giving an out-of-roundness of 1. 5 percent of the inner radius, had no significant effect on the behavior. The presence of holes in the outer skin did not affect the cylinder's performance.