Plastic Collapse at Lap Joints in Pressurized Cylinders under Axial Load

Abstract

Circular steel silos and tanks are often constructed from rolled‐steel plates with welded or bolted lap splices. Where the lap runs horizontally around the silo circumference, the lap connection causes a local eccentricity in the line of vertical thrust in the shell wall. This eccentricity induces high local bending stresses and circumferential membrane stresses, which are detrimental to the strength of the structure. Although elastic buckling of the shell wall may be the critical failure mode for thin lap‐jointed cylinders under axial load with no or small internal pressure, axisymmetric plastic collapse is the likely failure mode when the internal pressure is high, especially for relatively thicker cylinders. This paper presents a detailed study of the axisymmetric collapse behavior and strength of lap‐jointed cylinders under combined axial compression and internal pressure and establishes easy‐to‐use design equations for such shells.