The lashings on a stack of containers with interlocking fittings restrain the forces that cause __________.
• Container stack behavior in heavy seas or during ship motions • Difference between crushing, racking, buckling, and toppling as structural failure modes • Purpose of lashings vs. interlocking fittings (twistlocks) on container stacks
• Think about what interlocking fittings (twistlocks) already prevent by themselves before lashings are added. What extra problem do lashings specifically address? • Visualize a tall stack of containers when the ship rolls heavily to one side. How would the stack want to move or deform if there were no lashings? • Which of the four failure modes is mainly about the whole stack shifting side‑to‑side as a unit, rather than the walls of a container being crushed or bent?
• Be clear on the definition of crushing (compression failure), buckling (bending or instability of slender members), racking (distortion of a rectangular frame into a parallelogram), and toppling (overturning). • Ask: Do lashings mainly stop vertical compression, sideways frame distortion, local panel bending, or the stack from leaning and falling? Match that to the best term. • Remember that interlocking fittings already give vertical alignment and stacking. Lashings add restraint against lateral and overturning forces from wind and vessel motion.
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