Which mechanical vulnerability increased when Roman siege engines repeatedly bombarded masonry fortress walls?

💡 Explanation

When siege engines repeatedly impacted masonry walls the repetitive compressive force causes spalling because compressive stress waves reflects within the material, generating tensile stresses exceeding the material's tensile strength, causing surface fragments to eject. Therefore spalling results, rather than corrosion, buckling, or liquefaction which require different environmental or geologic triggers.

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