Which instability increased as Roman arch spandrel infill decreased?

💡 Explanation

Increased spandrel infill lowers the thrust eccentricity in the arch, because it adds weight closer to ground and stabilizes the stones; therefore reducing infill causes the thrust line to deviate, rather than directly compromising the voussoirs.

• Which effect allowed Roman torsion siege weapons to achieve projectile ranges beyond contemporary trebuchets?
• Which outcome typically occurred during prolonged sieges when Byzantine diplomats offered 'protection'?
• Which structural effect arises when water freezes within the porous concrete of Roman aqueduct arches during winter?
• Which structural consequence was mitigated most effectively by layering different materials in ancient ziggurat construction?
• Why was the torsion siege engine's maximum range limited?
• Which outcome resulted in rope bridges of the Inca civilization when using vegetable fiber rather than woven cable?