Which mechanism limited maximum stone span achievable in Roman arch construction before concrete?

💡 Explanation

Before concrete, arches relied on individual voussoirs, where tensile forces at the keystone’s bottom edge become significant as span increases, initiating cracking when tensile strength limits are surpassed. Therefore, tensile strength limits span, rather than shear which is managed by geometry, frame deformation which affects precision, or abutment compression which relates to arch stability.

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