Final answer:
An arch bridge primarily experiences compression forces and eliminates tension stresses. However, it does experience outward thrust at the base that needs to be restrained.
Step-by-step explanation:
An arch bridge does not experience much tension. Arch bridges are designed to carry forces through compression. The arch shape allows the forces on the bridge to be resolved into compressive stresses, pushing downward and eliminating tensile stresses pushing outward. However, arch bridges do experience outward thrust at the base, which needs to be restrained with internal ties or external bracing to maintain arch action and prevent collapse.