Permanent deformations are not apparent. Criteria for abutments, wing walls, and steel members need to be developed. Inelastic response may occur, resulting in concrete cracking, reinforcement yield, and minor spalling of cover concrete. The extent of damage should be sufficiently limited so that the structure can be essentially restored to its pre-earthquake condition without replacing reinforcement or structural members. Repair should not require closure.
Permanent offsets are small and there is no collapse.
Although there is no collapse, permanent offsets may occur and damage consisting of cracking, reinforcement yield, and major spalling of concrete may require closure to repair. Partial or complete replacement may be required in some cases. Criteria need to be developed for abutments, wing walls, and steel members. It is also recommended that a two-level design approach be adopted at least for Important bridges in higher seismic zones. The lower-level design requirements should be based on elastic design principles to ensure that there is no damage.