China Earthquake Reconnaissance Report: Performance of Transportation Structures During the May 12, 2008, M7.9 Wechuan Earthquake

摘要

This report documents the lessons learned from damage caused in the May 12, 2008, M7.9 earthquake in Wenchuan County, China. The damage to the 14 observed bridges reminded the researchers of damage suffered during the 1971 San Fernando Earthquake in California. The bridges had few seismic details such as long seats, large shear keys, or tightly spaced transverse reinforcement. Most arch and girder bridges collapsed due to surface rupturing of the seismic faults in the Longmen-Shan thrust zone. A significant portion of roadways and bridges were pushed away or buried by landslides in the steep slopes of mountainous terrain. Damage to bridge superstructure included unseating of girders, longitudinal and transverse offset of decks, pounding at expansion joints, and shear key failure. The bearings of several girder bridges were either crushed or displaced significantly. The substructure and foundation of bridges were subjected to shear and flexural cracks, concrete spalling, stirrup rupture, excessive displacement, and loss of stability. More damage occurred in simply supported bridges than in continuous spans. Curved bridges either collapsed or suffered severe damage. Evidence of directivity effects on bridges near the earthquake epicenter was observed during the earthquake. The San Fernando earthquake significantly changed the seismic design and construction of bridges in the United States. The Wenchuan earthquake is expected to have the same significance for China's bridge engineers.