Safety Assessment and Strengthening for Long Span Double-curved Arch Bridge with Design Drawing Lost

There are many old damaged double-curved arch bridges serviced for more than 40 years with design drawing lost are still used in West China. Based on the repair and improving the carrying capacity work of a damaged badly double-curved arch bridge whose design drawing is lost with main span of 41.0m constructed in 1962 in Sichuan province of China, health inspecting and safety assessment for this type bridge using non-destructive methods is studied. Then the strengthening design of filling concrete and enlarging the section method is proposed. High performance self-dense slight-expansion concrete and embedded bar techniques are applied in strengthening construction. After the strengthening work completed, the arch bridge is still in very good work condition experienced two devastating disasters of the 2008 Sichuan Wenchuan and the 2013 Sichuan Lushan earthquake, with the distance of bridge site to epicenter less than 100km, which proved the safety assessment and the strengthening design proposal are effective and feasible.