Earthquake damage to China's Miaoziping Bridge has now been fully repaired, following Saturday's placement of the final batch of underwater concrete after a difficult operation to install steel formwork deep underwater. The bridge over the Zipingpu Reservoir in the Sichuan province suffered severe damage in last year's major earthquake.
The bridge is part of the Duwen Expressway, which is due to open on 12 May. The provincial government said that repairing the bridge's fifth pier was of vital importance to the opening of the expressway to traffic and it took 53 days to achieve a satisfactory solution. Placement of the underwater concrete began after a third set of integral steel box formwork was successfully sunk to a depth 56m underwater on 16 April. Since then, 800t of concrete have been placed, using eight pouring conduits operating from the 100m-high deck.
The 1,436m-long Miaoziping Bridge had been completed but was not open to traffic at the time of the earthquake, which caused shifting of the piers and one of the T-girder spans to fall.
A report by M Hamada of Waseda University and Ö Aydan of Tokai University in Japan said that the earthquake caused the shifting of bridge girders longitudinally and laterally. One of the T-type girder approaches fell down. Surveying indicated that the distance between piers was increased by more than 500mm and that there were all-around fractures, spalling and bending cracks in the pier just above its foundation (see link below for link to the report on the website of the World Federation of Engineering Organisations).
