Many highway bridges were severely damaged or completely collapsed during the 2008 Wenchuan earthquake.A fi eld investigation was carried out in the strongly affected areas and over 320 bridges were examined. Damage to some representative highway bridges is briefl y described and a preliminary analysis of the probable causes of the damage is presented in this paper. The most common damage included shear-fl exural failure of the pier columns, expansion joint failure, shear key failure, and girder sliding in the transversal or longitudinal directions due to weak connections between girder and bearings. Lessons learned from this earthquake are described and recommendations related to the design of curved and skewed bridges, design of bearings and devices to prevent girder collapse, and ductility of bridge piers are presented. Suggestions for future seismic design and retrofi tting techniques for bridges in moderate to severe earthquake areas are also proposed.

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Y-branching multiwalled carbon nanotubes with a bamboolike structure were grown by chemical vapor deposition from a C–H–N gas system when B2O3 and Ti was supplied. Transmission electron microscopy images reveal that these novel junctions contain a tube branched into two tubes with nearly the same diameter. In addition, the tube walls show perpendicularly stacked graphite planes, which take on a bamboolike structure. The influence of preparation conditions on the structure of these carbon nanotubes is discussed. This novel structure may offer promising application for nanotube-based composites.

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