Key Design Techniques of High-Rise Piers of Jinyanghe River Bridge
Located in a valley of a high mountain area,the main bridge of Jinyanghe River Bridge is a continuous rigid-frame bridge with two main spans of 200 m,and three side spans of 106,115 and 40 m,capable of withstanding 7.7 magnitude earthquakes,with 10％probability of exceedance in 50 years.The main piers No.5-No.7 measure 113,196 and 182 m high,respectively,and the three piers exhibit significant transverse seismic responses.The higher piers No.6 and No.7 are sloped on two sides along the bridge width,and all the three piers keep constant dimension along the bridge length to facilitate construction.Dampers are installed in the superstructure to achieve seismic energy dissipation along bridge length.All the main piers are endowed with matched stiffness to allow the cross-sectional seismic responses to be with a rational proportion.All the main piers are rectangular composite piers,each consisting of four concrete-filled steel tubes,reinforced concrete webs,and reinforced concrete diaphragms installed every 12 m along the heights of the piers.The piers are consolidated with the pier-top girder segments,with dapped ends,while connected with the pile caps via bearing plates and PBL connectors.The calculations of the entire bridge structure indicate that the piers meet the load bearing demands at the serviceability limit state and the ultimate limit state as well as under the action of E2 earthquakes,and the pier-top horizontal displacements are smaller than the deformation allowances given in the codes.During the construction of the piers,the steel tubular skeletons were sequentially installed,encased with concrete using hydraulic climbing formwork,and connected by webs.A multi-point synchronous heavy lifting system was applied,instead of the large-scale tower cranes,to reduce the safety risk of mid-air work and cut down construction costs.
万方数据
维普
