Construction and control technology of the main bridge superstructure of Sutong Bridge

摘要

The Sutong Yangtze River Bridge(short as Sutong Bridge)is now the largest span cable-stayed bridge in the world.The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span,assistant span and tower area,erection of standard girders and closure of the middle span.The big block girders were hoisted by a floating crane,and the standard girders were hoisted by a double crane system on the deck.The pushing assistant method was adopted for the middle span closure construction.Furthermore,key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically.An all-stage self-adaptive geometry control method was used in the construction process.By accurately controlling the unstressed dimensions and shape of all structural components in each step,and realization that the control system and the controlled system adapt to each other,the goal was to make control of the final line shape and inner force of the bridge structure achievable.Two solutions,including GPS based and total station based dynamic geometry monitoring systems,were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state.Finally,research on the wind-induced vibration of the superstructure during the construction period was executed.Buffeting response analysis to the longest single and double cantilever states were carried out.The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made,and corresponding wind resistance measures were suggested.The as-built geometric error and cable force error were controlled in a required design range,and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.