The footbridge crossing the Beijing-Hangzhou Grand Canal is designed as an inversed Fink truss structure that is arranged in a main span of 450 m and two side spans of 15.9 m,with the total length reaching 198 m.Designers drew on the typical canal elements---the boats,sails and shadows,to create a unique structure over the canal.The deck consists of closed three-cell steel box beams.Fixed with the deck,the pylons and the connecting struts are all shuttle-shaped steel components that are arranged along the center line of the bridge.The stay cables,containing hot extruded high-density polyethylene steel strands that feature high stress ranges,are connected with the pylon head via forks and anchored to the deck by the cast button-headed anchorages that permit the adjustment of cable tensions.The overall stiffness of the inversed Fink truss bridge is significantly related to the tension forces of stay cables,thus the key in the design of such type of bridge lies in the determination of the effective initial stay cable tensions.Due to that the stay cable tensions in the side spans are relatively greater after the completion of the bridge and the locations of the anchorages are restricted by the construction space,integral load transfer plates are added at the connections of the stay cables and the deck,to guarantee a reliable load transfer path.As per the human-induced vibration analysis,a pair of TMDs are installed at two locations of the deck,each 28 m to the midspan to ensure the required human travelling comfort.
footbridgeinversed Fink trussstay cable initial tensionload transfer mechanism of end cableshuman-induced vibrationtuned mass damperbridge design
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