The main bridge of Malutang Bridge is a two-pylon cable-stayed bridge with a main span of 480 m,two side spans of 137 m and two end spans of 63 m.One abutment of the bridge is connected with a continuous arch tunnel.The superstructure consists of steel I girders that act compositely with the steel floorbeams,stringers and overlaid concrete slabs,and the full deck width reaches 32.2 m.The two diamond-shaped concrete pylons rise 247 and 254 m,respectively.The stay cables are arranged in spatial double cable planes.To smoothly connect with the tunnel,the deck of the bridge at the abutment is split into two,each carrying vehicles in one direction,thus avoiding the integral widening of the deck or designing the tunnel as an integral long tunnel,and shortening the length of the continuous arch tunnel as well.A longitudinal elastic restraint system with an elastic restraint stiffness of 12 MN/m is installed between the pylons and the superstructure to modify the structural responses of the bridge structure under vehicle,thermal and wind loads.As a result,the girder-end displacement is reduced by 37.4％and 35.9％,and the pylon-bottom longitudinal bending moment is decreased by 19％and 20％,under static and dynamic actions,respectively.Under static actions,the stresses in the steel girders are reduced by about 30 MPa,and the anti-cracking stress margin of the deck slabs is improved by 1.13 MPa.When the girders were lowered 10 cm onto the auxiliary piers,the anti-cracking stress margin of the composite slabs atop piers is improved by 117.7％,without inducing significant changes of the load bearing behaviors of other primary structures.The two-segment installation cycle effectively shortened the construction schedule.
维普
万方数据
