Study of Adaptability and Main Cable Slip Resistance Technique of Three-Tower Suspension Bridge

Three suspension bridges including Taizhou Changjiang River Highway Bridge are cited as examples.The adaptability of the three-tower suspension bridge is analyzed and the type selection of the intermediate tower,slip resistance safety coefficients between main cables and saddle troughs and global rigidity value of the bridge are studied.The results of the study reveal that the key to the technical breakthrough of applying the three-tower suspension bridge is the determination of rational longitudinal bending rigidity of the intermediate tower,the friction coefficient of 0.20 to be adopted between the main cables and saddle troughs is appropriate and it is proposed that the slip resistance safety coefficients between the cables and troughs should not be less than 1.65.As for the Taizhou Changjiang River Highway Bridge,the maximum vertical deflection of its stiffening girder due to the vehicle load that does not take into account of impact is 4.337 m(downward),the deflection-to-span ratio is 1/249 and the selected deflection-to-span ratio is a trial and practice of the global rigidity of the three-tower suspension bridge.If the friction coefficient of the Taizhou Bridge is taken as 0.2,the global rigidity can be further enhanced.