Character Analysis Of Lateral Force And Slip Friction Between Main Cable And Saddle In Suspension Bridge

As an important bridge structure to across the wide waters,multi-tower continuous suspension bridge has development limitations on calculation theory and construction technology.Actually,the antagonistic relations of anti-slip safety on main cable and ratio of deflection to span,kown as the "middle tower effect",is one of the key contradictions between the multi-tower suspension bridge design to solve.CoMPared with the calculation parameters of anti-slip safety on main cable,which is confined to general arrangement of structure and load subject currently,extracting the nominal friction coefficient of main cable and saddle through model experiment is the most effective method in practical engineering.However,in allusion to research the real slip conditions and action mechanisms of strands in saddle,it is necessary to build a fine contact structure model.The thesis opens up discussion on the issues of anti-slip between main cable and saddle through the following three aspects:(1)Based on the large-scale finite element software ABAQUS/Explicit,the partial fine contact structure model of main cable and saddle system was built to calculate and analysis the distribution patterns of lateral force.Friction contact relations between wires and wires to saddle were setted accurately during the model to discuss the iMPact of strand arrangement,strand tension and friction coefficient of structural components.(2)Based on the large-scale finite element software ABAQUS/Explicit,the complete fine contact structure model of main cable and saddle system was built to calculate and analysis the displacement form of strand tensioning end and the stress variation characteristics at the ends of strands and through the strands.The distribution patterns of lateral force under the corresponding conditions was plugged into the model to simulate the true layered-slipping state,which makes it more reasonable to analyze the characteristics of layered-slipping and force transfer mechanism from the mesoscopic level.(3)Aimed at solving the issues of anti-slip between main cable and saddle,strand arrangement,strand tension and friction coefficient of structural components were discussed to strengthen the anti-slip ability.Deeply,effect evaluation of installing horizontal friction plates or vertical friction plates to achieve the potential of anti-slip contribution was also researched in the paper.The results show that,the line form of lateral force is performed at negative exponential convergent and sharp drop occurs at the bottom of wires.The lateral force is the direct factor of layered-slipping.The layered-slipping phenomenon may be summed up as coming under three categories:upper wires slip before the lower wires,the middle wires slip before the lateral wires at the same odd layer and the strands slip as a whole as soon as the underlying wires slip ultimately.It is efficiently to improve the anti-slip ability of main cable to install horizontal friction plates or vertical friction plates while application of the horizontal friction plates is relatively limited.