Study On Reasonable Arch Axis Of Long-spanconcrete Arch Bridge

Large span arch bridge arch axis usually adopt catenary or parabolic,arc arch axisgenerally apply only to small and medium-span solid-web arch bridge,the circulararch axis rarely applied to large span arch bridge. However,the circular arch axis havethe consistent curvature,the advantages of easy construction. Therefore, to carry outlarge span concrete arch bridge reasonable arch axis’s research,has a very importantsignificance.1) Briefly describes several commonly used arch bridge arch axis equations andthe method for determining the reasonable coefficient of arch axis.Based on theconcept of reasonable arch axis, derivation Arc arch axis equation.2) According to optimization theory and ANSYS zero order and first orderoptimization method,take advantage of language APDL prepared based on main archbending strain energy minimization and pressure line with the smallest deviatio n fromthe arch axis two calculation program,analysis to compare Example for MupengBridge.3) Based on optimization method obtained the arch axis,by means of thethree-point coincide methods fitting arc arch axis, Through the main span180m ofthe Haima bridge dead weight, live load and additional internal forces of calculationand calculating of bearing capacity.The results show that,use circular arc arch axis toget the internal force and after optimization catenary arch axis’s internal force is littledifference. For the arc line at a reasonable arrangement also under construction archspan arch bridge can become a theoretical rational linear derivation,And theestablishment of a simple circular arch model to validate the derived formula4) The paper presents fitting arc arch axis method is applied to A main span400m’s steel truss arch bridge and a CFST arch bridge that’s calculation of span is336m，analysis and comparison of its force. On the text of the two instances of thearch-axis coefficient optimization,the results show that,using two arch axis obtainedaxial force is little difference,although chord member’s moment have some increasesand decreases,but the moment the smaller absolute value in itself,Able to meet thebearing capacity requirements.