Design Parameter Research On Long-span PC Continuous Rigid Frame Bridge

Long-span prestressed concrete continuous rigid frame the selection of design parameters in the design of the bridge is crucial, value reasonable or not directly affect the structure of self-respect and force performance. Therefore, developing large-span prestressed concrete continuous rigid-frame bridge design parameters for such research is of great significance to bridge construction.Firstly, research on bottom curves of box-girder has been launched. Combined with the engineering practice, established 3 representative numerical models. On the basis of model calculating, results about stress and deformation under the dead-weight and vehicle load conditions in given sections of box-girder were analyzed.Secondly, research on height-span ratio has been launched.This chapter has summarized and analyzed the range and characteristics of height-span ratio in long-span PC continuous rigid-frame bridge.Moreover,3 numerical models with different height-span ratio in root section, together with another 3 numerical models with different height-span ratio in middle section, were built.On the basis of model calculating, results about stress and deformation under the dead-weight and vehicle load conditions in given sections of box-girder were analyzed.Then, research on form of longitudinal prestressing has been launched. Combined with the engineering practice, established 3 representative numerical models, results about stress and deformation under the anchor position of the curved web beam prestressing tendon in the largest cantilever beam and the construction in given sections of box-girder were analyzed.Finally, research on rationality of rigidity of continuous rigid frame bridge has been launched. Combined with the engineering practice,design parameters of the double thin-wall pier has been optimized, established 3 representative numerical models. On the basis of model calculating, results about stress and deformation under the dead-weight and vehicle load conditions in given sections of box-girder were analyzed.Through parameter researches introduced above, some conclusions have been achieved.Results on bottom curves indicate that adopting higher power of bottom curve is beneficial for deadweight reduction, meanwhile, stress and deformations in some sections will increase, eventhough effect of such kind of increase is limited.Results of height-span ratio research show that the decrease of height-span ratio in root section will result in a rapid increase of stress and deformation,which is disadvantage for girder to bear lord, while the disadvantage caused by the decrease of height-span ratio in middle span could be balanced by the effect of prestressed tendon easily. Results on form of longitudinal prestressing indicate that the large-span continuous rigid frame bridge must be set up the curved web beam prestressing tendon.The best location for the anchor of the curved web beam prestressing tendon is the two thirds height of the box beam. Results on rationality of rigidity of continuous rigid frame bridge show that with the decrease of the spacing of the double thin-wall pier, results about stress and deformation under the dead-weight and vehicle load conditions of box-girder were slightly increased. So double thin-wall pier spacing neither too big or too small.