Mechanical Behavior Analysis On The Arch Single Pylon Cable-stayed Bridge With Wide Deck

To explore the mechanical behavior characteristic of wide deck arched single pylon PC cable-stayed bridge,the spatial analysis of PC box beam and the integral stiffness analysis of none end anchored cable single pylon system were conducted,based on the beam grid method,specific to the structural characteristic of wide deck single pylon double plane PC cable-stayed bridge.Segmentally cast-in-place method was used according to the background project,and the shape and stress status of that in construction and complete state were compared with those of the overall cast-in-place ones and segmentally cast-in-cantilever ones.Besides,after the structure dynamic calculation,it is verified that the structure dynamic performance met the related requirements.The main work and main results were listed as followings.(1)The spatial analysis was conducted for wide deck PC box beam base on beam grid method.The effects of different cross section division mode on calculation results for wide deck PC box beam were analyzed.For the same simplified structure,the calculation results in stress,deflection and axial displacements for beam grid methods were compared with those of solid element methods.The results showed that in spatial analysis of wide deck PC box beam,when beam grid method was used,the elements should be divided by box web according to the principle that neutral axis was the same,and for beam grid method the accuracy of deflection calculation was higher than stress calculation.And the transverse beam of wide deck PC box beam was under effect of non-negligible out-of-surface moments,being in a complicated stress status,and thus the transverse uniformity of pre-stressing force should be paid attention to in design,lowering the effects of out-of-surface moments for transverse beam.(2)The comparison analysis of main beam construction methods was conducted.Without changing the initial pre-stressing cable force in construction,analysis was conducted in 3 aspects,respectively,cable force,main beam stress and camber in construction.The result verified that it was feasible to change segmentally cast-in-place to overall cast-in-place without changing the initial pre-stressing force in construction,effects on force and displacement very little,negligible.And it was feasible to change segmentally cast-in-place to segmentally cast-in-cantilever,but camber and cable force adjustments scheme should be changed.(3)The overall stiffness analysis of none end anchored cable single pylon system was conducted.The sensibility of pylon top displacements and of maximum main beam deflection of live loads to pylon stiffness,cable stiffness,beam stiffness was studied and to stiffness of cable different positions were studied.It was verified that changing the main beam cross section height was the best method to optimize the overall stiffness.(4)The ability of wind resistance and shock resistance was verified by the analysis of dynamic behaviour of structure in complete state.(5)The main works of this paper were summarized and the following research was discussed.