Study Of The Force Behavior On Oblique Tower Of Cable-stayed Bridge With Backstays

Oblique tower of cable-stayed bridge with backstays is a new type of cable-stayed bridgewhich combines short-tower cable-stayed and cable stayed bridge with backstays, itsmechanics characteristics is very complex. The development and basic theory methods of theoblique tower of cable-stayed bridge with backstays are introduced in this paper. At last, theFEA softwares midas civil and midas fea are used to simulate an oblique tower ofcable-stayed bridge with backstays and analyze global and local mechanics performance,stiffness parameters effects.The main results can be obtained in this paper.Firstly, static finite element analysis on oblique tower of cable-stayed bridge withbackstays are carried out to simulate the construction process into a bridge operation process,and the cable force the end of the cable to exit. In the process of construction and operator, thebeam and the tower are in the range of reasonable state of compression. On the one hand, themain span lateral force and the resultant force direction of the cross-side lateral force arecloser to the tower axis direction, the axial pressure reserve to the towers, on the other hand,the cable-stayed horizontal direction of the force which helps the formation of eccentricmoment on beam force plays external pre-stressing effect. When the cable force of the largesttail cable exit, near the top of the tower at the displacement bias main span side has seriouslyexceed the maximum allowable value specification.Secondly, through finite element analysis on tower-beam-pier consolidation core area ofoblique tower of cable-stayed bridge with backstays, it can be found that principal tensilestress gradually decreases from the core area to side span box girder, the principalcompressive stress gradually increases from the core area to side span box girder. The lateralcable resultant force resulting from main span and side span produces counter clockwisebending moment which results in tensile stress at bottom plate of side span box girder andcompressive stress at roof of side span box girder.Thirdly, the variational stiffness of main parts effect on structure is studied in this study,the results show that the stiffness of main beam and main tower have greater effect ondisplacement and stress, less effect on the cable force. In addition, the approximate concave curve relate to the relationship between cable live load factor and the line stiffness ratio oftower and beam can be obtained. When the line stiffness ratio of tower and beam is close to1,the maxiumm value can be goten, however this value is still less than ε. The bridge hasshort-tower cable-stayed bridge characteristics.