山区高墩矮塔斜拉桥结构与美学设计

洪溪特大桥为跨越峡谷的山区桥梁,采用(150+265+150)m的双塔双索面预应力混凝土矮塔斜拉桥,桥塔横桥向为Y形,顺桥向塔柱截面从塔底往上逐渐线性收缩,到达上塔柱斜拉索锚固段后再线性渐变加大,塔梁固结,索面向外倾斜.通过强化桥面以上的结构体量,实现高墩矮塔斜拉桥桥面上下比例的协调匀称.采用M IDAS Civil进...

Aesthetics and Structural Design of Extradosed Bridge in Mountainous Area

The Hongxi Bridge,which crosses a ravine in a mountainous area,is a prestressed concrete extradosed bridge with a main span of 265 m and two side spans of 150 m.From elevation view,the two pylons are Y-shaped prestressed concrete structures,while from a side view,the pylon column tapers upward to the stay cable anchorage section,afterwards,grows wider towards the top.The pylons are fixed with the main girder,and the double cable planes flare outwardly.The structure volume above the deck is modified to create more aesthetically harmonious vertical layout of the extradosed bridge with high-rise piers.MIDAS Civil was used to carry out spatial finite element analysis.The calculation indicates that the structure can meet the design requirements.The pylon-to-girder connection locations were locally analyzed and transverse stresses in the superstructure were computed.To alleviate the stress concentration effect,the dimension of haunches was enlarged and the reinforcement of prestressing tendons was improved.Prestressing tendons were added to the diaphragms inside the main girder to balance the horizontal component of the stay cable forces along bridge width.The length computing coefficient was calculated using the simplified equations given in the codes and the Euler’s formula for critical buckling load calculation,to make the pylon design more acceptable in economy and aesthetics.