The computation of the node quoin,the length of the side and the radius of the spherical surface are given based on the principle of the quoin sum equaling,which provided the theory basis for the geometry design of 272 hedron.

Backgrounded by the main bridge of Zhanhe River Bridge at Chengdonghe Road,Pingdingshan City,the software MIDAS/Civil is used to establish a 3-dimensional finite element calculation model for the double X-shape arch bridge and the effect of arch rib sloping angle changes on the dynamic performance of the type of the bridge is studied respectively for six design alternatives.