DANG@TUNG@DANG

A Study on Shape-finding and Structural Analysis for Suspended Structures

Eiji IWASAKIC Masatsugu NAGAI

Recently, cable member has played an important role in realization of long-span suspended bridges. On the other hand, problem of shape finding of cable structures becomes very important since cable element is flexible and shape of cable does not settle until acting self-weight, pre-stress and external load.
In this paper, I propose a method to determine shape-finding for suspended structures by introducing two constraint conditions of cable pre-stress. First, I assume that known horizontal component of cable tension is equal at all pulley. Secondly, I suppose that the displacement equals zero at the position in which the girder is supported by cable. @Above-mentioned conditions are reasonable because bending moment of tower does not happen under the action of the dead load of girder and bending moment of girder has the same features as bending moment of continuous beam. This situation can be represented if the cable passes through the pulley on the supports, other cables or other beam element.
A cable element is proposed in this study for flexible cable structure with pulley. This element is formulated by modified functional of variational principle. It also has the same characteristics as ordinary finite element based on the displacement method in which displacements are unknown variables.
Several numerical examples are presented to confirm the accuracy and effectiveness of proposed shape-finding procedure.