STRUCTURAL ANALYSIS OF CABLE-STAYED STRUCTURES IN THE CONSTRUCTION SEQUENCE OF BRIDGES BUILT BY CANTILEVERING

Cable structures are often used as final or partial intermediate structures in construction stages of bridges like arch bridges or cable-stayed ones. These bridges are built often by cantilevering, i.e. with subsequent cantilever partial structures, which are cable-stayed too; hence, every construction stage is a cable structure to be analyzed. The methodology of structural analysis of these construction stages as well as the modeling of the structure for the determination of initial cable force are fundamental steps for establishing the actual state of stress and deformation. In the paper, a general methodology of analysis for construction sequences of cable-stayed structures is presented, which can be used both for the design of cable-stayed bridges and arch bridges. The proposed methodology is based on the simple analysis of multiple partial elastic schemes, which follow the actual construction sequence. The aim is that of obtaining a convenient final geometry through the control of deformations from the first stage to the last one, coincident with the service life configuration. Geometry and internal forces are contemporary checked, as well as cable forces are determined without the need of too many stressing adjustments. Results of analyses, performed for different case-studies, are reported, summarized and commented, in order to show the reliability and the wide range of applicability of the proposed methodology of analysis.