External Post-Tensioning Retrofit and High- and Low-Cycle Fatigue Study ofConnections and Joints in Steel-Concrete Box-Girder Bridges

摘要

This paper reports the study of a viaduct retrofit by means of external post-tensioning. The structureis a steel-concrete box-girder bridge and the retrofit has been necessary mainly owing to anadvanced corrosion state which has affected the structural steel of the boxes. During the design twosolutions have been conceived: I) cables with a parabolic development; ii) cables with a rectilineardevelopment. The advantages and the drawbacks of these solutions designed by S.I.GE.S s.a.s. arehere presented. In parallel with this problem, an on going study is being carried out on the: ⅰ)dynamic regime in order to identify the sensitive details; ⅱ) validation of the Finite Element (FE)model by means of output-only ambient vibration tests; ⅲ) optimization and physical testing of thecritical details. This study is devoted to improve both the high- and low-cycle fatigue strength insteel-concrete box-girder bridges and the results achieved so far are here reported.