Abstract

Pertuiset Bridge, built in the 80’s over the Loire River in Unieux (France), is one span stay cable of 132 meters

in length composed of one reverse Y shape pylon. Two layers of 13 stay cables supports the main span, and

backstay cables are composed of 2 layers of 10 cables anchored in a counterweight. The deck is composed

of two lateral prestressed beams and prestressed cross beams spaced at each 4m, and was built by cantilever

erection method. In this project, Freyssinet has proposed a complete portfolio of strengthening technologies

such as additional external PT, new micropiles, replacement of stay cables, shotcrete and CFRP. This

strengthening allowed to reduce excessive tensile stresses in the deck and therefore allowed the stay cables

replacement as well as the removal of traffic limitation of 3,5 tons (30 tons now).

Keywords: strengthening, stay cable replacement, post-tensioning, micropiles