Design expectations and monitoring response of the Certosa fly-over in Milan

The fly-over on the Milan Certosa railway junction, built between 1987 and 1989, represents a particular application of a cable-stayed bridge into a urban viability context. Design specifications were exacting and required: a) a section with a minimum depth; b) maximum reduction of any interferences with the rail traffic during all erection stages; c) a preliminary evaluation of the costs caused by the slowing down of the trains. The choice fell on a solution based on a cable-stayed bridge with spans of 45-90-45 m and with a deck depth of 1.60 m. The erection procedure was unusual: firstly, the two halves of the structure were manufactured outside the railway area, and then they were juxtaposed.