PSI - Issue 57

Jacques BERTHELLEMY et al. / Procedia Structural Integrity 57 (2024) 872–903 J. Berthellemy / Structural Integrity Procedia 00 (2023) 000 – 000

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Similar rounded gussets were also used for instance for the smaller overpass bridge of Cannes with a very strong plane curvature due to a radius of only 46m presented in Fig. 2. [3]. The use of box girders and LP plates were promoted by Cerema (called Setra at that time) to reduce the height of the thickness transitions as well for single spans [4],[5] as for multiple spans bridges in association with a lowering of the intermediate piers after concreting of the deck. The very innovative motorway bridge of Sedan was in 1985 the first welded bridge in France with a constant beam height where the difference of flange thickness were accompanied by corresponding opposite variation of the web height. According to the recommendations of Ch. Brignon, the web-flange fillet welds were therefore built stronger in the transition zone for the 48-70 mm thickness transition [6],[7]. As shown in Fig. 3-b, the cope hole was also avoided for this flange butt-weld realized on site between two prefabricated segments assembled in factory.

Fig 3-a : Very poor arrangements on a bridge built for the A31 in 1971, at cover plate end with a 245 mm long cope hole Fig 3- b : Sedan’s motorway bridge features realized by Baudin-Chateauneuf in 1986 with butt weld at the slope Figure 3 : Before 1987 cope hopes (3- a) were used exceptionally and “seagull wing” were preferred (3 -b) After 1987, the author of the present paper was also involved by Michel Virlogeux in the design of the anchoring flaps on the pylons of cable-stayed bridges for the bridge at Chalon-sur-Saone, which served as a prototype for this design. The welded plates are presented in Figure 4.

4-a Anchoring element during fabrication

4-b Location of the anchoring element on the completed bridge

In this case it was decided to butt weld a 100mm zone at the end of each plate in front of each anchor.