New French Standard Test Method for the Design of Surfacings on Steel Deck Bridges

ABSTRACT Basically, the behavior of bituminous surfacings on steel orthotropic decks, under heavy truck traffic and environmental conditions, is highly complex. Both the geometry of the structure and the very high flexibility of metallic plates make the deformations and stresses very severe in steel bridge surfacings. In particular, the repeated loading make the fatigue strength be an important parameter for the design of such bituminous wearing courses. In addition, these specific surfacings must also have durability over the expected temperature range, in particular it must be resistant to thermal cracking at low temperatures and to rutting at high temperatures. The technical studies led in parallel to the construction of the Millau Viaduct (France)—the highest bridge in the world- have provided in particular the opportunity of new progress in the development of appropriate laboratory testing equipment and of an original polymer-modified surfacing. A comprehensive research program including both a large laboratory testing campaign and a finite element parametric study was performed in order to develop a handy tool for design of plate surfacings. In particular, this paper presents the five-point bending fatigue test developed at the APPIA central laboratory for the performance-based design of bituminous wearing surfacings on orthogonally anisotropic steel bridges. The methodology of this five-point bending fatigue test is about to become a new French standard test method [AFN 06].