Tentative Design Rules for Innovative Bridge Decks Comprising Sandwich Plate System Panels

Bridge decks in Canada, a vulnerable part of our transportation infrastructure, have required rehabilitation that is costly and disrupts traffic. To increase the life of concrete decks concrete quality has been improved and various schemes used to reduce or eliminate cracking insofar as possible. The Canadian Highway Bridge Design Code, CAN/CSA-S6-00, a Limit States Design document gives the basic requirements for the Ultimate, Fatigue and Serviceability Limit States, as applicable, for bridges comprising different materials such as steel, concrete, wood. This paper presents the proposed Limit States Design rules for innovative bridge decks comprising Sandwich Plate System (SPS) Panels that replace concrete decks. The rules could form an integral part of Section 10 Steel Structures of the CHBDC. SPS deck panels are shop fabricated by injecting a two-part thermosetting liquid elastomer into a cavity formed by two steel faceplates bounded by perimeter bars. The elastomer core bonds to the steel, acts as a web and provides continuous support to the faces precluding local plate buckling and eliminates closely-spaced stiffeners though stiffening plates may be added. The flexural stiffness and strength are tailored as required by using appropriate thicknesses for the sandwich elements. The Shenley Bridge constructed in 2003 in Québec is presented as an example. Expected advantages of SPS panels are reduced time for construction, weight and maintenance. The elastomer dampens vibrations naturally. Composite action with main structural elements increases their stiffness and flexural strength appreciably. Long life is foreseen.