Wearing Surfaces for Orthotropic Decks

Chapter 8, "Wearing Surfaces", of the AISC Design Manual for Orthotropic Steel Plate Deck Bridges1 contains the most complete descriptions of current steel deck surfacing systems and specific information on surfacing materials to be found in English language references. This paper presents new information on steel deck surfacing systems in use in the United States, systems proposed for three large orthotropic steel plate deck bridges being constructed or to be constructed in North America, and suggestions on novel components for surfacing systems that possibly justify consideration and further research. Despite the number of unprotected steel plate deck bridges giving satisfactory service in this country, there is agreement that a steel plate bridge deck requires some type of surfacing. Most existing steel plate bridge decks employ "pattern" or "checkered" steel plates. Such plates have different regular patterns of metal projections on the plate surface. The principal objection to unprotected pattern plate for highway bridge decks has not been corrosion of the steel plate, but the low friction developed between the steel plate and rubber tires in most conditions of service. It is generally agreed that steel plate decks require surfacing to improve resistance to skidding. It then follows that the surfacing system must be impervious to moisture. Trapped moisture on a steel plate under a surfacing system, admitted through cracks or holes in the surfacing system, will create a corrosion condition considerably worse than if the surfacing system were not present. The importance of the steel plate deck in orthotropic plate construction, as a member to distribute loads to stringers and as the top flange of stringers and floor beams, requires that the steel deck not be subject to corrosion. Thus, the two foremost requirements for a steel deck surfacing system are that the system must not admit moisture to the steel plate and the surface of the system must provide good resistance to skidding.