The advancement of wire rope in movable bridges

Abstract

The paper describes the recent developments made in the design and manufacturing of wire rope for specific uses as Counterweight and Operation ropes on vertical lift bridges. New wire rope materials and designs provide increased strengths and improved mechanical properties allowing designers and engineers to take full advantage of the material strengths available. These developments involve high tenacity synthetic materials protected by high strength corrosion resistant carbon steel wires. This provides a hybrid wire rope with a high strength to weight ratio, low torque, and excellent operating characteristics that can outperform any wire rope related product currently available on the market. The results are longer field service, increased corrosion protection, less maintenance, and smaller diameter wire ropes in service applications. All of these characteristics are beneficial to the owner/operator of the movable structure. The paper will discuss the mechanical properties and benefits of improved wire rope constructions verses those currently specified for use in the American Association of State Highway and Transportation Officials (AASHTO) Standard Specification for Movable Bridges and the American Railway Engineering and Maintenance-of-Way Association (AREMA) Manual for Railway Engineering. The use of new technology in Vertical Lift Bridge applications is non-existent in the United States. The European community utilizes wire rope products as described above to transform movable structures into iconic bridges. AASHTO and AREMA have made recent progress in adopting new wire rope standards; however, the ever changing developments in wire rope will require more change over time.