Suspension bridge major wire-cable suspension bridge was the in Philadelphia, Pennsylvania. Designed by Charles Ellet, Jr. and completed in 1842, it had a span of 109 m. Ellet's Niagara Falls Suspension Bridge (1847–48) was abandoned before completion. It was used as scaffolding for John A. Roebling's double decker railroad and carriage bridge (1855). The Otto Beit Bridge (1938–39) was the first modern suspension bridge outside the United States built with parallel wire cables. The main forces in a suspension bridge of any type are tension in the cables and compression in the pillars. Since almost all the force on the pillars is
All-dielectric self-supporting cable No metal wires are used in an ADSS cable. Optical fibers are either supported in loose buffer tubes, or arranged in a ribbon configuration. To prevent strain on the fibers, most types provide the fibres with excess slack length compared to the length of the supporting member. Several designs of cable are used. In one type, small plastic tubes each containing up to eight fibers are filled with a gel compound, and stranded around plastic rods. The hydrocarbon gel compound prevents water from wicking along the length of the cable. The inner structure is wrapped with polyester tapes and encased