Ohio River Suspension Bridges: An Inspection Report

For many years, suspension bridges have been employed to economic advantage where long uninterrupted spans were required. While they have been supplanted for most common applications by cantilever and arch bridges in the United States, suspension bridges are a valid design type. Two American suspension bridges have been in service for over 100 years. A new form of suspension bridge, the cable-stayed bridge, is widely used in Europe and is expected to be as popular in the United States. The key to the success of suspension bridges lies in the use of high-strength wires that are consolidated into the main cables. These cables support very heavy loads, compared to common structural-steel members. This allows designers of suspension bridges to employ lower dead loads than necessary for other types of bridges for equivalent live loads and spans. Unfortunately, to achieve economy of construction, load-bearing redundancy is usually sacrificed in most suspension-bridge designs. If a main cable of a suspension bridge should beak, the bridge would collapse in a catast rophic manner. Therefore, defects in the main cable wires of a suspension bridge may be significantly more critical than defects in structural members of other bridge types