e-mosty March 2019 Long Span and Multiple Span Bridges - Page 46

Figure 2: The Cuzbac Bridge, France Figure 3: Loire River Bridge, France constructed, there has recently been a renewed interest in this structural form. The advantage of the multi span suspension bridges is in the ability to span long distances in water where conventional long-span bridges or shorter span viaduct construction is not economic. If end spans are added the suspended length can be increased by a factor of 3 or more compared with a single span. Multi-span bridges were common in the early development of suspension bridges. However, there can be a significant reduction in stiffness with this type of structure. The 6-span St Nicholas Bridge (Figure 4) over the Dnieper (Dnepr) River in Kiev was the longest length suspension bridge until the construction of the more famous Brooklyn Bridge. Most of the 20 th century multi-span bridges such as San Francisco West Bay Bridge, USA, the Seto- Chuo Crossing and Kurushima-Kaikyo Bridges in Japan (see Figures 5 - 7) have used two conventional 3-span bridges placed end to end with a common anchorage to overcome the stiffness problem. Twin span bridges (often called three tower bridges in China) can result in bridges that cover the same distance but are more economic to build. With the construction of the Taizhou Bridge 3 and Maanshan Bridges in China and with others being Figure 4: St Nicholas Bridge, Ukraine 1/2019