General Information

Figure 1 shows a suspension bridge that is used by motorcycles, bicycles and pedestrians.

Suspension bridge.
Suspension bridge over a river
Type Single-span suspension bridge
Main span ≅ 250 m
Deck width ≅ 2 m
Deck width to main span ratio ≅ 1:125
Pylon Reinforced concrete (H-shaped)
Girder Steel transverse beam

Sag to Main Span Ratio

Figure 2 shows a side view of a main span sector.

Main span.
Main span sector

The sag H ≅ 10 m, and the main span S ≅ 250 m; that gives a sag to main span ratio of 1/25.

  • How does a low sag to main span ratio affect the structural behavior of the bridge?
  • Main Cables

    Figure 3 shows a main cable in the main span region and a schematic cross-section of it.

    Main cable.
    Side view Cross-section
    Main cable and cross section of it

    A main cable consists of ten steel wire ropes, which are bound together by U-bolt clamps and plastic strips. Figure 4 shows the main cables in the bridge entrance region.

    Main cables.
    Main cables in the bridge entrance region
  • What are the main problems?
  • Hanger Cables

    Figure 5 shows a side view of a main span sector.

    Main span.
    Main span sector

    Figure 6 shows a mid-span region sector.

    Mid-span region.
    Main span mid-region sector

    The roadway and the main cable are about at the same elevation. The hanger cables are wrapped around the main cable and fixed with U-bolt clamps. Figure 7 shows a hanger cable before the mid-span region and a hanger cable in the mid-span region.

    Hanger cables
    Before the mid-span region Mid-span region
    Hanger cables before the mid-span region and in the mid-span region
  • What are some possible reasons for the used mid-span region connection?
    What are the main problems?