General Information

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

Suspended bridge.
Suspended bridge over a river
Tower-to-tower distance ≅ 35 m
Width ≅ 1 m
Tower Reinforced concrete
Cross-beam Built-up section
Number of walkway cables 3


Figure 2 shows a schematic lateral view of the bridge.

Lateral view.
Lateral view of a suspended bridge

The span (s) is about 35 meters, and the height difference between A and B is about 2 meters.

  • How does the ratio between the span (s) and the height difference (A - B) affect the feasibility of a suspended bridge?
  • Figure 3 shows a side view of a tower.

    Suspended bridge tower.
    Tower of a suspended bridge

    A tower is made of a front and a back (diagonal braced) unit; the former anchors the walkway and intermediate barrier cables, while the latter anchors the handrail and top barrier cables.

  • What are some possible reasons for the used tower configuration?
  • Bridge Cross-Section

    Figure 4 shows a schematic partial cross-section of the bridge.

    Cross-section of a suspended bridge

    A cross-beam consists of two side-by-side placed lipped channels, over which are placed two side-by-side placed rectangular hollow sections. Lipped channels and rectangular hollow sections are connected by U-bars and plates; the former are welded, while the latter are welded in the bottom region and bolted in the top-end region. The cross-beam spacing is about 1.5 meters, and the floor system is framed. The hangers are made of steel wire ropes and run below the lipped channels. The connection between hangers and lipped channels is by direct contact at the channels' ends and via the walkway cables at the channels' bottom sides. Figure 5 shows a bottom view of the bridge.

    Bottom view.
    Bottom view of a suspended bridge

    The walkway cables are marked by the numbers.

  • What are some possible reasons for the used cross-beam?
    What are the main problems of the hanger to cross-beam connection?
    What are the main pros and cons between hangers made of steel wire ropes and hangers made of steel rods?
  • Alternative Variant

    A schematic partial three-dimensional view of the applied variant and a variant with a single-unit tower are shown in figure 6.

    Applied and alternative variants.
     Three-dimensional view of two suspended bridges

    If the height difference between A and B of two meters in variant 1 is too big, the tower on shore B (e.g., access ramp gradient) will be adjusted accordingly.

  • What is a possible cross-section of variant 1?