General Information

Figure 1 shows a pedestrian suspension bridge.

Pedestrian suspension bridge.
Pedestrian suspension bridge over a river
Type Single-span suspension bridge
Main span ≅ 35 m
Deck width ≅ 1.5 m
Deck width to main span ratio ≅ 1:23
Pylon Reinforced concrete (A-longitudinal shaped)
Girder Curved steel truss

Pylons

Figure 2 shows a schematic lateral view of the bridge.

Lateral view.
Schematic lateral view of a pedestrian suspension bridge

Pylon A is placed in the river. Figure 3 shows a side view of the bridge.

Pedestrian suspension bridge.
Pedestrian suspension bridge with a tower in the river
  • What are some possible reasons for placing pylon A in the river?
    What are the main structural and constructive consequences?
  • Figure 4 shows a side view of pylon A and a schematic partial three-dimensional view of it.

    Pylon A.
    Side view 3D-view
    A-longitudinal shaped pylon of a pedestrian suspension bridge
  • What are some possible reasons for using this pylon shape?
  • Truss Girders to Pylon Connections

    The truss girders of the main and approach spans are connected to the pylons as shown in figures 5 and 6, respectively.

    Main span to pylon B connection.
    Connection between main span truss girder and pylon

    The mid-span regions of the bottom chords are directly connected to the support member.

  • What are some possible structural problems?

  • Approch span to pylon B connection.
    Connection between side span truss girder and pylon

    The truss end is connected to the pylon by a steel frame, embedded plates, and nuts and bolts.

  • What are some possible structural and/or constructive reasons for the used connection?
    Why are main span and appproach span connections different?
  • Curved Truss Girder

    Figure 7 shows a side view of the main span.

    Main span.
    Main span curved truss girder of a pedestrian suspension bridge

    The girder of the main span consists of a slightly curved steel truss.

  • Supposing to use a horizontal truss with the same height, width, and member size as the curved truss, would there be a structural safety or serviceability problem?
  • Main Cable

    A main cable consists of three side-by-side placed steel wire ropes, as shown in figure 8.

    Main cable.
    Main cable of a pedestrian suspension bridge

    A wire rope has a diameter of approximately 30 mm.

  • Are three steel wire ropes required for structural reasons?
  • Main Cable Anchorage

    Figure 9 shows a main cable anchorage.

    Main cable anchorage.
    Main cable anchorage

    The U-anchors have a different non-embedded length l.

  • Does the length l affect the structural behavior of the bridge?