General Information

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

Suspension bridge.
  Suspension over a river
Type Single-span suspension bridge
Main span ≅ 75 m
Deck width ≅ 2 m
Deck width to main span ratio ≅ 1:36
Pylon Reinforced concrete
Girder Steel truss

Hangers and their Connections

Figure 2 shows a schematic lateral view of the bridge.

Lateral view.
Lateral view of a single-span suspension bridge with two hanger types

There are two hanger types: type 1 is made of a steel wire rope (black lines), while type 2 is made of a steel rod (red lines); they are alternately arranged, and the spacing is approximately 0.8 m. The connections to the main cable and to the girder are shown in figures 3 and 4, respectively.

Hangers to main cable connections.
Connections between hangers and main cable

Type 1 is connected to the main cable by a U-bolt and a two-hole frame plate placed over the main cable, and the hanger termination consists of U-bolt clamps; type 2 has a ring termination and is connected to the main cable by a shackle and a cable band. The wire rope and the rod have approximately the same diameter.

Hangers to girder connections.
Connections between hangers and truss girder

Type 1 is connected to the gusset plate of the bottom node by an eye bolt and an angle plate; type 2 is connected to the gusset plate of the upper node by an angle plate and a washer and bolt.

  • Dos hanger type 1 structurally behave like hanger type 2?
    What are some possible reasons to use two different hanger types and connect them to the girder at different elevations?
  • Pylons' Backstay Cables

    Figure 5 shows a front view of a pylon.

    Pylon.
     Reinforced concrete pylon of a suspension bridge

    Besides the main cables, each pylon is connected to two sagging backstay cables made of steel wire ropes. The anchorage to the pylon is shown in figure 6.

    Backstay to pylon anchorage.
     Backstay to pylon anchorage

    The backstays are terminated with U-bolt clamps, and the anchorage consists of two U-brackets and a U-bar; the latter is placed over the cross-beam and welded to a U-bracket. Figure 7 shows the opposite anchorage.

    Backstay anchorage.
    Backstay anchorage

    The backstay is connected to the same bridge socket used for the main cable anchorage by a turnbuckle and an additional wire rope; the latter is bent around the socket and terminated with U-bolt clamps.

  • What is the purpose of the backstay cables?