General Information
Figure 1 shows a pedestrian suspension bridge.
![Suspension bridge in a park.](bridges/suspension-bridges/bridge-7/1-suspension-bridge.jpg)
Type | Single-span suspension bridge |
Main span | ≅ 50 m |
Deck width | ≅ 2 m |
Deck width to main span ratio | ≅ 1:25 |
Pylon | Reinforced concrete |
Girder | Steel half-through truss |
Hanger Cables
There are three types of hanger cables, as shown in the schematic lateral view in figure 2.
![Lateral view of a pedestrian suspension bridge.](bridges/suspension-bridges/bridge-7/2-lateral-view.jpg)
Type 1 consists of two cables with a turnbuckle; type 2, of one cable with a turnbuckle; type 3, of two cables. Type 1 is installed from the main span beginning until the mid-span region, followed by type 2 (only two hangers per main cable); type 3 is installed in the remaining mid-span region. The cables are made of steel wire ropes. An example of the three types of hanger cables is shown in figures 3 to 5.
![Hanger made of two cables and a turnbuckle.](bridges/suspension-bridges/bridge-7/3-hanger-turnbuckle.jpg)
The hanger cables are connected to the main cable by U-bolt clamps. The end fittings of the turnbuckles are eyed on the top, and hooked on the bottom; the former is connected to cable A, while the latter is connected to cable B, which is looped around an upper node of the half through-truss. The cables are terminated by U-bolt clamps: five for cable A, and three for cable B.
![Hanger made of a turnbuckle and a cable.](bridges/suspension-bridges/bridge-7/4-turnbuckle.jpg)
Cable B has two U-bolt clamps.
![Hanger made of two cables.](bridges/suspension-bridges/bridge-7/5-hanger.jpg)
One U-bolt clamp is installed on cable A, and four U-bolt clamps are installed on cable B.
What is the purpose of the above shown hanger cable concept?
What are the main problems of the above shown hanger cables?
Girder in the Pylon Region
The half-through truss in the pylon region is connected to a bottom structure, as shown in figure 6.
![Half-through truss in the pylon region.](bridges/suspension-bridges/bridge-7/6-pylon-region.jpg)
The bottom structure consists of a tapered truss made of circular hollow sections.