General Information
Figure 1 shows a suspension bridge that is used by motorcycles, bicycles and pedestrians.
| Type | Two-span suspension bridge |
| Main span | ≅ 70 m |
| Deck width | ≅ 2 m |
| Deck width to main span ratio | ≅ 1:35 |
| Shore Pylon | Reinforced concrete |
| Central Pylon | Steel and reinforced concrete |
| Girder | Steel transverse beam |
Cross-Section
Figure 2 shows a bottom view of a bridge sector.
The girders are made of circular hollow sections, over which are placed four steel wire ropes (marked by the numbers) and the timber stringers, which have a non-constant spacing and longitudinal support system. The steel wire ropes are anchored on both shores and run horizontally along the two spans. The deck is made of timber planks with a similar cross-section as the stringers.
What are some possible reasons for the above shown stringer arrangement?
Intermediate Main Span Supports
Figure 3 shows a schematic lateral view of the bridge.
Intermediate supports made of timber are installed in the main span shore region, and the hanger cable spacing is about constant along the two spans. The main span ≅ 70 meters, and span A ≅ 60 meters. Figure 4 shows intermediate supports viewed from below.
Failed Wires of a Hanger Cable
Figure 5 shows a hanger cable.
The hanger cable passes over the main cable, and the termination consists of U-bolt clamps. Enlarged view 1 is shown in figure 6.
Failed steel wires at the top outer side of the wire rope are noticeable.
What are the main consequences?
Stay Cables and Additional Girders
Figure 7 shows a schematic lateral view of the central pylon region.
The central pylon region includes four stay cables and six additional girders: the former are anchored at the cable barriers and the pylon, while the latter are connected to the cable barriers by short hanger cables. The cable barriers (top cables) are anchored on both shores and run horizontally along the two spans. Figure 8 shows the anchorage at the cable barrier of the B stay cables.
The anchorage consists of a direct (cable-to-cable) connection fixed with U-bolt clamps. Figure 9 shows the anchorage at the pylon.
The stay cables are bent around the pylon, and the termination consists of U-bolt clamps.
Figure 10 shows additional girder and short hanger cable 1.
