General Information
Figure 1 shows a suspension bridge that is used by motorcycles, bicycles and pedestrians.
| Type | Single-span suspension bridge |
| Main span | ≅ 70 m |
| Deck width | ≅ 1.5 m |
| Deck width to main span ratio | ≅ 1:46 |
| Pylon | Reinforced concrete (H-shaped) |
| Girder | Timber transverse beam |
Hanger Cable to Timber Girder Connection
Figure 2 shows a schematic cross-section of the bridge.
A single hanger cable runs from main cable 1 to main cable 2 via the timber girder bottom side. The hanger cable passes through the timber girder through two vertical holes. The forces are transferred by direct (cable to timber girder) contact. Figure 3 shows a hanger cable to timber girder connection viewed from below.
A longitudinal crack on the timber girder and an offset between the vertical hole and the hanger cable are noticeable. The double white arrow indicates the longitudinal direction of the timber fibers. A further connection viewed from the side is shown in figure 4.
A longitudinal crack and an offset between the vertical hole and the hanger cable are also noticeable. The hanger cable touches the stringer and a deck board.
What are the main consequences?
Figure 5 shows a further hanger cable to timber girder connection.
This connection has two additional cables (one per side). Additional cable 1 is looped once around the timber girder, fixed with U-bolt clamps, and connected to the hanger cable (over the deck region) by U-bolt clamps. Free space between additional cable 1 and the timber girder is noticeable.
Hanger Cables
Figure 6 shows a main span sector.
Noticeable are taut, slack, and twisted hanger cables; different numbers of U-bolt clamps; different hanger cable to main cable connections (e.g., with and without a bottom plate); and an irregular hanger cable arrangement.
Deck Deformation
Figure 7 shows a main span sector.
Deck deformation is noticeable.