General Information
Figure 1 shows a pedestrian suspension bridge.
| Type | Three-span suspension bridge |
| Main span | ≅ 50 m |
| Deck width | ≅ 2.5 m |
| Deck width to main span ratio | ≅ 1:20 |
| Pylon | Steel and reinforced concrete |
| Girder | Steel twin H-girder |
Turnbuckles
Figure 2 shows a schematic lateral view of the bridge.
Each main cable is connected to two turnbuckles. Figure 3 shows a side view of a turnbuckle.
The turnbuckles are of type open body; they are individual parts productions and are made of wide flat bars, circular hollow sections, threaded rods, and U-bars. The body has a length of l ≅ 1.2 m. Figure 4 shows a turnbuckle viewed from below.
The body is connected to the end fittings by the threaded rods and the U-bars, which are overlapping and joined by welding. Figure 5 shows the top region of a main span lamp.
The main cable touches the lamp, and the hanger cables are near the lamp.
Suppose to tighten the turnbuckles. What needs to be considered and inspected before the tightening process?
Hanger Cable to H-Girder Connection Failure
Figure 6 shows an schematic cross-section of the hanger cable to H-girder connection.
The connection consists of a short built-up T-section, two carriage bolts, a plate, and two nuts. The short T-section has three holes (one horizontal and two vertical) and is placed over the upper flange of the H-girder; the hanger cable passes through the horizontal hole, while the two vertical holes are for the carriage bolts, which pass through the flanges via holes and are connected to the plate located under the bottom flange. Figure 7 shows a hanger cable to H-girder connection viewed from above and from below, while figure 8 shows a failed connection.
| Viewed from above | Viewed from below |
The carriage bolt failed; the failure is located on the bottom flange outer side level.
Does this failure affect the safety of the bridge?