General Information
Figure 1 shows a truss bridge that is used by motorcycles, bicycles and pedestrians.
![Steel truss bridge over a river](bridges/truss-bridges/bridge-1/1-truss-bridge.jpg)
Main span | ≅ 45 m |
Type | Through truss bridge |
Truss material | Steel |
Truss height | ≅ 3 m |
Deck width | ≅ 3 m |
Bent Caps Connections Failures
Figure 2 shows a schematic lateral view of the bridge.
![Schematic lateral view of a steel truss bridge](bridges/truss-bridges/bridge-1/2-lateral-view.jpg)
The vertical alignment consists of one horizontal and two inclined sectors. The continuous through truss is supported by two abutments, two pile bents, and two cantilever piers. The truss-to-bent caps and truss-to-pier caps connections are shown in figures 3 to 5.
![Filed connection between bottom chord and bent cap](bridges/truss-bridges/bridge-1/4-enlarged-view.jpg)
The bottom chord is partially embedded in the bent cap, and a crack under the bottom chord region is noticeable.
![Filed connection between bottom chord and bent cap](bridges/truss-bridges/bridge-1/5-pile-bent-truss-connection.jpg)
Bent cap 2 is shorter than bent cap 1 (h1 > h2), and the bottom chord is connected to a steel bearing, which is detached from the bent cap.
![Connection between bottom chord and pier caps](bridges/truss-bridges/bridge-1/6-piers-truss-connection.jpg)
The bottom chords are partially embedded in the pier caps, and no cracks are observable.
Truss Members
Figure 6 shows a side view of a truss sector.
![Truss members of a steel truss bridge](bridges/truss-bridges/bridge-1/7-truss.jpg)
The arrangement of the web members consists of zig-zag diagonals with verticals. Upper and bottom chords are made of H-profiles, the verticals are made of circular hollow profiles, and the diagonals are made of a built-up section that consists of two side-by-side placed U-profiles that are joined by intermitted welding, as shown in figure 7.
![Truss diagonal made of a built-up section](bridges/truss-bridges/bridge-1/8-diagonal-member.jpg)