General Information

Figure 1 shows a truss bridge that is used by motorcycles, bicycles and pedestrians.

Truss Bridge.
Steel truss bridge
Main span ≅ 45 m
Type Through truss bridge
Truss material Steel
Truss height ≅ 3 m
Deck width ≅ 3 m

Truss Supports

Figure 2 shows a schematic lateral view of the bridge.

Lateral view.
Schematic drawing of a steel truss bridge

The continuous through truss is supported by two abutments, two pile bents, and two cantilever piers. Figure 3 shows the bridge viewed from shore 1.

Truss bridge.
Steel truss bridge over a river

Enlarged view 1 (pile bent to truss connection) is shown in figure 4.

Enlarged view 1 (pile bent to truss connection).
Connection between steel truss and RC pile bent

The bottom chord is partially embedded in the bent cap, and a crack on the bent cap under the bottom chord is noticeable. Figure 5 shows the opposite pile bent to truss connection.

Pile bent to truss connection.
Free space between truss and pile bent

The bottom chord is connected to a steel bearing that does not touch the bent cap. Figure 6 shows a side view of the two cantilever piers.

Cantilever piers.
Connection between cantilever piers and truss

No cracks are noticeable on the pier caps.

  • What are some possible reasons for the crack and the free space?
  • Truss Members

    Figure 7 shows a side view of a truss sector.

    Truss.
    Truss members of a truss bridge

    Upper and bottom chords consist of H-profiles, the verticals of circular hollow profiles, and the diagonals have a rectangular hollow cross-section.

  • What are some possible structural and/or constructive reasons for the used truss members?
  • Figure 8 shows a diagonal viewed from the front.

    Diagonal.
    Diagonal member of a truss bridge; composed profile and weld seams

    A diagonal consists of a built-up section made of two side-by-side placed U-profiles that are joined by welding.

  • What are some possible reasons for using a built-up section?
    Does the weld seam layout affect the structural behavior of the diagonals?