General Information

Figure 1 shows a pedestrian truss bridge.

Truss bridge.
Through-truss bridge over a highway.
Main span ≅ 19 m
Type Through-truss bridge
Truss material Steel
Truss height ≅ 2.5 m
Deck width ≅ 2 m

Hollow Structural Sections K-Connection

Figure 2 shows the bridge.

Steel truss bridge.
Through-truss bridge made of square hollow sections.

The web members' arrangement consists of zig-zag diagonals and vertical end posts; the chords and the web members are made of square hollow sections, and the truss is non-continuous (3-span truss). Figure 3 shows a schematic three-dimensional view of the connection between the diagonals and the upper chord (K-joint).

Square hollow sections K-connection.
Three-dimensional drawing of an SHS K-joint with a gusset plate.

The ends of the diagonals are cut (two planes) and slotted. A rectangular gusset plate (longitudinally oriented) is welded at the mid-width of the upper chord's under side; the slotted diagonals are fitted to the mating gusset plate and connected by welding. Figure 4 shows a K-joint.

K-joint (1).
SHS K-joint with a gusset plate of a through-truss bridge.

The diagonals have an inclination angle (α) of about 64° and are smaller than the chords; the double-ended arrow (-e) indicates joint eccentricity.

  • What are the structural and constructive peculiarities of the above shown K-joint configuration?
  • Figure 5 shows a schematic lateral view of the K-joint and two further configurations.

    Square hollow sections (SHS) K-joints.
    SHS K-joint configurations.

    Variant 1 consists of a gapped K-joint with positive eccentricity (e), while variant 2 consists of an overlapped K-joint with zero eccentricity (e = 0). Both variants have slotless diagonals.

  • What are the factors that affect the decision-making process of the K-joint configuration?
    Which factor(s) lead to the original K-joint configuration?
  • Figure 6 shows a further connection viewed from below.

    K-joint (2).
    SHS K-joint with a gusset plate of a through-truss bridge.

    In K-joint (2), the gusset plate is shorter than the slots.

  • What is the purpose of bigger slots?
    Does K-joint (1) structurally behave like K-joint (2)?