Traffic Camera Pole

Figure 1 shows a traffic camera pole.

Traffic camera pole.
Traffic camera pole with a knee brace and a stay cables

The structure consists of a mast arm structure with a knee brace and a stay cable. The length l ≅ 4 m. Figure 2 shows the pole top region.

Top region.
Top region of a traffic camera pole.

The pole and the mast arm are made of circular hollow sections, while the knee brace of an L-section. The latter is connected to the pole and mast arm by bolted gusset plates and round pole clamps. The stay cable is tensioned by a turnbuckle and connected to the pole and mast arm by U-bolts. A schematic lateral view of the above shown structure and a variant without the knee brace and stay cable are shown in figure 3.

Mast arm structures.
Structure 1 Structure 2
Schematic structural drawings of two traffic camera poles.

The red arrow represents the camera force.

  • What are some possible reasons for using structure 1 instead of structure 2?