Target 061101: Backhoe Accident
On February 14th, 2006, a semi carrying a backhoe was heading east on Interstate 70 near Hays, Kansas. The backhoe, weighing 8 tons, was sitting on the flatbed trailer on top of a flatbed trailer. It had its shovel arm extended, in order to keep it from hitting such things as low bridges, power lines, etc. The extended shovel arm is made of hardened refined steel. The truck and its cargo were headed for an overpass which the driver thought was high enough to allow for passage underneath. The bridge was made of commercial-grade concrete, reinforced with 1.5 inch steel rebar, spaced at 6 inch intervals in a criss-cross pattern,layered at 1 foot vertical spacing.
As fate would have it, the driver had miscalculated. The virtually unstoppable force (the rig and its cargo) met the virtually unmovable force (the bridge), and something had to give.
What gave first was the cabling which held the backhoe to the trailer. The backhoe, still moving forward under the force of its inertia slid off the back of the trailer and onto the street.
To the credit of the backhoe maker, what gave second was the bridge. The backhoe arm sliced through the bridge like a knife, cutting almost 3/4ths of the way through it, and causing the rest bridge at that point to snap and break in two. To the credit of the bridge builder, the bridge didn't fall down.
The backhoe's arm, though severely damaged, showed less give than anything else involved. Here, you can see the arm sticking out of the top of the bridge, looking, from that vantage point, almost entirely unbent and unscathed.
Many thanks to Ed Thrall for this target.