A while ago I posted an old photo of a bridge strength test.
Here's another that didn't go to plan with the bridge wrecked and a life lost
Bendigo Advertiser, 15th May 1901
The ability of a bridge to safely carry loads was tested by driving heavy vehicles over it. At King's Bridge, a steam roller and a traction engine were used for the test - together they weighed 30 tons which was far in excess of the load limit of 25 tons.
Scroll down the following link
During the test, one section collapsed. The traction engine fell into the creek bed, dragging Mr Boldt with it and crushing him
Photo linked from above storey