Bridge Failure

It costed the Owner more than RM5 million and unaccounted losses in production for the failure of this 70 over meter main span bridge.Why was it failed?
The evidences are all there, a huge trailer carrying a large excavator with the blade on it and the vertical struts of the steel bridge are neatly cut horizontally in a straight line.
There it was, this trailer carrying the excavator swung to one side of the bridge and the tractor's blade neatly cut one side of the trusses, causing that side to immediately bent down, the lorry tilted towards failed side, the bridge twisted horizontally to the other side, the whole superstructure jumped out of the bridge piers into the river. Lucky for the driver, because the truss bridge is springy enough to slow down the sinking into the fast river flow and the water level was low. He managed to crawl out of the lorry and hanged on the bridge and swam to the bank.

Human factor is always difficult to control especially uneducated and irresponsible personnel. The solutions are:
(a)  Severe warnings and constant reminding on the procedures and loading requirements to all users. In this case, the driver was immediately sacked,
(b)  construction of the steel guides before the bridge at both sides of the bridge approach to restrict width and height of the loads of the vehicles,
(c)  provide a wider span bridge superstructure to have larger side clearance.