bhyde@inmet.UUCP (09/19/83)
#N:inmet:7600004:000:928
inmet!bhyde Sep 18 12:30:00 1983
My father recently outlined a pleasing line of reasoning about the
bridge in Conn. that collapsed. Consider the shape of the slab:
a b
------------/
/ / It is somewhat more trapezoidal than this.
/ / <-- traffic flow --
/-----------/
c d
Each time a lone truck would drive over the bridge in one lane or the
other it would lift all the wieght off of either b or c. At that point
the bolt which failed would drift. A micron everytime? The shape of
the slab is important; very few bridges have it. The shape provides
leverage.
At two in the morning it is easier to get a large number of trucks
in the same lane and alone.
Of course there was a bolt to be poped off too. Some about of
force behind the "drift" is called for. It is a big object to
rock back and forth so it would seem easy to obtain that force.