Read http://skyscraper.org/EXHIBITIONS/VERTICAL_URBAN_FACTORY/concrete.php
for more about Turner and his mushroom system. Basically he discovered that
if you flare out the top of a concrete column, ie put on a mushroom cap, the
column will support a greater amount of weight and allow for thinner floors
without the need for reinforced beams. Essentially a post and beam
construction without the beams.



The prototype bridge in Bob's modeling looks to have columns with a flared
top, ie the mushroom system, allowing for a thin road deck. But I would
caution about lengthening the span when modeling, as it won't "look right".
Engineering statics and dynamics are precise science, especially when it
comes to bridges. A certain span will require a certain depth in beam or
floor thickness. The greater the span the thicker the structure. But
everything has a limit.



Doug Harding

www.iowacentralrr.org