After looking at the loading on the timbers in the above grade section of the barn (the "forebays" as Jim called it) I realized that I'd need some pretty substantial timber in the ties to support the load over 14' if the joists in all bays were oriented in the same direction. By turning the middle bay joists 90 degrees (see attached image) I've been able to bring the deflection to acceptable levels for a 57.5 psf load without having to resort to timbers greater than 8" in height.
Is there anything I may be overlooking?

[img:left]http://www.paddleways.com/blog/gypsyrose/images/MonitorBarnFloorJoistsV2.jpg[/img]