Within the last 10 years, the 23-mile long Lake Pontchartrain Bridge
have had multiple utility type sheds added about every 1-2 miles (I
believe on the west side).  It appears to be some type of repeater,
but I can find no documentation about them.  The structure is separate
from the bridge but is directly adjacent to it.  Wires come in and out
of them, have four concrete pillar/anchors and a bridge for utility
access.  They are viewable from google maps (on the highest zoom
setting, satellite mode).  If anyone could find about who operates
them, what type of devices they are and what they are for, I would
finally be able to have a good night's sleep.