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bridge inspection

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Bill,

Unless Texas is different from other states (O.K., I *know* Texas is 
different from other states), political subdivisions cannot expend public 
monies on maintenance of private property, even if they are reimbursed.  Here 
in Arizona, in particular Pima County, even subdivision streets can't be 
maintained by County forces until they are accepted into the County street 
system.

That said, I would suggest that you use AASHTO's "Manual for Condition 
Evaluation of Bridges" for your evaluation.  *If* the largest vehicle using 
the bridge is a school bus, than I would use the H-15 criteria to determine 
adequacy and require the owners to post maximum load signs reflecting the 
actual load capacity.  The worst thing that can happen to you is for you to 
use your own however well intentioned criteria, which is less than AASHTO's, 
and have something happen to a school bus.

After the Silver Bridge disaster, which precipitated national bridge 
inspection programs, I inspected a couple of bridges for a county in southern 
Arizona.  One was a small, single span bridge which would be built as a 
culvert today and the other was a multi-span, single lane, wood bridge.  At 
one time, both bridges had had at least parts of their superstructures washed 
out.  The washed out parts of the superstructure had been replaced with 
salvaged steel from lord knows where.  The single span deck used salvaged 
compression chords from an old truss bridge as beams and had the lacing side 
installed up and the solid plate side down.  The deck was wood, and all sorts 
of debris fell into the cavity of the salvaged compression chords.  Analysis 
showed that it should not have been able to support its own weight, let alone 
the weight of school buses that passed over the bridge while it was being 
inspected.  The bridge was immediately closed and a detour down into the wash 
was bladed until an adequate deck could be installed.  (For those of you 
without knowledge of Arizona, our rivers and washes are dry about 350 days a 
year, and maybe run torrentially for about 3 days a year.)

Re: Federal Funds:  I don't know of a county that doesn't receive federal 
highway funds one way or another.

HTH

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

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