Stone Arch Bridges of Washington County MD of Washington County, MD

56 Pages·2009·4.47 MB·English

Stone Arch Bridges
ooff WWaasshhiinnggttoonn CCoouunnttyy, MMDD
Presentation for the Countyy Enggineers
Association of Maryland (CEAM)
2009 Spring Conference
May 14, 2009
Scott Hobbs, P.E. John Latimer, IV
Capital Projects Engineering Gruber-Latimer Restoration, LLC
Washington County Division of Public Works
Overview
•• IInnttrroodduuccttiioonn
• Washington County Bridges
• Bridge Inspection Program
• Funding
• Decision Making
• Desiggn
• Rehabilitation
• Costs
•• RReeppaaiirrss
• Closing
• Questions
Washington County Division of Public Works
Introduction
• WWashhiington CCounty goes to great efffforts to preserve andd maiintaiin iits
infrastructure, including our stone arch bridges.
– To ensure the maximum useful life of our structures.
– TTo proviidde acceptabblle serviice to thhe pubblliic.
Washington County Division of Public Works
Washington County Bridges
• MMaajjoorr SSttrruuccttuurreess - CCuullvveerrttss oorr bbrriiddggeess wwiitthh ssppaannss ooff 2200’++
• Minor Structures - Culverts or bridges with spans 6’-20’
• 90 Majjor Structures owned and maintained byy Countyy
– 14 Stone Arch Bridges
• 185 Minor Structures owned and maintained by County
– 12 Stone Arch Bridges
• 179 Major Structures owned and maintained by SHA
– 7 Stone Arch Bridges
• 221155 MMiinnoorr SSttrruuccttuurreess oowwnneedd aanndd mmaaiinnttaaiinneedd bbyy SSHHAA
– 7 Stone Arch Bridges
• Approx. 580,000 major bridges in U.S.
Washington County Division of Public Works
Washington County Division of Public Works
Bridge Inspection Program
• Federal Aid Highway Act of 1968 and Surface Transportation
Assistance Act of 1978.
– National Bridgge Insppection Standards ((NBIS))
• Primary purpose is to locate and evaluate existing bridge deficiencies
ttoo eennssuurree tthhee ssaaffeettyy ooff tthhee ttrraavveelliinngg ppuubblliicc.
– Stone arch bridges were not built to carry the vehicles of today.
– Provide a thorough bridge inspection. Document and monitor the
deficiencies until apppproppriate reppairs can be made.
• In turn, we can adequately preserve and maintain our historic structures.
Washington County Division of Public Works
Bridge Inspection Program
• NBIS require major structures to be inspected at least every 2 years.
– Set national standards for proper safety inspection and evaluation of bridges
– Briddggee inssppeecctioon reeppoortss
• Local jurisdictions determine the inspection cycle for minor structures.
EEvveerryy 44 yyeeaarrss iinn WWaasshhiinnggttoonn CCoouunnttyy.
Washington County Division of Public Works
Bridge Inspection Program
• From the Inspection Reports,
thhe County evalluates:
> Structure Inventory &
AAppraiisall ((SSII&&AA)) RRattiings,
> Bridge Sufficiency Ratings
(BSR),
>> aanndd PPOONNTTIISS RRaattiinnggss
• Based on the numbers, our
ssttoonnee aarrcchh bbrriiddggeess aarree aatt tthhee
top of the priority list for
repairs.
Washington County Division of Public Works
Bridge Inspection Program
• Structural Inventory and Appraisal
(SI&A) Ratings
–– EEaacchh ccoommppoonneenntt ooff aa bbrriiddggee
gets a rating value from 0 to 9.
Washington County Division of Public Works
Bridge Inspection Program
• AA bbriiddge iis consiidderedd structuralllly
deficient if:
• Deck, Superstructure, Substructure,
or Culvert are rated a 4 or less (poor
or worse condition).
– Some of our stone arch bridges
needing repairs are considered
structurally deficient.
Washington County Division of Public Works