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Published byJudith Newton Modified over 9 years ago
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St Johnsbury BF 7000(20) Bridge 6 on VT Route 2B over the Lamoille Valley Rail Trail Presenter: John Byatt, PE Consultant Project Manager
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PROJECT LOCATION
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Purpose of Meeting Present the project background and existing conditions Present the replacement structure selected Discuss maintenance of traffic options Receive public input
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Meeting Agenda Vtrans Project Development Process Project Background Existing Conditions Preferred Alternative Maintenance Of Traffic Schedule Questions
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Phases of Development Project DefinitionProject DesignConstruction Project Funded Project Defined Contract Award Identify resources & constraints Evaluate alternatives Public Participation Quantify areas of impact Environmental permits Develop plans, estimate and specifications
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Who are you representing? A.Municipal Official B.Resident C.Local Business D.Independent Organization E.Other
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What is your reason for attending this meeting? A.Specific Concern B.General Interest C.Live in close vicinity D.Other
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Which would you be most concerned about? A.Closure Duration B.Bridge Aesthetics C.Environmental Impacts D.LVRT Impacts E.Other F.Not really concerned
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Description of Terms Used Beams (Superstructure) Deck Abutment (Substructure) Bridge Rail
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More Terms Used Beam (Superstructure) Deck Abutment (Substructure) Span Pier (Substructure) Water Span Bridge Length Elevation View of Bridge
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Project Background The structure is owned and maintained by the State Funding will be 80/20 Federal/State (no local funds) Functionally labeled as an Urban Minor Arterial Posted Speed = 35 mph (Design Speed) Existing bridge is a three-span steel beam w/ concrete deck Bridge length = 129 feet (42’ maximum span) Bridge Width = 25 feet (curb-curb with 5’ sidewalk) The bridge was built in 1936 (77 years old)
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Traffic Data “Current Year” 2016 “Design Year” 2036 Average Annual Daily Traffic820860 Design Hourly Volume8590 Average Daily Truck Traffic2030 %Trucks1.62.2
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EXISTING BRIDGE DEFICIENCIES Deficiencies Structurally Deficient The bridge and approaches are too narrow for the roadway classification and design speed The bridge railing is substandard On-going maintenance needed Inspection Rating Information (Based on a scale of 9) Bridge Deck Rating4 Poor Superstructure Rating4 Poor Substructure Rating4 Poor Rating Definitions 9 Excellent 8 Very Good 7 Good 6 Satisfactory 5 Fair 4 Poor 3 Serious 2 Critical 1 Imminent Failure
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Special Concerns Railroad Clearance to be maintained Geotechnical Issues/Sensors Groundwater Issues Existing Water Main 4f Historic Requirements Impact to LVRT Retaining wall at driveway
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Looking west over Bridge
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Pier deterioration at beam support
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Looking under the bridge at deck and beams
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Rust and Leakage under Deck
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Undermining of West Abutment
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Temporary Repair at West Abutment
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Project Goals Improve overall condition of the crossing Improve substandard bridge width Improve substandard rail Meet historic requirements Minimize impacts to rail trail, utilities, buildings, egress, right-of-way and cultural resources
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Alternatives Discussion Considered closing the bridge permanently Considered an at-grade trail crossing Rehabilitation was ruled out due to the deteriorated condition of the existing bridge Full bridge replacement is preferred alternative Prefabricated Steel Plate Arch structure was selected as the bridge type
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What will bridge look like?
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Typical Bridge Section
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Proposed Roadway Section
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Ways to Maintain Traffic Road Closures – Main method - Traffic to use state signed detour route via Route 2. One-way Alternating Traffic – Temporary traffic signal would control traffic through construction site. Would be used before or after road closure Would not be used throughout construction Rail Trail would be closed during construction Abutter access will be maintained to property
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State Detour Route Green Route: 3.4 Miles Purple Detour Route: 4.4 Miles Added Miles: 1.0 Miles End to End Distance: 7.8 Miles Major Factors Added Miles: 1.0 Traffic Volume: 820 vpd Duration
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Mitigation Strategies for Bridge Closures Some ideas on how these impacts are often mitigated: Accelerated construction duration including: Allowance for working 24 hours per day and 7 days per week Incentive/Dis-incentive clause to encourage the contractor ($$) Noise limits included in contract for night time work Municipalities are compensated for bypass impacts Grant assistance from Agency of Commerce & Community Development
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One-way Alternating Traffic
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Accelerated Bridge Construction Driven steel piles with precast concrete cap for abutment
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Accelerated Bridge Construction Precast Concrete Cap placed in two sections
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Accelerated Bridge Construction Precast concrete Abutment in place
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Options to Maintain Traffic 6 week road closure with 3 weeks of alternating one- way traffic –Standard construction methods –7 days per week –Extended (12+ hour) days 8 week road closure with no alternating one-way traffic –Standard construction methods –7 days per week –Extended (12+ hour) days
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Options to Maintain Traffic 6 week road closure with no alternating one-way traffic – –Accelerated Bridge Construction (ABC) techniques –7 days per week –24 hour construction allowed –Increased Costs
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How often do you use this segment of Route 2B? A.Daily B.Weekly C.Monthly D.Rarely E.Never
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What is your preferred MOT option? A.6 week closure/3 week one-way alt B.8 week closure C.6 week closure with ABC
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Schedule Dependent on Project Development time and ROW acquisition time Current construction is Summer 2017
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Did you find this presentation to be? A.Too technical in nature B.Too simplified C.Just about right D.Not much use at all
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Questions
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