Andover BF 0132(14) Alternatives Presentation Meeting FAS Route 132 - - PowerPoint PPT Presentation

Andover BF 0132(14) Alternatives Presentation Meeting

FAS Route 132 – Bridge #9 over Trout Brook

October 22, 2018

Introductions

Laura Stone, P.E.

VTrans Scoping Engineer

Gary Laroche, P.E.

VTrans Project Engineer

Carolyn Carlson, P.E.

VTrans Design Project Manager

Purpose of Meeting

• Provide an understanding of our approach to the

project

• Provide an overview of project constraints
• Discuss alternatives that were considered
• Discuss our recommended alternative
• Provide an opportunity to ask questions and voice

concerns

Location Map

Bridge 9 Project Location

Meeting Overview

• VTrans Project Development Process
• Project Overview

– Existing Conditions – Alternatives Considered – Recommended Alternative

• Maintenance of Traffic
• Schedule
• Summary
• Next Steps
• Questions

VTrans Project Development Process

Project Definition Project Design Construction Project Funded Project Defined Contract Award

• Quantify areas of

impact

• Environmental

permits

• Develop plans,

estimate and specifications

• Right-of-Way

process if necessary

Initiated

• Identify resources &

constraints

• Evaluate alternatives
• Public participation
• Build Consensus

Project Overview

• Existing Conditions
• Alternatives Considered
• Recommended Alternative

Description of Terms Used

Existing Conditions – Bridge #9

• Roadway Classification – Major Collector (Class 2 TH/FAS Route)
• Bridge Type – 84’ Long Rolled Beam Bridge
• Ownership – Town of Andover
• Constructed in 1939

Looking East over Bridge

Existing Conditions – Bridge #9

• Bridge 9 is Structurally Deficient due to the deck rating

– localized spots with heavy deterioration, concrete spalling and large sections of exposed reinforcing steel. – Potential for full depth pop-outs

• The rolled beams are in satisfactory condition, but have

areas of heavy rust scaling, especially in the areas where deck spalling is present, and have minor section loss.

• Both backwalls are failing with most of the concrete

spalled with exposed reinforcing steel throughout. There is a potential for holes forming in the approaches due to the loss of roadbed material

Existing Conditions - Bridge #9

• Deck Rating

4 (Poor)

• Superstructure Rating

6 (Satisfactory)

• Substructure Rating

5 (Fair) Deck Deterioration

Existing Conditions - Bridge #9

• Skeletal Abutments
• Failing Backwalls
• Poor Condition bridge seats

Substructure

Existing Conditions - Bridge #9

• Class II Wetlands in Southeast Quadrant
• Wildlife Corridor
• Clear span meets required bankfull width

Hydraulics and Environmental Resources

Existing Conditions

• ADT of 830
• DHV of 120
• % Trucks: 19.6
• Design Speed of 40 mph
• Aerial Utilities

Design Criteria and Considerations

• No Action

– Additional maintenance required within 10 years

• Deck Replacement

– Structural deficiencies would be addressed – Widen to match the corridor – 30 year design life – Meets all ANR and hydraulic standards

• Superstructure Replacement

– Widen to match the corridor – 30 year design life – Meets all ANR and hydraulic standards

• Full Bridge Replacement On Alignment

– Widen to match the corridor – 75 year design life

• Full Bridge Replacement Off Alignment

– Widen to match the corridor – 75 year design life

Alternatives Considered – Bridge #9

Recommended Alternative - Bridge #9

• Full Bridge Replacement

– Widen to match the corridor – New integral abutments – 80’ span with skew similar to existing – 75 year design life

Proposed Typical Section

Proposed Layout Full Replacement On Alignment - Bridge #9

• 10’/3’ typical, 75 year design life

Proposed Profile

Maintenance of Traffic Options Considered

• Offsite Detour
• Phased Construction
• Not an option for full bridge replacement
• Temporary Bridge

Road Closure

• Detour chosen and signed by Town
• Shortest route is 6.4 miles end-to-end
• 8 week closure

• The shortest local detour

route, has an End-to-End distance of 6.4 miles

• Truck route available with

end-to-end distance of 23.4 miles

Traffic Control – Offsite Detour

What would be the maximum acceptable length of closure for Bridge #9? RAISE OF HAND

• A. 2 weeks
• B. 4 weeks
• C. 6 weeks
• D. 8 weeks
• E. 10 weeks
• F. 12 weeks
• G. No Preference

Temporary Bridge

• One Lane Upstream Temporary Bridge with Traffic Signal

‐ Would require hillside cut

Temporary Bridge Layout

Recommended Scope

• Full Bridge Replacement with Traffic Maintained on an

Offsite Detour

– Widen to match the corridor – New integral abutments – 80’ span with skew similar to existing – 75 year design life – 8 week closure – No/Minimal Right of Way – No Utility Relocation – Construction Year: 2023

Andover BF 0132(14) Alternative 1 Alternative 2 Alternative 3 Alternative 4 Deck Replacement Superstructure Replacement Full Bridge Replacement On‐ Alignment Full Bridge Replacement Off‐Alignment

• a. Offsite

Detour b. Temporary Bridge

• c. Phased

Construction

• a. Offsite

Detour b. Temporary Bridge

• c. Phased

Construction

• a. Offsite Detour
• b. Temporary

Bridge

• a. Existing

Bridge Total Project Costs $1,052,640 $1,454,335 $1,412,918 $1,449,294 $1,415,390 $1,248,928 $2,241,756 $2,044,398 $2,240,248

Annualized Costs

$35,090 $48,480 $47,100 $48,310 $47,180 $41,630 $29,890 $27,260 $29,870

TOWN SHARE

$26,316 $72,717 $70,646 $36,232 $70,770 $62,446 $112,088 $204,440 $224,025

TOWN %

2.50% 5% 5% 2.50% 5% 5% 5% 10% 10%

Project Development Duration

2 Years 4 Years 2 Years 2 Years 4 Years 2 Years 3 Years 4 Years 4 Years

Construction Duration

2 months 9 months 6 months 2 months 9 months 6 months 6 months 18 months 9 months

Closure Duration (If Applicable)

21 days n/a n/a 21 days n/a n/a 60 days n/a n/a

Typical Section ‐ Bridge (feet)

10'/3' (26')

Geometric Design Criteria

Substandard horizontal and vertical alignment at Approach

Utilities

No Relocation No No Relocation No No Relocation Relocation

ROW Acquisition

No Yes No No Yes No No Yes Yes

Design Life

30 30 75 75

Alternatives Matrix

Preliminary Project Schedule

• Construction Start – 2023

– Total Cost Estimate: $2,241,756

• Estimated Town Share: $112,000

This is a list of a few important activities expected in the near future and is not a complete list of activities.

Wait for Town response to recommendation on proposed project

• Develop Conceptual plans and distribute for comment
• Request a Public Information meeting
• Process local agreements
• Right-of-Way process (if needed)
• Town is responsible for any chosen detour route

Next Steps – Bridge #9

Andover BF 0132(14) Questions and Comments

FAS Route 132 – Bridge #9 over Trout Brook

October 22, 2018