doug neely, pe aashto technical subcommittee for movable

Chincoteague Bridge Replacement

Doug Neely, PE

AASHTO Technical Subcommittee for Movable Bridges

May 16th, 2011

Project Location

• Bridge on Rte 175 Over Black

Narrows and Lewis Creek Channel

• Accomack County and Town of

Chincoteague, Virginia

• 100 Miles from Norfolk

• Owner: VDOT

• Designer: Hardesty & Hanover

• Contractor: American Bridge

• Contractor Bid: $68.7 million

• CEI: Jacobs

Old Bridge Alignment

Old BlackNarrows Bridge

Old ChincoteagueSwing Bridge

Site Plan

Existing Site Conditions

Town of Chincoteague & Marsh Island

Old Chincoteague Bridge

Existing Soil Conditions

C-3

C-4

C-5

C-2

Maddox

C

Alignment Study

Selected Bridge Alignment

Old ChincoteagueSwing Bridge

Old BlackNarrows Bridge

New SingleLeaf Bascule

New Rte 175 Bridge

New Marsh IslandConnector Bridge

Site Plan

Constructability Adjustment

Site Plan New SingleLeaf BasculeNew Rte 175 Bridge

New Marsh IslandConnector Bridge

Bascule Span Overview

• Fabricator: Steward Machine

• 92’-0” Span Length

• Closed Pit Pier

• 5” Half-Filled Grating*

• 1662 Kip Leaf

* With 1” overfill

Bascule Span Typical Section

Bascule Span Clearances

Span Closed

• 60’-0” navigable channel

• 15’-8” min. clearance

Bascule Span Clearances

Span Open

• 60’-0” navigable channel

• Unlimited vertical clearance

Bascule Span Fabrication

Bascule Span Fabrication

• Bascule span and towers shop

assembled

• Included permanent assembly

of trunnion

• Rack supports after trunnion

shaft and hub

Bascule Span Fabrication

Bascule Pier Deck Removed

Bascule Pier Stringers Removed

Bascule Span Removed

Bascule Pier Construction

Bascule Pier Construction

Bascule Pier Construction

Bascule Pier Construction

Operating Machinery

• Fabricator: Hardie-Tynes

• Reducers: Chicago Gear

• 26” Trunnion diameter

• Gear driven

• 3:40 operating cycle time

• 65mph max. sustained wind

Operating Machinery

• 10hp squirrel cage w/ chain drive

• Control of e drive at desk

• Manually install chain

• Two 75hp motors

• Primary: 122hp @ 870rpm

• Secondary: 224hp @ 150rpm

Electrical System

• Contractor: Dorey Electric Company

• Vendor: Link Control Systems

• Control System: Electromagnetic relays

• Interlocking control logic

Electrical System

• Service: 3 phase, 4 wire, 200 amp (min.) at

480 volts

• 150kW standby generator

• System A / System B

Bascule Span Complete

Bascule Span Complete

Questions?

• Dedication Ceremony: October, 2010

• Winner: 2010 ACI Infrastructure Award