St. Anthony Falls Bridge Replacement

Jon Chiglo, P.E., Project Manager

Agenda

• Project characteristics and features

• Project construction phases

St. Anthony Falls I35W Bridge

Bridge Description

• Bridge reflects series of modern arch forms – elegant simplicity

• Four-span bridge, approximately 1,223 feet long

• 504 foot main span over Mississippi River

Bridge Description

• Variable depth superstructure 25 feet to 11 feet

• Concrete piers supported by footings and drilled shafts socketed into rock

Bridge Description

• Two parallel bridges, each with two box girders

• Striped for five lanes each direction (10 total) with 13 and 14 foot shoulders (actual design loading considers for seven lanes in each direction)

• Future configuration of four lanes in each direction plus light rail or bus transit lane

Safety Enhancements

• Geometric enhancements that eliminate all existing sub-standard roadway geometry

• High performance concrete with prestressing for superior durability

• “Smart bridge” with integrated bridge sensor/monitoring system

Multiple Levels of Redundancy

• Two bridges, each with two box girders

• Hundreds of high-strength steel strands embedded in each box girder

• Pier under each box girder

• Multiple drilled shaft foundations socketed into bedrock

A Sculptural Bridge White, Modern, Winter Blending

View from the Cantilever at the GuthrieView from north shore near St. Anthony Falls

Pier Shape and Retaining Walls

• Gabion stone retaining walls – various layers of native stone creating a geological profile of stone along the Mississippi River

• Sculpted piers with reflective curves work in harmony with the connecting superstructure forms

Traffic Restoration

Chris Roy, P.E., Area Manager

Detour Map

Traffic Restoration Projects

Goal

Get congestion back towards normal

Traffic Restoration Project Guidelines

• Must increase capacity, improve safety, or manage traffic (ITS)

• Must build in a weekend or on weeknights– No traffic impact for peak periods allowed

• Must be within circle of impact

• Must be let before end of September– Most must be done by end of August

• Designers have one week from concept to construction

• Final cost – less than $7 million

Traffic Restoration Projects• Consider some 40+ projects

• Built 24 projects including– Adding lanes on 94, 694 and 100– Rebuilding an interchange– Enhancing ramp geometry and capacity– Continuous lighting, temp concrete median barrier– Frontage road construction– Bus shoulders– ITS improvements – TMC cameras and loop detectors

• Construction costs 6.0 million

Evening Congestion Impacts2:00 to 7:00 p.m. – Relatively Unchanged

Week of July 23, 2007 Week of Sept. 10, 2007

Tremendous Cooperation

• Quick turn around on everything– Layouts, plans, design exceptions– Environmental documents & approvals– Contract documents and bidding process– Stakeholder involvement– External agency review and approvals