“From Tragedy to Triumph”

I-35W Bridge

Khani Sahebjam, PE

Vice President | HDR Engineering, Inc.

Former Deputy Commissioner/Chief Engineer | MnDOT

History

• Bridge background – Bridge completed 1967

– 1907 feet long • 3 span continuous truss

– Main span 456 feet

– ADT 141,000

– Sufficiency rating – 50.0

– Annually inspected • In depth fracture critical

– 500 hours annual average by MnDOT maintenance

– Scheduled replacement 2020-2025

I-35W Bridge - Looking North July, 1967

August 1, 2007

The Collapse

Collapse occurs at 6:05 pm

Wednesday, August 1, 2007

Over 100 vehicles on the

bridge at the time

13 fatalities, 140 injuries

Emergency Response

• 6:05 p.m. – Numerous calls to 911 – Motorists on bridge,

construction workers, citizens in area assist injured

– Emergency personnel from Twin Cities and Western Wisconsin respond

• 6:10 p.m. – District Emergency

Operations Center activated

MnDOT’s Regional Transportation Management Center (RTMC)

Immediate traffic control for ramp and freeway closures provided by FIRST units, maintenance units, and contractors in the vicinity

Response the First 12 Hours

• Unified command center set up on collapse site. – Minneapolis Fire Department in charge of rescue

operation

– Hennepin County Sheriff in charge of recovery

August 1, 2007

First 12 Hours | continued

• 7:00 p.m. – More than 150 employees

activated, most just returned without a call

• 10:00 p.m. – Governor and Mayor provide an

update to public. Number of victims unknown.

– Rescue operations ended, recovery begins

• 11:00 p.m. – Detour maps for a.m. rush posted

on MnDOT web site • Overnight

– Expanded signing and barricades of closed I-35W

– Converted TH 280 to a freeway

I-35W Detour Map

August 2, 2008

• MnDOT Engineers assess stability of wreckage for recovery personnel

• MnDOT retains Wiss Janney Elstner and TranSystems / Lichtenstein for forensic investigation

Command Site

• Federal Agencies arrive at command site FEMA, FBI, Coast Guard, OSHA, OIG, FTA, NTSB, Rick Capka, and National FHWA staff

• NTSB leads investigation team

• MnDOT engineering team begins to organize for rapid replacement

Media Coverage

August 2, 2008

• Governor Conducts interviews throughout morning

• 2 p.m. news conference Governor announces – Emergency Statewide Bridge

Inspections beginning with underdeck trusses – Forensic Investigation Team

• Wiss Janney Elstner • Transystems

• MnDOT provides bridge background and responds to questions

• National and International News Organizations present • National Transportation Safety Board updates

NTSB Chairman Mark Rosenker

Responding to Media Requests

• Daily 2 pm news conference – Became only means to respond to

volume of requests – Format - statement, update on

specific issue, take questions – Length was 30 to 45 minutes – When it ended, held questions till

next day

• MnDOT goal was transparency – Document requests were

voluminous – Website posting of plans,

inspection reports, bridge studies – Dedicated I-35W website included

all documents

August 3 Press Conference

Media on Top of Nearby

Buildings

Responding to Media Requests

| continued

• MnDOT priority was local media requests

• Within days, some media began own investigations and speculation

• Correcting factual errors consumed time

Spectators and media on

adjacent 10th Avenue Bridge

Recovery of Victims

• Aug 6 – Careful bridge demolition began to aid recovery and NTSB investigation

• Navy divers from Norfolk, VA assist in recovery

• NTSB investigation team supervises removal – All steel members marked and

indexed – Members removed by torch –

underwater cuts could take 1-4 hours

– Extensive coordination required with divers, sheriff, investigator,s and contractor

– Balanced desire to recover victims vs. need to preserve evidence

Navy Dive Team

Diver Perspective

Recovery of Victims | continued

• Aug. 20 – Navy Divers recover 13th victim, site turned over to MnDOT

• Sept. 6 - Navigation channel opened to commercial traffic

• Sept. 27 – Final steel removed from river

Removing Wreckage from Navigation

Channel

Executive Branch Response

• Aug 3 - First Lady Laura Bush visits the site and victim’s families

• Aug 4 - President Bush pledges to cut red tape that could delay recovery

• Aug 21 - President declares emergency under Robert T. Stafford Act authorizing funds for safety and recovery efforts

Traffic Restoration

• Work to convert Hwy 280 to a freeway including closing at-grade signalized intersections to cross traffic, upgrading ramp termini signal systems and lengthening frontage road

• Add lane each direction on I-94 from Hwy 280 to I-35W by overlaying and restriping shoulders

• Many temporary projects on other Metro alternate routes

NTSB Investigation

Construction Materials Staging

Construction equipment and vehicles

Piles of aggregate

U10 west node

Dead Load of Original 1967 Bridge

Compression

diagonal Tension

diagonal

Orange and red shading: exceeds yield stress

Stress

Yield

stress

0

Allowable

After 1977 and 1998 Modifications Orange and red shading: exceeds yield stress

Compression

diagonal

Tension

diagonal

Stress

Yield

stress

0

Allowable

Loads at Time of Accident

Compression

diagonal Tension

diagonal

Orange and red shading: exceeds yield stress

Stress

Yield

stress

0

Allowable

Accident Loads on 1-Inch-Thick Gusset

Plates

Compression

diagonal

Tension

diagonal

Stress

Yield

stress

0

Allowable

Bridge Rebuild Legislative/Congressional

Hearings

• Aug 15 – Hearings with Minnesota House and Senate Transportation Committee

• Sept 5 – MnDOT staff testified before the U.S. House of Representatives Committee on Transportation and Infrastructure

Timeline • August 1 – Bridge Collapses

• August 4 – Issue Request for Qualifications

• August 8 – Short Listed Teams

• August 23 – Request For Proposals Released

• September 14 – Technical Proposals Received & Technical Evaluation

Begins

• September 18 – Financial Proposals Received

• September 19 – Project Letting

• September 20 – City of Minneapolis Grants Municipal Consent

• October 8 - Project Award to Flatiron/Manson

• November 15 – Construction begins

Evaluation Criteria

• Quality (50 percent) – Experience and authority of key individuals

– Extent of quality control/quality assurance

– Safety

– Measures to evaluate performance in construction

• Aesthetics/Visual Quality (20 percent) – Visual enhancements to the structure

– Involvement of the public after letting

• Enhancements (15 percent) – Roadway enhancements

– Structural enhancements

• Public Outreach/Involvement (15 percent) – Impacts to the public

– Approach to communications

Best Value Selection Process

• Based on cost plus time divided by technical score

• Resulted in Flatiron/Manson being awarded the best value contract – 91.47 technical score – $233.8 million cost – 437 days to complete

Pier Shape

“Open” Railing

• Drivers perspective – heading southbound towards city center

Retaining Walls

Safety Lighting

Mass Concrete

Cold Weather Protection

Eco-friendly Concrete

• Inspired by ancient symbol for water

• A new self-cleaning and pollution eating concrete

• One on each end of bridge

Why Project was Successful

• Common goal by all

• Funding in place within days

• Well prepared

• Sound partnerships

• Streamlined processes

• Servant leadership

• Situational leadership

Outcomes

• Process changes – Inspections (Gusset plates) – Design procedures – Peer review of design for major bridges – Maintenance follow up – Placement of construction material on bridges

• NTSB reports gusset plate design flaw main cause of

collapse

• State established $38 million to compensate survivors and families of those who died

Current Status

• Building public trust and confidence in transportation system and MnDOT

• Litigation continues – State paid Plaintiffs

– Bridge Contractor settled with Plaintiffs

– Consultant ‘A’ settled with State

– Consultant ‘A’ settled with Plaintiffs

– Consultant ‘B’ settled recently with MnDOT

Washington State I-5 Skagit River Bridge

Temporary Bridge Extension

Bridge Collapse May 23, 2013

Washington State I-5 Skagit River Bridge

• No fatalities

• Fast recovery

• Truck hit

• Funding debate

Questions?

Thank you.