handout Dan Dorgan 1of2 6pp.pdf

8/20/2019 handout Dan Dorgan 1of2 6pp.pdf

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–Agency’s Emergency Response

Dan DorganState Bridge Engineer

Minnesota Department of Transportation

February 15, 2010

I-35W Bridge

• Bridge Background

• Bridge Collapse August 1, 2007

Emergency Response

Rescue Operations

Traffic Management

• August 2, 2007

Investigation Begins

Media Coverage

• Responding to Public and Media

• Recovery of Victims and Bridge Removal

•Mn/DOT Actions Following August 2007

•NTSB Investigation

•Minnesota Legislature: Victims Fund andTransportation Funding

•Impact on Employees

•Observations - Lessons Learned

II--35W Bridge35W Bridge

DowntownDowntownMinnea olisMinnea olis

UniversityUniversityof of

MinnesotaMinnesota

http://maps.google.com/

I-35W BridgeBridge Background

•Bridge Completed in 1967

•1907 Feet Long

•3 span continuous truss

• Main span 456’

•11 approach spans

•ADT 141,000

•Sufficiency Rating – 50.0

•Annually Inspected

•Mn/DOT 20 year plan called forReplacement/Renovation 2020-25

July 1967

Two Previous Studies of the Bridge

2001 University of Minnesota –“Fatigue Evaluation of the DeckTruss of Bridge 9340”

“ –Redundancy Analysis”

Multi Girder Approach Spans HadRequired Retrofits for Cracks atDiaphragm Connection


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Previous Bridge Modifications

1977 Concrete overlay

1998 Railing repair, drainage system, minor deckrepair

1999 Paintin Portion of Truss S ans

1999 Anti Icing System

2001 Curb & Slab repair

Average yearly Mn/DOT Maintenance Hours 500

Contract Maintenance Work at Time of Collapse

Contract to replace concreteoverlay, and repair joints.

Work completed:

North bound – two inside lanes

South bound – two outside lanes

Scheduled completion datewas September 30, 2007

Contractor employees and Mn/DOTinspectors on bridge at collapse

August 1, 2007

The Collapse

Collapse occurs at 6:05 p.m.

Wednesday, August 1, 2007Over 100 vehicles on thebridge at the time• 13 fatalities• 140 injuries North End – I 35W Bridge – South End

North End Main Span


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Pier 6 South End Main Span South Spans

Emergency Response

6:05 p.m.

Numerous calls to 911

Motorists on bridge, constructionworkers, citizens in area assistinjured

mergency personne rom w nCities and Western Wisconsinrespond

6:10 p.m.

District Emergency OperationsCenter activated

Mn/DOT’s RegionalTransportation Management

Center (RTMC)

Immediate traffic control for ramp andImmediate traffic control for ramp and

freeway closures provided by FIRST units,freeway closures provided by FIRST units,maintenance units, and contractors in themaintenance units, and contractors in thevicinityvicinity


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Response the First 12 Hours

Unified commandcenter set up oncollapse site.

p s. re epar men ncharge of rescue operation

Hennepin County Sheriff incharge of recovery

Rescue operationswell coordinated byemergencyresponders.

August 1, 2007

First 12 Hours – continued)

6:20 p.m.

Maintenance started converting I-35W temporary traffic controlmeasures to longer term trafficcontrol standards with barriers andsigns

20 changeable message signsactivated

800 megahertz communicationsystem was critical for responders

First 12 Hours – continued)

7:00 p.m. Over 150 employees activated,

most just returned without a call

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

up a e o pu c. um er ovictims unknown.

Rescue Operations Ended,Recovery Begins

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

on Mn/DOT Web site

Overnight

Expanded signing and barricadesof closed I-35W

Converted T.H. 280 to a freeway

I-35W Detour Map

Key Decisions – Early August 2

nd

• Division of Tasks

•Dedicate a team to bridge replacement

•collapsed bridge

•Retain a forensic expert for the collapse investigation

•Previous planning for a bridge emergencyreplacement addressed typical interchangebridges, not a major river crossing.


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August 2, 2008

• Mn/DOT Engineers assess stability ofwreckage for recovery personnel

• Mn/DOT retains Wiss Janney Elstnerand TranSystems/Lichtenstein for

• Federal Agencies Arrive at CommandSite FEMA, FBI, Coast Guard, OSHA,OIG, FTA, NTSB, Rick Capka andNational FHWA staff

• NTSB Leads Investigation Team

• Law Enforcement and NTSB UpdateVictims’ Families

• Mn/DOT Engineering Team is organizedfor rapid replacement

Command Site

Media Coverage August 2nd

– Governor Conducts interviewsthroughout morning

– 2:00 pm Press ConferenceGovernor announces

○ Emergency Statewide BridgeInspections beginning withunderdeck trusses

○ Forensic Investigation Team WissJanneyElstner

Transystems

○ Independent Review ofMn/DOT Inspection Program

FHWA Participates

Mn/DOT provides bridge background

and responds to questions

– National and International NewsOrganizations present

– National Transportation SafetyBoard Begins Updates


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Responding to Public and Media Requests

Held Daily 2:00 pm PressConference• Became only means to respond to

volume of requests• Format was Statement, Update on specific

issue, Open to questions• Length was held to a reasonable time – 30

to 45 minutes• When it ended, held uestions till next da

Approach to Press Conferences• Share the information we possess• Be factual and calm• Avoid speculation. Ok to admit you don’t

know.• It is Ok to stop and think before

answering.• Use non-engineering terms when possible• Provide information that informs the public• Keep accusatory questions in perspective

– lives have been lost

8/3/07 Press Conference


(Continued)

Mn/DOT goal was to betransparent• Document requests were

voluminous• Website posting of plans,

inspection reports, bridge

studies• Dedicated I-35W Website

included all documents

Later needed to removeinspectors names aftercalls were made to theirhomes.


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(Continued)

Mn/DOT priority was localmedia requests

,own investigations andspeculation.

Correcting factual errorsconsumed time

Document ManagementSystem established to gatherand store all bridgeinformation

Spectators and Media on Adjacent10th Avenue Bridge

National Response

Aug. 2 – Secretary Peters andFHWA Administrator Capka onsite

Aug. 4 - President Bush pledgeso cut re tape t at cou e ay

recovery

Several site visits by SecretaryPeters and President Bush, andcontinuing presence by RickCapka

Within days, Congress authorizes $250million in Emergency Relief money to replacebridge and restore highway facilities to pre-disaster conditions

Total Federal Emergency Relief $373.5M

Access to site controlled by po lice and fending –24/7

Aug. 6 – Careful bridge demolition began to a idrecovery, and NTSB investigation

Navy Divers from Norfolk, VA assist in recovery

NTSBInvesti ation TeamSu ervisesRemoval

Recovery of VictimsRecovery of Victims

All steel members marked and in dexed

Members removed by torch – underwater cutscould take 1-4 hours

Extensive coordination required with divers,sheriff, investigators and contractor

Site protocol followed during recovery of victims

Navy Dive Team

Navy Divers Perspective

Assigned bridgeengineers to assistNTSB not previouslyinvolved in bridge

Aug. 20 – Navy Divers

recover 13th victim, site

Sept. 6 - Navigationchannel opened tocommercial traffic

Sept. 27 – Final steelremoved from river

Removing Wreckage from Navigation Channel


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Structural Steel Laid Out

On River Flats

September 2007 – November 2008

Anticipate and Act

Identify what we should do Resulting from the investigation or internal process reviews

Don’t wait – Take action

Take opportunities to communicate what you are doing

Encouraged and reassured our staff Keep them focused

Understand rebuilding credibility is a journey

Minnesota Actions Following

August 1, 2007

Bridge Inspection

Aug. 2 - Governor directs MnDOT to inspec tall bridges on the trunk highway systemin priority order

Inspection continued of all MnDOTbridges, with priority to fracture criticalbridges and those rated “structurallydeficient”

By December 21, 2007

• 3875 MnDOT bridges inspected• 840 Local Bridges

• Supplemented MnDOT inspectionteams with PB Americas, MichaelBaker, HDR, Volkert, and STV

Peer Review of Major Bridge Designs – April 2008

Spans over 250 feet

Minnesota Actions (Continued)

Unique bridge types

Independent design review by a separate design firm

Design Criteria and Assumptions

Review of Design

Constructability Review


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Bridge Inspection

Governor Directs Mn/DOT to conduct an independent “Stem toStern” review of bridge inspection program Mn/DOT retains PB Americas to conduct 301 bridges inspected and used in Condition Rating Comparison

Findin s – June2008


Condition ratings for 282/301 bridges within 1 NBI rating MnDOT Program Consistent with other States and complies with NBIS Better documentation to track- inspection findings to follow up

maintenance actions Clarify responsibilities between routine and fracture critical inspection

teams

Process Reviews of Internal Procedures

Completed as a follow-up to PB study and Legislative Auditor Study

Internal QC/QADesi n Procedures areunder review


Inspection

Consolidated documentation of QA/QC procedures for Routine andFracture Critical Inspections

Increased use of UT to assess corrosion

Maintenance

Revised procedures to document maintenance follow up to inspectionfindings

Gusset Plate Reviews and Inspections

January 15, 2008

NTSB urges truss and gusset

plate load ratings for bridges

citing design error in I-35W

Bridge.

Mn/DOT developed a checkingprocess for gusset plates inOctober-November 2007

No software or rating methodsexisted for checking trussgusset plates, few examples inreferences

Mn/DOT began the analysis ofseveral bridges in Fall 2007

January 15, 2008 Press Conference

Mn/DOT conducted news conference following NTSBPress Conference on January 15 Informed the public we had already begun the design review of

gusset plates on our truss bridges Commit ted to com let in the rocessb Jul of 2008 Shared the purpose was to determine if original designs were

correct Noted we had no reason to suspect a similar error – this was

precautionary

Rivets/bolts in shear and bearing

Buckling at ends of diagonals

Truss Bridge Gusset Plate Checks Performedby Mn/DOT in 2008

Tension at ends of all tension members

Block shear at ends of all tension members

Gusset Plate free edge unsupported length to thickness ratio

Gusset Plate Rating Results

By July 1, 2008:

25 trusses load rated toverify original design wascorrect

y ugus , :

25 bridge fieldinspections of gussetscompleted

No design deficiencies

similar to I-35W foundWabasha Bridge


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Results of Reviews

Typical Areas of Loss• Gusset Plates Below:

• Deck Joints• Drain Pipes

• Section Loss Areas:• Interior Face Along Chord (Red)• Interior Face Along Edges of

Dia onals Green• Interior Face Along Edges of

Verticals (Blue)• Exterior Face Along Top of

Lateral Brace Gusset Plate

• Extensive use of ultrasonicdevices to measure platethickness

Blatnik Bridge

Documentation of Losses

Visual (≤ 1/8”) & NDT (≥ 1/8”) Quantify Depths Quantify Areas Identify Locations Include Contours

Results of Reviews

St. Cloud Bridge – closed and replacement accelerated Blatnik Bridge in Duluth – gusset stiffened to restore full

safety factor Winona Bridge – reinforced gusset due to corrosion All necessary repairs were completed by July 2008

Blatnik Bridge

Local press conference on the day we restricted or closed abridge.

Commissioner, State Bridge Engineer, District Engineer, andElected Officials Participated.

Commissioner emphasized safety was our number onepriority.

Press Conferences Held in Each City Impacted

Described what our inspectors had discovered. Why we needed to act. Stated we were acting conservatively “out of an abundance of

caution”. Committed to repairing as soon as possible. Promised to update them on progress.

DESOTO BRIDGE – St. Cloud

Closed March 20, 2008-Replacement Accelerated

BLATNIK BRIDGE - Duluth

Restricted May 6, 2008 – 1 Lane Each Direction

Repairs Completed July 2008

Overlay weight andPrevious Corrosion had

reduced Safety Factors at29 Locations

$1.1 Million Repair Job


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WINONA BRIDGE

Closed Temporarily June 3, 2008

Repairs Completed July 2008

WINONA BRIDGE

$108,000 total cost

Corrosion hadreduced Safety

Factors at 15 locations

Revised Bridge Construction Load Specifications inresponse to FHWA August 8, 2007 Advisory – April2008

Minnesota Actions

• Unless otherwise allowed in plans, limits construction to loadingssimilar to design liveload.

• Construction materials limited to 65,000 lb per 1000 SF.

• Individual Stockpiles limited to 25,000 lb per 100 SF.

• Vehicles, materials, equipment limited to 200,000 lbs per span.

• Alternate loadings require submittal by contractor’s engineer andapproval of Mn/DOT Project Engineer.

Legislative/Congressional

Hearings and Investigations

Congressional Hearing September 2007

Several Minnesota Legislative Hearings RegardingTransportation Issues and the I35W Bridge

Investigative Report to Joint Committee toInvestigate the I35W Bridge Collapse – May 2008

Office of the Legislative Auditor, State ofMinnesota “Evaluation Report: State Highwaysand Bridges – February 2008”

National Transportation Safety Board

Investigation

NTSB led the investigation with a team of professionalsincluding metallurgists, engineers, and experiencedinvestigators

nves ga on oc e as een pos e on ewebsite at: www.ntsb.gov under Highway Accidents.

Process was very disciplined progressing through factfinding, analysis, conclusions and recommendations.

NTSB parties and contributors to the investigationincluded the FHWA, Wiss Janney, Elstner andTransystems, Mn/DOT, Jacobs Engineering, and PCI.

NTSB Investigation Results – November 13-14, 2008 NTSB Public

Hearing

Collapse of I-35W Highway Bridge

Minneapolis, Minnesota – August 1, 2007 – Page 152

Probable cause – “inadequate load capacity dueto a design error by Sverdrup & Parcel and Associates, of the gusset plates at the U10

,

1) Substantial increases in the weight of the bridge,which resulted from previous bridge modifications,and

2) The traffic and concentrated construction loads on

the bridge on the day of collapse.”


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NTSB Investigation Results Continued)

Collapse of I-35W Highway Bridge

Minneapolis, Minnesota – August 1, 2007 – Page 152

“Contributing to the design error was the failure ofSverdrup & Parcel’s quality control procedures toensure that the appropriate main truss gusset platecalculations were performed for the I-35W bridge andthe inadequate design review by Federal and Statetransportation officials.

Contributing to the accident was the generally acceptedpractice among Federal and State transportationofficials of giving inadequate attention to gusset platesduring inspections for conditions of distortion, such asbowing, and of excluding gusset plates in load ratinganalyses.”

Mn/DOT Communication Following

November 13-14, 2008 NTSB Hearing

Commissioner responded to mediafollowing the hearing expressing thanks

.

Due to actions already taken, Mn/DOTwas able to state action was complete orunderway regarding all NTSBrecommendations.

2008 Transportation Bill○ License Plate Fee and 5 cent Gas Tax Increase

○ $1.8 billion in bonding of which $600M bridges

○ Up to 3.5 cent added gas tax for bond payments

○ By June 2018, replace all bridges rated SD and below 50,

Minnesota 2008 Transportation Funding

and FC bridges, unless reason documented to remain in

service○ Approximately 120 bridges to be repla ced or repaired

Victims Fund Legislation○ Existing statutory limits on liability inadequate

○ $37 million in payments completed

Bridge Replacements Completed to Date

41 bridge projects are completed orunderway.

13 ma or brid e ro ects lanned overthe next 8 years with 6 Mississippi Rivercrossings.

Impacts on Employees and Organization

Responded well on August 1. They returned without a call. Tremendous strength and perseverance shown. Stress debriefings were valuable tools to share emotions. We watched for signs of employee struggles with mental and

h sical health. Reassi ned to other duties as needed. Communicate with employees as often as possible, rather than

the news be their source. Provided reassurance. Important to have Governor and other leaders in forefront to help

reassure the public. Media communication handled by Assistant Commissioner and

Bridge Engineer to allow employees to focus on their job.


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Observations and Lessons Learned

Existing partnerships/relationships with the FHWA,

Minneapolis, and other agencies were key in respondingto the tragedy. Dedicating a team solely to rapid replacement was

needed. Others dealt with colla se. Establish a Web Site to make information public versus

responding to individual data requests. Daily News conferences are manageable, individual

interviews are overwhelming.

Observations and Lessons Learned

Continued)

A redundant traffic management systemis invaluable.

Understand politics will be part of it.

Within tragedy is also the impetus toreview processes and improve, be opento the opportunity.

Documents

handout Dan Dorgan 1of2 6pp.pdf