bridge # us 2 wb off ramp over i 35 ramp & lake 69101 … · the current load rating on the...

2015 FRACTURE CRITICAL

BRIDGE INSPECTION REPORT

MnDOT Bridge Office

3485 Hadley Avenue North

Oakdale, MN 55128

BRIDGE #

DISTRICT: COUNTY: CITY/TOWNSHIP:

Date(s) of Inspection:

Equipment Used:

Inspected By:

Report Written By:

Report Reviewed By:

Final Report Date:

69101

US 2 WB OFF RAMP over I 35 RAMP & LAKE

District 1 St. Louis Duluth

- 05/04/2015

Carter, Rodney; Nelson, Bill; Potter, Farrell; Theisen, Scott

Bill Nelson

Jennifer Zink

10/28/2015

State Highway AgencyOwner:

I. FINDINGS SUMMARY 1

II. INSPECTION LOGISTICS 2

III. FRACTURE CRITICAL MEMBERS/FATIGUE PRONE DETAILS 3

IV. INSPECTION FIELD NOTES 7

V. PICTURES 9

APPENDIX A: SI&A 15

APPENDIX B: 7 DAY FC REPORT 17

APPENDIX C: STRUCTURAL ASSESSMENT REPORT - FC 20

APPENDIX D: 1997 LOAD RATING 23

SECTION PAGETable of Contents

MnDOT Bridge No. 69101 2015 Fracture Critical Bridge Inspection Report

Location Map

Bridge 69101

3

This report documents the findings of the fracture critical inspection on MnDOT Bridge No. 69101 (USTH 2 Westboundoff Ramp over ISTH 35 Ramp and Lake). The fracture critical members were the steel pier caps at Piers 10 and 11.These pier caps were the only members inspected on the bridge. The inspection was completed on May 4, 2015.

I. Findings Summary

1. The current load rating on the bridge that was completed in 1997 did not take into consideration the load-carryingcapacity of the steel pier caps (Appendix D). In the 2011 fracture critical report, it was recommended that a new loadrating be completed taking into account the steel pier caps. As of the writing of this report, no new load rating has beencompleted.

Recommendation: Perform a new load rating taking into account the strength of the steel pier caps.

2. There is corrosion and minor flaking rust throughout the steel pier caps, but no significant section loss.

Recommendation: Continue to monitor the pier caps for advanced corrosion and section loss.

Significant Findings

Comments

The NBI ratings are the same as reported in 2013.

Suggested

NBI Condition Ratings

Item Current

NBI Condition Summary

Deck 7 (Good Condition) 7 (Good Condition)

Superstructure 7 (Good Condition) 7 (Good Condition)

Substructure 7 (Good Condition) 7 (Good Condition)

Channel 8 (Banks are protected) 8 (Banks are protected)

There are no inventory updates.

Inventory Updates

MnDOT Bridge No. 69101

2015 Fracture Critical Bridge Inspection Report

1

II. Inspection LogisticsThis report documents the fracture critical inspection on the steel pier caps located on Piers 10 and 11 on Bridge69101. The inspection was completed on May 4, 2015 by Bill Nelson, Farrell Potter, Rodney Carter and Scott Theisen.The 2015 Fracture Critical Bridge Inspection Report was written by Bill Nelson.



Bridge Description

Bridge 69101 is a flyover ramp from westbound USTH 2 to northbound I 35 and is considered an approach to Bridge69100 (Bong Bridge). Bridge 69101 crosses over a lake, a trail, Oneota Street, and an off ramp from northbound I-35.The bridge was constructed in 1983.

Steel pier caps are located at Piers 10 and 11, which are considered to be fracture critical. Piers 10 and 11 are“integral” caps that consist of welded steel I-girders anchored to a tapered concrete pier wall with four 2.50" diametersteel anchor bolts. There is a line of load path redundant diaphragms located on each side of the integral steel piercaps. The steel cap web plates are 1” thick and taper down in depth on the cantilever end sections. The flanges are20” wide and 1.50” thick. There are four welded web stiffeners on each face of the pier cap located near the center ofthe cap above the bearings. There is a 3” thick horizontal anchor rod bracket welded between each pair of webstiffeners approximately halfway up the web of the steel cap.

The design loading is HS 20, using 1977 and interim (1978-1981) AASHTO design specifications. The last load ratingwas performed in 1997. The operating rating is HS 45.2 and the inventory rating is HS 27.1. The bridge is not posted(open to legal loads). There have been no significant structural modifications since the bridge was constructed. TheMn/DOT Bridge Office has plans on file and are available on EDMS.

MnDOT District 1 was contacted prior to the inspection of the bridge to allow for coordination of necessary laneclosures and traffic protection. This inspection included an in-depth visual inspection of the steel pier caps located atPiers 10 and 11. No other portions of the bridge were inspected. The steel pier caps were accessed from below usinga 16 foot extension ladder. Access equipment was provided by MnDOT District 1.

Inspection Access

No special requirements were needed for this inspection.

Special Requirements

FRACTURE CRITICAL MEMBERS:Integral Steel Pier Caps1. Visual “hands-on” inspection concentrating on tack welds.2. Visual “hands-on” inspection concentrating of “tight fit” detail at web stiffener/top flange connection.

FATIGUE PRONE DETAILS:1. Check all welded and bolted connections for integrity.2. Check all fracture critical members for tack welds.

OTHER MISCELLANEOUS INSPECTION DETAILS:1. Visual inspection of Piers 10 and 11 and bearings.

Inspection Procedures

2



Fracture Critical MembersThe National Bridge Inspection Standards (NBIS) defines a “Fracture Critical Member” (FCM) as “A steel member intension, or with a tension element, whose failure would likely cause a portion of or the entire bridge to collapse.” Theonly fracture critical members on the bridge are the integral steel pier caps located at Piers 10 and 11.

Fatigue Prone DetailsThis section identifies fatigue prone details present on the primary structural steel members of this bridge. Steelstructural members subjected to tension or reversal stresses can develop fatigue cracks. The three primary parametersaffecting fatigue crack propagation are stress range, the number of stress cycles, and the type of detail. Other factors,such as out-of-plane bending, heat straightening, or field-welded repairs can increase the likelihood of fatigue cracking.

For the purpose of designing bridges for fatigue caused by in-plane bending stress, AASHTO describes weld detailsand connections using an alphabetical designation ranging from stress category “A” (best fatigue resistance) to stresscategory “F” (most susceptible to fatigue crack growth). Fatigue detail categories are defined in Table 6.6.1.2.3-1 of the2009 AASHTO LRFD Bridge Design Specifications. Refer to the table below for the applicable fatigue prone details.

III. Fracture Critical Members/Fatigue Prone Details

3

Fatigue Prone Details Member & Location Detail Description & Photo Reference

AASHTO Stress

Category

AASHTO Detail

Number Potential Crack Initiation Point

Steel Pier Caps

“Tight fit” detail at web stiffener/top flange connection. - NA In adjacent welds

and base metal Steel Cap (Pier #11)

Tack welds at web stiffener/top flange connection. D NA In tack weld and

adjacent base metal

MnDOT Bridge No. 69101 2015 Fracture Critical Bridge Inspection Report

4

Pier 10 & 11 Integral Steel Pier Cap

Pier 10 & 11 Cross Section at Bearings

5

Pier 10 Plan Elevation

Pier 11 Plan Elevation

6

IV. Inspection Field Notes



Inspection field notes reference photos in Section V.

7

MnDOT Bridge #69101 2015 Fracture Critical Inspection Report

Pier #10 Location Notes

Concrete Pier Wall

[2015] No significant change (Photo 1). [2013] There are two delaminated and spalled areas of concrete on the south face of the pier wall, approximately six square feet. [2009] 4 SF of spalling and delamination at the base adjacent to the off ramp guardrail.

Steel Pier Cap

[2015] No significant change (Photos 2-4). [2013] Complete paint system failure with areas of surface and flaking corrosion along the top and edges of the top flange and the edges of the bottom flange. [2009] paint failure and corrosion, mainly along the flanges. There is isolated flaking rust, but there is little or no section loss.

Bearings [2015] Paint failure and surface rust (Photo 5).

Pier #11 Location Notes

Concrete Pier Wall

[2013-2015] Same as previously reported (Photo 6). [2009] No notable damage or deterioration.

Steel Pier Cap

[2015] No significant change (Photos 7-10). [2013] Complete paint system failure with areas of surface and flaking corrosion along the top and edges of the top flange. There are tack welds at every stiffener against the top flange. None of the tack welds were cracked. [2009] paint failure and corrosion, mainly along the flanges. There is isolated flaking rust, but there is little or no section loss. On the N face there are 3 tack welds between the bearing stiffeners and the top flange. The plans designate this as a “tight-fit” connection. No tack welds shown on plans.

Bearings

[2015] Paint failure and surface rust (Photo 11).

8

Photo 1 - Pier 10 Typical

Photo 2 - Pier 10 N Side Typical

Pictures

9

Pictures

Photo 3 - Pier 10 SW Side

Photo 4 - Pier 10 Typical Pier Cap

10

Pictures

Photo 5 - Pier 10 N Side Bearing

Photo 6 - Pier 11 Typical

11

Pictures

Photo 7 - Pier 11 Typical Pier Cap

Photo 8 - Pier 11 Corrosion on Bottom Flange Under G2

12

Pictures

Photo 9 - Pier 11Typical Corrosion Bottom Flange

Photo 10 - Pier 11 G2 to Pier Cap Connection

13

Pictures

Photo 11 - Pier 11 Typical Bearing

14

Appendix A: SI&A

15

5 - Not eligible

1 - No Restriction

3 - FTG PILE

Posting

24

GENERAL

1A

AT THE JCT TH 2 & 35

01 - Beam Span

1426.2

45.2Operating Rating

134.7

Latitude

99999

GR Transition

Deck Geometry

Superstructure 7 - Good Condition

N

Parallel Structure

0 - Not Required

0 - Not Required

1983

29930 sq. ft.Painted Area

1 - CONC

1 - CONC

Deck Rebars

Appr. Span Detail

Service Under

County

City

1983

Appr. Span Type

Sect., Twp., Range 8

Duluth

District 1

MnDOT Structure Inventory ReportBridge ID: over

069 - St. Louis

Desc. Loc.

Township

District

Owner 01 - State Highway Agency

BMU Agreement

Main Span Type

4 - Steel Continuous

Agency Br. No.

Longitude

Custodian 01 - State Highway Agency

Crew

Year Built

MN Year Reconstructed

FHWA Year Reconstructed

MN Temporary Status

Bridge Plan Location 1 - CENTRAL

Main Span Detail

0 - NoneDeck Membrane

6 - Highway - waterway

Service On 1 - Highway

Skew 0

Culvert Type

Barrel Length

NUMBER OF SPANS

MAIN: 12 APPR: 0

Main Span Length

Structure Length

Deck Width (Out-to-Out) 25.8

Deck Material 1 - Concrete Cast-in-Place

Wear Surf Type 4 - Low Slump Concrete

Wear Surf Install Year 1983

Wear Course/Fill Depth 0.17 ft.

1 - Epoxy Coated Reinforcing

1983Deck Rebars Install Year

36796Structure Area (Out-to-Out)

36791Roadway Area (Curb-to-Curb)

Sidewalk Width 0.00 0.00

Curb Height 0.00 0.00

Rail Type 23 23

0 - No flareStructure Flared

N - No parallel structure

MISC. BRIDGE DATA

Field Conn. ID 4 - Bolted

Abutment Foundation

Pier Foundation

1 - ONOn-Off System

Year Painted

5Unsound Paint %

PAINT

D - Organic Zinc - 3309Primer Type

H - VinylFinish Type

Posted Load

Traffic

0 - Not RequiredHorizontal

BRIDGE SIGNS

0 - Not RequiredVertical

17Userkey

Unofficial Structurally Deficient

05/07/2015Routine Inspection Date

12Routine Inspection Frequency

Inspector Name Bridge Office FC Unit

Status A - Open

7 - Good ConditionDeck

Substructure

8 - Banks are protected

Culvert N - Not Applicable

1 - MEETS STANDARDSBridge Railing

1 - MEETS STANDARDS

1 - MEETS STANDARDSAppr. Guardrail

1 - MEETS STANDARDSGR Termini

SAFETY FEATURES

6

4

9 - Bridge Above Flood Water ElevationsWater Adequacy

9 - Superior to present desirable criteriaApproach Alignment

NBI APPRAISAL RATINGS

05/04/2015Frac. Critical

DateFreq

Underwater

Pinned Asbly.

Drainage Area (sq. mi.)

Waterway Opening

0 - No nav. control on waterwayNavigation Control

Pier Protection

Nav. Clr. (ft.)

Nav. Vert. Lift Bridge Clear. (ft.)

I - LOW RISKMN Scour Code 1995Year

WATERWAY

5 - HS 20Design Load

CAPACITY RATINGS

1 - LF (LF)

1 - LF (LF)Inventory Rating 27.1

Rating Date 4/1/1997

A: 1 - No Restriction

B: 1 - No Restriction

C:

- 049N 14W-

INSPECTION

Maint. Area

7 - RAMP, WYE, CONNECTOR

1

Route On Structure

SB-WBNB-EB

Bridge Match ID (TIS)

Roadway O/U Key

02 - USTHRoute Sys

Roadway Name or Description

Level of Service

1 - 1-way trafficRoadway Type

6937Control Section (TH Only)

Reference Point

10/1/1984Date Opened to Traffic

1.0Detour Length

1Lanes On 1Under

4500ADT

0HCADT

12 - Urban - Principal Arterial - Other Freeway or ExpresswayFunctional Class

If Divided

22.80

RDWY DIMENSIONS

Roadway Width

Vertical Clearance

ft.

ft.

Max. Vert. Clear. ft.

22.7Horizontal Clear. ft.

Lateral Clearance ft. ft.

22.0Appr. Surface Width ft.

22.8Bridge Roadway Width ft.

Median Width On Bridge ft.

ROADWAY

1994

Date: 10/28/2015

sq. ft.

sq. ft.

ft.

ft.

ft.

STRUCTURE

Structure Evaluation 7

7 - Good Condition

Channel

Underclearances

VEH: SEMI: DBL:

Unsound Deck %

ft.

ft.

ft.

ft.

2

ft. ft.

ft.

ft.ft.

ft.

mi

3 - FTG PILE

Historic Status

MnDOT Permit Codes

NBI CONDITION RATINGS46Deg Min Sec44 30.46

Deg Min Sec92 9 12.09

ft.

0ADTT %

Spec. Feat.

Y

Y/N

Legislative District 07B

Cantilever ID F - Friction Hinge

Number

Year

NUnofficial Functionally Obsolete

Unofficial Sufficiency Rating 97.6

IN DEPTH INSP.

Vert. Horiz.

Lt

Lt

Lt

Rt

Rt

Rt

US 2 WB OFF RAMP69101 I 35 RAMP & LAKE

TOTAL: 12

mo.

sq. ft.

US 2 WB off ramp

HS

HS

(Material/Type)

(Material/Type)

16

Appendix B: 7 Day FC Report

17



7 Day Fracture Critical Report (Report Date: 06/04/2015 )

Disclaimer: The condition ratings in this report are only suggested. It is the responsibility of the Bridge Owner to approveinspection data in SIMS.

Bridge # 69101

Facility Carried: US 2 WB OFF RAMP

Bridge Owner: State Highway Agency

Inspection Date(s): - 05/04/2015

Primary Inspector: Nelson, Bill

Other Inspector(s): Carter, Rodney; Potter, Farrell; Theisen, Scott

Method of Access:

Traffic Control: Pier caps were accessed with a ladder from behind the guardrail - no traffic control required.

Fracture Critical Inspection of Steel Pier Caps ONLYScope of Inspection:

NoCritical Structural Deficiencies (Yes/No)

YesNew Load Rating Recommended (Yes/No)

NoTraffic Safety Hazard (Yes/No)

NoStructural Analysis Recommended (Yes/No)

Facility Intersected: I 35 RAMP & LAKE

The current load rating on the bridge does not takeinto consideration the load-carrying capacity of thesteel pier caps. In the 2011 fracture critical report, itwas recommended that a new load rating becompleted taking into account the strength of thesteel pier caps. No new rating has been completed(also recommended in 2013).

NBI Condition Ratings

CommentsSuggestedCurrentItem

Deck 7 7

Superstructure 7 7

Substructure 7 7

Channel 8 8

QuantityElement Condition Ratings

54321

Suggested Element Condition Rating Changes in RED

Element Description#

106 Weathering Steel Girder or Beam 2,517 LF 0 2,517 0 0

107 Painted Steel Girder or Beam 1,761 LF 0 1,409 352 0 0

210 Reinforced Concrete Pier Wall 246 LF 218 28 0 0

215 Reinforced Concrete Abutment 26 LF 25 1 0 0

300 Strip Seal Deck Joint 77 LF 77 0 0

301 Poured Deck Joint 258 LF 206 52 0

310 Elastomeric (Expansion) Bearing 24 EA 12 12 0

311 Expansion Bearing 15 EA 15 0 0

313 Fixed Bearing 21 EA 18 3 0

321 Concrete Approach Slab-Concrete Wearing Surface 1 EA 0 1 0 0

333 Masonry, Other or Combination Material Railing 2,852 LF 2,139 713 0

358 Concrete Deck Cracking Smart Flag 1 EA 0 1 0 0

359 Underside of Concrete Deck Smart Flag 1 EA 0 1 0 0 0

373 Steel Hinge Assembly 12 EA 12 0 0 0 0

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QuantityElement Condition Ratings

54321

Suggested Element Condition Rating Changes in RED

Element Description#

377 Low Slump O/L (Concrete Deck with Epoxy Rebar) 36,796 SF 36,796 0 0 0 0

380 Secondary Structural Elements 1 EA 1 0 0 0

387 Reinforced Concrete Wingwall 2 EA 2 0 0 0

410 Modular Deck Joint 77 LF 77 0 0

422 Painted Beam Ends 6 EA 0 3 3 0 0

427 Painted Steel Pier Cap 50 LF 0 0 50 0 0

964 Critical Finding Smart Flag 1 EA 1 0

966 Fracture Critical Smart Flag 1 EA 1 0 0

981 Signing 1 EA 1 0 0 0 0

982 Approach Guardrail 1 EA 0 1 0

984 Deck & Approach Drainage 1 EA 0 1 0

985 Slopes & Slope Protection 1 EA 0 1 0

988 Miscellaneous Items 1 EA 0 1 0

Element Rating Notes:

ELEMENT #427: [2015] The paint on Pier caps 10 and 11 continues to deteriorate, but there is no significantsection loss (Photos 1-3).[2013] On Pier Caps 10 and 11, the paint system on the top surface of the top flange has extensive deteriorationwith surface corrosion along the edge of the flange. There are scattered areas of failed paint and surface corrosionon the edges of the bottom flange on Pier Caps 10 and 11. On the north face of Pier Cap 11, there is one tack weld(four total) between the top flange of the pier cap and the vertical stiffeners. None of the tack welds were cracked.

Steel is starting to rust. Active corrosion bottom of bearings and anchor bolts. 2012- Both caps have activecorrosion.(2014) no change.

ELEMENT #966: [2015] The steel pier cap at Piers 10 and 11, as shown on the plans, are integral caps and areconsidered fracture critical. A fracture critical inspection was completed on the caps of Piers 10 and 11 on May 4,2015.From E. Piers #11 & 12 have "fracture critical" integral steel pier caps (anchored to the concrete pier shaft) - theseare welded I-girders which do not require internal inspection, but should have a close-up inspection with a snooperor manlift. blasting and painting would aid in inspection in FC areas. (2014)no change.

General Notes:

Inventory Item Notes:

58. Deck NBI:

36A. Brdg Railings NBI:

36B. Transitions NBI:

36C. Appr Guardrail NBI:

36D. Appr Guardrail Terminal NBI:

59. Superstructure NBI:

60. Substructure NBI:

61. Channel NBI:

62. Culvert NBI:

71. Waterway Adeq NBI:

72. Appr Roadway Alignment NBI:

19

Appendix C: Structural Assessment Report - FC

20

BRIDGE OWNER:

DATE INSPECTED:

FACILITY CARRIED:

TYPE OF INSPECTION:

BRIDGE NO.:

STRUCTURE TYPE:

FEATURES INTERSECTED:

FRACTURE CRITICAL

SPECIAL:

State Highway Agency

05/04/2015

US 2 WB OFFRAMP

69101

Steel Continuous

Stringer/Multi-beam or Girder

I 35 RAMP & LAKE

PURPOSE:

This report is a structural assessment of the structure and its ability to carry loads based on conditionsidentified in the attached bridge inspection report. The assessment is only a cursory review intended toprovide guidance as to the relative hazards for structural conditions and deficiencies identified. This report ismandatory for all fracture critical bridges and is completed by the MnDOT Bridge Office upon receipt of the7 Day FC Report; however, it is an OPTIONAL tool for agencies to utilize at their discretion for all otherinspection types.

DAMAGE:

OTHER:Check all that apply:

Redundancy: Structural Load Path

Internal

RivetedConnectionType:

Welded

Other:

Bolted

PINNED ASSEMBLY:

ROUTINE

1. Was a critical finding identified during this inspection or upon

3. Does the condition of any bridge component indicate impaired

2. If a critical finding was identified, what is the current status?

Yes No

Pending Resolved

N/A

Yes No

Yes" above, state briefly the finding(s):a) If selected "

a) Briefly state actions taken:

structural review?

function? Examples of bridge components with impaired functioninclude elements that are: frozen or immoveable, out-of-plumb ormisaligned, distorted or structurally deformed, excessivelydeteriorated, cracked, broken, eroded or scoured.

21

4. Does the overall condition of the bridge, or any of its components Yes No

Continue monitoring the paint failure at the steel surface at the pier caps. Continue monitoring the cracked tack welds between the top flange of the pier cap and the verticalstiffeners.

mentioned in Question 3, suggest the need for detailed structuralanalysis and/or a revised load rating?

Bridge Office Reviewer Jihshya J. Lin5/25/2015

If selected "Yes" above, state briefly the component(s) and condition(s):a)

If selected "Yes", state the reason for this recommendation and indicate a proposed timeframe ina)

accordance with State of Minnesota Rule 8810.9500 (Subpart 2):

Explain recommended actions:

6. Other comments:

5. Based on the structural assessment of these findings, recommendations include:

Repair/Maintenance

Other Increased Inspection Frequency

Monitoring Plan

22

Appendix D: 1997 Load Rating

23

bridge # us 2 wb off ramp over i 35 ramp & lake 69101 … · the current load rating on the...

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