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BRIDGE INSPECTION House Transportation Finance November 12, 2008 Dan Dorgan State Bridge Engineer Duane Hill Assistant District Engineer Duluth.

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Presentation on theme: "BRIDGE INSPECTION House Transportation Finance November 12, 2008 Dan Dorgan State Bridge Engineer Duane Hill Assistant District Engineer Duluth."— Presentation transcript:

1 BRIDGE INSPECTION House Transportation Finance November 12, 2008 Dan Dorgan State Bridge Engineer Duane Hill Assistant District Engineer Duluth

2 2 Focus Today Brief overview of bridge inspection requirements Actions taken in the last year in the bridge inspection area

3 3 Bridge Inspection Requirements See Appendix for information regarding: Governing Regulations for Inspections Bridge Inspection Frequency Bridge Inspector Qualifications

4 4 Gusset Plate Reviews January 15, 2008 NTSB urges truss and gusset plate ratings for bridges citing design error in I-35W Bridge. No software or rating methods existed for checking gusset plates MnDOT began developing a checking process for gusset plates in October 2007 MnDOT had already begun the analysis of several bridges

5 5 Gusset Plate Rating Results By July 1, 2008: 25 trusses rated to verify original design By August 1, 2008: 25 bridge inspections of gussets completed No design deficiencies similar to I-35W found

6 6 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 Hastings Bridge – unsupported edge stiffened to meet code requirements

7 7 Fracture Critical Bridge Inspection Positions Office of Legislative Auditor in February 2008 recommends MnDOT provide additional funds for fracture critical inspections. MnDOT identifies 8 additional inspection positions Bridge Office: 1 Inspection Engineer position filled 2 Inspector positions filled 3 Engineering positions in process District 6, Rochester and Metro: 2 Inspection Engineer positions in process

8 8 Governors Inspection Program Governor ordered on August 2, 2007: In-depth inspection of all state and local Fracture Critical Bridges Routine inspection of all state and local structurally deficient bridges Routine inspection of all other state highway bridges Stem to Stern review of MnDOTs Bridge Inspection Program

9 9 Governors Inspection Program By December 20, 2007 T.H. System: 3,875 Routine and FC Inspections Completed 270 by Consultants Local System: 141 FC Inspections Completed 43 by Consultants 843 Structurally Deficient Bridges

10 10 17 Critical Findings Identified During Statewide Inspections 6 Bridges Closed Norman County Road 3 Mountain Lake Township Road in Cottonwood County Municipal Street 5 in Russell State Game Preserve Road 222 in Wabasha County Redwood Township Road 185 in Redwood County Municipal Street 18 in the City of Carver 6 Bridges with Load or Lane Restrictions 5 Bridges Repaired, Including 2 State Highway Bridges T.H. 11 bridge over the Red River of the North in Kittson County was closed briefly until repairs were made on a beam that showed cracking T.H. 10 near Little Falls was also closed briefly for repair after inspectors discovered damage to a beam, apparently caused when it was hit by a truck following the bridges previous inspection

11 PB Americas Inc. Process Review

12 12 Findings MnDOT is in compliance with NBIS in the areas of: Bridge inspection organization Qualifications of personnel Inspection frequency Inspection procedures Inventory Additionally, MnDOT inspector ratings were consistent with Consultant inspector

13 13 Recommendations Develop procedures to track maintenance action items resulting from inspection findings Provide more inspection training to Program Administrators Hire more fracture critical bridge inspectors Develop and document inspection procedures for complex bridges Ensure that inspection data is entered into the database within the newly required interval Clarify responsibilities among fracture critical inspectors and agency owners Develop standardized narrative bridge inspection reports

14 14 Documenting Post-Inspection Bridge Maintenance Office of Legislative Auditor recommended implementing standard procedures to document post-inspection bridge maintenance follow up. A Bridge Inspection/Maintenance Assessment Form has been developed and distributed to Districts. Purpose is to document maintenance actions to be scheduled. By December 2008, a standard Bridge Maintenance Scheduling and Completion Spreadsheet will be adopted to track completion of maintenance actions.

15 15 Fracture Critical Inspection QA Process - 7 Day Inspection Summary 7 Day Inspection Summary submitted by Inspection Team Leader provided to the Bridge Office gives a quick look at changes and significant findings within 7 days of the inspection: Significant Deficiency noted? New Load Rating recommended? Traffic or Safety Hazard present? Bridge Element Condition summary? Significant findings that may need further review in the next 6 months? Purpose is to identify deficiencies that may require immediate action before the In-Depth Report is written and reviewed

16 16 Fracture Critical Inspection QA Process - In-depth Bridge Inspection Evaluation Internal structural review by a Bridge Office Engineer of the In-Depth Inspection Report within 30 days of submitting a draft report Were critical findings resolved promptly? Are conclusions logically stated and correct? Is the structure functioning as designed? Should the load rating be re-evaluated? Owner must acknowledge receipt of the report, and concurrence or disagreement with the evaluation and recommendations

17 17 Routine Inspections – Longstanding QA Processes All Inspection Reports reviewed and signed by the Program Administrator, who must be a Registered Engineer Annual Audits conducted by MnDOT and FHWA for NBIS compliance 20 to 25 Counties/Cities/Districts (20% of state total) audited by reviewing records provided to the Bridge Office Of the 20%, 8 to 12 Counties/Cities/Districts receive field review each year to audit inspection procedures, qualifications of inspection staff, inspection files and documentation, and field inspection

18 18 Audit Rotational Map 2007 Agencies Include: RockNobles PipestoneMurray LincolnLyon RedwoodYellow Medicine RenvilleLac Qui Parle ChippewaKandiyohi SwiftBig Stone StevensPope District 4District

19 19 Tracking Process for Inspection Completion Began reporting quarterly in Sept, 2008: Number of inspections overdue by 1 and 3 months Number of inspections completed but not entered into PONTIS database within the required 90 days

20 20 Recurring Inspection Training Training scheduled for 2009: Refresher training to be held at multiple locations statewide to maintain inspector certifications – see Appendix for topics FHWA Bridge Safety Classes to be held at MnDOT Training Center Bridge Safety Class 1 – Engineering Concepts for Bridge Inspectors (1 week class) Bridge Safety Class 2 – Safety Inspection of In- Service Bridges (2 week class) Fracture Critical Inspection Class – Techniques for Steel Bridges (3.5 day class)

21 21 Technical Memorandums In February 2008, updated the following Technical Memorandums for the most current FHWA requirements: Critical Deficiencies Found During Bridge Inspections – process to address, report and resolve Guidelines for Fracture Critical Inspections of Fracture Critical Bridges, Special Inspections for other Bridges, and Underwater Inspections – procedures, frequency, inspector qualifications, Quality Assurance and reporting

22 22 Inspection Equipment and Technology Additional ultrasonic testing equipment purchased for expanded Fracture Critical staff Contracting for Ground Penetrating Radar of selected bridge decks for delamination detection Reviewing software and devices for use in electronic field data collection to aid bridge inspectors Ordering additional snooper and trailer-mounted inspection platform for smaller bridges

23 23 Removal of Potential Concrete Spalls from Bridge Decks Bridge crews have routinely removed loose concrete from older structures Maryland Ave/I-35E incident of July 26, 2008 should not have occurred Information, guidance and reminder to devote resources for identifying and removing potential spalls was sent to Districts on 7/28, 8/4 and 10/23/08 Priorities for underdeck inspection and removal assigned according to deck condition As of November 5, 2008, Districts report removing potential spalls from at least 16 bridges

24 24 National Involvement and Leadership MnDOT has shared with other states in numerous forums our experiences and learnings from the I- 35W bridge The process MnDOT developed to review the adequacy of gusset plates has been shared nationally and included in our manuals on the web Participating in national research on gusset plate design and analysis Participated in round table discussions of Bridge Inspection practices with Midwest States

25 25 Bridge Monitoring Installations and Research State of the art bridge monitoring systems installed in I-35W St. Anthony Bridge A monitoring system is included in the Eastbound Wakota Bridge, currently under construction Since the early 1990s, bridge monitoring systems have been used on at least 17 MnDOT bridges University of Minnesota currently conducting research for MnDOT titled Bridge Health Monitoring and Inspection – A Survey of Methods to survey available technologies and assess their capabilities MnDOT and the U of M are also developing a project to monitor an existing bridge

26 26 Appendix

27 27 Governing Regulations for Inspections National Bridge Inspection Standards (NBIS) Requirements established via Federal Rulemaking by the Federal Highway Administration American Association of State Highway and Transportation Officials Manual for Condition Evaluation of Bridges Minnesota State Statute and Rules MnDOT Policies

28 28 Bridge Inspection Frequency Bridge Inspection Cycles – bridges are inspected once every 24 months per National Bridge Inventory System. In Minnesota, if the condition of the deck, superstructure or substructure is rated 4 or less, bridges are inspected annually. Fracture critical bridges get an in-depth inspection at least once every 24 months. Underwater bridge inspections are required every 60 months.

29 29 Bridge Inspector Qualifications MnDOT has 75 certified inspection Team Leaders that meet State and Federal requirements. Qualifications required for certification include: Professional Engineering license or 5 years of experience performing inspections Successful completion of 3 week FHWA approved inspector training Passing a proficiency field exam (MN requirement) Attending refresher training to maintain certification

30 30 Bridge Safety Inspection Seminars – Refresher Training 2008 Topics Railroad Bridge Inspections 2007 Statewide Bridge Inspection Effort – Governors Mandate I-35W Bridge Collapse and Investigation Critical Findings Process PONTIS Online Demo for Inspection Date Entry Bridge Scour evaluation and documentation Structural Inventory Reports information and updating 2009 Topics (proposed) Fracture Critical Inspections I-35W Bridge Collapse and Investigation Bridge Railings and Guardrail inspection and coding instructions PONTIS Online Demo for Inspection Date Entry Inspection note-taking and proper documentation of findings Measuring section loss Load ratings Bridge Inspection Manual Updates Gusset plate elements Scour and channel cross sections Hinge bearings Work Zone Safety during Bridge Inspections

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