AASHTO T‐18 BRIDGE MANAGEMENT ,

EVALUATION AND REHABILITATION

Idaho Transportation DepartmentMatt Farrar

Introduction• Matt Farrar

– State Bridge Engineer

– Responsibilities include

• Bridge Design and Construction Support• Bridge Management, Planning and Programming

– AASHTO SCOBS T‐18 Bridge Management, Evaluation, and Rehabilitation‐ Chairman

T – 18 Update• What is T‐18?• AASHTO SCOBS• Subcommittee on Bridges and Structures• 20 Technical Committees• T‐18 is the Technical Committee for Bridge Management, Evaluation, and Rehabilitation

• T‐9 is the Technical Committee for Bridge Preservation

• T‐14 is the Technical Committee for Steel Bridges

T – 18 Update (Continued)

• T‐18 Responsibilities

–Maintain and Update the Manual for Bridge Evaluation (MBE)

–Maintain and Update the NEW Manual for Bridge Element Inspection

T – 18 Update (Continued)

T – 18 Update (Continued)Manual for Bridge Evaluation

T – 18 Update (Continued)

• Revised MBE SECTION 1 – INTRODUCTION

– Reorganization– No Commentary

– “Provisions to support

the NBIS

Requirements”

T – 18 Update (Continued)Ballot Item ‐ Revisions to MBE Sections 1 Introduction

… The purpose of the Manual for Bridge Evaluation (MBE) is to serve as a resource for use in developing specific policy and procedures for the inspection and evaluation of existing highway bridges.

… The MBE is incorporated by reference in the CFR (23 CFR 650 Subpart C)

… Throughout this Manual there are subsections titled in part “ Provisions to support the NBIS Requirements”. These subsections were developed to provide specific guidance and best practices which are considered to be required under the regulations.

T – 18 Update (Continued)Article 1.4.1- PROVISIONS TO SUPPORT THE NBIS REQURIEMENTS

A quality control and quality assurance (QC/QA) program is to include periodic field review of inspection teams, periodic bridge inspection refresher training for program managers and team leaders, QC/QA measures for inventory data, and independent review of inspection reports and computations. The bridge inspection Program Manager is responsible to develop a QC/QA program that generally conforms to the provisions of Section 1.4. Specific details are to be determined by the Bridge Inspection Program Manager.

T – 18 Update (Continued)

• Revised MBE SECTION 2 – BRIDGE FILES (RECORDS)

– Reorganization – No Commentary

– “Provisions to support

the NBIS Requirements”

T – 18 Update (Continued)Ballot Item ‐ Revisions to MBE Sections 2 ‐ Bridge Files and Documentation2.0—INTRODUCTION… The bridge file provides information that directly relates to requirements of the National Bridge Inspection Standards (Article 2.1) and other supplemental information that bridge owners may find useful in managing bridges (Article 2.2).2.1—PROVISIONS TO SUPPORT THE NBIS REQUIREMENTS… Throughout this Manual there are subsections titled in part “ Provisions to support the NBIS Requirements”. These subsections were developed to provide specific guidance and best practices which are considered to be required under the regulations.

T – 18 Update (Continued)Ballot Item ‐ Revisions to MBE Sections 2 ‐ Bridge Files and Documentation2.1—PROVISIONS TO SUPPORT THE NBIS REQUIREMENTS

2.1.1 General File Information

2.1.2 Field Inspection Information

2.1.3 Critical Findings and Actions Taken

2.1.4 Waterway Information

2.1.5 Significant Correspondence

2.1.6 Other Inspection Procedures and Requirements

2.1.7 Load Rating Documentation

2.1.8 Posting Documentation

2.1.9 Scour Assessment

2.1.10 Scour Plan of Action

T – 18 Update (Continued)Ballot Item ‐ Revisions to MBE Sections 2 ‐ Bridge Files and Documentation2.2—SUPPLEMENTAL DOCUMENTATION IN BRIDGE FILE

2.2.1 General

2.2.2 Plans and Drawings

2.2.3 Construction Documentation

2.2.4 Original Design Documentation

2.2.5 Unique Considerations

2.2.6 Utilities and Attachments

2.2.7 Maintenance and Repair History

2.2.8 Additional Waterway Documentation

2.2.9 Traffic Data

T – 18 Update (Continued)

• MBE SECTION 6 – LOAD RATING

– New Gusset Plate Rating Provisions

– New Gusset Plate Analysis Example

T – 18 Update (Continued)New Gusset Plate Rating Provisions

• Guidance on Section Loss due to Corrosion

• Tension Members Reduced Net Area

• Compression Members Uniform and Localized Corrosion

-1/4 inch -1/2 inch -3/4 inch

-1/4 inch

-1/2 inch

T – 18 Update (Continued) New Gusset Plate Rating Provisions

1. Revised variables for shear resistance, Ω (shear reduction factor) and vy (resistance factor for shear yeilding)

2. New provisions for compression resistance, revised Whitmore Width derived from 30 degree angles and Lmid

30°

30°

Whitmore Width

Lmid

T – 18 Update (Continued) New Gusset Plate Rating Provisions

3. New resistance factor for block shear

4. New tension and compression chord splice checks

5. Based on reliability of factor ß of 3.5 for Inventory Rating and 2.5 for Operating Rating

T – 18 Update (Continued) New Gusset Plate Rating Provisions

3. In general, FHWA has indicated re‐rating won’t be required unless there is a change in condition or load.

4. Very compact gussets in compression may have less capacity, although this aspect does not usually control truss capacity, inmy opinion.

5. May see increases in shear yielding and block shear rupture capacities if FHWA guidance was followed

T – 18 Update (Continued)• Other 2013 Manual for Bridge Evaluation Ballot Items (…continued)– Various ballot items to clarify examples, application of distribution factors and load factors

– Ballot item to clarify application of live load factors on buried structures

T – 18 Update (Continued)Major Revisions and Updates to the AASHTO

Guide Manual for Bridge Element Inspection, 1st

Edition

Why Update to the 1st Edition of the AASHTOGuide Manual for Bridge Element Inspection?

• FHWA sponsored training classes “Introduction to Element Level Bridge Inspection”

• Perhaps 5 agencies had begun to implement the new elements

• Comments received have been incorporated into the manual

• Legislation (MAP-21) mandates element level inspection for NHS

T – 18 Update (Continued)

T – 18 Update (Continued)AASHTO GUIDE FOR COMMONLY RECOGNIZED (CoRe) STRUCTURAL ELEMENTS

• AASHTO has Developed a Core Elements to New Elements Data Migrator - FREE

Recap of AASHTO Guide Manual for Bridge Element Inspection, 1st Edition

• Four condition states for all elements.– Follows – Good, Fair, Poor, Serious convention.

• Wearing surfaces separated from deck element.– Deck element units changed to square feet.

• Steel protective coatings separated from steel.

• All smart flags have been incorporated into condition state language.

• New elements for timber trestle and framed/built up tower supports.

T – 18 Update (Continued)

Element TypesNational Bridge Elements (NBE’s)

• Represent the primary structural components of bridges necessary to determine overall condition and safety.

Bridge Management Elements (BME’s)• Elements define secondary bridge components.

Joints, wearing surfaces, protective coatings,etc.

Agency Developed Elements• Supports agency developed elements.

T – 18 Update (Continued)

AASHTO Guide Manual for Bridge Element Inspection, 1st Ed

“Old Element Format”

New AASHTO Manual for Bridge Element InspectionNew Format – The condition state table for each element has been consolidated. The result of this change is a cleaner and easier to read element description.

“Generic labels have been added along with color coding for the condition state titles (Good, Fair, Poor, Severe”

“The defect flags available for any given element have been expanded to include all defined element defects”

New AASHTO Manual for Bridge Element InspectionBridge Management Element

“Generic labels have been added along with color coding for the condition state titles (Good, Fair, Poor, Severe”

“The defect flags available for any given element have been expanded to include all defined element defects”

New AASHTO Manual for Bridge Element Inspection

A number of “Other” Material Elements have been added to capture new materials and unusual materials (FRP, etc.)

New AASHTO Manual for Bridge Element InspectionUpdates of Appendix ,B, C & D

Appendix B – Inspection ExamplesAppendix C – Element GroupingsAppendix D – Materials and Defects

“US Customary UnitsUsed Throughout”

New AASHTO Manual for Bridge Element Inspection

Appendix B –Inspection Examples

Improved Examples including Quantity Bookkeeping

New AASHTO Manual for Bridge Element InspectionUpdates of Appendix A,B, C & DDefect Flags Expanded

“Defect Flags available for any given element have been expanded to include all defined element defects.”

New AASHTO Manual for Bridge Element InspectionAlso in Appendix D -

“Compilation of all defects by material type and condition state descriptions”

New AASHTO Manual for Bridge Element InspectionNew Elements Added “Prestressed Concrete Top Flange

“All prestressed bridge girder top flanges where traffic rides directly on the structural element regardless of the wearing surface or protection system used”

New AASHTO Manual for Bridge Element Inspection1st Edition Substructure Elements and Units

New Substructure Elements and Units

What’s in the future for the T‐18– Revisions to Sec. 4

Inspection – Revisions to Sec. 7 Fatigue

Evaluation– NCHRP 12‐82 Reliability

Based Bridge Inspection Methods

– NCHRP 20‐07 Complex Bridge Inspection Procedures

– NCHRP 20‐68 Advances in Superload Permit Practices

ConclusionImprovements to the Manual for Bridge Evaluation (MBE) and Manual for Bridge Element Inspection (MBEI) will continue so as to be a more useful tools for bridge inspection and load rating.