FHWA Update 2020 020 AASHTO Rating and Design Bridge (RADBUG) User - - PowerPoint PPT Presentation

Thom

• mas S

as Saad ad, P P.E. Seni nior S r Struc ructura ral E Engi gineer r FHWA Resource C e Center thomas.saad@dot.gov

FHWA Update

2020 020 AASHTO Rating and Design Bridge (RADBUG) User Group Meeting

August 3, 2020

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 Key FHWA Program Initiatives  FHWA Bridge Load Rating Initiatives  FHWA Resources, Tools and Training for Bridge Design and Analysis

Engineers

Presentation Outline

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• National Bridge Inspection Standards

(NBIS) Rulemaking

• Specifications for the National Bridge

Inventory (SNBI)

• Critical Findings Database

FHWA Program Initiatives

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• Required by MAP-21
• Update methodology, training, and

qualifications for inspectors

• Update frequency of inspection,

including a risk-based approach

• Establish procedures for reporting

and monitoring of critical findings

• Establish national certification of

bridge inspectors

• Ensure uniformity of the inspections

and evaluations (NBIS and National Tunnel Inspection Standards)

NBIS - Overview of Proposed Changes

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• Changes and lessons learned

since last update (2004)

• Element level data
• Load rating vehicles
• Clarifications
• Fill gaps
• Address other questions and

requests for change

Method 1: Simplified Risk Method 2: Rigorous Risk

• Routine Interval

 24 months  ≤ 12 months (3 criteria)  > 24 and ≤ 48 months (9 criteria)

• Underwater Interval

 60 months  ≤ 36 months (2 criteria)  72 months (4 criteria)

• NSTM Interval

 24 months  ≤ 12 months (3 criteria)  > 24 and ≤ 48 months (4 criteria)

• Routine Interval

 ≤ 12, 24, 48 or ≤ 72* months  *>48, Service Insp. at 24 months  Min. 5 criteria, min. 4 damage mode types

• Underwater Interval

 ≤ 36, 60 or ≤ 72 months  Min. 5 criteria, min. 4 damage mode types

• NSTM Interval

 ≤ 12, 24 or ≤ 48 months  Min. 5 criteria, min. 4 damage mode types

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Proposed 650.311 Inspection Interval

Method 1: Simplified Risk Method 2: Rigorous Risk

• Routine Interval

 24 months  ≤ 12 months (3 criteria)  > 24 and ≤ 48 months (9 criteria)

• Underwater Interval

 60 months  ≤ 36 months (2 criteria)  72 months (4 criteria)

• NSTM Interval

 24 months  ≤ 12 months (3 criteria)  > 24 and ≤ 48 months (4 criteria)

• Routine Interval

 ≤ 12, 24, 48 or ≤ 72* months  *>48, Service Insp. at 24 months  Min. 5 criteria, min. 4 damage mode types

• Underwater Interval

 ≤ 36, 60 or ≤ 72 months  Min. 5 criteria, min. 4 damage mode types

• NSTM Interval

 ≤ 12, 24 or ≤ 48 months  Min. 5 criteria, min. 4 damage mode types

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Proposed 650.311 Inspection Interval

Summary of Process

• NPRM Process Started in 2012
• NPRM Published November 12, 2019
• NPRM Closed March 13, 2020
• 265 sets of Comments submitted

 190 Comments were submitted w/o attachments  75 Comments had one or more attachments  Attachments ranged in length from 1 to 30 pages

• 19 Internal FHWA commenters (237 total comments)

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Categorizing Comments

• 90 day load rating

requirement

• 30 day load posting

requirement

• Inspection of private

bridges

• Reporting of critical

findings

• Agreements for delegating

functions

• Inspection intervals
• Cost of implementation
• Supplemental NPRM

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• 1,450 comments from docket

 1,290 from 39 States  160 from:  4 Federal Agencies (34)  Counties & County Associations (15)  AASHTO (7)  Michael Baker (19)  Other Industry (7)  Professional Associations (2)  NTSB, MTA, NSBA (3)  Individuals (73)

SNBI Comment Counts

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• NextGen
• Tools

 Crosswalk  Converter

• Transition period

 Publish SNBI  Collect transitioned dataset on a specific date  Collect new data items by a specific date  New historical items going forward only

Transition Plan

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• Develop a CFD framework – identify data & collection tool
• Draft CFD Specifications & create collection tool

(SharePoint)

• Conduct two pilots – Bridge CFs and Tunnel CFs

 Revise the specification and collection tool based on the results of the

pilots and comments/suggestions received from DBEs and BSEs.

• Assist with the implementation of the CFD

Critical Finding Database (CFD) Effort Overview

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• There are 2

SharePoint lists

 One for Bridges  One for Tunnels

• 20 Items in each

list

• Lists are created

in SharePoint 365

CFD Effort Overview

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• Scope and purpose
• Definition of a CF
• Address CF vs. Resolve CF
• Examples of CFs to be included in this

database

• Examples of CFs NOT to be included in this

database

• Reporting tool
• Access your State’s CFD:



https://usdot.sharepoint.com/teams/fhwa-hibs- CriticalFundingDB/



Select your email address to sign in



Select Bridge_CFD or Tunnel_CFD to report CFs



Select your State folder

Specifications for CFD

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• Bridge CF pilot – Completed in June 2019

 Four (4) piloting FHWA Divisions: Minnesota, Pennsylvania, Washington State, and West

Virginia

 Report Critical Findings occur during 1st and 2nd quarters of FY19

• Tunnel CF pilot – From January to February 2020

 Six (6) piloting FHWA Divisions: California, District of Columbia, Idaho, Indiana, Michigan,

and Virginia

 Report Critical Findings occur during 1st and 2nd quarters of FY20

Bridge CF and Tunnel CF Piloting Programs

Bridge Pilot - Data Summary

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Tunnel Pilot - Data Summary

2 4 6 8 10 12 10200 Ventilation System 10650 Fire Detection System 10700 Fire Protection System 10750 Emergency Communication System

NTEs with High Number of CFs Occurred

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• Plan to initiate effort Fall 2020
• Prepared a roll out plan
• Will conduct webinars to inform Division Bridge Engineers
• Start collecting data

Next Step - Implementation

 Load rating of bridges continues to be a big challenge for the industry  It is critical to assuring safety of traveling public and providing mobility  The FHWA has ongoing efforts to provide policy and guidance to assist

State DOTs

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FHWA Bridge Load Rating Initiatives

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 Special Hauling Vehicles  Emergency Vehicles  Heavy Duty Tow and Recovery

Vehicles

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Image Source: FHWA

Changing Truck Weights

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Table le 3 3-8. . Tru rucks a and Tru ruck Mi Mile les b by y Avera rage W Weight: 1987, , 1992, 992, 1 199 997, 7, and 2002 20021

Average weight (pounds) 1987 1992 1997 2002 Percent Change, 1987 to 2002 Number (thousands) VMT (millions) Number (thousands) VMT (millions) Number (thousands) VMT (millions) Number (thousands) VMT (millions) Number VMT Total 3,624 89,972 4,008 104,987 4,701 147,876 5,415 145,624 49.4 61.9 Light-heavy 1,030 10,768 1,259 14,012 1,436 19,815 1,914 26,256 85.9 143.8 10,001 to 14,000 525 5,440 694 8,000 819 11,502 1,142 15,186 117.6 179.2 14,001 to 16,000 242 2,738 282 2,977 316 3,951 396 5,908 63.6 115.8 16,001 to 19,500 263 2,590 282 3,035 301 4,362 376 5,161 43.2 99.3 Medium-heavy 766 7,581 732 8,143 729 10,129 910 11,766 18.8 55.2 19,501 to 26,000 766 7,581 732 8,143 729 10,129 910 11,766 18.8 55.2 Heavy-heavy 1,829 71,623 2,017 82,832 2,536 117,931 2,591 107,602 41.7 50.2 26,001 to 33,000 377 5,411 387 5,694 428 7,093 437 5,845 15.9 8.0 33,001 to 40,000 209 4,113 233 5,285 257 6,594 229 3,770 9.7

• 8.4

40,001 to 50,000 292 7,625 339 9,622 400 13,078 318 6,698 9.0

• 12.2

50,001 to 60,000 188 7,157 227 8,699 311 12,653 327 8,950 73.8 25.1 60,001 to 80,000 723 45,439 781 51,044 1,070 74,724 1,179 77,489 63.1 70.5 80,001 to 100,000 28 1,254 33 1,529 46 2,427 69 2,950 144.3 135.2 100,001 to 130,000 8 440 12 734 18 1,051 26 1,571 238.5 257.2 130,001 or more 4 185 5 227 6 312 6 329 43.2 77.9

Changing Truck Weights

Source: https://ops.fhwa.dot.gov/freight/freight_analysis/nat_freight_stats/docs/13factsfigures/table3_08.htm

Office of Infrastructure

Truck Platooning

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Image Source: USDOT

 Period of Performance: 08/13/2018 to 12/12/2020

“The objective of this task order is to produce a comprehensive report for FHWA that covers the technical aspects of truck platooning impacts on bridges with a focus on structural safety.” The report shall include a brief discussion of:

 The truck platooning technology  Identify most common, probable truck platooning scenarios  Document the research methodology and findings  Recommend load models for bridge evaluation  Propose design specification modifications  Recommendations for further research

Objective

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Office of Infrastructure

Shear Load Rating for Concrete Bridges

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John Holt, Uriel Garcia, et al. (2018), Concrete Bridge Shear Load Rating, Synthesis Report, FHWA-HIF-18-061, Federal Highway Administration, November 2018. https://www.fhwa.dot.gov/bridge/loadrating/pubs/hif18061.pdf

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Project Deliverable

 Period of Performance: 07/01/2019 to 6/30/2021  A critical review of relevant specifications, technical

literature, and transportation agency and industry practices and experiences were performed for the synthesis report. The review investigated the specifications and provisions related to shear design and shear rating for concrete bridges specified in the current and previous editions of the AASHTO Manual for Bridge Evaluation (MBE) Standard Specifications and Load and Resistance Factor Design (LRFD) Specifications.

 A survey of select State DOTs was conducted to help

define challenges that need to be addressed in this review.

 The report includes a history of changes in shear design provisions in

AASHTO design specifications and the MBE. The report also provides a summary of States’ practices and identifies the issues that States are facing in rating existing concrete bridges using the MBE shear provisions. The final report was published in November 2018, and it is available at FHWA’s website.

 Fifteen findings are identified and documented in the report. Some could

be addressed through an AASHTO Agenda Item with modifications to the MBE or the LRFD.

Major Findings

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 Finding 7: Estimation of the strain—correctly--for use in MCFT-based

calculations is critical.

 Finding 8: Using MCFT and the strain equations in LRFD when prestressing

is on the compressive flexural side can provide incorrect and overly conservative shear strengths.

 Finding 9: MCFT-based shear strength calculations are load dependent.  Finding 10: An existing girder not meeting minimum shear reinforcement

requirements with MCFT may be have its shear strength unduly penalized.

 Finding 12: Reinforcement detailing should be verified for adequacy when

load-rating concrete bridges in shear.

Further Work from Original Task Order

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MCFT Procedures and Examples - Objective

 Produce technical guidance with examples for FHWA that covers the

technical aspects of concrete bridge shear load rating using the MCFT. A study shall be performed to develop methods for determining shear resistance for sections that do not meet minimum reinforcement requirements (either minimum longitudinal tension reinforcement or minimum shear reinforcement), based on the available shear test dataset that is in published literature.

 The procedure shall include how to accurately compute strain, resistance,

concurrent force effects and rating factor including the shear-moment interaction and the strain-force effect consistency in shear resistance

• determination. Minimum three (3) examples shall be developed to

demonstrate the MCFT shear load rating procedure.

Office of Infrastructure

Load Rating

• f Tunnel Structures

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 Period of Performance: 09/05/2017 to 07/28/2020  Produce a reference guide for FHWA that covers the technical aspects of load rating

• f tunnel structures and provides practical, representative step-by-step examples.

 This reference guide shall provide sufficient technical details and breadth

appropriate for explaining the load rating specifications and guide governing U.S. highway tunnel structures.

 A set of examples will help illustrate the requirements, procedures, and methods.  Conduct two workshops and to develop two validation examples.

Reference Guide for Tunnel Load Rating Objective

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 The Guide is complete and available at

https://www.fhwa.dot.gov/bridge/loadrating/pubs/hif19010.pdf

 It includes tunnel load rating guidance and four load rating examples  Two validation examples will be published separately – 95% complete  Two virtual workshops scheduled this month

Tunnel Load Rating Reference Guide Status

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 Period of Performance: 05/2020 to 02/2022  The overarching objectives of this task order are to 1) identify best practices from

State DOT’s bridge load rating, posting and overweight permitting programs; and 2) develop model frameworks for the future.

 The model frameworks will aim at addressing potential gaps in bridge load rating, posting and

• verweight permitting processes and promoting efficiency and consistency and ultimately improving

safety and mobility through implementation of advanced technologies.

 Increased use of advanced technologies can significantly improve productivity, efficiency and

consistency in bridge load rating, posting and overweight permitting. Possible benefits have not been fully realized. Identify potential for widespread use of automation, standardization or other associated technologies in bridge rating, posting and overweight permitting.

Advancing Bridge Load Rating: Best Practices and Model Frameworks

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FHWA/NHI Bridge Design Courses (www.nhi.fhwa.dot.gov) and Reference Manuals

 NHI Course

e 130081: LRFD for Bridge Superstructures (4 day) **

 NHI Course

e 130092: LRFR for Highway Bridges (4 day)

 NHI Course

e 130093: LRFD Seismic Analysis and Design of Bridges (4 ½ day) **

 NHI Course

e 130094: LRFD Seismic Analysis and Design of Tunnels, Walls and

• ther Geotechnical Features (4 day)

 NHI Course

e 130095: LRFD Design and Analysis of Skewed and Horizontally Curved Steel Bridges (2 ½ or 4 ½ days)**

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FHWA/NHI Bridge Design Courses (www.nhi.fhwa.dot.gov) and Reference Manuals

 NHI Course

e 130102: Engineering for Structural Stability in Bridge Construction (2.5-3.5 days)**

 NHI Course

e 130122: Design and Evaluation of Bridges for Fatigue and Fracture (2 day)**

 NHI Course

e 130126: Strut and Tie Modeling for Concrete Structures (1.5 day)**

 Bridge Security Design Manual **  Steel Bridge Design Handbook (updated)**  Post-tensioned Box Girder Design Manual**  Refined Analysis Manual**

** Manuals can be found by searching www.fhwa.dot.gov/bridges

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FHWA/NHI Bridge Design and Analysis Courses

(www.nhi.fhwa.dot.gov)

 Some web-based training opportunities that are

free of charge

 3 PDHs or 0.3 CEUs offered  Topics include:

 LRFD Design of Bridge Decks and Bearings  LRFD Steel I-Girder Details Design  Prestressed Concrete Girder Topics  Introduction to LFRD for Foundation Design

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 To further support State’s efforts in meeting the NBIS’s requirements in

load rating and FHWA's initiative of implementing the LRFR method, a series of webinars have been planned to provide continued awareness for local, regional, and State transportation agencies.

 No. 28: Load rating of Tunnels (October 2019)  No. 29: Introduction to NHI Course 130092, LRFR for Highway Bridges (December 2019)  No. 30: Bridge Load Testing for Load Rating (April 2020)

 Recordings are available at  https://www.fhwa.dot.gov/bridge/loadrating/

FHWA Bridge Load Rating Webinar Series

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Tha hank y you!

• u!

Thomas as S Saad aad, , P.E .E. Senio enior Structural al E Eng ngineer ineer FH FHWA R Res esource C e Cent enter er thomas.saad@dot.gov