Comparison of AASHTO Bridge Load Rating Methods

NCHRP Report 700 – A Comparison of AASHTO Bridge Load Rating Methods......Page 1
Report Web Page......Page 0
Transportation Research Board 2011 Executive Committee......Page 2
A Comparison of AASHTO Bridge Load Rating Methods......Page 3
About the National Academies......Page 5
Author Acknowledgments......Page 6
Foreword......Page 7
Contents......Page 9
Summary......Page 11
1.1 Surveying/Soliciting Data......Page 13
2.1.1 NBI/Virtis Data Review/Comparison with Virtis Data......Page 15
2.1.2 Refinement of the Bridge Selections—Final Bridge Domain......Page 16
2.2.1 Introduction......Page 19
2.2.3 Vehicle Options......Page 24
3.1.2 Virtis/BRASS......Page 26
3.1.3 Final Bridge Breakdown......Page 27
3.1.4 Live Loads......Page 28
3.2 Reliability Index Calculation Spreadsheet......Page 30
3.2.3 Reliability Index Calculation......Page 34
3.3 Rating Factor Comparison Spreadsheet......Page 37
3.3.2 Main Sources of Difference in Rating Factors Between LFR and LRFR......Page 38
3.4.1 AASHTO Legal Vehicles......Page 44
3.5 Special Permit Vehicles......Page 48
3.6.1 Simple Span Steel Girder Bridges......Page 57
3.6.2 Continuous Span Steel Girder Bridges......Page 58
3.6.3 Simple Span Prestressed I-Girder Bridges......Page 59
3.6.4 Simple Span Prestressed Box Girder Bridges......Page 60
3.6.5 Simple Span Reinforced Concrete T-Beam Bridges......Page 61
3.6.6 Simple Span Reinforced Concrete Slab Bridges......Page 62
3.6.8 Continuous Prestressed Concrete I-Girder Bridges......Page 63
3.7 Comparison of Reliability Index to Live Load Factors......Page 65
3.7.4 AASHTO Legal Vehicles......Page 66
3.8 Selection of Load Factors for Implementation in the MBE......Page 68
3.9 Effect of Using Proposed Live Load Factors on Rating Factors......Page 81
3.9.1 Simple Span Steel......Page 82
3.9.2 Simple Span Prestressed I-Beams......Page 84
3.9.4 Simple Span Reinforced Concrete T-Beams......Page 85
3.9.8 Continuous Span Prestressed Concrete I-Beams......Page 86
3.9.9 Average Ratio of Rating Factors for Existing and Proposed Live Load Factors......Page 87
4.1 Proposed Revisions to the MBE......Page 94
4.2 Data Archiving......Page 102
Appendices A through R......Page 103
Abbreviations used without definitions in TRB publications......Page 104