BDEM UPDATE & LG GIRDER

Louisiana Transportation Conference2/27/2018

Zhengzheng “Jenny” Fu, P.E.Assistant Bridge Design Administrator

LADOTD Bridge Design Section

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ACKNOWLEDGEMENTS

SDR Engineering Consultants, Inc.

DOTD Staff

Dr. Ayman Okeil, LSU

All Users

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OUTLINE

BDEM Revisions (Rev. 7 and 8)

LG Girder Special Details

Future Work

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Index

Preface

Revision History

Part I Policies and Procedures

Part II Design Specifications (Supplement AASHTO Specifications)

Volume 1 - Bridge Design

Volume 2 - Movable Bridge Design

Volume 3 - Structural Supports for Permanent Highway Signs and High Mast Lighting

Volume 4 - Highway Safety Hardware

Volume 5 - Bridge Evaluation/Rating

Part III Design and Detail Aids

Part IV Background Information

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BDEM Revision History

Part II Vol 1 Chapter 5 and 13 & Part III Chapter 1

Preface, Part II Vol. 3 and 4

Historic bridges

Updated deck design tables

Misc. minor revisions

Part II Volume 5 -Rating

Deck design examples

Intermediate diaphragm

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BDEM Rev. 7 – Updated Preface

BDEM organization and format Maintenance and revision of BDEM (including implementation

policy for new edition of AASHTO Specifications) Implementation policy of BDEM revisions for consultant and in-

house projects Archived Manuals ( including archived BDEM pages and yearly

version of BDEM) Guidelines and BDTMs (part of BDEM)

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BDEM Rev. 7 – Published Part II Volume 3 – Permanent Highway Signs and High Mast Lighting

Supplements AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals

Discussed specific design, details and plan preparation for DOTD permanent highway overhead signs, breakaway signs and luminaires

Referenced DOTD special details for Roadside Traffic Signs and Overhead Traffic Signs.

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BDEM Rev. 7 – Published Part II Volume 4 –Highway Safety Hardware

Referenced AASHTO Roadside Design Guide (RDG) as a guide Provided design, detail and plan preparation information for DOTD

roadside barriers, median barriers, end treatments, and temporary barriers

Discussed general criteria, design process, standard plans, special details, specifications, EDSMs, and DOTD Approved Material Lists related to highway safety hardware.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.4 Material Properties – Included a Structural Concrete Class Summary Table

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.7.3.6.2 Deflection and Camber – Clarified deflection and camber definitions and revised symbols

Deflections Estimated Cambers Field Measured Camber*D1 –due to prestress force at transfer C1 – at release = D1-D2 MC1 – measured at 18 hoursD2 –due to girder self-weight C2 – at erection (PCI Multiplier method) after releaseD3 –due to non-composite dead load = 1.80D1 – 1.85D2 MC2 – measured at 21 days D4 –due to composite dead load C3 – final = C1 – D5 prior to deck pour

(exclude wearing surface) D5 – due to all dead loads = D3+D4

* Contractor is required to provide these measurements.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.10.11 Provisions for Seismic Design – Specified concrete shear keys to resist lateral seismic load (replaces current practice of angles and anchor bolts)

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.11.4 Development of Prestressing Strand – Clarified policy on straight, debonded and draped strands.

Straight strands shall be used whenever possible.

Debonded strands are not allowed without prior approval.

Draped strands are allowed when needed, however tie down points shall be kept consistent within a project whenever possible. The uplift force at each tie down device shall be limited to 40 kips.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.14.1.2 – Precast Beams

Specified new concrete girder policy Included a girder efficiency study in commentary Referenced new PCI Report No. CB-02-16 “Recommended Practice for

Lateral Stability of Precast, Prestressed Concrete Bridge Girders”.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Girder Policy

LG girders (LG-25 to LG 78) shall be used for all new construction, bridge widening, and rehabilitation projects.

AASHTO type girders (Type II, III, IV, BT-72 and BT-78) and Quad Beam can be used for rehabilitation projects with prior approval.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Girder efficiency study

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Girder Stability

Girder stability during each phase of construction is the responsibility of the contractor, however EOR is responsible for designing a girder that can be picked up and supported on dunnage.

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Contractor’s Responsibilities EOR’s Responsibilities

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BDEM Rev. 8 – Revised Part II Volume 1 -Chapter 5 – Concrete Structures

Section 5.14.1.4 Bridges Composed of Simple Precast Girders Made Continuous - Introduced “Link Slab” and “Floating Span”

Link Slab – A portion of continuous deck connecting adjacent simple spans. Replaces current practice of continuity diaphragms.

Floating span – No fixed bearing in a continuous unit. Entire unit is supported by expansion bearing pads. Applicable to bridges without extreme lateral and uplift forces.

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Link Slab and Floating Span LTRC Research Project – Ouachita River Bridge (Harrisonburg)

2-span fixed unit

New Design

4-span floating unit (span 1-4)

Original Design2-span floating unit (span 14-15 & 16-17)

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Link Slab and Floating Span LTRC Research Project – Ouachita River Bridge (Harrisonburg)

2-span fixed unit

New Design

4-span floating unit (span 1-4)

Original Design2-span floating unit (span 14-15 & 16-17)

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Link Slab and Floating Span LTRC Research Project – Ouachita River Bridge (Harrisonburg)

New DesignOriginal Design

F E

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BDEM Rev. 8 - Part II Volume 1 Chapter 14 – Joints

and Bearings

New Chapter

Section 14.6.2 – Established policy for the use of bearing types and riser types. Specified method B and additional design and detail requirements for steel-reinforced elastomeric bearing design.

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BDEM Rev. 8 - Part II Volume 1 Chapter 14 –

Joints and Bearings

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BDEM Rev. 8 - Part III Chapter 1 – LG Girder

Section 1.1 – LG Girder Preliminary Design Charts

Section 1.2 – LG Girder Bearing Design Charts

Section 1.3 – LG Girder Special Details

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BDEM Rev. 8 - Part III Chapter 1 – LG Girder

Section 1.1 – LG Girder Preliminary Design Charts

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BDEM Rev. 8 - Part III Chapter 1 – LG Girder

Section 1.2 – LG Girder Bearing Design Charts (new)

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BDEM Rev. 8 - Part III Chapter 1 – LG Girder

Section 1.2 – LG Girder Bearing Design Examples (new)

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BDEM Rev. 8 - Part III Chapter 1 – LG Girder

Section 1.3 – LG Girder Special Details

Common Details + Specific Details for each girder type

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LG Girder Special Details

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LG Girder Special Details

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LG Girder Special Details

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LG Girder Special Details

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Future Work

Part II Volume 5 – Clarify As-Designed Rating and As-Built Rating Requirement

Implement 8th Edition of AASHTO Spec.

Part I – Policies and Procedures

Part II Volume 1 Chapter 10 – Geotechnical Provisions

LU Girder Design Aids and Special Details

Thank you!

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