Table of Contents

From Delaware DOT Bridge Design Manual
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Section 101 Introduction

101.1 Purpose
101.2 Limitations of the Design Manual
101.3 Modifications to the Design Manual
101.4 Policy
101.5 Applicable Design Specifications and Standards
101.5.1 Design Specification Reference Nomenclature
101.5.2 Design Specifications
101.5.3 AASHTO Interim Specifications and New Editions
101.5.4 Deviations from Specifications
101.5.5 Order of Precedence
101.5.6 Additional Reference Manuals and Documents
101.6 Terms
101.6.1 Bridge Types
101.6.2 Roadway Types Functional Classification National Highway System
101.6.3 Project Types
101.7 FHWA Stewardship and Oversight Agreement
101.8 Computer Software
101.9 Feedback
101.10 References

Section 102 Bridge Design Submission Requirements

102.1 Plan Presentation
102.1.1 Drafting Standards
102.1.2 Plan Sheet Sequence
102.1.3 Bridge Sheet Preparation General and Project Notes Bridge Plan and Elevation Lay-Out Plan Other Plans
102.1.4 Bridge Number
102.2 Special Provisions Development
102.3 Quantities and Cost Estimates
102.4 Construction Schedule
102.5 Bridge Design Procedures
102.5.1 Quality Assurance and Quality Control
102.5.2 Designed-In Value Alternatives Analysis Life-Cycle Cost Analyses
102.5.3 Documentation of Design
102.5.4 Design Exceptions and Design Variances
102.5.5 Chronology of Submissions
102.6 Preliminary Design
102.6.1 Hydrologic and Hydraulic Report
102.6.2 Scour Evaluation Report
102.6.3 Foundation Reports
102.6.4 Conceptual Type, Size, and Location Plans
102.6.5 Type, Size, and Location Submission Type, Size, and Location Submission Requirements
102.7 Preliminary Construction Plans
102.8 Semi-Final Construction Plans
102.9 Final Construction Plans
102.10 Plans, Specifications, and Estimate
102.11 Bid-Cycle Requirements
102.11.1 Addenda
102.11.2 Bid Opening and Bid Review
102.12 References

Section 103 Bridge Geometry and Structure Type Selection

103.1 Introduction
103.2 Terms
103.3 Bridge Geometric Design Requirements
103.3.1 Bridge Length
103.3.2 Minimum Width of Bridges Shoulder Width Requirements for Deck Drainage Sidewalks Bicycle and Shared Use Facilities Superelevation
103.3.3 Protection for Median Gap of Parallel Structures
103.3.4 Horizontal Clearance and Pier Protection Over Rivers, Streams, Wetlands, and Floodplains Over Roadways / Grade Crossings Over Railroads
103.3.5 Vertical Clearance Over Rivers, Streams, Wetlands, Floodplains Over Roadways / Grade Crossings Over Railroads
103.3.6 Bridge Skew
103.3.7 Approach Slabs
103.4 Structure Type Selection
103.4.1 Bridge Types Structural Steel Concrete Bridges Timber Bridges Culverts
103.4.2 Selection of Superstructure Type Spans less than 20 feet Spans from 20 feet to 30 feet Spans from 30 feet to 90 feet Spans from 90 feet to 165 feet Spans greater than 165 feet
103.5 Construction
103.5.1 Future Re-decking Considerations
103.5.2 Consideration for Future Widening
103.5.3 Hauling Permits
103.5.4 Maintenance of Traffic
103.5.5 Inspectability
103.6 Substructure Type Selection
103.6.1 General Considerations
103.6.2 Abutments and Wingwalls
103.6.3 Piers
103.7 Retaining Walls
103.7.1 Wall Types Post and Plank Walls Sheet Pile Walls Reinforced Concrete Walls Anchored Walls Proprietary Retaining Walls
103.8 Bridge Rehabilitation versus Replacement Selection Guidelines
103.8.1 Cost
103.8.2 Safety
103.8.3 Bridge Type
103.8.4 Bridge Standards
103.8.5 Feature Crossed
103.8.6 Comprehensive Assessment of Rehabilitation versus Replacement
103.9 Accelerated Bridge Construction
103.9.1 Decision-Making/Planning Process ABC Rating Score FHWA Decision Flowcharts / ABC AHP Software Tool Emergency Projects Repair and Rehabilitation Projects
103.9.2 ABC Methods/Techniques Foundation and Wall Elements Rapid Embankment Construction Prefabricated Bridge Elements and Systems Structural Placement Methods Fast-Track Contracting
103.10 Requirements for the Design of Highway Bridges over Railroads
103.11 References

Section 104 Hydrology and Hydraulics

104.1 Introduction
104.1.1 Terms
104.1.2 Coordination
104.1.3 Design Responsibilities
104.1.4 Field Data Collection
104.1.5 Topographic Survey and Extent of Hydraulic Study
104.2 Hydrology
104.2.1 Introduction
104.2.2 Documentation
104.2.3 Precipitation The Rational Method Delaware Regression Method (SIR 2006-5146) Published Reports Flood-Frequency Analysis of Recorded Stream Gage Data Other Methods/Models
104.2.4 Methodology Selection Guidance
104.2.5 Design Flood Frequency
104.2.6 Confidence Intervals
104.2.7 Frequency Mixing (Probability of Coincidental Occurrence)
104.3 Hydraulics
104.3.1 Culverts Sizing Site Conditions and Skew Shape/Material Environmental Considerations
104.3.2 Bridges Sizing Site Conditions and Skew Shape/Material
104.3.3 Hydraulics for Dam Safety Projects Sizing Site Conditions and Bridges Near Non-regulated Dams Shape/Material Dam Safety Regulations
104.3.4 Tidal Hydraulics – Bridges and Culverts General Use of Qualified Coastal Engineers Tidal Hydraulic and Scour Analysis Tidal Modeling Freeboard for Tidal Bridges Sea Level Rise Tidal Hydraulics References
104.3.5 Hydraulics Methodologies and Software HEC-RAS HY-8 Two-Dimensional Hydraulic Models
104.4 Scour Evaluation and Protection
104.4.1 Scour Investigation
104.4.2 Scour Components Long-Term Scour Contraction Scour Local Scour
104.4.3 Scour Flood Magnitude
104.4.4 Design Considerations Scour Due to Lateral Movement Spread Footings Dams and Backwater Streambed Material Scour in Cohesive Soils Scourability of Rock
104.4.5 Scour Countermeasures Riprap Protection Guide Banks Scour Protection at Culverts
104.4.6 Scour Evaluation Documentation
104.4.7 Scour Plan Presentation
104.5 Streams
104.5.1 Stream Stability Analysis
104.5.2 Bank Protection
104.5.3 Channel Modifications
104.5.4 Stream Diversions
104.5.5 Ice and Debris
104.6 Hydrologic and Hydraulic Report
104.6.1 Hydraulic Summary Data Sheet and Definitions
104.7 Plan Presentation
104.8 Laws, Policy, Regulations and Permits
104.8.1 FEMA Compliance
104.8.2 New Castle County Requirements
104.8.3 Tax Ditches
104.8.4 Risk Assessment or Analysis
104.8.5 Aids to Navigation
104.8.6 DelDOT Project Development Manual
104.9 References
Appendix 104-1: Hydraulic Field Assessment Checklist
Appendix 104-2: Hydraulic Survey Form
Appendix 104-3: H&H Report Hydraulic Data Summary Sheet
Appendix 104-4: H&H Report Sample Format

Section 105 Geotechnical Investigations

105.1 Introduction
105.2 Terms
105.3 Subsurface Investigations
105.3.1 Estimating Soil and Rock Properties
105.3.2 Estimating Ground Water Table Elevation
105.3.3 Estimation of Bearing Capacity
105.3.4 Estimation of Settlement
105.3.5 Estimated Depth of Unsuitable Materials
105.3.6 Global Stability
105.3.7 Corrosive Environment
105.3.8 Lateral Squeeze
105.4 Subsurface Investigation Request
105.4.1 Request for Test Borings Quantity and Location of Structural Borings Depth of Structural Borings
105.4.2 Boring Logs
105.4.3 Coordination for Soils/Rock Testing Typical Soil Tests Typical Rock Tests
105.5 Geotechnical Report
105.6 Foundation Report
105.6.1 Concise Foundation Report
105.6.2 Foundation Report Submittals
105.6.3 Quality Assurance and Quality Control
105.6.4 Geotechnical Design References
105.7 References

Section 106 Final Design Consideration – Superstructure

106.1 Introduction
106.2 Terms
106.3 Design Loads
106.3.1 Dead Loads Considerations for Deck Haunch Distribution of Dead Loads
106.3.2 Live Loads
106.4 Bridge Decks
106.4.1 Deck Type Considerations
106.4.2 Concrete Decks Concrete Deck Design Considerations Deck Thickness Deck-Reinforcing Steel Deck Haunch Concrete Cover Deck Placement Sequence Deck Overhangs Concrete Deck Finishing Future Wearing Surface/Overlays Concrete Deck Construction Joints Temporary Protective Shield
106.4.3 Finished Deck Elevations
106.5 Bridge Barriers and Railings
106.5.1 DelDOT Standard Bridge Barrier and Railing Applications
106.5.2 Bridge Barrier Design Considerations
106.5.3 Protective Screening, Shielding, and Fencing
106.5.4 Bridge Lighting
106.6 Deck Joints
106.6.1 Jointless Bridges
106.6.2 Strip Seal Joints
106.6.3 Steel Finger Joints
106.6.4 Longitudinal Joints
106.7 Approach Slab Design
106.7.1 Approach Slab Geometry and Design Requirements
106.8 Steel Superstructure Design Considerations
106.8.1 Structural Steel – Material Requirements Grade 50 Steel Weathering Steel High-Performance Steels
106.8.2 Fatigue and Fracture Considerations Redundancy Requirements Welding and Weld Procedures
106.8.3 Steel-Rolled Beams and Plate Girders Minimum Plate Thicknesses Plate Girder Geometric Proportionality – General Practice
106.8.4 Shear Connectors
106.8.5 Stiffeners, Diaphragms, and Bracing
106.8.6 Bolted Connections
106.8.7 Protective Coatings Paint Systems Galvanization
106.8.8 Steel-Plate Girder and Rolled Beam Bridges Method of Analysis Diaphragms/Cross-Bracing Bearings for Horizontally Curved and/or Skewed Steel Superstructures
106.8.9 Erection Analysis and Erection Plans Requirements for Designer Erection Submittal Requirements for Contractor’s Engineer
106.8.10 Deck Placement Sequence Analysis and Design
106.9 Prestressed Concrete Bridge Superstructures
106.9.1 Materials
106.9.2 Design Methodology Design Methodology
106.9.3 Diaphragm Requirements
106.9.4 Minimum Spacing of Prestressing Tendons
106.9.5 Tensile Stresses Due to Prestressing
106.9.6 De-bonding Versus Draping
106.9.7 Tensile Stresses at Service Limit State After Losses
106.9.8 Reinforcement Composite Shear Reinforcement Anchorage Zone Reinforcement
106.9.9 Skew Effects Grade and Cross-Slope Effects Horizontal Curve and Flare Effect
106.9.10 Camber Consideration for Staged Construction Camber Simple Spans Made Continuous
106.10 Bearings
106.10.1 Elastomeric Bearings Steel-Reinforced Elastomeric Bearings
106.10.2 High-Load Multi-Rotational Bearings Pot Bearings Disc Bearings Spherical Bearings Mechanical Bearings
106.10.3 Guidelines for Bearing Selection Bearing Type Preferences Feasibility due to Fabrication, Installation and Testing Limitations
106.10.4 Loads, Rotation and Translation
106.10.5 Design Requirements Elastomeric Bearings High-load Multi-Rotational Bearings Design Limitations
106.10.6 Consecutively Fixed Piers
106.10.7 Accommodations for Future Bearing Replacement
106.10.8 Bearings for Horizontally-Curved and/or Skewed Bridges
106.10.9 Anchorage to Structure Sole Plates Masonry Plates and Anchor Rods
106.10.10 Lateral Restraint
106.10.11 Uplift Restraint
106.10.12 Bearing Schedule
106.11 References

Section 107 Final Design Considerations – Substructure

107.1 Introduction
107.2 Terms
107.3 Foundation Design
107.3.1 Settlement Considerations
107.3.2 Spread Footing Foundations
107.3.3 Deep Foundations
107.3.4 Pile Foundations Precast-Prestressed Concrete Piles Steel Pipe Piles Steel Shell and Cast-in-Place Piles Steel H-Piles Timber Piles Drilled Shaft Foundations Micropiles, Auger-cast Piles, and New Pile Technologies Selection of Deep Foundation Type Pile-Bearing Capacity
107.3.5 Additional Foundation Details Design Footing and Pile Resistance Scour Stepped Footings Corrosion and Deterioration
107.4 Substructure Design
107.4.1 Abutment Design Semi-Integral Abutments Integral Abutments Reinforced-Concrete Stub Abutments Reinforced-Concrete Cantilever Abutments Abutment, Backwall, and Wingwall Details
107.5 Pier Design
107.5.1 Pier Analysis and Design
107.5.2 Fixity Considerations
107.5.3 Pier Detailing
107.5.4 Pile Bents
107.5.5 Protective Sealing of Surfaces
107.6 Retaining Wall Design
107.6.1 Mechanically Stabilized Earth Walls Select Granular Backfill Designer Responsibility MSE Wall Manufacturer Responsibility
107.6.2 Reinforced-Concrete Cantilevered Walls
107.6.3 Post and Plank Walls
107.6.4 Sheet-Pile Walls Steel Sheet Piles Concrete Sheet Piles
107.7 Culvert Design
107.7.1 Culvert Hydraulics
107.7.2 Culvert Foundation Design
107.7.3 Concrete Culverts Precast Concrete Box Culverts Cast-In-Place Concrete Box Culverts Reinforced Concrete Rigid Frames Concrete Arches Precast Proprietary Structures
107.7.4 Pipe Culverts
107.7.5 Culvert Details Headwalls Wingwalls Cutoff Walls Scour Aprons Guardrail Attachments Protective Sealing of Surfaces
107.8 Architectural Treatments
107.9 Temporary Excavation Support Systems
107.10 References

Section 108 Bridge Load Rating

Section 109 Bridge Preservation Strategies

109.1 Introduction
109.1.1 Bridge Inspections and Load Ratings
109.1.2 Environmental Considerations
109.1.3 Rehabilitation Design Criteria
109.2 Material Testing
109.2.1 Concrete Compressive Strength Alkali-Silica Reaction Evaluation Chloride Content Freeze-Thaw Half-Cell Potential Petrographic Analysis
109.2.2 Steel Chemical Analysis Mechanical Properties
109.3 Concrete Bridge Decks
109.3.1 Condition Survey Visual Inspection Delamination Survey Reinforcing Corrosion Survey Deck Coring
109.3.2 Deck Evaluation
109.3.3 Deck Removal Methods
109.3.4 Preventive Maintenance and Rehabilitation General Patching Low-Permeability Overlays Widening and Partial-Width Re-decking Barrier Reconstruction
109.3.5 Concrete Deck Replacement General Cast-in-Place Concrete Precast Concrete
109.4 Steel Grid Decks
109.4.1 General
109.4.2 Existing Steel Grid Deck Evaluation Connection Failure and Fatigue Corrosion Delamination of Surfacing Reduced Skid Resistance
109.4.3 Design Considerations
109.5 Timber Decks
109.5.1 General
109.5.2 Design Considerations
109.6 Safety Considerations
109.7 Deck Joints
109.8 Approach Slabs
109.9 Slabs, Beams, and Girders
109.9.1 Reinforced-Concrete Slabs General Design Considerations Repair and Strengthening
109.9.2 Prestressed Concrete Beams General Design Considerations Repair Methods
109.9.3 Steel Beams and Girders General Design Considerations Repair and Strengthening Fatigue Evaluation and Repair Fire Damage Surface Preparation and Painting Cathodic Protection Heat Straightening
109.10 Bearings
109.11 Foundation and Substructure
109.11.1 General
109.11.2 Design Considerations
109.11.3 Repair Methods Bearing Seat Repairs Post-Tensioning Repairs Underwater and Splash-Zone Repairs Pile Repairs Scour and Undermining Repairs
109.11.4 Stabilization and Underpinning
109.12 Retaining Walls
109.12.1 General
109.12.2 Design Considerations
109.12.3 Repair Methods
109.13 Culverts
109.13.1 General
109.13.2 Design Considerations
109.13.3 Repair Methods
109.14 Utilities
109.15 Moveable Bridges
109.16 References

Section 110 Ancillary Structures

110.1 Introduction
110.2 Terms
110.3 Overhead Sign Structures
110.3.1 Overhead Sign Structure Types and Geometrics Cantilever Sign Structures Span-Type Sign Structures Bridge-Mounted Signs
110.3.2 General Design Considerations Designer Responsibility Materials Design Criteria Consideration for Future Conditions
110.3.3 Design Process
110.3.4 Foundations
110.4 Sound Barrier Walls
110.4.1 Design Criteria Designer Responsibility General Criteria Materials Detailing Connections Loads Miscellaneous
110.4.2 Foundations
110.5 References

Section 111 Construction Coordination

111.1 Working Drawings
111.1.1 Required Working Drawings
111.1.2 Working Drawings Review Procedure Consultant Review of Working Drawings
111.1.3 Technical Guidelines for Review of Working Drawings
111.2 Contractor Requests for Information
111.3 Value Engineering Proposals (by Contractor)
111.4 Plan Revisions
111.5 As-Built Drawings
111.6 References

Section 200 DelDOT References to AASHTO Manual

Section 300 Typical Bridge Design Detail