Table of Contents

From Delaware DOT Bridge Design Manual
Jump to navigation Jump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

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
101.6.2.1 Functional Classification
101.6.2.2 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
102.1.3.1 General and Project Notes
102.1.3.2 Bridge Plan and Elevation
102.1.3.3 Lay-Out Plan
102.1.3.4 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
102.5.2.1 Alternatives Analysis
102.5.2.2 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
102.6.5.1 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
103.3.2.1 Shoulder Width Requirements for Deck Drainage
103.3.2.2 Sidewalks
103.3.2.3 Bicycle and Shared Use Facilities
103.3.2.4 Superelevation
103.3.3 Protection for Median Gap of Parallel Structures
103.3.4 Horizontal Clearance and Pier Protection
103.3.4.1 Over Rivers, Streams, Wetlands, and Floodplains
103.3.4.2 Over Roadways / Grade Crossings
103.3.4.3 Over Railroads
103.3.5 Vertical Clearance
103.3.5.1 Over Rivers, Streams, Wetlands, Floodplains
103.3.5.2 Over Roadways / Grade Crossings
103.3.5.3 Over Railroads
103.3.6 Bridge Skew
103.3.7 Approach Slabs
103.4 Structure Type Selection
103.4.1 Bridge Types
103.4.1.1 Structural Steel
103.4.1.2 Concrete Bridges
103.4.1.3 Timber Bridges
103.4.1.4 Culverts
103.4.2 Selection of Superstructure Type
103.4.2.1 Spans less than 20 feet
103.4.2.2 Spans from 20 feet to 30 feet
103.4.2.3 Spans from 30 feet to 90 feet
103.4.2.4 Spans from 90 feet to 165 feet
103.4.2.5 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
103.7.1.1 Post and Plank Walls
103.7.1.2 Sheet Pile Walls
103.7.1.3 Reinforced Concrete Walls
103.7.1.4 Anchored Walls
103.7.1.5 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
103.9.1.1 ABC Rating Score
103.9.1.2 FHWA Decision Flowcharts / ABC AHP Software Tool
103.9.1.3 Emergency Projects
103.9.1.4 Repair and Rehabilitation Projects
103.9.2 ABC Methods/Techniques
103.9.2.1 Foundation and Wall Elements
103.9.2.2 Rapid Embankment Construction
103.9.2.3 Prefabricated Bridge Elements and Systems
103.9.2.4 Structural Placement Methods
103.9.2.5 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
104.2.3.1 The Rational Method
104.2.3.2 Delaware Regression Method (SIR 2006-5146)
104.2.3.3 Published Reports
104.2.3.4 Flood-Frequency Analysis of Recorded Stream Gage Data
104.2.3.5 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
104.3.1.1 Sizing
104.3.1.2 Site Conditions and Skew
104.3.1.3 Shape/Material
104.3.1.4 Environmental Considerations
104.3.2 Bridges
104.3.2.1 Sizing
104.3.2.2 Site Conditions and Skew
104.3.2.3 Shape/Material
104.3.3 Hydraulics for Dam Safety Projects
104.3.3.1 Sizing
104.3.3.2 Site Conditions and Bridges Near Non-regulated Dams
104.3.3.3 Shape/Material
104.3.3.4 Dam Safety Regulations
104.3.4 Tidal Hydraulics – Bridges and Culverts
104.3.4.1 General
104.3.4.2 Use of Qualified Coastal Engineers
104.3.4.3 Tidal Hydraulic and Scour Analysis
104.3.4.4 Tidal Modeling
104.3.4.5 Freeboard for Tidal Bridges
104.3.4.6 Sea Level Rise
104.3.4.7 Tidal Hydraulics References
104.3.5 Hydraulics Methodologies and Software
104.3.5.1 HEC-RAS
104.3.5.2 HY-8
104.3.5.3 Two-Dimensional Hydraulic Models
104.4 Scour Evaluation and Protection
104.4.1 Scour Investigation
104.4.2 Scour Components
104.4.2.2 Long-Term Scour
104.4.2.3 Contraction Scour
104.4.2.4 Local Scour
104.4.3 Scour Flood Magnitude
104.4.4 Design Considerations
104.4.4.1 Scour Due to Lateral Movement
104.4.4.2 Spread Footings
104.4.4.3 Dams and Backwater
104.4.4.4 Streambed Material
104.4.4.5 Scour in Cohesive Soils
104.4.4.6 Scourability of Rock
104.4.5 Scour Countermeasures
104.4.5.1 Riprap Protection
104.4.5.2 Guide Banks
104.4.5.3 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
105.4.1.1 Quantity and Location of Structural Borings
105.4.1.2 Depth of Structural Borings
105.4.2 Boring Logs
105.4.3 Coordination for Soils/Rock Testing
105.4.3.1 Typical Soil Tests
105.4.3.2 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
106.3.1.1 Considerations for Deck Haunch
106.3.1.2 Distribution of Dead Loads
106.3.2 Live Loads
106.4 Bridge Decks
106.4.1 Deck Type Considerations
106.4.2 Concrete Decks
106.4.2.1 Concrete Deck Design Considerations
106.4.2.2 Deck Thickness
106.4.2.3 Deck-Reinforcing Steel
106.4.2.4 Deck Haunch
106.4.2.5 Concrete Cover
106.4.2.6 Deck Placement Sequence
106.4.2.7 Deck Overhangs
106.4.2.8 Concrete Deck Finishing
106.4.2.9 Future Wearing Surface/Overlays
106.4.2.10 Concrete Deck Construction Joints
106.4.2.11 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
106.8.1.1 Grade 50 Steel
106.8.1.2 Weathering Steel
106.8.1.3 High-Performance Steels
106.8.2 Fatigue and Fracture Considerations
106.8.2.1 Redundancy Requirements
106.8.2.2 Welding and Weld Procedures
106.8.3 Steel-Rolled Beams and Plate Girders
106.8.3.1 Minimum Plate Thicknesses
106.8.3.2 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
106.8.7.1 Paint Systems
106.8.7.2 Galvanization
106.8.8 Steel-Plate Girder and Rolled Beam Bridges
106.8.8.1 Method of Analysis
106.8.8.2 Diaphragms/Cross-Bracing
106.8.8.3 Bearings for Horizontally Curved and/or Skewed Steel Superstructures
106.8.9 Erection Analysis and Erection Plans
106.8.9.1 Requirements for Designer
106.8.9.2 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
106.9.2.1 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
106.9.8.1 Composite Shear Reinforcement
106.9.8.2 Anchorage Zone Reinforcement
106.9.9 Skew Effects
106.9.9.1 Grade and Cross-Slope Effects
106.9.9.2 Horizontal Curve and Flare Effect
106.9.10 Camber
106.9.10.1 Consideration for Staged Construction Camber
106.9.10.2 Simple Spans Made Continuous
106.10 Bearings
106.10.1 Elastomeric Bearings
106.10.1.1 Steel-Reinforced Elastomeric Bearings
106.10.2 High-Load Multi-Rotational Bearings
106.10.2.1 Pot Bearings
106.10.2.2 Disc Bearings
106.10.2.3 Spherical Bearings
106.10.2.4 Mechanical Bearings
106.10.3 Guidelines for Bearing Selection
106.10.3.1 Bearing Type Preferences
106.10.3.2 Feasibility due to Fabrication, Installation and Testing Limitations
106.10.4 Loads, Rotation and Translation
106.10.5 Design Requirements
106.10.5.1 Elastomeric Bearings
106.10.5.2 High-load Multi-Rotational Bearings
106.10.5.3 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
106.10.9.1 Sole Plates
106.10.9.2 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
107.3.4.1 Precast-Prestressed Concrete Piles
107.3.4.2 Steel Pipe Piles
107.3.4.3 Steel Shell and Cast-in-Place Piles
107.3.4.4 Steel H-Piles
107.3.4.5 Timber Piles
107.3.4.6 Drilled Shaft Foundations
107.3.4.7 Micropiles, Auger-cast Piles, and New Pile Technologies
107.3.4.8 Selection of Deep Foundation Type
107.3.4.9 Pile-Bearing Capacity
107.3.5 Additional Foundation Details
107.3.5.1 Design Footing and Pile Resistance
107.3.5.2 Scour
107.3.5.3 Stepped Footings
107.3.5.4 Corrosion and Deterioration
107.4 Substructure Design
107.4.1 Abutment Design
107.4.1.1 Semi-Integral Abutments
107.4.1.2 Integral Abutments
107.4.1.3 Reinforced-Concrete Stub Abutments
107.4.1.4 Reinforced-Concrete Cantilever Abutments
107.4.1.5 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
107.6.1.1 Select Granular Backfill
107.6.1.2 Designer Responsibility
107.6.1.3 MSE Wall Manufacturer Responsibility
107.6.2 Reinforced-Concrete Cantilevered Walls
107.6.3 Post and Plank Walls
107.6.4 Sheet-Pile Walls
107.6.4.1 Steel Sheet Piles
107.6.4.2 Concrete Sheet Piles
107.7 Culvert Design
107.7.1 Culvert Hydraulics
107.7.2 Culvert Foundation Design
107.7.3 Concrete Culverts
107.7.3.1 Precast Concrete Box Culverts
107.7.3.2 Cast-In-Place Concrete Box Culverts
107.7.3.3 Reinforced Concrete Rigid Frames
107.7.3.4 Concrete Arches
107.7.3.5 Precast Proprietary Structures
107.7.4 Pipe Culverts
107.7.5 Culvert Details
107.7.5.1 Headwalls
107.7.5.2 Wingwalls
107.7.5.3 Cutoff Walls
107.7.5.4 Scour Aprons
107.7.5.5 Guardrail Attachments
107.7.5.6 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
109.2.1.1 Compressive Strength
109.2.1.2 Alkali-Silica Reaction Evaluation
109.2.1.3 Chloride Content
109.2.1.4 Freeze-Thaw
109.2.1.5 Half-Cell Potential
109.2.1.6 Petrographic Analysis
109.2.2 Steel
109.2.2.1 Chemical Analysis
109.2.2.2 Mechanical Properties
109.3 Concrete Bridge Decks
109.3.1 Condition Survey
109.3.1.1 Visual Inspection
109.3.1.2 Delamination Survey
109.3.1.3 Reinforcing Corrosion Survey
109.3.1.4 Deck Coring
109.3.2 Deck Evaluation
109.3.3 Deck Removal Methods
109.3.4 Preventive Maintenance and Rehabilitation
109.3.4.1 General
109.3.4.2 Patching
109.3.4.3 Low-Permeability Overlays
109.3.4.4 Widening and Partial-Width Re-decking
109.3.4.5 Barrier Reconstruction
109.3.5 Concrete Deck Replacement
109.3.5.1 General
109.3.5.2 Cast-in-Place Concrete
109.3.5.3 Precast Concrete
109.4 Steel Grid Decks
109.4.1 General
109.4.2 Existing Steel Grid Deck Evaluation
109.4.2.1 Connection Failure and Fatigue
109.4.2.2 Corrosion
109.4.2.3 Delamination of Surfacing
109.4.2.4 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
109.9.1.1 General
109.9.1.2 Design Considerations
109.9.1.3 Repair and Strengthening
109.9.2 Prestressed Concrete Beams
109.9.2.1 General
109.9.2.2 Design Considerations
109.9.2.3 Repair Methods
109.9.3 Steel Beams and Girders
109.9.3.1 General
109.9.3.2 Design Considerations
109.9.3.3 Repair and Strengthening
109.9.3.4 Fatigue Evaluation and Repair
109.9.3.5 Fire Damage
109.9.3.6 Surface Preparation and Painting
109.9.3.7 Cathodic Protection
109.9.3.8 Heat Straightening
109.10 Bearings
109.11 Foundation and Substructure
109.11.1 General
109.11.2 Design Considerations
109.11.3 Repair Methods
109.11.3.1 Bearing Seat Repairs
109.11.3.2 Post-Tensioning Repairs
109.11.3.3 Underwater and Splash-Zone Repairs
109.11.3.4 Pile Repairs
109.11.3.5 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
110.3.1.1 Cantilever Sign Structures
110.3.1.2 Span-Type Sign Structures
110.3.1.3 Bridge-Mounted Signs
110.3.2 General Design Considerations
110.3.2.1 Designer Responsibility
110.3.2.2 Materials
110.3.2.3 Design Criteria
110.3.2.4 Consideration for Future Conditions
110.3.3 Design Process
110.3.4 Foundations
110.4 Sound Barrier Walls
110.4.1 Design Criteria
110.4.1.1 Designer Responsibility
110.4.1.2 General Criteria
110.4.1.3 Materials
110.4.1.4 Detailing Connections
110.4.1.5 Loads
110.4.1.6 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
111.1.2.1 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