Design of Bridge Deck Drainage
File : pdf, 2.3 MB, 138 pages
TOC
1 : HEC 21 Introduction
1.1 Scope
1.2 Design Objectives
1.2.1 Minimization of Spread
1.2.2 Avoidance of Hydroplaning
1.2.3 Integration into Structural Dimensions
1.2.4 Aesthetics
1.2.5 Minimization of Maintenance
1.2.6 Bicycle Safety
1.3 Systems
1.3.1 Deck and Gutters
1.3.2 Hardware–Inlets, Pipes, and Downspouts
1.3.3 Bridge End Collectors
1.4 Outline of Design Conditions
2 : HEC 21 Typical System Components
2.1 Terminology
2.2 Requirements
2.2.1 Similarities to Pavement Components
2.2.2 Differences with Pavement Components
2.2.3 Structural Considerations
2.2.4 Maintenance Considerations
2.3 Deck and Gutters
2.4 Hardware–Inlets, Pipes, and Downspouts
2.5 Bridge End Collectors
3 : HEC 21 Estimation of Design Storm Runoff
3.1 Selection of Design Spread and Frequency
3.2 Calculation of Runoff
3.2.1 Using Spread Plus Rational Method
3.2.1.1 Coefficient of Runoff
3.2.1.2 Rainfall Intensity
3.2.1.3 Time of Concentration
3.2.2 Using Hydroplaning Avoidance
3.2.3 Using Driver Vision Impairment
3.2.4 Using Other Methods
4 : HEC 21 Flow in Gutters
4.1 Sheet Flow to Gutters
4.2 Gutters of Uniform Cross Slope
4.3 Composite Gutter Selections
4.4 Gutters with Curved Cross Sections
4.5 Gutter Flow at Sags
4.6 Guidance for Nontypical Bridge Deck Gutters
5 : HEC 21 Bridge Deck Inlets
5.1 Typical Inlet Designs
5.2 Factors Affecting Interception Capacity and Efficiency
5.3 Anti-Clogging Design Features
5.4 Inlet Locations
5.4.1 Hydraulic Spacing
5.4.2 Structural Constraints
5.4.3 Maintenance Considerations
6 : HEC 21 Underdeck Collection and Discharge System
6.1 Hydraulic Design
6.2 Longitudinal Storm Drains
6.3 Anti-Clogging Features
6.3.1 Minimum Scouring Velocities for Sand and Grit
6.3.2 Inlet Traps
6.3.3 Cleanouts and Maintenance Downspouts
6.4 Vertical Downspouts
6.4.1 Capacity
6.4.2 Location to Conform to Structure and Aesthetic Needs
6.5 Outfall Design
6.6 Discharge to Air
6.7 Bridge Expansion Joints
7 : HEC 21 Bridge End Collectors
7.1 Similarities to Pavement Drainage
7.2 Design Flows
7.3 Differences Between Highway Pavement and Bridge Deck Drainage
7.4 Typical Bridge End Drainage Systems
8 : HEC 21 Design Procedures
8.1 Preliminary Data Analysis
8.2 Establishment of Governing Design Element–Rainfall Intensity
8.2.1 Rational Method Rainfall Intensity
8.2.2 Hydroplaning
8.2.3 Driver Visibility
8.3 Inlet Sizing
8.4 Collection System Details
8.5 Design of Bridge End Collectors
8.5.1 Location Guidance
8.5.2 Inlet Information
8.5.3 Outfall Pipe Information
9 : HEC 21 Bridge Deck Drainage Method
9.1 Constant-Grade Bridges
9.2 Flat Bridges
10 : HEC 21 Illustrative Examples
10.1 Example 1–500 Foot, 3 Percent Grade Bridge (No Inlets Needed)
10.2 Example 2–2,000 Foot, 1 Percent Grade Bridge
10.3 Example 3–1,200 Foot, 3 Percent Grade Bridge
10.4 Example 4–4,000-Foot Long, 68-Foot-Wide Flat Bridge
10.5 Example 5–800-Foot-Long, 36-Foot-Wide Flat Bridge
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