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GEOMETRIC DESIGN OF HIGHWAYS. Chapter1 Introduction. Definitions:. Geometric design: pertains to the design of the visible features of the highway Design Controls: They are the factors affecting the different geometric design elements of highways. GEOMETRIC DESIGN COURSE CONTAINS:.
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GEOMETRIC DESIGN OF HIGHWAYS Introduction
Chapter1Introduction Basic Design Control
Definitions: • Geometric design: pertains to the design of the visible features of the highway • Design Controls: They are the factors affecting the different geometric design elements of highways. Introduction
GEOMETRIC DESIGN COURSE CONTAINS: Chapter 1:Introduction. Chapter 2:Basic Design Control. Chapter 3:Sight Distance. Chapter 4:Horizontal Alignment. Chapter 5:Vertical Alignment. Chapter 6:Cross-sectional elements. Chapter 7:Highway Intersections. Basic Design Control
Chapter 2Basic Design Control Basic Design Control
Basic Design Control Basic Design Control
Primary Control 1-Highway Classification Basic Design Control
Primary Control( Cont.) 2-Topography • The nature of the surrounding topography and land use may govern in many cases the choice of best alternative of highway location. • It also governs highway slopes, drainage, speed, … Basic Design Control
Traffic Volume Average Daily Traffic (ADT), AWDT,AMDT, AADT. Design Hourly Volume (DHV) = k × ADT Rural: K=11-20%, Urban: K=7:18% Traffic Composition Percent of non passenger cars (T) Primary Control (cont.) 3-Traffic Data: It must include volume, Composition, and projection Basic Design Control
Total Attracted Generated Developed N.Growth Current Primary Control (cont.) • Traffic Projection Normal Growth, Generated, Attracted, Developed. Future ADT = Current ADT (1+ TPF) Basic Design Control
Dependent Control 1-Speed (Distance over time……..mph,kph, ft/sec.) Running speed: Distance / overall time. Operating speed: The highest overall speed in such a way it is not greater than the design speed. Design speed: The speed selected for design of highway elements. - It is the max. safe speed - It is the speed that at least 95% of the drivers use speed less than or equal to it. Basic Design Control
Dependent Control (cont.) 2-Design VehicleIs that vehicle selected to represent all vehicles on the highway Types: - Passenger Car (PC) - Single Unit Truck (SUT) - Bus - Semitrailer Combination (WB-40) - Semitrailer Combination (WB-50) - Semitrailer Fulltrailer (WB-60) Single Unit Truck (SUT)is the type of the vehicle considered according to Egyptian Specifications Basic Design Control
13.4 m Max. 12.8 m Turning 8.7 m Min. SUT 9.1m 2.6 m Dependent Control (cont.) Design Vehicle Turning Radii Basic Design Control
Design Designation They are the major controls for which a given highway is designed • Design Year ( Ex. 20 Years Ahead) • Current ADT • Future ADT • DHV • Directional Distribution (D) • % Truck (T) • Design Speed (V) • Control of Access ( None, Partial, or Full) • Design Level of Service (A, B, C, D, or E) Basic Design Control