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Reviewed Questions on Highway Geometric Design

Prepared by: Dr.-ing. Do Quoc Cuong

Checked by: Associate Prof. Dr. Tran Thi Kim Dang

Division of Highway and Traffic Engineering

I. Theory

1. How are highways classified according to their functions?

2. How are highways classified according to the design purpose? Please detail classification of conventional highways for design purpose?

3. What is the definition of traffic volume, average daily traffic volume or design traffic volume, peak-hour traffic volume? What are these traffic volume used for?

4. What is the design speed? Please present the design speeds according to the highway classifications followed by TCVN 4054-2005? What geometric elements are calculated by the design speed?

5. What is the definition of horizontal alignment (road plan), vertical alignment (road profile), and road cross section?

6. Please draw a figure to illustrate a horizontal alignment of highway (including beginning and ending points, angle for changing direction, name of sticks, tangents, curves, contours, etc)?

7. Please draw a figure to illustrate a vertical alignment of highway (including all items of a vertical alignment)?

8. Please draw a fore & back slope cross section of highway and provide all elements of this cross section? Please draw other types of cross section (full fore slope, full back slope cross section)?

9. Please present contents of combination between horizontal and vertical alignment of a highway, and combination between vertical alignment and cross section of a highway?

10. Please present concept of resistance forces including rolling resistance force, air resistance force, longitudinal resistance force, inertial resistance force? Please write the equation of vehicles motion on a highway? Defintion of D (motive power factor)? What are the effects of motive power factor D?

11. Please present the concept of frictional force between tires and pavement surface?

12. Please present the following issues: Definition, application areas, and calculated method of stopping sight distance S1? (Figure to illustrate is required).

13. Please present the following issues: Definition, application areas, and calculated method of opposing sight distance S2? (Figure to illustrate is required).

14. Please present basic principles to design a horizontal alignment on a map?

15. What are superelevation and rate of superelevation?

16. Please present the methodology to calculate the critical minimum radius of horizontal curve (with maximum rate of superelevation)? Figure to illustrate is required.

17. Please present the methodology to calculate the sharpest horizontal curve without superelevation? Figure to illustrate is required.

18. Please present the methodology to determine lateral friction factor f according to AASHTO 2011 and Vietnam?

19. Please present the methodology to revolve superelvevation about the center line of highway? Figure to illustrate and calculation of superelevation transition section are required.

20. Please present the methodology to revolve superelvevation about the inside edge of pavement? Figure to illustrate and calculation of superelevation transition section are required.

21. What are reasons for widening pavement on a sharp horizontal curve? Please present the methodology to calculate the widened width of pavement on a sharp horizontal curve? Figure to illustrate is required.

22. Please draw a figure to set up a widen width on a sharp horizontal curve of two-lane highway?

23. Why do we have to design spriral transition curves on a highway with a high design speed? Please present the methodology to determine the minimum length of spiral transition curve? Figure to illustrate is required.

24. Please write an equation of spiral transition curve? Concept of spiral curve parameter A? Please transfer a point on spiral transition curve into descarte co-ordinates? Figure to illustrate is required.

25. Please present basic steps to calculate and set up a spiral transition curve? Figure to illustrate is required.

26. Why do we have to clear obstacle on sharp horizontal curves? Please present drawn methodology to determine sight distance on sharp horizontal cuvers? Figure to illustrate is required.

27. Please present calculated methodology to determine sight distance on sharp horizontal cuvers? Figure to illustrate is required.

28. Please present basic principles to coordinate horizontal curves? - Figure to illustrate is required.

29. Please present basically technical requirements of longitudinal grade on highway profile such as: maximum and minimum grade, maximum and minimum length of grade?

30. Please present the methodology to calculate the minimum radius of crest vertical curve? - Figure to illustrate is required.

31. Please present the methodology to calculate the minimum radius of sag vertical curve to ensure sight distance at night and comfort for passenger? - Figure to illustrate is required.

32. critical elevations when design a vertical alignment or profile of a highway? - Figure to illustrate is required if any.

33. Present the methodology to determine a lane width (Figure to illustrate is required).

34. Present methodology to determine number of lanes of a highway? Write down minimum number of lanes and minimum roadway width according to TCVN 4054-2005?

35. What are basic principles to determine back slope and fore slope of a cross section of road?

II. Excercise

Given: highway class

Calculate:

1. Maximum longitudinal grade of highway (in case of TOYOTA Camry 2.4 vehicle).

2. Stopping sight distance S1. - Figure to illustrate is required.

3. Opposing sight distance S2. - Figure to illustrate is required.

4. Minimum horizontal curve radius (with a maximum superelevation rate). - Figure to illustrate is required.

5. Frequently used horizontal curve radius (with a superelevation rate of 4%).- Figure to illustrate is required.

6. Minimum horizontal curve radius without superelevation.- Figure to illustrate is required.

7. Superelevation transition length corresponding to minimum horizontal curve radius (revolving about the center line of highway). - Figure to illustrate is required.

8. Widen width on a horizontal curve with minimum radius. Set up this width on this curve. - Figure to illustrate is required.

9. Length of spiral curve in case of minimum horizontal curve radius. Set up this length on this curve. - Figure to illustrate is required.

10. Clearance distance on a horizontal curve with a minimum radius (assume that the turning angle is 15 degree).- Figure to illustrate is required.

11. Minimum radius of vertical crest and sag. - Figure to illustrate is required.

12. Number of lanes corresponding to the minimum traffic volume in table 3 of TCVN 4054-2005. - Figure to illustrate is required.

13. A compound circular curve having radii of 200 m and 130 m is to be designed to connect two tangent deflecting by 750. If the deflection angle of the first curve is 450 and the PCC (point of compound curve) is located at station Km 1 + 725 m, determine the deflection and the corresponding chord lengths (every 25m) for setting out the curve.

14. A +2 % grade on a highway (design speed of 80 km/h) in rolling terrain intersects with a -1% grade at station (Km1 + 025) at an elevation of 32.5 m.

i. determine the minimum radius of vetical curve and select radius of curve

ii. define length of vertical curve

iii. define the begin of vertical curve (TD) and,

iv. end of vertical curve (TC)

v. calculate the elevation of each 25-m station

15. A building is located 11.5 m from the travel line of the inside lane of a curved section with whose deflection angle is 42 degree and radius is 70m. The road is level (grade = 0%) and widening space is 0.8 m. Determine the spot speed limit considering meeting sight distance of 150 m and the curve radius

16. A motorway is designed in a area of mountainous terrain which has design speed of 80 km/h. A curved section in the designed road whose radius is 300m.

i. Determine an appropriate superelevation rate

ii. Attain the superelevation on the curved section of roadway using method of crowned pavements is rotated about the profile of the center line

17. A rural road is designed in a area of rolling terrain where the ADT (Annual Daily Traffic) for 3200 veh (passenger car)/day. A curved section in the designed road whose radius is 250m. Point of intersection () station is Km 1 + 350. Determine the following criteria:

i. an appropriate length of transition curve

ii. criteria to locate transition curve (T, t, p, remaining circular curve,...)

iii. station of N (point of transition curve) and T (point of circular curve).

iv. perpendicular distances for setting out transition curve at every 25m station.

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