1. Chapter C Cross Section (ANSWERS ) www.transportation.alberta.ca

3. 1. An 800 mm diameter culvert is needed in a 14 m fill. What gauge thickness should be used? Answer: Refer to Figure C-4.5a (page C-20). Gauge thickness should be 3.5.

5. 2.On a highway with 800 AADT, an embankment is 10 m high and could be built at 3:1 slope or 4:1 slope. What is the best solution and why? Answer: See Section C.5.3.1 3rd paragraph. The 4:1 slope is the best solution provided that roadside barriers are not required. The life cycle cost for installation, maintenance and additional collision cost associated with barrier protection exceeds the cost of the additional fill material. This has been demonstrated through economic analysis.

6. 3.For design of a railway underpass (highway going under), is a 4.9 m clearance acceptable? Answer: See Figure C-9.3.2 Clearance Box for Railway Underpass No. 4.9m is less than the minimum for highways (exceptions are sometimes allowed on local roads).

8. 4.a) Is a barrier warranted? Information provided: Design Speed = 110 km/h Embankment sideslope = 4H:1V AADT = 4,500 vpd Embankment height = 7m Show your work. Answer : No. See Figure C-5.3.1a. b) A 200mm diameter tree is located 9m from the edge of the driving lane. Is the tree considered a hazard? Why or why not? Answer: Yes. If the diameter > 100 mm it is considered a hazard. (Roadside Design Guide, November 2007).

10. 5. Determine the desirable clear zone distance on a horizontal curve? Information provided: Design Speed = 70 km/h Sideslope 4H:1V AADT = 1,200 vpd Horizontal Radius = 700 m Answer: See Table C.5.2a and b. 5m - 6m on inside of curve and 5.5m - 6.6m on outside.

12. 6. Based on AT’s policy- provide a wide subgrade to allow for two future overlays (typical 80 mm each). On new construction projects, what subgrade width is required? Information provided: - Granular base course (GBC) depth = 280 mm - First stage (lift) ACP depth = 70 mm -Final stage (lift) ACP depth = 90 mm -Two future overlays = 160 mm -Answer: Total depth = 600 mm. a) RAU-211-110 ? 11m + 0.6 x 2 x 5 = 17m b) RAD-212.4-120 ? 12.4m + 0.6 x 2 x 5 = 18.4m c)RCU -209 -110 ? 9m + 0.6 x 2 x 4 = 13.8 m See Figures CB6-3.50M5, CB6-3.50M6.

16. 7. Based on AT’s policy- provide a wide subgrade to allow for two future overlays (typical 80 mm each). On grade widening projects, what subgrade width is required per side? Information provided: - Granular base course (GBC) depth = 300 mm - First stage (lift) ACP depth = 40 mm - Final stage (lift) ACP depth = 60 mm -Two Future overlays = 160 mm -Answer: Total depth = 560 mm a)Existing RCU-208-110 grade widen to an RAU-211-110 ? (11m - 8m)/2 + (5 x 0.560 ) = 4.30 m per side.

17. Grade Widening Z = 5 (T+0.16m)