Highway Engineering 1 lecture 2

a UR has a kerb and channel

An UR is black with grey stones and the RR is grey with black stones

An UR has a footpath and a RR has none

A RR has a subsoil drain

The RR has been strengthen to take live stock walking on it

The RR has a feathered edge

Camber-usually 3%. under channel drains, waterproofing surface, road boundaries, pavement layers

Camber 6%, footpaths, berms, kerbs and pavement layers

There are no similarities between a Urban road and a rural road

Direct route between two points

Useable in all weather conditions

Provides a smooth comfortable surface

allows traffic to ravel safely at a reasonable uniform cruising speed

Is pleasing to the eye and has lots of nice scenery

has petrol stations every 500m

Communicating with the community even though the construction is a Permitted activity

Considering Risks

Include time, cost implications, resources and raising community expectations

Take into consideration the principles of the Treaty of waitangi

all of the above

Hold initial discussions with community leaders, key agencies and local government politicians to gauge the level of understanding and support for the proposed project

Clearly state the issues that are being consulted on

Disseminate information and educational material to the community on the rationale for the project

Included community leaders etc in the site selections process and scoping of the community interest

Seek legal advice - compliance with the ACT is crucial

all above

1. keep grades and curvature to the minimum necessary to satisfy the service requirements of the highway 2. Always provide adequate sight distance and avoid sudden changes in sight distance especially near intersections 3. Avoid having a sharp horizontal curve on or adjacent to a pronounced vertical curve 4. Locate the highway wherever possible along property boundaries not through the middle of blocks of land particularly farm land

5. Where it is practical maximize use of existing highway alignment to reduce land purchase costs 6. Avoid areas or objects of historical, recreational or cultural significance 7. Never have two roads intersecting near a bend or at the top or bottom of a hill 8. Avoid at grade intersections with railway lines. If possible cross the railway where it enters a cutting

9. Keep road and stream crossing to a sensible minimum and if possible have crossing at right angles 10. Avoid horizontal curves in bridges, tunnels or culvert structures 11. Avoid where possible unstable ground prone to erosion or land slips 12. Avoid low lying land prone to flooding 13. Avoid if possible locations with rock close to the surface

14. In hilly terrain the highway should cross ridges at their lowest point. Avoid creating severe breaks n the natural skyline 15. Minimize destruction of natural forest areas where some felling is necessary locate the road on a curve to preserve an unbroken background and minimize visual impact. 16. Avoid placing a road at right angles to natural drainage pattern 17. Balance volumes of cut and fill within a section of road to avoid need to purchase or tip large quantities of fill 18. To relieve the monotony of driving on a long straight road it is an advantage to site it so as to give a view of some prominent feature ahead.

All of the above

1. choose site 2. buy the land 3. decide where to place the road 4. Draw it on a map 5. Take it to council for approval

1. Fix end points of alignment 2. Examine the region containing both end pints and all feasible routes between them 3. Decide on a number of broad bands in which to concentrate further investigations (8 to 16km wide for major motorway) 4. Narrow bands down to corridors 3-8kms wide 5. Compare three corridors in detail and select the best 6. Generate a route within the selected corridor 1-1.5km wide 7. Search route area and locate one or more possible alignments up to 30 m wide 8. Select final alignment

Lane

Median

Traffic Islands

Right and left turn lanes

Median openings

Shoulder

Carriageway

Road Classification, Traffic volumes and composition,

Design speed, design vehicle, Environment,

Access, Drainage, Utility services

6%

2%

3%

different radii turning in the same direction

two curves in same direction with little or no straight in between

to curves turning in opposite directions with little or no straight in between

different radii turning in the same direction

two curves turning in the same direction with little or no straight in between

two curves turning in opposite directions with little or no straight in between

different radii turning in same direction

two curves turning in same direction with little or no straight in between

two curves turning in opposite directions with little or no straight in between

the amount by which the outer edge of a curve on a road or railway is banked above the inner edge

the camber of 3%

An intersection is the junction at grade (that is to say, on the same level) of two or more roads either meeting or crossing.

An intersection may be three-way (a T junction or Y junction – the latter also known as a fork), four-way (a crossroads), or have five or more arms.

The distance it takes in the dark to see an elephant

The distance at which a driver will be able to perceive an object of a specific height on the road ahead and safely stop their vehicle before it reaches that object

not steeper than 10% average or 12.5% maximum

lot access can be up to 1V:5H

Minimum grades for roads with kerb and channel = 0.3%, Unkerbed roads =0.5% Unkerbed roads with side drainage = 0%

1. Identify Controls

2. Prepare Horizontal Alignment

3. Select grading points

4. Prepare longitudinal section Show natural GL and Grading Points Include Intersections,structures, services, and crossings

5. Prepare Trial grade-line Consider controls try to coordinate horizontal and vertical alignments

6. Calculate earth works quantities

7. Adjust vertical alignment so that : Controls are met Earthworks are minimized

operating speed, required sight distances, overtaking requirements, drainage systems

Earthworks, topography, flood levels, water table levels

Geotechnical conditions, existing intersections, property entrances

overpasses and underpasses, pedestrian access, services

All of the above