External Works: The Major Characterisics of a road (Design notes)
pavement or carriageway designed to take vehicleur traffic and is the structural element
Footway is the area generally used for pedestrians and requires no structural element
Verge is the area that seperates the pedestrians from the traffic, verges tend to have services running under them, where this is not possible they go under the footway. it is not possible to run drainage under verges
Hard Shoulder & Central Reservation found on major roads the former used for vehicles in distress and the later for seperating the traffic travelling in different directions
value of loading is required which can be defined as 1x commercial vehicle (1500kg) unloaded; how many of them use the road in each direction dead load weight and dynamic weight distribution.
Make up of the carriage ways can be flexiable or rigid construction
Flexiable consists of a granular material eg tarmac or Rigid concrete which may be reinforced.
the flexiable material is designed to move in sympathy with sub grade is a suitable material for weak sub grade- tends to be thicker than concrete
Rigid construction requires the installation of expansion and contraction joints to allow for thermal movement concrete is much stronger (it is a structural material) and good for bridging soft spots in the subgrade so will be well suited to roads with grounds of variable subgrade.