3. Urban Road Construction and Reconstruction

3.1 Introduction

Techniques for urban roads are essentially similar to those for rural roads, but there are some additional unique factors.

3.2 Public Utilities

Road reserve the normal location for many public utility services e.g. water mains, electricity supply lines, telephone lines, gas mains, etc. Most services (except sewers) placed under footpath areas so that maintenance and repair can be carried out without disruption to traffic.

3.3 Provision of Materials

Stockpiling of materials usually more dificult in an urban environment, so greater coordination of material requirements required than in a rural setting.

3.4 Setting Out

Survey pegs more likely to disturbance from vehicles and humans than in a rural environment. Recovery pegs are usually located near property boundaries to minimise disturbance.

3.5 Plant

The work area in urban road reconstruction is often relatively small and so careful plant selection is required. The type and size of plant may also be limited by the amount of work that can be opened up and backfilled in one day.

Plant varies from job to job, but for reconstruction work typically consists of:

• Small dozer - for ripping and dozing.
• Loader and trucks - for removal of spoil and delivery of pavement materials.
• Grader - for trimming and spreading.
• Rollers - for compaction.

3.6 Drainage During Construction

Drainage of work during construction requires careful attention at all times. Work should be carried out so that there will be no ponding of water, should storms occur. The job should be checked at the end of each day's work to ensure that any overnight rain will be carried away from the work are without damage to the work.

In urban work, the permanent underground stormwater drainage system will be used as far as practicable for site drainage. The construction of storwater drains should, when feasible,be the first work carried out. It will be normal to commence the drainage work at the lowest point and work upstream.

Flooding of the job or saturation of loose material can cause long, costly delays and can reduce the soundness of work.

3.7 Rock Excavation

In urban work rock excavation poses more difficulties than it does in a rural environment. Special care must be taken to restrict explosive charges to a size which will cause no damage to buildings by ground vibration. Care must also be taken to prevent any flying rock from blasting operations. Use of effective matting is essential in this regard.

Inspection of all buildings prior to any blasting is essential. Note should be made of any existing cracks or defects so as to minimise subsequent claims for damages.

A similar type of problem may arise with the use of vibrating rollers in urban areas and care must be taken to minimise damage claims.

Page last modified 7 July 1999.