As cities develop and face overcrowding, the areas surrounding them that are not yet developed start slowly getting absorbed into the city. But to make navigation between the new suburbs and the city easier, city planners first need to make sure there are enough roads connecting the two. Road construction is an exciting part of civil engineering that is absolutely essential for the smooth running of a city. Road building consists of five main steps. Let’s take a closer look at each.
Planning the Road Work
Time spent in the proper planning of a road construction project to unearth potential issues can save a lot of time and costs. This stage consists of assessing the need for the street and current and expected traffic patterns. Civil designers also perform a cost-benefit analysis to check if the road is worth the investment. This stage also involves research and documentation such as layout drawings, environmental implications, and hydraulic reports detailing the reasons for all the drainage modifications needed due to the road construction project.
Setting Out is the stage involving implementation of the road work design into the actual construction site. During this process, site boundaries are formed, and foundations are built. The structural parts needed are outlined. A series of boards are placed along the suggested road line. A traveler board is used to control the dug-up levels between profile boards. The profile board level is measured with a line level consisting of a spirit level on a nylon string. This string is moved around until the bubble is centered.
This is the stage requiring the most manual labor. During this process, a tractor shovel or bulldozer is used to take off the topsoil before scraping and grading the area to open up the underlying ground. The soil beneath the formation layer is called subgrade. The subgrade level needs to be tested for strength before further excavation. The thickness of the sidewalk depends on the strength of this subgrade level. The subgrade is therefore reinforced. The weaker materials are removed and replaced with selected fill to make the subgrade denser. The subgrade can be strengthened with materials such as chemicals or cement. The subgrade is then covered with plastic or sprayed with a binder to prevent the level from getting moist, since moisture can weaken the subgrade. By the end of the Earthworks stage, all the excavation work is completed, and the actual construction starts.
Starting the Paving
The actual road construction begins during this stage. Paving can be rigid or flexible. Rigid surfaces are longer-lasting with fewer maintenance costs. Flexible surfaces are cheaper and can easily expand or contract with the change in temperature, and so don’t need expansion joints.
Ensuring Quality Control
Once the road surface can be constructed, a number of quality control tests are carried out before marking the road construction project as complete. The tests check for parameters such as drainage, grading levels, and safety. If all the checks are satisfactory, the road is then flagged to open for vehicles and motorists.
Road construction is key to thriving communities and well-designed cities. Roads that have been built after a lot of planning and research need far less maintenance over future decades.