This project involves the route survey which includes: reconnaissance survey, theodolite traversing and leveling operations as well as soil tests which includes; plastic limit test, liquid limit tests and moisture content determination, compaction tests and California bearing ratio tests.
This project also involves the design of the pavement and the geometric design of the roadway.
1.1 GENERAL INTRODUCTION
The relevance of road to life and its activities cannot be over emphasized.
Road is as old as the origin of man and plays a vital role in the life of the people in communities, states, countries. It is quite obvious that life would have been very difficult without the existence of roads. Nigeria for instance acknowledged the importance of road such that the local, state and federal government are all involved in the development and maintenance of road network.
History has shown that provision of roadway is a necessary tool for civilization. It advances prosperity increase and this bring about demand for better and faster communication facilities especially roads.
The continuing increase in Nigeria’s population has made the daily movement of passengers and goods an increasing complex problem.
1.2 RECONNAISSANCE SURVEY
This is a quick type of survey or a rapid examination of the ground and its adjacent natural features usually made without survey instruments to limit the alternative routes in terms of cost to one or two.
The following factors are normally considered in reconnaissance survey.
v Overall cartage of goods
v Nearness to road materials quarries
v Traffic conditions
v Soil conditions
v Right of way or road land
v Ruling gradient
v Type of road surface
v Number of major and minor bridges
v Approximate length and cost
v Curvative along the alignment
The road under consideration (A by pass from IMT/ Federal Secretariat road to Industrial center and Mass Communication Department) has been graded and motor drivers and pedestrians use it. On the sides of the proposed road are existing buildings and farm lands.
The traffic capacity of the road is low because of the poor grading of the road.
Because the road has not been properly paved, less pedestrians use the road and motorist prefer going through the longer way by passing through mass communication department when going to industrial center.
When the road is properly improved, all these problems will be eliminated and a lot of benefit will be accrued, benefit to the intending business center as a result of more people using the road and reduction in travel time.
1.3 GEOMETRIC DESIGN
This is the aspect of the highway design that is solely meant to take care of the road user and level of service rendered to him. The paramount factor of consideration included expected traffic capacity, design speed and volume. O’ Elaharty E. A in his book “Highway Traffic Planning and Engineering” states that proper geometric design will inevitably reduce the number and severity of highway accidents while ensuring high traffic flow with minimum delay. He continued by saying that improper design would result in the early obsolesce of the new highway with constant economic loss to the community.
1.4 FACTORS INFLUENCING THE CHOICE OF STATION
a. Easy Measuring Condition: Stations were chosen to avoid obstacles during drainage or tape exercise.
b. Intervisibility: Station were chosen and placed such that the station does not obstruct the other station line of sight.
c. Tranversing at closed Distance should avoided: This is to avoid angular error that would be introduced there to target at short range not be properly bisected.
1.5 FACTORS WHICH FAVOUR THE SELECTION OF ROUTE OR ROAD ALIGNMENT
There are several factors which normally favour the selection of a route alignment for high way construction.
i. The route should be as straight as possible. This implies less cost of construction, maintenance and operation of vehicles as wear and tear on curves route are entirely eliminated.
ii. Vertical and horizontal elignment should be eased out with maximum radius of curvature in relation to the design speed and maximum route of superelevation.
iii. Good sight distance should be maintained. Sight distance or visibility is the distance measured along the center line of the road over which the driver can see the opposite object on the road for necessary application of brake.
iv. Applicability of proper road drainage: Immediate evacuation of rain water on pavements as well as embarkment of a highway is necessary is to last till the end of the design life generally taken as 20years.
v. Availability of road building materials such as stone, gravel, sand, laterite etc along the highways bring down the cost of the construction as well as maintenance cost.
vi. Good formation soil should be ensured.
1.6 AIM AND OBJECTIVE OF THE PROJECT
This aims at giving student practical knowledge in the design of a roadway in order to aid her in designing a related project in real practice in future.
1.7 SCOPE OF THE PROJECT
The scope of this project includes the leveling, theodolite traversing of the road, design of the curve, soil investigation and pavement design of the route of study.