Investigation of Road Project

1. Investigation of Road Project

2. Object of road Investigation To locate the alignment of a road which provides maximum transportation facilities with minimum cost of construction and maintenance.

3. 1. Reconnaissance Survey It is examines the general character of land between the terminal stations in the field, along the proposed alternative alignments marked on the map is known as reconnaissance survey. In this survey, simple survey instruments like prismatic compass , abney level etc may be used to collect the additional details.

4. Objects Reconnaissance Survey :- 1. To collect details of obstruction along the route which are not available in the map. 2. To collect geological features of field . 3. To collect information regarding the availability of local construction material, water and labour. 4. To determine the approximate values of gradient and length of gradient. 5. To determine approximate estimate of construction of road. 6. To determine two or three best possible routes.

5. 2. Preliminary Survey In this survey to find the details of alternative alignments found suitable during the reconnaissance survey. In this survey, the survey instruments are used such as chain, tape, prismatic compass, plane table, theodolite etc.

6. Objects Preliminary Survey :- 1. To collect all necessary information & details of topography, drainage and soil of various alignments found after the reconnaissance survey. 2. To compare different alignments as per the requirements of a good road alignment. 3. To estimate the cost of construction the road. 4. To finalise the best alignment from construction, maintenance and traffic operation point of view.

7. 3. Location Survey The detailed examination of the alignment finally recommended during the preliminary survey is known as ‘Location survey’. In this survey, the survey instruments are used such as chain, tape, plane table, theodolite etc.

8. Objects Location Survey :- 1. The alignment finalised at the design office after preliminary survey. 2. The detailed survey should be carried out for collecting information necessary for the preparation of plans and construction details for highway project. 3. To determine total cost of the road project.

9. Road Alignment The position occupied by centre line of a road in plan is called ‘Road Alignment’. • Requirement of an Ideal Alignment of road :- i) Short, ii) Easy, iii) Safe, iv) Economical, v) Utility, vi) Natural aspects

10. Requirement of an Ideal Alignment of road :- 1. Short :- a) The alignment should be as short as possible. b) Short alignment provide economy in the cost of construction, maintenance & transportation. c) The alignment should be as straight as possible. 2. Easy:- a) The alignment must be easy in construction, maintenance & traffic operations. b) The alignment should be easy for the operation of vehicles with easy gradients.

11. Requirement of an Ideal Alignment of road :- 3. Safe :- The alignment should be safe for traffic operation so the alignment should be safe from the view point of stability of natural hill slopes, embankment and cut slopes. 4. Utility:- The alignment should offer maximum utility by connecting intermediate important towns and villages. 5. Natural aspect:- The alignment should pass through regions of natural beauty and scenery to have good natural aspect.

12. Factor affecting Road Alignment i) Need of traffic, ii) Purpose & class of road, iii) Obligatory points, iv) Curve, v) Gradient, vi) Sight distance, vii) Number of drainage crossing, viii) Railway & river crossing, ix) obstruction, x) Formation of bed, xi) Earthwork, xii) Lengthy straight route, xiii) Availability of labour and materials, xiv) Aesthetical aspect.

13. Factor affecting Road Alignment :- 1. Need of traffic :- a) Alignment should suit need of traffic. b) For fast moving traffic, it must be as straight as possible. c) For slow moving traffic, it may have sharp bend. 2. Purpose and class of Road :- a) The alignment should be selected according to the purpose & class of road. b) The national highway connecting two important towns should be kept perfectly straight as far as possible. c) Other category of road can be deviated when straight alignment is not possible.

14. Factor affecting Road Alignment :- 3. Obligatory points :- The alignment should pass through obligatory points such as intermediate important towns, group of village etc. so to connect obligatory points alignment may be changed. 4. Curve :- Curve must be as flat as possible. 5. Gradient :- To avoid excessive fall or rise the alignment, the gradient should be flat and less than design gradient.

15. Factor affecting Road Alignment :- 6. Sight distance :- The geometric design of the road should be done such that any obstruction on the road length could be visible to the driver from distance ahead. This distance is known as ‘Sight distance’. • The minimum sight distance, should be available in every section of the road. • There should be enough distance visible ahead for safe overtaking operation of vehicle moving at design speed on the road. • The alignment should be finalised in such a way that it should provide good sight distance.

16. Factor affecting Road Alignment :- 7. Drainage crossing :- Maximum number of drainage crossing, alignment must be changed. So the alignment should have minimum number of drainage crossing. 8. Railway & River crossing :- The alignment should cross river or the railway line at right angles. 9. Obstruction :- Alignment should be free from obstruction. It can be changed to avoid well, lake, pond, building etc

17. Factor affecting Road Alignment :- 10. Formation bed :- Alignment should run on good soil as far as possible, to fulfill this requirement alignment can be changed. 11. Earthwork :- The alignment should have less earth work, so to avoid excessive cutting or filling, the alignment must be changed. 12. Availability of labour :- Alignment should provide where labour & material are available for the construction of road. Hence to satisfy the requirement the alignment of road is changed.

18. Factor affecting Road Alignment :- 13. Lengthy straight route :- The alignment should be monotony caused due to lengthy straight routes. Hence alignment must be have slight bend to break the monotony & slight bend to keep the divert alert. 14. Aesthetical aspect :- The alignment pass through regions of natural beauty & scenery, to fulfill this requirement , alignment can be changed.

19. Survey operation during fixing Alignment :- 1. The centre line of the road is transferred from the map on the ground by using transit theodilte. Fixing the stakes at suitable intervals along the centre line in the direction of the progress of work 2. The reference points for the centre line should be located carefully & they will not be disturbed. 3. The starting and ending points of all the curve should be fixed. 4. The distance measured along the centre line of the road including curved portion should be done continuously. 5. The angles of intersections at the road crossing with the centre line should be measured by transit theodolite.

20. Drawing required for Road project :- • Key plan • Index map • Preliminary survey plan • Detailed location survey plan • Longitudinal section • Detailed cross section • Land acquisition plan • Drawing of cross drainage and masonry structures

21. Drawing required for Road project :- 1. Key plan :- - The map which shows the proposed road, existing roads, and connected important places is known as ‘Key plan’. - The size of the map depending upon area to be covered. - Generally it should not be exceed 240mm x 330mm (A4 size).

22. Drawing required for Road project :- 2. Index map:- - The map which shows the general topography of the area where details are represented by conventional sign is known as ‘Index map’. - Generally the size of the map should not be exceed 240mm x 330mm (A4 size) - Usually the scale taken 1cm = 0.5km.

23. Drawing required for Road project :- 3. Preliminary survey plan:- - Preliminary survey plan shows the details of various alternate alignment and other information collected during preliminary survey. - The size of this plan varies from 240mm x 330mm to 880mm x 1230mm(A0 size) - The scale may varies from 1cm = 1km to 20cm= 1km

24. Drawing required for Road project :- 4. Detailed location survey plan:- - This plan shows the ground plan along with alignment of road and contour. - It also shows all existing structure, river and other natural details. - Maximum size of the drawing is A-1 size or 625mm x 880mm.

25. Drawing required for Road project :- 5. Longitudinal section:- - It shows the section of the proposed road alignment and it also include i) datum line ii) formation level, iii) ground level, iv) gradient, v) depth of cutting and filling, position of cross drainage etc. - It also draw to same scale as detailed plan. - The longitudinal section helps to decide the formation level of the road, on which economical earth work is obtained.

26. Drawing required for Road project :- 6. Detailed cross section:- - The scale of this section is same as that of longitudinal section. - Cross section should be drawn when there are abrupt changes in level. - This drawing shows the quantity of cutting and filling.

27. Drawing required for Road project :- 7. Land acquisition plans:- - This plans shows general details such as buildings, wells, nature of land and other details required for assessing the values. - The scale may be used 1cm = 40m. - The maximum size of the plan is 880mm x 1230mm.

28. Drawing required for Road project :- 8. Drawing for cross drainage and Masonry structures:- - This plans shows the details cross drainage & and other masonry work. - The scale may be used 1cm = 1m. - Details of any complicated portion of the structure is enlarged to scales upto 8cm = 1m, but some times care should be taken, that size of drawing must not exceed the standard size.