Preparation of Detailed Project Report (DPR) for Road Projects
Preparation of DPR involves following components
1.0 Understanding Scope of Work
2.0 Traffic Surveys
3.0 Engineering Investigations
4.0 Detailed Designs
5.0 Tender and Construction Drawings
6.0 Project Costing
7.0 Economic Analysis
8.0 Formulation of Construction Packages
9.0 Compiling Project Report
Scope of Services
UNDER STANDINGTHE TOR
- 1. First and foremost thing is to study carefully and understand the Terms of Reference (ToR) or Scope of Services of the project.
- 2. Once the ToR is understood, the conceptualization of the project would beeasy.
- 3. Mostly the ToR for a particular type of projects remains same across anyorganization.
- Duration of the Project, Phases (Feasibility, PPR, DPR) and Reporting requirements
- Proposals for improvements, if any, (type of cross section, grade separators, major Bridges, Bypasses etc.)
- Any special types of Surveys and project specific considerations
- Requirements for Economic and Financial Analysis,
- Issues on Right of Way (RoW) and Land Acquisition
- Social and Environmental surveys
SURVEYS AND INVESTIGATIONS
1. Reconnaissance Survey
2. Traffic Surveys
3. Topographic Surveys
4. Engineering Surveys
5. Soil & Material Investigations
6. Social And Environmental Surveys
- 1. The initial task of identifying the homogeneous traffic links shall be undertaken on the identified road sections
- 2. homogeneous traffic links will be established through identification of the major intersections and urban centres
- 3. The fixation of locations will be made for traffic volume surveys, both at mid sections and intersections
- a) Traffic Volume Surveys
- b) O-D And Commodity Surveys
- c) Turning Movement Surveys
- d) Parking Surveys
- e) Speed And Delay Surveys
- f) Cross Pedestrian And Animal Surveys
- g) Axle Load Surveys
- h) Truck Terminal Surveys
- i) Willingness to pay Surveys
- 1. Traffic volume count survey gives ADT
- 2. ADT is to be converted to AADT based on seasonal variation factors
- 3. Seasonal variation factors can be obtained by fuel consumption rates or past traficdata
- 4. AADT thus obtained shall be used as base year traffic
- 5. Traffic is to be forecasted for at least next 10 years
- 6. Traffic Growth rates can be obtained using
- a) Trend Analysis
- b) Econometric Model
- c) A more rational method will be to establish a relationship between the socio-economic variables such as Population, Net State Domestic Product (NSDP)and Per-Capita Income (PCI) on the one hand and the past registration data of different categories of vehicles on the other to determine the elasticity of transport demand with respect to different categories of vehicles. According toIRC: 108 - 1996, an econometric model should be derived.
Axle Load Surveys
- 1. Traffic loading has a significant impact on pavement performance and design.
- 2. damage that vehicles create to a road depends very strongly on the axle loads of thevehicles.
- 3. The exact relationship is influenced by the type of road structure and the way theroad deteriorates but a `fourth power’ damage law gives a good approximation.
- a) Measurements will be made for two days over a 24-hour period on random sampling basis.
- b) analyse the axle load survey data to bring out the Gross Vehicle Weight (GVW) and Single Axle Load (SAL) distributions by truck type and axle configuration.
Engineering Surveys And Investigation
1. Road Inventory Survey
2. Inventory And Condition Assessment Of Existing Cross Drainage Structures
3. Preparation Of Strip Plan
4. Assess Adequacy Of Drainage
5. Pavement Condition Survey
6. Pavement Roughness Survey
7. Pavement Composition Survey
8. Benkelman Beam Deflection (Bbd) Survey
Road Inventory Survey
A) The Road Inventory survey consists of recording the physical features along and across the project road in a prescribed format.
- 1. Average width of pavement, shoulders and formation
- 2. Surface type of carriageway and shoulders
- 3. Right of Way (ROW)
- 4. Average embankment, height, type and condition
- 5. Location of major Bridges, RoBs, Flyovers.
- 6. Type and location of Side Drains
- 7. Road Side Land Use
- 8. Utility lines and trees within the boundaries
- 9. Location and Condition of Traffic Sign Boards
- 10. Location of Bus stops, Parking areas and other amenities
- 11. Location of Major industries and business centers
- 12. Location and details of cross roads
- 13. Sight distance details
- 14. Perched water table, HFL, Depth of submergence the road is subject to
- 15. Areas subject to chronic flooding and submergence
- 16. Recording urban and Rural areas, name of places and settlements
Inventory and Condition Assessment of Existing Cross Drainage Structures
- a) The location of each bridge and culvert shall be recorded, along with its type and the carriageway width.
- b) A detailed inspection of bridges and culverts shall be carried out to assess their condition. This would lead to a report preparation on condition of bridges and structures
- c) The structures, which show deficiency in terms of capacity and strength, shall be reviewed in the light of repair/rehabilitation possibilities with suitable recommendations.
Assess Adequacy of Drainage
- 1.) Inadequacy of drainage reflects in terms of fast deterioration of the pavement aswell as causes inconvenience to the traffic,
- a) General condition of drainage
- b) Connectivity of drainage turnouts en-route into the network topography
- c) Condition in cut sections
- d) Condition at embankments
Pavement Condition Survey
- Detailed field studies shall be carried out to assess the adequacy and effectiveness of the existing pavement. The data Shall generally cover
- a) Pavement condition (surface distress type and extent)
- b) Shoulder condition
- c) Embankment condition
- d) Drainage condition
Pavement Roughness Survey
- a) Roughness is a critical attribute for modeling the economic variables of investment. The roughness is measured in International Roughness Index (IRI), the unit of IRI is m/km.
- b) The roughness surveys shall be conducted using a fifth wheel Bump Integrator (preferably vehicle equipped with ROMDAS).
- c) The test vehicle shall be run on the wheel path on both the directions preferably three times and the average result is reported as the IRI
Pavement Composition Survey
To know the pavement composition and to collect the soil samples for testing, trial pits of size 1m x 1m shall be made at the interface of pavement with shouldersaccording to the following procedure:
- a) Mark the location of the pit-half on the pavement and balance on the shoulders.
- b) Dismantle the marked area to full depth of pavement.
- c) Ascertain the pavement composition
Benkelman Beam Deflection (BBD) Survey
- The procedure for carrying out BBD survey shall be in conformity with IRC:81-1997. Deflections are measured at 50m intervals staggered on both directions of traffic and then apply the method of cumulative differences to divide the sectionsfor arriving at the characteristic deflections.
- a) Traffic regulation arrangement during carrying out Benkelman Beam Deflection surveys shall be as follows
- b) Cordon the area with suitably spaced cones and provide temporary traffic signs.
- c) Carryout the Benkelman Beam survey work.
- d) Shift the cones and temporary signs to next location.
- 1. Existing Sub-Grade And Embankment Soils
- 2. Construction Materials Investigation
- 3. Borrow Areas
- 4. Quarries For Aggregates
- 5. Quarries For Sand
- 6. Sources For Other Construction Materials
- Material investigation aims at collecting all material samples that is being used under the present road and anticipated borrow material and subject to standard testing procedure to recommend most appropriate designs
- a) Soil sampling, field density tests and laboratory tests on existing sub-grade and soil sampling of embankment soils.
- b) Investigating borrow materials for embankment, sub-grade and granular sub-base.
- c) Investigating aggregate and sand quarries
- d) Locating water sources for construction work
- e) Identifying sources for other construction material such as cement, bitumen and steel.
- f) Samples of borrow soils, sand, crushed rock and gravel for use in embankment, and pavement structure.
Subgrade Soil Samples
- a) The tests being performed are
- b) Grain size distribution test for each sample,
- c) Atterberg limits for each sample,
- d) Moisture density relationship (Heavy Compaction) for each sample,
- e) Unsoaked CBR tests at optimum moisture content at three energy levels.
- f) Four days soaked CBR at three energy levels on each homogenous group of soils. Soaked CBR at FDD and 97% of the MDD is to be determined from the graphs plotted for CBR vs Density at three energy levels.
- a) Topographical survey is the backbone of detailed engineering design.
- b) Accuracy of the information collected during this survey has direct bearing on almost all the design activities involved in project preparation.
- c) The beginning of topographical surveys is made with collection of preliminary information of latitude and longitude of the region as well as approximate reduced level above mean sea from Survey of India maps available in the region.
- d) Setting up permanent bench marks and control stations to be used during construction
- e) Establishment of horizontal control with GPS to have unique coordinate system of northing and easting along the project corridor.
- f) Establishment of vertical control to have the elevation coordinate hooked to nearest GTS stations along the project corridor.
- g) Collection of Digital Terrain Model data containing the existing highway, rivers, streams and other topographical features to form the basis for the new designs;
- h) Preparation of base plans containing the entire natural and manmade features like buildings, fences, walls, utilities, temples and other religious structures etc. that would govern the finalization of horizontal alignment.
- i) Coding for various types of features is comprised of four characters.
- j) The first two characters describe the type of feature and the last two characters indicate the string number.
- k) The string number i.e. the last two characters are alphanumeric, such as, A1-A9, BO-B9.......... ZO- Z9,AA-AZ, BA-BZ, .…….. ZA- ZZ.
- a) With a view to obtain an accurate surface cross section on the pavement shall be collected at 25m intervals at the tangent sections and 10-25m in curve sections.
- b) The cross-sections levels were taken on the embankment profile or ground as necessary to define ground profile properly.
- c) Center line of carriageway (Code CC**);
- d) Edge of carriageway (Code CE**);
- e) Paved shoulder (Code SH**). This is where the seal has been extended past the normal edge of the road to include a part of the shoulder;
- f) Edge of shoulder (Code SS**); Where ** indicates left or right string
- g) Point on undisturbed original ground level (OG);
- h) Point on partially or completely filled surface of the top of embankment/ formation(ET**)
- i) Point on bottom of embankment (EB**); Where ** indicates left or right string
4.0 DETAILED ENGINEERING DESIGN
4.1 Engineering Design
4.1.1 Highway Geometric Design
4.1.2 Design Of Built-up Areas
4.1.3 Design Of Pavement And Shoulders
4.1.4 Overlay Design
4.1.5 Design Of Service Road And Bypass
4.1.6 Design Of Embankments
4.1.7 Design Of Roadside Drainage
4.1.8 Detailed Design Of Bridges/Structures
4.1.9 Design Of Arboricultural And Landscaping
4.1.10 Design Of Intersection And Interchange
4.1.11 Design Of Traffic Safety Features, Road Furniture And Road Markings
4.1.13 Weighing Station, Parking Areas And Rest Areas
4.1.14 Design Of Wayside Amenities
4.1.15 Design Of Communication System
4.1.16 Design Of Bus-Bays And Lay-By
4.1.17 Design Of Miscellaneous Items
5.1 Project Costing
5.1.1 Finalisation Of Unit Rates
5.1.2 Preliminary Estimate Of Quantities
5.1.3 Preliminary Costing
5.2 Economic Analysis
5.2.1 Construction/Improvement Cost
5.2.2 Vehicle Operating Costs And Time Costs
5.2.3 Accident Costs
5.2.4 Social And Environmental Costs
5.2.5 Estimation Of Project Benefits
5.2.6 Economic Analysis By Section
5.2.7 Finalisation Of Improvement Option
5.3 Financial Analysis
5.3.1 Determination Of Toll Rates
5.3.2 Compilation Of Project Costs
5.3.3 Identification Of Preliminary Project Revenue Stream
5.3.4 Financial Analysis
5.4 Formulation Of Construction Packages
5.5Submission Of Project Report Highway Geometric Design
Horizontal Alignment: The proposed centerline shall be finalised using asophisticated highway design software, All the curves having poor geometry shall be improved to the acceptable design standards
Vertical Profile: The existing longitudinal section of the project road shall be obtained from modeling the ground data. The finished profile shall depend on the thickness of the pavement layer determined from pavement design provision for necessary profile corrective and camber corrective course.
– Avoid cutting/scraping of existing pavement at strengthening only sections
– Compatibility of design speed to horizontal geometry of the section
– Provide adequate vertical curve at the grade change from stopping sight distance criterion.
Cross Section: The proposed cross sections are broadly composed of carriage way, medians, raised footpath, hard shoulders, earth shoulder and drainage provisions. While running cross-sections care shall be taken in applying appropriate super elevation parameters, strengthening & widening, and improvement options based on rural, built-up etc.
- a) The earthwork in cutting and filling shall be obtained from the software directly at a specified interval along with Mass haul diagram.
Design of Built-up Areas
This activity shall focus on design of urban areas in the form of parking lane, service road, sidewalk and roadside drainage underneath the sidewalk etc. All these details shall be clearly shown in the horizontal plan and also typical cross sections shall be prepared.
Design of Pavement and Shoulders
a) The performance of pavement in terms of functional performance, structural performance, structural capacity, and safety contribute to the need for an overlay.
b) Functional performance refers to the ability of the pavement surface to provide a reasonable riding quality measured in terms of roughness.
c) Structural performance is the ability to retain the integrity of the pavement by preventing distress in the form of cracks, ruts, potholes, etc.
d) Structural capacity is the pavement's ability to accommodate the axle load on the pavement. Safety aspect refers mainly the skid resistance and hydroplaning potential.
Design of Service Road and Bypass
• This activity shall focus on design of service road and bypass in terms of number of lanes and pavement composition.
• The local traffic component shall be segregated and would determine the number of lanes to be provided in the service road. Depending on this traffic loading and soil investigation already carried out, the pavement composition shall be decided.
Design of Embankments
• The embankments would be designed after detailed analysis and as per the relevant standards and latest software available. General design parameters shall follow IRCguidelines.
Design of Roadside Drainage
- 1) Drainage is an important aspect in the design of highway. With poor drainage conditions the pavement will not sustain till the end of design life.
- a) Design of kutcha drain on both sides near RoW limits in rural sections
- b) Covered pucca drains near urban areas if necessary
- c) Design of chutes in high embankment areas for drainage of surface water – In super elevation sections median drains shall be provided
- d) As a slope protection measure for high embankment section, turfing on slopes or pitching shall be designed as per the design standards.
Detailed Design of Bridges/Structures
- a) Based on the detailed survey, sub-surface investigation and design standards and specifications developed bridge/structures shall be designed.
- b) General design parameters and loadings shall follow IRC guidelines, amended when necessary in consultation with client.
- c) In selecting foundation type, the consultant shall also take into account the time required for construction of alternatives, and give preference to those which minimise construction time.
- d) In developing the standard designs and for those designs, which cannot be standardized, computer programs for design and drawing shall be used extensively. On the basis of the investigation and design standards, detailed designs for minor bridges and culverts shall be prepared.
Design of Arboricultural and Landscaping
Appropriate plans shall be developed for planting of trees, horticulture and floriculture on the unused land of the RoW in order to beautify the project corridor view and improve the overall aesthetics.
Design of Intersection and Interchange
- a) To avoid skew crossing wherever possible
- b) To provide control radius of minimum 12.5 m for right turning traffic
- c) To provide radius of minimum 9.0m for left turning traffic
- d) To provide maximum possible length for weaving section in case of rotary
- e) To provide 3.0m additional width of carriageway at weaving sections
- f) To provide adequate sight distance for all traffic movements
- g) To provide slip lanes for left turning where the volume is assessed to be high and also land is available
- h) IRC: SP41-1994 Guidelines of Design of At-grade Intersection in Rural and Urban areas and M/ORT&H type designs for intersection on National Highway, 1992shall be followed in the design of intersections. For developing designs for interchanges at identified intersections IRC: 92-1985 “Guidelines for the design of interchanges in urban areas” and AASHTO guidelines shall be followed.
Design of Toll Plaza
- a) Design toll plaza layout based on traffic segregation, acceptable queue length, toll collection system and the average waiting time shall be made.
- b) The plaza shall be designed based on the forecast traffic in such a way that the traffic shall be subject to minimum delay and inconvenience. Also necessary facilities shall be provided in the design for effective toll collection.
Design of Traffic Safety features, Road Furniture and Road Markings
Design of traffic signs and road markings, to effectively guide and control the traffic, shall be carried out based on current national and international practices.
Weighing Station, Parking Areas and Rest Areas
Sites for Weighing stations, parking areas and rest areas shall be selected based on the data collected and as per the discussions with the MoRT&H.
Design of Wayside Amenities
Design of the Wayside Amenities carried out in accordance with the comments and suggestions of client and suitable layouts shall be prepared accommodating petrol pump, first-aid medical facilities, restaurant, vehicle parking, toilets, telephone kiosks, etc.
Design of Communication System
An emergency telephone communication system to be used even by a person in emergent condition with little effort shall be designed. This would be a public access telephone system dedicated to control center, which shall coordinate services like fire, ambulance, police and retrieval of breakdown vehicles, besides emergency highway maintenance operations.
Design of Bus-bays and Lay-by
Review of design of bus-bays, in accordance with comments of clients, as per IRC and M/ORT&H guidelines and drawings shall be made.
Design of Miscellaneous Items
Designs for guardrails, street lighting and other necessary roadside appurtenance shall be carried out based on IRC and other current international practices.
Traffic Management Schemes during Implementation
Traffic management during construction is an integral part of execution of highway projects. An efficient scheme or traffic management shall be developed based onMoRT&H and IRC guidelines, which would include traffic diversion plans during construction and maintenance and other measures for traffic control and safety.
- a) Unit rates shall be normally based on Schedule of Rates of respective departments
- b) The unit rates calculated for similar roadwork and bridgework items shall be reviewed and updated for cost calculation. In specific projects
Preliminary Estimate of Quantities
- 1) Quantities of various items shall be worked out based on the typical cross sections already prepared chainage wise. Total item wise quantities for bridges and C-D structures shall also be calculated considering the design features and present condition of bridges.
- a) Construction Cost
- b) Maintenance Cost
- c) Land Acquisition Cost
- d) Environmental Cost
- e) Cost of Utility Relocation.
- 1) In order to carry out the economic analysis, all economic costs shall be estimated by each homogenous section. These costs comprise of the following:
- a) Cost of construction/improvement.
- b) Vehicle operating costs and time costs.
- c) Accident costs.
- d) Social and environmental costs.
Estimation of Project Benefits
- 1) The benefits from each improvement option shall be derived by using the approach of "with" and "without" project scenario, for each homogeneous section. The benefits would comprise the following:
- a) VOC savings
- b) Travel time savings
- c) Savings in Accident costs
- d) Socio-Environmental benefits
- a) Financial analysis, by each section, shall be carried out for the identification of potential BOT candidates. The revenue stream, as generated in the previous tasks shall be included into the analysis in two stages:
- b) Revenue only from toll imposition
- c) Revenue from other sources as well.
Formulation of Construction Packages
- a) The project corridor shall be divided into several construction packages depending on the length of the project corridor. These shall cover and facilitate:
- b) Enabling more contractors to bid
- c) Uniformity in work
- d) Speed in implementation of the project speedily
- e) Economy in construction
- f) Efficient Project management