Project Coordination Unit · So far, the construction concerns, environment–friendly approach adopted in design. The Consultant has tried their best knowledge, lesson learnt and

Ministry of Federal Affairs and Local Development

Department of Local Infrastructure Development and Agricultural Roads

Project Coordination Unit

Rural Reconstruction and Rehabilitation Sector Development Program, Phase 2 (RRRSDP-2)

Contract No. PCU/QCBS/01/2013

Survey, Design &Cost Estimate of Shankhu - Paluwari - Nagarkot Road

CH: 0+000 – 10+046.48 Km Kathmandu District

Volume – I MAIN REPORT

March, 2016 Submitted by

ERMC (P.) Ltd. (Environment & Resource Management Consultant) New Baneshwor, Kathmandu, Nepal P. O. Box: 12419, Kathmandu Tel.: 977-01-4483064, 4465863 Fax: 977-01-4479361 Email:[email protected], Website: www.ermcnepal.com

mailto:[email protected]

http://www.ermcnepal.com/

RRRSDP-2 i

ACKNOWLEDGEMENT

ERMC would like to extend special gratitude to all the concerned RRRSDP central Project coordination

Unit and district team, officials of DDC, DTO and especially the local people of the project area who

guided, advised, and cooperated ERMC and joined the survey team and guided/assisted during

conduction of detailed engineering survey work. We also appreciate the contribution of all the individuals

involved in this project works for their kind co-operation and help at every step of Detail Engineering

Survey and Design of Shankhu-Palubari-Nagarkot Road in Kathmandu District.

.

RRRSDP-2 ii

Table of Contents Abbreviation Salient

Feature Executive

Summary

CHAPTER-I: INTRODUCTION ..................................................................................................... 1

1.1 RRRSDP Districts for Implementation .......................................................................................... 1

1.2. OBJECTIVES ................................................................................................................................ 2

1.3. SCOPE OF WORKS ..................................................................................................................... 2

CHAPTER-II: METHODOLOGY ................................................................................................... 4

2.1 THE STUDY TEAM ....................................................................................................................... 4

2.2 Desk study..................................................................................................................................... 4

2.3 Identification and Selection of Roads............................................................................................ 4

2.4 Meetings ........................................................................................................................................ 4

2.5 Meeting with Local Level Stakeholders......................................................................................... 5

2.6 Detailed Engineering Survey, Design and Cost Estimate............................................................. 6

2.7 Field Verification of Design / Estimate .......................................................................................... 8

CHAPTER-III: THE PROJECT ...................................................................................................... 9

3.1 Project District ............................................................................................................................... 9 3.2 Description of Alignment ............................................................................................................. 10 3.3 Population Served & Traffic Data: .............................................................................................. 10 3.4 Potential Area & Growth Centers................................................................................................ 11 3.5 Project Rationale......................................................................................................................... 11

CHAPTER-IV: GEOLOGY AND GEOMORPHOLOGY .............................................................. 13

4.1 Geological Study......................................................................................................................... 13 4.1.1 Introduction ................................................................................................................................. 13 4.1.2 Regional Geology and Geomorphology...................................................................................... 13 4.1.3 Surface Geology ......................................................................................................................... 13 4.1.4 Slope Stability Condition ............................................................................................................. 14 4.1.5 Engineering Geological Mapping ................................................................................................ 14 4.1.6 Geological Hazard Mapping ....................................................................................................... 15

4.2 Construction Material Survey...................................................................................................... 15 4.3 Land Use Pattern / VDC & Settlements...................................................................................... 15 4.4 Conclusions ................................................................................................................................ 15

CHAPTER-V: HYDROLOGY AND METEOROLOGY ................................................................ 16

5.1 General........................................................................................................................................ 16

5.2 Rainfall ........................................................................................................................................ 16

5.3 Design Discharge ........................................................................................................................ 16

5.4 Cross Drains............................................................................................................................... 17

RRRSDP-2 iii

5.5 Side Drains .................................................................................................................................. 18

5.6 Selection of Cross-drainage Structures Type ............................................................................. 18

CHAPTER-VI: GEOMETRIC STANDARDS & DESIGN ............................................................. 20

6.1. Road Classification ..................................................................................................................... 20

6.2. Design Standard ......................................................................................................................... 20

6.2.1. Design Speed............................................................................................................................. . 20

6.2.2. Geometric Design ....................................................................................................................... 20

6.2.3. Horizontal Curvature ................................................................................................................... 20

6.2.4. Super Elevation ........................................................................................................................... 20

6.2.5. Minimum Radius of Curvature..................................................................................................... 21

6.2.6. Widening on Curves .................................................................................................................... 21

6.2.7. Stopping Sight Distance Sight Distance ..................................................................................... 22

6.2.8. Gradient....................................................................................................................................... 23

6.2.9. Summit Curves............................................................................................................................ 24

6.2.10. Valley Curves .............................................................................................................................. 24

6.3. ROAD CROSS- SECTION .......................................................................................................... 25

6.3.1. Cross Section Design.................................................................................................................. 26

6.3.2. Shoulder Width............................................................................................................................ 26

6.3.3. Carriageway Width ...................................................................................................................... 26

6.3.4. Formation Width .......................................................................................................................... 26

6.3.5. Right of Way................................................................................................................................ 26

6.3.6. Camber........................................................................................................................................ 26

6.3.7. Pass Bay ..................................................................................................................................... 27

6.3.8. Carriageway width at culvert/ bridge ........................................................................................... 27

6.3.9. Level of road embankment above hfl .......................................................................................... 27

6.3.10. Lateral Clearance ........................................................................................................................ 27

6.3.11. Vertical Clearance ....................................................................................................................... 27

6.4. Cut / Fill Batter Slopes ................................................................................................................ 27

CHAPTER-VII: ENVIRONMENTAL MITIGATION MEASURES ................................................. 28

7.1. Consideration Made in Alignment Selection, Survey and Design Phase ................................... 28

7.2. Drainage Outlet Protection Works............................................................................................... 28

RRRSDP-2 iv

7.3. Selection of Slope Protection Work............................................................................................. 29

7.4. LIST OF SOME ENVIRONMENT PROTECTION WORKS: ....................................................... 29

DETAILED ENGINEERING DESIGN ......................................................................................... 30

8.1 Design Method ............................................................................................................................ 30 8.2 Review & Redesign..................................................................................................................... 30 8.3 Design & Drawings ..................................................................................................................... 30 8.4 Horizontal Curve Design ............................................................................................................. 30 8.5 Design of Structures and other geometric Features ................................................................... 30 8.6 Pavement Proposed .................................................................................................................. 30 8.7 Field Verification of Design / Estimate ........................................................................................ 36

CHAPTER-IX: COST ESTIMATE ............................................................................................... 37

9.1. Summary ..................................................................................................................................... 37

9.2. Quantity Estimate ........................................................................................................................ 37

9.3. Rate Analysis .............................................................................................................................. 37

9.4. Cost estimate .............................................................................................................................. 37

9.5. Conclusion................................................................................................................................... 37

CHAPTER-X: CONCLUSION & RECOMMENDATIONS ........................................................... 38

Annexes

Annex1: DCP Test

Annex 2: Horizontal Curve Data

Annex 3: Bench Marks List

Annex 4: Photographs

RRRSDP-2 v

ACRONYMS

ADB ADDI BCR BG BS

Asian Development Bank Appraisal Document for Donor Investment Benefit Cost Ratio Building Group Baseline Survey

CE Community Empowerment DDC District Development Committee DFID Department for International Development (UK) DoLIDAR Department of Local Infrastructure Development and Agricultural Roads

DoR DoS DPR DRCN

Department of Roads Description of Services Detailed Subproject Report District Road Core Network

DTMP District Transport Master Plan DTO District Technical Office

EIA Environmental Impact Assessment EIRR Economic Internal Rate of Return ERMC Environment Resource Management Consultant (the consultant of RRRSDP-2) GDP Gross Domestic Product GoN Government of Nepal

ICD Institutional Capacity Development

IEE IPDP IRR

Initial Environmental Examination Indigenous People Development Plan Improved Rural Roads

LBFAR Local Body Financial Administrative Regulation LEP Labor-based, Environmentally-friendly, and Participatory (approach) LSGA Local Self-Governance Act MoFALD Ministry of Federal Affairs and Local Development

MYRP NGO

Multi Year Rolling Plan

Non Government Organization

NPV net present value O&M Operation & Maintenance

OFID PCR PCU PFP

PIP

OPEC Countries for International Development Subproject Completion Report Subproject Coordination Unit Program Financing Plan Subproject Program Investment Plan

Subproject PMS Program Monitoring System Subproject

PPTA Subproject Preparatory Technical Assistance

RES RFP RIRR RoW

Rapid Environmental Screening Request for Proposal Rural Infrastructure Rehabilitation & Reconstruction Investment Plan of GoN Right of Way

RP Resettlement Plan

RRMC Rural Road Maintenance Committee

RRMFC RRMMS RRRSDP SDC

Rural Road Maintenance Fund Committee Rural Road Maintenance Management System Rural Reconstruction and Rehabilitation Sector Development Program

Swiss Agency for Development and Cooperation SRN Strategic Road Network ToR Terms of Reference VDC Village Development Committee VOC Vehicle Operation Cost ZoI Zone of Influence

Detail Engineering Survey and Design of Sankhu - Palubari - Nagarkot Road

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(Kathmandu)

SALIENT – FEATURES OF THE PROJECT

1. Name of Project : Shankhu – Paluwari - Nagarkot Road

2. Location

Region : Central Development

Zone : Bagmati

District : Kathmandu

VDC : Bajrayogini and Suntol VDC 3 Major Settlements : Sankhu/Bajrayogini, Palubari, Kattike and

Nagarkot

4 Population served : 4819

5 Terrain : Rolling & Hilly

6 Classification of Road

Classification : District Core Road Network

Existing Surface : partially graveled, earthen

Proposed Surfacing Surface : Blacktopped

7 Road Alignment

Starting Point : Shankhu of BajrayoginiVDC#6

Ending Point : Baluwapati - Deupur VDC#8, Kavre

Length : 10.046 km

DTMP Code : 27DR037

8 Cross Section

Right of Way : 10m either Side

Formation Width 6.25 m including drain

Roadway width : 5.25 m

Carriageway Width : 3.75 m

Shoulder Width : 0.75 m either Side

9 Earthwork

Cut Volume (Cum) : 48,736.91 cu.m

Fill Volume (Cum) : 34735.42 cu.m

10 Retaining Structure

Gabion Wall (Cum) : 2660 cum

Cement Masonry Wall : 1855.56 cum

11 Drainage

Drain 8533.24 R m Pipe culvert : 23Nos

Slab Culvert : 4Nos

Outlet Protection Works 32Nos

12 Project Cost

Overall Total Cost including

Contingency and VAT : NRs.232,716,449.2

Overall Total Cost excluding

Contingency and VAT : NRs. 200,617,628.6

Cost per Km excluding

Contingency and VAT : NRs. 19,968,311.16


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(Kathmandu)

EXECUTIVE SUMMARY

This report is the findings of detailed engineering survey and design of District Road Sankhu - Palubari -

Nagarkot Road (Kathmandu)”that was carried out for upgrading of road stretch that connects the different

settlements of Bajrayogini and Suntol VDCs of Kathmandu and Deupur VDC of Kavre with core city area of

Kathmandu Metropolitan City and different strategic road networks. The road is located in the north - east

part of Kathmandu district.

This road is designed for upgrading to blacktopped standard and the proposed intervention comprises:

Widening of narrow section to NRRS 2055 standard

Improvement of steep gradient

Provision of passing bays

Improved drainage system with lined drain and adequate cross-drainage structures

Upgrade the road geometry to minimum design standard of DoLIDAR; and

Minimizing Environmental hazards

The total length of road is 10.046 km. The road alignment starts from Shankharapur Municipality Ward #11

and passes through Sankhu, Palubari, Kattike and finally reaches to Nagarkot and Baluwapat - Deupur

VDC Ward #8 of Kavre district.

This road will provide access to market, education institutions, and Health centre and government service

offices. In addition it is also a potential heritage route to religious places of Sankhu and Bajrayogini and

tourist route to Nagarkot.

The Consultant has conducted the detail survey work of proposed road with total station using digital

terrain model. Walkover survey has been conducted to confirm the feasibility of road. Local peoples

including district technical office (DTO) team are consulted prior to commencement of work.

Existing road has been followed as far as possible while fixing the alignment; however these will be shifted

in some places especially at hair-pin-bends to maintain the geometric design parameters and at

problematic areas of steep gradient where locals allowed doing so. As far as the topography allows the

ruling longitudinal gradient has been followed. Only in exceptional cases where the alternative alignment

is difficult and not justifiable, the gradient is adopted to 12% and even more keeping view of resettlement

limitation and other social reasons and to escape from unfeasible cut/fill and possible damage to houses.

The road is designed to all weather type of District Core Road Network standard of general width of 5.25 m

with 3.75 m carriageway including 0.75 m shoulder on either side and with vehicle-passing zone at

intervals as proposed in the design standard.

In order to manage the surface run-off lined drain is proposed with cross-drainages at frequent interval

focusing to be located at vertical intersection valley points. Consideration is given to safe discharge of the

drainage outlets in natural gullies. Type of crossings has been determined keeping view of nature and

characteristics of gullies, river, stream and spring.

Unnecessary heavy cut/fill has been avoided as far as possible; however this could happen to some extent

especially in hair-pin bends, where the combined effect of design grade limitation and abrupt change of

topography contour could induce such consequences and at sections with steep existing gradients.

Nepal Rural Road Standard (2055) with Second revision of December 2014 of MoFALD and DOLIDAR has

been followed during detailed engineering survey and design. So far, the construction concerns,

environment–friendly approach adopted in design.

The Consultant has tried their best knowledge, lesson learnt and expertise to cover all aspects of best

practices in road design in mountainous terrain and to produce a quality design report with optimal

economical and environmental consideration.


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(Kathmandu)

After the submission of design/cost estimate to PCU/DTO a joint field visit verification from DTO and

Consultant of design/drawing have been made to assess adequateness and appropriateness of proposed

geometric design, retaining and cross drainage structures and other protection works with existing ground

reality need. The findings from field verification and comments & suggestions from DTO have been

incorporated in design/estimate.


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1. CHAPTER-I: INTRODUCTION

The Rural Reconstruction and Rehabilitation Sector Development Program, Phase 2 (RRRSDP-2) is

the follow-on program of RRRSDP-1 which was successfully completed in June 2013. The

Government of Nepal is financing for the current preparatory stage of RRRSDP-2 with a purpose to

carry on this Program into physical construction stage later after securing funds from bilateral and

multilateral development partners after accomplishing the preparation of all specific designs and

documents. So this Program preparation modality of DoLIDAR is considered to be rather unique due

to the fact that it is commissioned without any external or donor‟s PPTA support and funding

assistance.

The agreement for consultancy services for this preparatory phase was signed on July 10, 2013

between PCU/ DoLIDAR and ERMC (who is the successful bidder) for carrying out feasibility, detailed

engineering surveys and design works of some 1087 km of roads and feasibility studies of 35 bridges

inclusive of other field surveys/ studies of allied components related to geological, geotechnical,

environmental, social and resettlement prerequisites in the 20 districts (same RRRSDP-1 districts).

DDC selected the list of roads and bridges from DTMPs/DRCNs and forwarded to the PCU for

inclusion in RRRSDP-2. After thorough review of the DTMP roads or selected roads of districts and

other relevant documents and data, the Consultant made discussions with the Client at the central

level concerning candidate roads to be included for feasibility study and detailed engineering toward

preparation of Detailed Project report.

This detailed engineering survey, design and cost estimate report has been produced as result of field

investigation, topographical survey along with the geological, hydrological study of road alignment and

review of relevant maps, reports and documents.

1.1 RRRSDP Districts for Implementation

The RRRSDP-2 implementation proposed to be continued in the same 20 districts of RRRSDP-1

listed below in the table and map:

Table: Names of Districts for RRRSDP-2 Implementation

Eastern Development Region: Panchthar, Ilam, Jhapa, Morang, Sunsari, Dhankuta,

Central Development Region: Sindhuli, Sindhupalchowk, Kathmandu, Lalitpur, Bhaktapur, Kavre, Dolakha, Chitwan,

Western Development Region: Parbat, Manang, Mustang,

Mid Western Development Region: Rolpa, Rukum,

Far western Development Region: Dadeldhura


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1.2. OBJECTIVES

To achieve the program goal of reduce the poverty the program will continue and strengthen the

overall objectives of RRRSDP-1 to improve connectivity, enhanced economic and employment

opportunities and to ensure increased access to markets and social services for rural communities.

1.3. SCOPE OF WORKS

The consultant shall prepare Detailed Project Reports (DPR) of the each Road Subprojects.

Preparation of Detailed Engineering Survey, Design and Cost Estimate of Individual Road

Subprojects is one of major part of Detailed Project Report Preparation (under Part A of 2.2 of Scope

of Consulting Services). Following are the task under engineering report:

(i) Detailed field investigation including topographical survey, geological observation,

hydrological study &incorporating meteorological secondary information, slope stabilization

features, drainages patterns, and other features for road design..

(ii) Cross-drainage requirements will be assessed for proposing new structures for bridges,

culverts, and causeways as appropriate or improvements will be recommended for

structurally unsound structures.

(iii) Engineering surveys will be done following the standard engineering practices with horizontal

and vertical controls and benchmarking with all details necessary for a detailed design of

roads.

(iv) Material availability surveys will also be conducted for record. Local rates for construction, of

various items, local and imported materials, transportation charges, etc., will be enquired and

established as per the prevailing market rates and labour wage rates are to be confirmed from

district rates for cost estimating purpose.


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(v) Computer aided software designs will be done for road designing. However manual designs

in some cases can be done.

(vi) The detailed designs will be done or prepared by the Consultant following the DoLIDAR‟s

Rural Road Design Standards.

(vii) Detailed and standard drawings will be also prepared as mentioned in the DoLIDAR

Technical Guidelines.

(viii) The designs and drawings will consist of the location map and layout, design profile, design

cross-section plan, other structural detailing and drawings and standard/typical drawings.

(ix) Engineering technical specifications for each work item will be written taking into account

relevant standard specifications in use in the country and elsewhere for similar works and in

accordance with the Codes of Practices.

(x) The detailed cost estimate will be prepared using the calculated quantities and unit rates,

derived from standard applicable District Rates and DoLIDAR Work Norms.

(xi) Detailed Subproject Report (DPR) will be prepared following the agreed Table of Content.

(xii) Detailed economic analysis of individual road subprojects will be carried out and presented in

the DPR.

(xiii) Contract packaging will be suitably done as agreed with the Client for all subprojects, and

respective bidding documents will be prepared following the DoLIDAR practices and

frameworks.

(xiv) Similarly engineering subproject implementation schedules will be prepared.


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2. CHAPTER-II: METHODOLOGY

2.1 THE STUDY TEAM

The study team of Consultants for detailed engineering comprised a Road Expert (Team Leader), one

Social Specialist, one Environmental Specialist, one Resettlement Specialist, Road Engineer, one

Bridge Engineer, one Geo-technical Engineer, one Geologist, one Hydrologist and one Transport

Economist.

In addition to the above mentioned core team, the Consultants had fielded special survey team for

conduction of detailed engineering survey and design of road sub-projects. Furthermore other

necessary human resource and all required logistics was mobilized for the study of road in terms of

engineering feasibility, social viability, environmental sustainability and economically beneficial.

2.2 Desk study

The Consultant collected documents, drawings, study reports, maps, walkover survey report and

existing DTMP to acquire and extract key information for conduction of detail engineering study of the

selected alignment route. The Consultant had studied all these documents prior to field movement to

perform detail alignment survey.

Following activities were carried out during desk study:

- Studied the maps and previous reports that indicated the route alignment.

- Collected all relevant guidelines, norms, handout, specification and maps required for desk

study.

- Nepal Rural Road Standard (NRSS 2055) and DoLIDAR Norms & Specification has been

studied and referred for adoption of design standard and specification.

- Collected and referred existing DTMP of district road core network and its priority ranking.

- Collected relevant geological map to acquire geological/geotechnical feature of road

alignment.

- Study has been made to find out the possible environmentally sensitive areas from where the

alignment passes through

2.3 Identification and Selection of Roads

DDC selected and provided the road lists to the PCU for inclusion in RRRSDP-2 before

commencement of Consultant's services. After thorough review of the DTMP roads or selected roads

the Consultant made discussions with the Client for the selection of candidate roads.

.A candidate new road has been identified which is technically feasible, economically viable; environmentally and socially responsible

2.4 Meetings

Meeting – I: Prior to commencement of feasibility/detailed engineering study a meeting was organized

on August 1, 2013, in the Project Coordination Unit (PCU) Office at DoLIDAR. Discussions were held

on work delivery, understanding of program requirements and responsibilities of the Consultant‟s

team members in general, and procedures and time frame management in particular.


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Meeting – II: Likewise, on August 5, 2013, orientation meeting as a kick-off point for feasibility/detailed

engineering was held among the team members of the Consultant. Discussion on how to move

forward to accomplish the task in a systematic manner keeping in view of the limited time was done.

Also, the Team Leader drew attention of the individual professionals for carrying out the duties and

responsibilities as prescribed by the ToR of the Program Agreement for consultancy services. A need

of management support system, communication, and coordination was expressed. The participants in

this meeting were:

Meeting – III:A Meeting was arranged by ERMC on December 08, 2013. The following points were

highlighted for action:

o Collect information about household, family/settlement and water supply along the road

alignment.

o For the environmental part, only IEE can be done (no need to do EIA being rural roads).

o It should be differentiated beforehand what costs to put in IEE part and what in contractor

part.

o Include bio-engineering, demand of the community infrastructures and their costs in the

BoQ.

o Only genuine works that can be achieved should be included in the report. No

exaggeration will be entertained.

o Since all kinds of implementation plans (like Social Action Plan, Resettlement Plan,

Environmental Plan, Indigenous People Development Plan) are done for the same road

(and naturally it belongs to the same groups of people), utmost care should be taken so

that there is no duplication.

o Endangered human groups should be addressed more than the other groups.

o Utmost care must be taken while analyzing survey data and reports should be attractive,

meaningful and precise.

Orientation to Field Detailed Engineering survey Team

On November 24 an orientation and interaction session was organized at RRRSDP Office of the

Consultant by the TL in presence of PD and other senior road designers and all road and bridge

survey teams being mobilized in 18 districts. They were thoroughly briefed about survey works with

specially prepared ToR for field works for uniformity, accuracy and quality outputs.

Key points discussed:

Topography Survey and Details, Survey Codes, D-Cards, Total Station Closing & Error Distribution,

National Grids, GPS, DTM, CAD, DoLIDAR Norms, Recommended Gradients, First Meeting with

DTO/DDC and Local Concerned, Records and Report, Meeting Minuting, DoLIDAR's Letter of Jestha

1, 2070 and Letter from RRRSDP Consultant to DDCs, ID Cards, Information from Field, etc.

2.5 Meeting with Local Level Stakeholders

Local people were contacted prior to conduction of detailed engineering survey. Meeting with

DTO/DDC was also held regarding the plan of the team for the study of road sub-projects selected by

districts.


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2.6 Detailed Engineering Survey, Design and Cost Estimate

I Field Team Mobilization:

Engineering team comprising of highway Engineer, geologist, Environmentalist and sub-

engineer/senior surveyor and local supervisor with other sector specialists had been mobilized in field

for detailed survey works equipped with necessary survey equipment and accessories.

Prior to conduction of detail survey Results of previous feasibility/walkover surveys were verified

FIELD SURVEY TEAM COMPOSITION

Following are the member of survey team:

1. Ravindra Thapa Team Leader/Civil engineer (9849026213)

2. Anil Aryal Surveyor

II Topographic Survey

Strip survey method was used in the field which included fixing of the base stations and taking details

15m either side for preparing a topographic map of the road strip.

Topography survey is carried out in adequate details and accuracy to prepare exact DTM of the road

alignment in 1:1000 scales. Horizontal and vertical control points are established by monument of

concrete pillar at an interval of 500m.

Initially traverse survey was carried out with high accuracy (1:70,000 to 1:148,000) to establish traverse

station and other permanent control points. Topographical details were carried out from these traverse

station to attain accuracy at higher level.

Close traverse method was applied for horizontal traversing.

1. Establishment of Control Points / Benchmarks: Permanent monument has been installed as

benchmarks (approx. size 15 cm x 15 cm x 60 cm) with 1:2:4 cement concrete nails embedded as

per the DoLIDAR standards at intervals not exceeding 500 m according to site condition. The

Control point (size 10 cm x 10 cm x 45 cm) with 1:2:4 concrete are installed at 250 m interval on

an average. Description cards are prepared for each benchmark / control point with three

reference points.

2. Traverse and Fly Leveling

The coordinates of control points is presented in NEZD (Northing, Easting, Elevation and

Description) format along with point number and remark. Closed traverse survey is carried out

to confirm the control point coordinates. All traverse angles and distances shall be double

checked with reciprocal observations. Traverse and level shall be calculated at the site

itself for accuracy and quality control and data validation. If reasonable accuracy

(1:10,000) is not achieved, the traverse shall be repeated.

3. Centerline and Cross Section Survey

a. Centerline of road is marked using Abney level by the method of chaining and pegging which


RRRSDP-2 7

Kathmandu

then followed by Total station survey.

b. Cross sections survey has been carried out at intervals not exceeding 10 m. Where

topographic features such as ridges and valleys are encountered, additional cross sections

taken.

c. The cross sections generally extend to 15 m either side of road centerline and extended

further whenever site demands.

d. Enough points taken at each cross-section or for each string to cover full width of the road

including roadside feature, side drain, toe of cut/fill slope retaining wall, cross drainage

structure etc.

e. Topographical survey also included individual building, utilities (water supply, electricity,

telephone poles etc.), landslides, canals, footpaths, temples, Kushmas, drainages, cross

structures, retaining structures, land use patterns and other information such as fences etc.

f. At bridge side the bank lines, lowest water level HFL, direction and distribution of flow taken.

4. Digital Terrain Model

DTM (a digital representation of ground surface topography or terrain) has been carried out using

SW–DTM or other acceptable software and verified in field. All feature lines and configurations of

existing features shall be completed in AutoCAD compatible maps. D-Cards of BM and BL, field

sketches and raw downloaded data shall be submitted together with DTM. Check of data

consistency, error distribution and adjustments shall be clearly documented. All data and records

have been submitted in digital format.

III. Hydrological study / Cross drainage Survey

Cross-drainage requirements has been assessed with identification of type requires such as bridges,

culverts, and causeways as appropriate

IV Geological Studies:

Geological observation inclusive of soil type, geology and geomorphology, slope stabilization,

vegetation, land erosion situation, landslide prone areas, gully formation, and other features have

been conducted for proper design of road.

V. Alignment Description / Inventory of Land use/Public Infrastructures

Alignment descriptions for road and other necessary features are properly recorded in detail.

Inventory of public infrastructure and land use pattern were taken with locations

VI. Material availability surveys

Material availability survey has been conducted to acquire the information on construction material.

Local rates for construction, of various items, local and imported materials, transportation charges,

etc., enquired and district rates collected for cost estimating purpose.

VII. Design drawings:

(i) The detailed engineering design and drawings is based on the data collected during detailed

engineering survey.


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Kathmandu

(ii) The detailed designs has been done or prepared by the Consultant following the DoLIDAR‟s

Nepal Rural Road Design Standards 2055 and detailed and standard drawings are prepared

as mentioned in the DoLIDAR Technical Guidelines.

(iii) The designs and drawings consist of the design profile, design cross-section plan, and other

standard/typical drawings.

(iv) Engineering technical specifications for each work item will be written taking into account

relevant standard specifications.

VIII Detailed Cost Estimate:

(i) The detailed cost estimate has been prepared using the calculated quantities and unit rates,

derived from standard applicable District Rates and DoLIDAR Work Norms.

(ii) Contract packaging will be suitably done for all subprojects, and respective bidding

documents will be prepared following the DoLIDAR practices and frameworks.

2.7 Field Verification of Design / Estimate

After the production of design drawings and cost estimate of road sub-project, joint field

verification from DTO and Consultant representative have been done to verify the result of

survey, design works with the existing ground reality and to assess whether the proposed

retaining and drainage structures are appropriate as per the field condition


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Kathmandu

3. CHAPTER-III: THE PROJECT

3.1 Project District

Kathmandu District is located in middle of Bagmati Zone of the Central Development Region of Nepal.

It borders with Bhaktapur and Kavrepalanchowk district to the East, Dhading and Nuwakot district to

the West, Nuwakot and Sindhupalchowk district to the north, Lalitpur and Makwanpur district to the

South.

According to the National Census 2011 projection, the total population of the district is 1744240

comprising 831239 female (48%) and 913001 male (52%) residing in 436344 households. Kathmandu

district has an average population density of around 4415.8 people per square km. The average

family size is 4. The average literacy rate is about 86.3%.

Kathmandu district is multi caste society where the people belong to different caste live in. The

different castes found in the district are Newar, Brahmin, Chhetri, Gurung, Tamang, Malla, Thakuri,

Damai, Kami, Sarki, etc. The common language is Nepali followed by Newari.

The district has one metropolitan city, one municipality and fifty-seven VDCs, ten constituency areas.

The total area of the district is 395 sq.kM. The district lies partly in the plain and partly in the hills. The

lowest elevation point is 1262 meter and the highest elevation point is 2732 meter from mean sea

level. The maximum temperature of the district is 32°C and minimum 2°C, annual rainfall of the district

is 176 mm. Kathmandu is the capital city of Nepal where most of the corporate offices and industries

are located. Tourism is one of the main industries of the district.

Transportation Scenario

The district has major access to the Tribhuvan Rajpath (Highway) in west part and Araniko Highway

in east part. Total 267.79 km (228.24 km Feeder and 89.55 km Highway) connects to the different part

of the district and adjoining districts. The Kathmandu outer Ring Road (39km) and Kathmandu-Terai


RRRSDP-2 10

Kathmandu

Fast-track (11km section) is on the planning, which will pass through majority VDCs of Kathmandu

and also linking them to the district headquarter and to other districts respectively.

The district inventory identified just over 1078.29 km of roads, including 267.79 km of strategic roads

and 713.24 km of rural roads. In coordination with the DTICC and DDC, 39 rural roads with a length of

209.52 km (excluding new construction roads of length 2.54 km) were identified as making up the

district road core network (DRCN), and the remaining 503.72 km were classified as village roads. The

existing SRN roads link up 22 VDC headquarters and existing DRCN roads connects remaining 28

VDC headquarters. The DRCN road of 82.51 km black top, 57.70 km gravel and 69.31 km earthen is

identified, which is as shown in table below:

Road Class Total Length Black Top Gravel Earthen

Strategic road networks 267.79 171.09 25.4 71.3

Urban roads 97.26 79.30 1 16.96

District road core networks 209.52 82.51 57.7 69.31

Village roads 503.72 91.25 113.62 298.85 Total 1078.29 424.15 197.72 456.42

3.2 Description of Alignment

Shankhu - Paluwari - Nagarkot Road Sector (CH: 0+000 to 10+046) is located in north-east part of

Kathmandu District. The road alignment starts from Bajrayogini VDC Ward#6, Sankhu and passes

through Sankhu, Palubari, Kattike of Suntol VDC and finally reaches to Nagarkot and Baluwapati-

Deupur VDC Ward#8 of Kavre district.

The DTMP code of this road is 27DR037.

The total length of this road is 10.046 km. The road is graveled and partially blacktopped at initial

section 0+000 km – 3+000 km and end section of 9+900 km -10+046 km and earthen surface at

3+000 km – 9+900 km. The average existing width of road is 5.50 m at ch 0+000 – ch 2+600 and

3.00 m from 2+600 to onward.

This road connects the different settlements of Bajrayogini and Suntol VDCs of Kathmandu and

Baluwapati- Deupur VDC of Kavre with core city area of Kathmandu Metropolitan City and different

strategic road networks of feeder roads.

The road is designed with a number of switch-backs to connect the river valley of Salinadi with

Nagarkot peak.

Most of the alignment passes through cultivated land with few bushes and forest areas in between.

Sankhu/Bajrayogini, Palubari, Kattike and Nagarkot are the major settlements of this road corridor.

The road starts at Sankhu, Bajrayogini#6 – historical religious place of Nepal. Initially the road follows

paddy field up to 3+300km and meets forest at 3+300km – 3+600km. The road again passes through

cultivated land at 3+600km – 4+000km and forest at 4+800km – 7+200km and meets Kattike village

at 7+200km – 7+600km and finally reaches to Nagarkot Hotel area at 7+600km – 10+046km.

3.3 Population Served & Traffic Data:

Presently the total population served by this road is 4819 benefitting people of Shankhu, Palubari and

Nagarkot. The traffic number is 125 PCU with 115 VPD.


RRRSDP-2 11

Kathmandu

Proposed Road

Figure 2: Showing proposed Road

3.4 Potential Area & Growth Centers

Sankhu located at Bajrayogini VDC ward no 6 is one of the most popular historical and religious place

of Nepal. Similarly, Nagarkot is well-known view point and tourist centre of Kathmandu district. The

fertile land of this hinterland can be developed as pocket area of cash crop, green vegetable and diary

production.

3.5 Project Rationale

The rationale for construction of road is as followings:

This road to joins large settlements of Bajrayogini and Suntol VDCs of Kathmandu and

Baluwapati- Deupur VDC of Kavre with core city area of Kathmandu Metropolitan City and

different strategic road networks of feeder roads.

The road will play a vital role to increase cash crop production and dairy farming in the zone of

influence area by improving access to densely populated Kathmandu Metropolitan city.

Construction of the road is expected to help the people of the area to receive better education

and quick access to medical facilities. Government‟s other services will also be delivered better

as the road will encourage government employees to visit the area and its vicinity more

frequently, or extend the duration of their stay.

It is expected to reduce the travel time considerably and thus people can utilize the saved time

for other productive works.

RRRSDP-2 12


Kathmandu

This will promote religious and other tourism as being located in such historical and view point

area.

The proposed road is expected not only to be an excellent facility to link several ecological,

cultural and demographic zones of the district but it will also open new possibilities for

entrepreneurs with new visions and plans. Furthermore, the road upgrading will use local

labor that will generate employment to local people and minimize emigration to other major

cities and abroad for search of work. Consequently, local people will get long-term benefit,

which will boost up their economic status within the road corridor and adjoining area

RRRSDP-2 13

4. CHAPTER-IV: GEOLOGY AND GEOMORPHOLOGY

4.1 Geological Study

4.1.1 Introduction

A geological survey has been carried out along the 10.046 km long alignment of the Sankhu –

Palubari – Katike - Nagarkot Road. Geologically the road alignment belongs to the Lesser

Himalayan rocks.

4.1.2 Regional Geology and Geomorphology

This road follows the rocks of the Sarung Khola Formation of the Lesser Himalaya. The Sarung

Khola Formation is composed of gneiss and schist. Some part of the road alignment in the valley

sediments and some part of the road alignment passes through the Lesser Himalayan rocks. There

are no any geological structures like fault and thrust along and nearby the road alignment. The road

alignment starts from Sankhu and passes through Palubari and ends at Nagarkot. There are no

major tributaries along the road alignment. The topography of along the road alignment is flat slope

to gentle slope, passes through valley sediments, residual soil, colluvial deposits after then some

part of the road alignment follows the rocky terrain of the Lesser Himalaya. The road alignment

passes through bushes and forest as well as settlements and cultivated land.

4.1.3 Surface Geology

Along the road section, the rocks of the gneiss and schist of the Sarung Khola Formation is

exposed and also covered by the residual soil with thick colluvial deposits as well as and valley

sediments.

Figure 1: Regional Geological Map of Kathmandu Area (Stocklin and Bhattarai, 1977)

RRRSDP-2 14

Kathmandu

4.1.4 Slope Stability Condition

a. Landslide and Cut Slope Failures

Less than five cut slope failures are observed which are mostly in residual and colluvial soils

deposits. The main causes of slides are precipitation, surface water condition, and undercutting

slope by road cutting. Almost all failures are occurred after opening of the road alignment. These

instabilities are found between the chainage 8+600+10+000 on hill slope. These slides are shallow

depth and can be mitigated by the arrangement of the surface drain as well as trimming of the slope

and applying the bioengineering works in the barren land on the slope. Remaining of the length of

road has good stability, because of low height cut slope. So there are no anymore failures along the

road.

b. Rock Slope Stability

Most of places in the rocky area, the orientation of the bedding plane is opposite to dipping of the

hill slope so the rocks have good slope stability.

4.1.5 Engineering Geological Mapping

The road alignment passes through slightly limestone and colluvial, residual soil deposits.

Thickness of colluvial and residual soil deposits range from 1 to more than 3 m. The natural hill

slope ranges from 5 to 65 degrees.

Figure : Stereographic Protection of the Rock Mass along Road section

The road alignment between this chainage is on residual soil and alluvial deposits and some part

on rocks of limestone. The hydrological condition of the road alignment is wet and some places wet

to dry and also seepage. The land use pattern is forest, cultivated land and settlements. After

widening of the road, there is very less chance to meet the cut slope failure due to low height cut

slope and land use pattern. The bedrocks of the Shivpuri Gneiss are exposed along the road

alignment.

RRRSDP-2 15

Kathmandu

4.1.6 Geological Hazard Mapping

Along the road, soil and rock are found low to medium hazard. The low hazardous soil covers 90%

length of the road comparing with area of the medium hazardous of soil and rock. The slope

stability of this section is good so necessity for realigning any of the subsection is not envisaged on

account of geological consideration

4.2 Construction Material Survey

Stone for structural works can be used from the places adjacent to the proposed road, within 5 km

distance in fewer quantities. Along with it existing stone soling at some sections of the road surface

can be used. For the construction purpose stone quarry is also available at Melamchi River, about

15 km far from Kattike bhanjyang. Considering these, 12 km lead is proposed for stone collection.

The excavated mass during construction can be used for filling.

Other construction materials such as GI wire, aggregates, cement and sand can be extracted,

procured or borrowed from Kathmandu valley as there are lots of crusher plant and sand collection

depot.

4.3 Land Use Pattern / VDC & Settlements

From To Land Use Pattern VDC Place

0+000 0+370 Paddy field / Sankhu bazaar Bajrayogini Sankhu

0+370 0+600 Bushes Suntol Palubari

0+600 3+300 Cultivated land Suntol Palubari

3+300 3+600 Forest Suntol Palubari





7+200 7+600 Settlement Suntol Kattike

7+600 10+046 Settlement Suntol Nagarkot Hotel area

4.4 Conclusions

1. About 80% road alignment passing on colluvial and residual soil deposits but 20% of the

alignment on the rocks of gneiss.

2. In the colluvial/residual soil deposits, the road alignment is influenced by the seepage and

considered high possibilities of failures. So recommended to manage the surface drain.

3. Stability condition is good in rock, but unstable area can be seen only in colluvial and

residual soil deposits, these unstable can be mitigated by simple engineering structures,

arrangement of surface drain, trimming slope and using bioengineering works.

4. The road has low soil and rocks hazard.

RRRSDP-2 16

Kathmandu

5. CHAPTER-V: HYDROLOGY AND METEOROLOGY

5.1 General

The main purpose of the hydrological studies is to evaluate the discharge across and along the proposed

road alignment due to monsoon rainfall so that appropriate drainage structures can be selected and

designed. The type, size, span and shape of cross and side drains are then fixed according to the

corresponding design discharge.

5.2 Rainfall

The proposed road lies in Kathmandu District. Rainfall stations located in this district are presented in

Table 5.1. Mean Annual Rainfall (MAR) and Monsoon Wetness Index (MWI) at these stations are obtained

from “Hydrological Estimations in Nepal”, DHM, 2004. About 80% of rainfall occurs in monsoon, which

starts around the middle of June and continues until the end of August.

Table 5.1: Summary of Rainfall Stations

Station Name

Index

No.

Latitude

Longitude

Elevation

(m)

MAR

(mm)

MWI

(mm)

THANKOT 1015 2741 8512 1630 2005 1594

KATHMANDU AIRPORT 1030 2742 8522 1337 1402 1096

SANKHU 1035 2745 8529 1449 2019 1664

PANIPOKHARI(KATHMANDU) 1039 2744 8520 1335 1504 1172

BUDDHANILAKANTHA 1071 2747 8522 1350 1962 1576

SUNDARIJAL 1074 2746 8525 1490 2894 2563

NAIKAP 1076 2741 8515 1520 DNA DNA

SUNDARIJAL 1077 2745 8525 1360 DNA DNA

NAGARJUN 1079 2745 8515 1690 DNA DNA

JETPURPHEDHI 1081 2747 8517 1320 DNA DNA

Hourly rainfall design intensities of different return periods at these rainfall stations are obtained from

“Maximum storm flood for the design of road structures of Nepal”, Prem Chandra Jha, Ph.D. Dissertation,

Moscow, 1996 and presented in Table 5.2.

Table 5.2: Hourly Rainfall Design Intensities for the proposed road

Return Period, T (years) 2 5 10 20 50 100

Hourly Rainfall Design Intensity (mm/min) 0.64 0.72 0.79 0.85 0.94 1.00

5.3 Design Discharge

The design discharge for the hydraulic design of cross and side drains of this road has been estimated by

“PCJ 1996” [Maximum storm flood for the design of road structures of Nepal]. PCJ 1996 uses hourly rainfall

design intensity (Table 5.2). Flood discharges from unit area (1 sq.km) for different return periods,

estimated by this method are presented in Table 5.3.

Table 5.3: Design Floods of different return periods by PCJ 1996

Return Period, T (years) 2 5 10 20 50 100

Design Floods by PCJ 1996 (m3/sec/km

2) 0.9 2.9 4.4 6.0 8.0 9.6

RRRSDP-2 17

Kathmandu

5.4 Cross Drains

Cross drains are mainly designed to pass the stream flows. However in some cases the cross drains are

provided to divert the flows coming from side drains. Following steps are followed for locating cross drains:

Identifying stream points and valley curves in topographical map

Verifying these locations during field visit and survey

Locating finally after study of designed plan and profile of the road

Following design criteria are adopted for the design of cross drains after hydrological analysis:

Design flood frequency: 20 years

Design intensity: 0.85 mm/min

Design flood: 6.0 m3/sec/km

2

The design discharge for a cross drain is a high flow corresponding to the selected return period. In order to

economize on construction costs, frequency of flood is selected for return periods, depending upon the

importance of the structure. For this road, it is recommended to design the cross drains for 20 years return

period flood.

The drain size varies based on the design discharge. The design discharge for each drain is different. It

means there will be many sizes of cross drains in a road. For crossing of small streams, rivulet and springs

not carrying debris pipe culvert is good option. It is not practicable even not economical to construct pipe

culvert of many sizes. Hence it is decided to use pipe culverts of 60, 90 and 120 cm for crossing the drains.

By experience, the 60 cm diameter pipe is not recommended for cross drains because of choking and

clogging by sediment and debris coming from upslope of mountain catchments. However it can be used for

crossing of irrigation channel, road intersection and flow with low discharges. The 120 cm diameter pipe

should also be avoided due to the difficulties of handling and transporting. In most of the places where

seasonal waterways occur in the monsoon and for flash flood, stone or concrete causeways are

recommended.

The hydraulics of pipe culverts is worked out in Table 5.4. Maximum flow capacity and velocity are

determined at a suitable head. The design discharge of a crossing is compared with flow capacity of a pipe

and then size is fixed from standard pipe sizes.

Table 5.4: Hydraulics of proposed cross drains (pipe culverts)

CD type

Size

(m)

Full

flowing

area, m2

Max.

design

slope, %

Length

of

CD, m

Max.

Head

loss, m

Friction

coeff.(f)

Max.

Velocity,

m/sec

Max.

flow,

m3/sec

Pipe culvert 0.60 0.28 3 6 0.18 0.05 2.66 0.74

Pipe culvert 0.90 0.63 3 6 0.18 0.05 3.26 2.05

Pipe culvert 1.20 1.12 3 6 0.18 0.05 3.76 4.21

Table 5.4 gives an idea of maximum flow capacity and velocity of proposed pipe culverts so as to define the

proper size of the culvert based on design discharge coming to a culvert. The maximum design slope for

these culverts is assumed as 3% so as to create self flushing velocity. Table 5.4 shows the full flow

capacities, head losses and the design slopes for different pipes. Head losses are calculated by Darcy -

Weisbach formula for pipe flow. The coefficient of friction (f) for concrete pipe in this formula is assumed as

0.05. The maximum velocity at exit point for all size of pipes shall be maintained by providing an apron. The

length of pipe in average is assumed to be 6 m.

For medium size streams where flow more and carrying boulders, pebbles and gravels and span is up to 6

m, box or slab culvert are recommended. The actual span of these culverts is fixed according to field

survey. For larger streams bridges of suitable span based on field survey are recommended.

RRRSDP-2 18

Kathmandu

The list of proposed cross drains is provided in Annex 4.

5.5 Side Drains

Side drains are recommended for catching the flows from road surface and upside adjoining areas. In some

stretches side drains exist but most of the side drains will be occupied by new design width of the road and

hence new side drains are proposed along the full length of this road. The design discharge for a side drain

is a high flow corresponding to the selected return period. In order to economize on construction costs,

frequency of flood is selected for return periods, depending upon the importance of the structure. For this

road, it is recommended to design the longitudinal side drains for 5 years return period flood. Following

design criteria are adopted for the design of side drains after hydrological analysis:

Design flood frequency: 5 years

Design intensity: 0.72 mm/min

Design discharge: 2.9 m3/sec/km

2

Table 5.5 shows the maximum flow capacity and velocity of side drains at maximum longitudinal slope of

10% and having full flowing area. The side drains must follow the longitudinal slope of the road and in most

of the cases hill road has a maximum slope of 12%. Cross sections of proposed side drains types (A, B &

C) are presented in Figure 5.1.

Table 5.5: Flow capacity of proposed side drains at maximum slope of 10%

Drain Type b, m d, m A, m2 P, m R, m n S V, m/s Q, m

3/s

Tick Drain [A] 0.8 0.3 0.12 1.154 0.104 0.016 0.10 4.34 0.52

Tick Drain [B] 0.8 0.45 0.18 1.368 0.131 0.016 0.10 5.07 0.91

Trapezoidal Drain [C] 0.45 0.45 0.2025 1.31 0.155 0.016 0.10 5.66 1.15

As the design discharge is less than 1.5 m3/sec/km

2with medium intensity of rainfall, tick type drain of

concrete masonry [Type B] having medium draining capacity is recommended for this road. It is also

recommended that the length of side drain should not be more than 300 m. Hence a cross drain of 90 cm

diameter is proposed to cater the discharge of side drain at 300 m interval.

Figure 5.1 Proposed types of Side Drains

5.6 Selection of Cross-drainage Structures Type

Pipe culverts:

RRRSDP-2 19


Kathmandu

Pipe culverts are proposed in areas where the discharge is concentrated and at intersection points

of vertical gradients. Vehicular access to the construction site is necessary for transportation of the

pipe.

The minimum culvert size proposed is 600 mm diameter. The minimum size was selected to lessen

the risk of the blockage and make it easier to clear blockages once they occur. The maximum size

was selected in consideration of the difficulties of handling and transporting larger size pipes during

construction.

Floodway

In consideration to the road design standards floodways will be preferred over large culverts.

Floodways will be cheaper to construct and will be more likely to accommodate flood events outside

the 10-year design period without damage.

Slab culverts

Slab culverts will be preferred for cases where the topography would make construction of a

floodway difficult.

RRRSDP-2 20

6. CHAPTER-VI: GEOMETRIC STANDARDS & DESIGN

Geometric design standard of Nepal Rural Road Standard (2055) with 1st

revision of September 2012 with

District Road Core Network class have been followed while carrying out detailed engineering survey and

design of RRRSDP-2 roads proposed for improvement, upgrading and new construction. Work Norms and

specification of DoLIDAR in general and Norms for Rate Analysis as per Standard Specification for Road

and Bridge Works for specific items is followed for cost analysis of sub-projects and preparation of contract

packages.

6.1. Road Classification

Project roads fall under the category of District Road Core Network as per Nepal Rural Road Standard -

2055 (Revised-2071, December 2014) as it connects village headquarter with strategic road network and

District headquarter. 6.2. Design Standard

6.2.1. Design Speed

The sight distance, radius of horizontal curve, super elevation, extra widening of pavement, length of

horizontal curve and the length of vertical curve (summit and valley) depend on the design speed, which in

turn depends on class of road and nature of terrain. According to the design standards, the design speed

for hill terrain is 25 km/hr and minimum is 20 km/hr.

6.2.2. Geometric Design

The technical standards are set considering minimum initial investments with the scope for gradual

upgrading. The roads can be upgraded in a compatible manner as the traffic volume increases and

availability of resources justify additional inputs.

The design standards / parameters adopted for the sub-project follow DoLIDAR Rural Road Design

Standards, DRCN.

HORIZONTAL ALIGNMENT

6.2.3. Horizontal Curvature

The purpose of introducing curves is to deflect a vehicle traveling along one of the straight, safely and

comfortably, through the angle (deflection angle), to enable it to continue its journey along the other

straight.

A horizontal curve serves for change in direction to the centerline of a road and safe turning to the vehicles

in horizontal plane.

6.2.4. Super Elevation

Super elevation is provided to maintain the design traffic speed at a given radius.

Coefficient of Lateral Friction (f)

RRRSDP-2 21

Design Speed kM/hr Recommended Minimum Radius ,m Super elevation e =10% Super elevation e = 7 %

15 10 20 12.5 25 20 30 30

Kathmandu

The value of the coefficient of lateral force depends basically upon vehicle speed, type and condition of

road type and surface as well as the condition of tyresThe factor affecting the coefficient(I) 'f' is adopted as

per IRC recommendation i.e. if the value of 'f' = 0.15,is adopted, the passenger shall not feel discomfort.

Maximum Super Elevation Value

In plain terrain, non-motorized vehicles travel with high centre of gravity, so the maximum value of super elevation shall be limited to the following values;

Terai 7%

Hill 10%

The designer should aim at providing flatter super elevation but it should not be less than the camber.

Super-elevation is defined as the raising of the outer edge of the road or track along curves. It will reduce

effect of radial force on the vehicle.

6.2.5. Minimum Radius of Curvature

On a horizontal curve, the centrifugal force is balanced by the effects of super elevationand side friction. The following formula fulfils the condition of equilibrium:

e + f = V2/127R

or

R= V2/127(e + f)

Where,

V = Vehicle Design Speed, km/hr

R = Radius, m

e = Super elevation ratio, meter per meter.

f = Coefficient of side (lateral) friction between the vehicle tyres and pavement. A constant value of coefficient

of side friction is adopted at 0.15.

The recommended minimum radius value is tabulated in Table 10.1

The recommended minimum radius value is tabulated in Table below:

Table Minimum Radius for Horizontal Curve

For the section of the road where difficult site conditions are in predominance, the minimum radius of

horizontal curves adopted are ruling minimum of 15 m and absolute minimum radius of 12.5 m is provided.

6.2.6. Widening on Curves

At sharp horizontal curves, it is necessary to widen the carriageway to provide safe passage of vehicles.

Widening is dependent on curve radius, width of carriageway and type of vehicle (length and

RRRSDP-2 22

e

Kathmandu

width).Widening has two components: (1) mechanical widening to compensate for the extra width occupied

by the vehicle on the curve due to tracing of the rear wheels, and (ii) psychological widening vehicles in a

lane tend to wander more on a curve than on a straight reach.

In single lane roads the outer wheels of vehicles use the shoulders whether on the straight or on a curve.

Therefore use of the mechanical component of widening should be sufficient on its own.

For single lane roads, only mechanical widening is required for low traffic speed.

W = (L2/ 2R)

Where, We= extra widening

N= number of traffic lanes

L= length of wheel base (6.1 m)

R= radius of curve

The recommended increase in width is given in Table below

Table: Recommended Minimum Widening for Single Lane Road

Curve Radius (m) Up to 20 21-60 Above 60

Increase in width ( for 3 m carriageway),(m)

1.5

0.6

Nil

Increase in width ( for 3.75 m

carriageway),(m)

0.9

0.6

Nil

6.2.7. Stopping Sight Distance (SSD)

Visibility is an important requirement for the safety of travel on the roads. For this it is necessary that sight

distance of adequate length should be available in different situations to permit drivers enough time and

distance to control their vehicles so that the chances of accident are minimized. The stopping sight

distance is the clear distance ahead needed by a driver to bring his vehicle to a stop before collision with a

stationary object in his path and is calculated as the sum of braking distance required at a particular speed

plus the distance travelled by the vehicle during perception and brake reaction time (lag distance).Total

reaction time of drivers depends on a variety of factors and a value of 2.5 seconds and coefficient of

longitudinal friction varying from 0.40 for 20 km/hr to 0.35 for 100

km/hr. Stopping Sight Distance (Ds) shall be:

Ds = 0.278Vt+ V2/254f

Where,

Ds = Stopping Sight Distance, m

V = Speed, km/hr

t= Perception and Brake Reaction Time, seconds (2.5 seconds)

f = Coefficient of Longitudinal Friction (Varies as speed varies)

RRRSDP-2 23

Kathmandu

The Safe Stopping Site Distance is provided in Table below.

Table :Safe Stopping Site Distance

Speed, kM/hr Perception and Brake Reaction Time, t (Sec)

Coefficient of Longitudinal Friction

Safe Stopping Sight Distance ,m

15 2.5 0.40 15 20 2.5 0.40 20 25 2.5 0.40 25 30 2.5 0.40 30 40 2.5 0.38 45

VERTICAL ALIGNMENT

All vertical curves are suggested simple parabolas according to the Nepal Road standards. Vertical curves

are unavoidable due to drainage problems and topography of project area. This road project is located in

hilly terrain so vertical curves are designed according to the Nepal Road standards.

6.2.8. Gradient

The selection of ruling gradient depends on several factors such as type of terrain, length of the grade,

speed, pulling power of vehicles and presence of horizontal curves.

Recommended gradient for different terrain conditions are given in Table below:

S.No

Design Standard

District Road (Core

Network)

Hill

Terai

1

Ruling gradient (%)

7

5

2

Limiting gradient (%)

10

6

3

Exceptional gradient (%)

12

7

4

Limitation of maximum gradient length (m) above

average gradient of 7%

300

-

5

Maximum recovery gradient (%) to be applied after

gradient in excess of 7% for a minimum recovery

length of 150 m

4

-

6

Maximum gradient at bridge approach (%)

6

5

7

Minimum gradient on hill roads (for better drainage)

(%)

0.5 (max 1%)

-

However in case of existing roads it is very difficult to maintain the longitudinal gradient within the design

limit throughout because of several factors. Among them following are some examples:

There can be unnecessarily heavy box cutting for very long stretch if we don't escape from

keeping the design grade for short stretch in some sections. This means adopting more

gradient in some short section will save heavy cut/ fill for long stretch.

RRRSDP-2 24

Case Length of Summit curve (m)

For safe stopping sight distance

When the length of curve exceed the required L = (N*S2)/(1.5 + 0.035 S)

Kathmandu

Changing the existing alignment may not prove practical every time for the improvement of

gradient. Hence, keeping high gradient for short stretch may resolve the issue of

resettlement and other social dispute that may result from realignment

Most of the existing roads are found non engineered road in terms of gradient. Hence,

some section need steeper gradient, also because to maintain the relief gradient in hair-

pin-bend and other structures.

It is not wise to destroy or ruin the stable and normal road sections in the cost of improving

problematic part without logical justification.

The problems that consultant faced during survey and design of road is to maintain the design gradient as

the existing road was with steep gradient. The consultant has tried to realign the road wherever possible. A

separate investigation had been made to explore the possibility of grade improvement after that carried out

re-survey in some sections also.

Vertical curve

Vertical curves are introduced for smooth transition at grade changes. Both summit curve and valley curve

should be designed as parabolas. The length of vertical curves is controlled by sight distance

requirements, but curves with greater lengths are aesthetically better.

6.2.9. Summit Curves

The length of summit curves is governed by the choice of sight distance. The length is calculated on the

basis of the following formulae

Case Length of Summit curve (m)

For safe stopping sight distance

When the length of curve exceed the required

sight distance (i.e., L>S ) L = (N*S

2)/(4.4)

When the length of curve is less than the required

sight distance (i.e., L< S )

L = 2S – (4.4)/N

N = deviation angle, i.e. the algebraic difference between the two grade

L = Length of parabolic vertical curve (m)

S = stopping sight distance (m)

The above formula has been derived based on the following assumption

Height of driver's eye (H) = 1.2 m (above the pavement surface)

Height of subject above the pavement surface = 0.15 m

6.2.10. Valley Curves

The length of valley curves should be such that for night travel, the headlight beam distance is equal to the

stopping sight distance. The length of curve may be calculated as follows:

RRRSDP-2 25

Kathmandu

sight distance (i.e., L>S ) When the length of curve is less than the required

sight distance (i.e., L< S )

L = 2S – (1.5 + 0.035 S)/N

Where,

N = deviation angle, i.e the algebraic difference between the two grade

L = Length of parabolic vertical curve (m)

S = stopping sight distance (m)

The above formula has been derived based on following assumption

Head light height = 0.75 m

The beam angle = 10

6.3. ROAD CROSS- SECTION

Following road width and other cross-sectional features have been adopted in design of RRRSDP-2 roads.

Figure: Single Lane Road with drain in Hill area of District Road – Core Network

Carriage way width in passing bays = 5.5 m

Roadway width in passing bays = 7 m

RRRSDP-2 26

Kathmandu

Fig District Road - Core Network, Single Lane Road in Terai

6.3.1. Cross Section Design

The cross section design was carried out taking plan and profile under consideration. For embankment

areas, the side slopes of 1.5 H : 1 V are adopted and side slopes in cutting varies based on soil

classification.

6.3.2. Shoulder Width

According to the DoLIDAR Standard the Shoulder Width is 0.75 m either side adopted.

6.3.3. Carriageway Width

According to the NRRS this road adopted carriageway width 3.75 m.

6.3.4. Formation Width

Roadway width of 5.25 m which includes carriageway and its shoulder width and formation width of 6.25 m

including drain has been proposed..

6.3.5. Right of Way

Total right of way for this road section is 20 m (10 m either side of the road).

6.3.6. Camber

Recommended camber cross slope on straight road sections is given in Table below.

Camber

District Road (Core Network)

Village Road

Hill

Terai

Hill

Terai

Carriage way cross slope

Earthen (existing)

5

5

5

5

RRRSDP-2 27

Kathmandu

(%)

Gravel

4

4

4

4

Bituminous Seal Coat

3

3

-

-

Unpaved shoulders on paved carriageway should be at least 0.5 per cent steeper than the cross fall of the

carriageway. However, 1 per cent more slope than the carriageway is desirable.

6.3.7. Pass Bay

The increased width at passing zones should allow two trucks (2 axles) to pass. The width of carriage way

should be 5.5 m and length about 12 m along the outside edge and 30 m along inside. This means that

passing zones and lay bys should be tapered gradually towards the carriageway so that vehicles can leave

or join the traffic stream safely. At passing places, vehicles would be expected to stop or slow to a very low

speed.

Normally, passing place should be located every 300 m for Hill and 500 m for Terai. The location of

passing place depends on the sight distance and should be provided at or near blind and sharp summit

curves; where the likelihood of vehicles meeting between passing places is high and where reversing

would be difficult. In general passing places should be constructed at the most economic location as

determined by the terrain and ground condition, such as at transitions from cut to fill, rather than at precise

intervals.

6.3.8. Carriageway width at culvert/ bridge

The recommended carriageway width at culverts and for Single lane is 4.25 m and Intermediate lane 6m.

Width is measured from between parapet walls or Kerbs and additional width for footpath can be

considered as per site requirement and volume of pedestrian flow.

6.3.9. Level of road embankment above HFL

In flat terrain the road embankment should be high enough so that the level of sub grade is above the

highest flood level (HFL). HFL at site can be found from inspecting the site and local enquiry. Minimum

recommended level of sub grades are given below for district road (core network) 1 m desirable but

minimum is 0.5 m for village road 0.5 m (minimum)

6.3.10. Lateral Clearance

Lateral clearance between roadside objects and the edge of the shoulder should normally be as given below: Hill road - normally 1.0 m but may be reduced to minimum 0.5 m in steep and difficult areas and where the cost of providing the full clearance is high.

6.3.11. Vertical Clearance

A vertical clearance of 5 m should be ensured over the full width of roadway at all underpasses, and

similarly at overhanging cliffs. The vertical clearance should be measured with reference to the highest

point of the carriageway i.e. the crown or super elevated edge of the carriageway. However, in the case of

overhead wires, poles etc. clearance shall be at least 7.0 m above the road surface.

6.4. Cut / Fill Batter Slopes

Cut/fill slope designs are normally based on geo-technical parameters, such as soil and rock properties,

terrain slope, water tables and height of cut slope.

RRRSDP-2 28

Kathmandu

The cut slope gradient should be between 1:0.3 (V: H) and 1:1.5 depending on subsurface conditions and

other characteristics. Attention shall be paid to the geological condition of the slope prior to cutting of the

slope.

As a rule, cutting and removal of soil mass should be performed from upper to lower portion to maintain

the slope stability. Cutting work should be carried out during dry season. The final cut slopes should be

treated with adequate drainages, slope protection works and/or bioengineering works to increase stability

against effects of rainfall and infiltration of water.

7. CHAPTER-VII: ENVIRONMENTAL MITIGATION MEASURES

As per Environmental Protection Act 2053 and Environmental Protection Regulation 2054 Initial

Environment Examination (IEE) is mandatory for all kind of District and Rural roads and hence IEE are

conducted for each sub-project to investigate the possible environmental impacts during and after

implementation of project in socio-economic & cultural aspects, biological and physical sectors of proposed

road influence zone.

Detailed Cost estimate of environment management plan to mitigate and safeguard the adverse impacts

will be prepared separately and be incorporated as civil works item in Bill of Quantity of bidding document.

In general the provision of bioengineering is made in this estimate. In order to discourage uncontrolled cut

and throw of spoil mass a separate item of transportation of excess mass from roadwork has been

introduced in detailed estimate for mass management. EMP will cover rehabilitation of public

infrastructures and will address to slope stabilization work. However mitigation of adverse environmental

impact should be began right from feasibility, alignment study and design phase. Following are some

attempts that the consultant has tried to address to minimize environmental impact during its planning

phase.

7.1. Consideration Made in Alignment Selection, Survey and Design Phase

Following attempts and considerations have been made during detailed engineering as part of

environmental mitigation measures in planning phase:

i. Road alignment selection that avoids landslide-prone and geological unstable areas, sensitive

ecosystems, and important cultural and religious sites;

ii. Road alignment selection that avoids large scale cutting and filling and that is based on mass

balancing;

iii. Proper design of cut slopes to minimize possibility of destabilization;

iv. Provision of suitable drainage facilities utilizing discharge to natural drainage channels;

7.2. Drainage Outlet Protection Works

Construction of side drain and culverts and other drainage work (for quick drain out the surface run-off)

alone is not always enough for water management. The possible erosion and gulley formation inclusive of

damage of cultivated land and other private property is common at outlet of culverts. That is why there is

always dispute with local farmers regarding the location of cross-drain during construction works. Keeping

RRRSDP-2 29

Kathmandu

view of these, different types of outlet protection works have been designed and proposed in the cost

estimate as one of the mitigation matter of adverse environmental impact.

7.3. Selection of Slope Protection Work

In general, following points are considered while planning a slope protection work:

Use of bio-engineering on all exposed cut and fill slopes, weak and fragile zone and on completed

spoil tips to minimize subsequent erosion. Tentative cost estimate for the bio engineering work has been

calculated and provisioned this report but now it is excluded from the current contract package.

Implementation of Bio engineering works will be carried out after detailed field verification during the

implementation of project. The site in which bioengineering application is required will be identified then

priority to implement will be given to local Users Committees mobilizing forest groups and Mothers Groups

(if available). Small Contractor having specific experience of bio engineering works will be another option.

Water management structures as an essential factor for quick and effective drainage of surface

run-off have been introduced. Side drain and other cross drainage structures have been selected and

determined keeping view of nature and characteristics of gullies, stream and spring.

Restrain measures such as retaining wall and structures like gabion wall and stone masonry have

been provided to retain the fill mass and for prevention of toe failure.

7.4. LIST OF SOME ENVIRONMENT PROTECTION WORKS:

As per findings of field investigations following environmental protection measures have been proposed in

design and estimate of roadwork.

S. No. ENVIRONMENT PROTECTION MEASURES 1 Provision of spoil mass transportation up to nearby tipping sites

2 Shifting of Electric poles, water supply pipelines etc from roadway to safe sites

3 Bioengineering works along with small slope protection civil structures

4 Rehabilitation and reconstruction of irrigation canals

5 Inlet and outlet protection works of cross drainages, culverts to mitigate the damage to

cultivated land, private property etc

6 Provision of breast walls in potential and existing landslide area

7 Proper drainage management to protect the road and roadside slope from adverse effect of

accumulated water


RRRSDP-2 30

Kathmandu

8. DETAILED ENGINEERING DESIGN

8.1 Design Method

Design of the road was carried out by SW_ROAD 2006 and SW_DTM 2006 computer software developed by SOFTWEL (P) Ltd, Nepal. Design was carried out using strip survey method so that alignment could be optimized as per requirement. The design works are based on the Digital Terrain Model created from the 3D points captured through the detailed survey.

Centerline was generated using the design environment and accordingly the profile and cross- sections were generated. Through an interactive design environment, the centerline (plan and profile) is optimized by adjusting the cross-sections.

8.2 Review & Redesign

Attempts have been made to minimize the cut/fill volume of earthwork and unnecessary stuff of structures.

Once the computer designed plan and profiles printed, the profiles were thoroughly reviewed and

redesigned wherever necessary to optimize the design and to keep it in right track within the norms and

standard. Necessary adjustment has been made in difficult areas where to follow the design standard is

likely not justifiable and impractical.

8.3 Design & Drawings

(v) The detailed engineering design and drawings is based on the data collected during detailed

engineering survey.

(vi) The detailed designs has been done or prepared by the Consultant following the DoLIDAR‟s Nepal

Rural Road Design Standards 2055 (with 2nd Revision of December 2014) and detailed and

standard drawings are prepared as mentioned in the DoLIDAR Technical Guidelines.

(vii) The designs and drawings consist of the design profile, design cross-section, plan and other

standard/typical drawings.

8.4 Horizontal Curve Design

The horizontal curve design table along with different features and parameters of horizontal alignment has

been presented in annex and in drawings.

8.5 Design of Structures and other geometric Features

The list of retaining and cross drainage structures extracted from detailed design output is presented in

annexes. Similarly, the standard drawing represents the adopted design standard of road cross-sections.

The list of passing bays is also attached in annex.

8.6 Pavement Proposed

The pavement is based on CBR values taken from DCP-CBR correlation chart. This Sankhu– Paluwari-

Nagarkot Road is proposed with blacktopping with gravel sub-base and base of graded crushed stone

aggregate materials. The road pavement structure is designed as follows:


RRRSDP-2 31

Kathmandu

Road Pavement Structure Design Calculation for the Sankhu - Paluwari - Nagarkot Road

under RRRSDP-2

Traffic growth rate(r) = 5% (assumed for rural road)

The accuracy of design will also depend very largely on the accuracy of traffic prediction over the chosen

life of 15 years. According to IRC and Road Note 29, it suggests to take a normal traffic growth rate of 4%,

but in Nepal from its past trends traffic growth rate of 5% for rural roads is appropriate though „Flexible

Pavement Design Manual- 2070‟ by DoR suggests to use a traffic growth of 7% for strategic (SRN) roads.

And the type of pavement selection will depend on not only projected traffic volume but also economic

considerations as well.

Design period (n) = 15yrs

The projected traffic volume of 15 years includes the construction years (the road being upgraded traffic

growth will continue to grow during construction as well and the road cannot be fully closed during

construction).

LDF (Load Distribution Factor) = 0.75 (for 2 lane road)

According to latest traffic count done by RRRSDP-2 on Sankhu - Paluwari – Nagarkot Road the recorded

traffic volume per day is 115 VPD and this value converted to Passenger Car Unit (PCU) shows only 125

PCU only. Equivalency factor used for converting the commercial vehicles (bus, trucks, tractors) to PCU

Is 3 for Bus up to 40 passengers & Minibus and similarly for Truck up to 10 tones gross weight is also 3.

Since the values of VDP and PCU are closer we can assume 17~ 20% of PCU as number of buses and

mini buses and 8~10% of PCU as trucks plying on the road. Because the loads imposed by cars and light

vehicles do not contribute significantly to the structural damage caused to road pavements by traffic. For

the purpose of structural design, therefore, only the numbers of commercial vehicles having unladen

weight exceeding 1500 kg and their axle loading are considered.

Now, assume number of buses (8ton) =25, say (@20%of125PCU)

Assume number of trucks (10ton)=13,say(@10% of 125 PCU)

Cumulative Equivalent Standard Axles (ESA) at base year= (A*VDF) = (Number of traffic x vehicle

Damage factor, which taken as 0.91for bus and 2.5for truck as per Overseas Road Note (ORN) 31.

NB: It can be calculated using, VDF = (Axle load (kg)/8160) ^4.5)

A*VDF =25x0.91+13x2.5=22.75+32.5=55.25 ESA/ day

So, the cumulative number of 8160kg (82KN) equivalent standard axle over design life is calculated as

mailto:@20%25of125PCU

mailto:@10%25


RRRSDP-2 32

Kathmandu

follows:

Numerically, Ns = [365*[(1+r)^n-1] *(A*VDF)*LDF]/r

VDF = Vehicle damage factor = multiplier to convert the number of commercial vehicles of different axle

loads & configuration to the number of standard axles load repetitions. It is defined as the equivalence

factor of standard axles per commercial vehicle.

Ns= [{365*{(1+0.05)^15-1}*(55.25)*0.75}]/0.05=[{365*1.079*55.25*0.75}]/0.05=326390.76 ESA =

0.326,391 Million Standard Axle (msa). However with the upgrading of roads the additional traffic may be

attracted or diverted on this road from other ends coming from Bhaktapur and Sindhupalchok districts. In

absence of traffic count data, it is proposed to increase the above value by 50%.This makes the design

traffic value as 1.5*0.326391= 0.4896 msa. See Map below to have an idea of traffic diversion or attraction

possibility.

Hence as per ORN 31, this traffic falls into ClassT2 (0.3msa to 0.7msa).

RRRSDP-2 33


Kathmandu

Sankhu –Palubari–Nagarkot Section


RRRSDP-2 34

Kathmandu

Therefore, referring to ORN 31 again the pavement thicknesses for granular road-base materials

with this traffic class T2 and sub grade strength classes based on the range of CBR values as

shown below in the Table in different sections figure out to as follows:

Table: Summary of the Dynamic Cone Penetration Test (DCP) Test Results Showing CBR Values in Different Sections of Sankhu- Paluwari- Nagarkot Road under RRRSDP-2

S.N. Chainage Depth of Layers in cm CBR

Valu e in

%

Sub-grade Strength Classes for Design as per ORN31

Granular Base

Course (BC) and

Sub-base Course

(SC)Thicknesses in

mm with Surface

Dressing (SD)

Refined** &

Recommended

Thicknesses of

BC

& SC***In mm

Remarks

1

0+000

0.0-13.9

17.8

S4

BC=150

SC=175

BC=100

SC=175

30 mm

Asphalt

Concrete

(structural

surface)=@ 50 mm of BC

13.9-59.5

7.8

59.5-62.7

Very

high due

to rock soling

BC=100

SC=150

BC=100

SC=150

Provided

minimum

Thicknesses

of BC&SC

2

0+500

0.0-33.0 6.8

S3

BC=150

SC=250

BC=150

SC=250

50 mm BC

reduced to

take

Care by 30

mm strength

contributing

33.0-38.4 6.1 38.4-71.6 4.8

71.6-100.0

10.8

3

1+000

0.0-44.0 7

S3

BC=150

SC=250

BC=100

SC=250

44.0-49.0

9.5

49.0-97.3 4.2

4

1+500

0-23.4 7.8

S3 (For

getting very high value)

BC=150

SC=250

BC=100

SC=250

23.4-28.0 53.4

28.0-100.0 4.4

5

2+000

0.0-12.0 23.3

S5

BC=150

SC=100

BC=100

SC=150

Minimum

thickness of

SC should be

150 mm as

per ORN.

12.0-28.1 76.7 28.1-36.1 29.9

36.1-63.5

26.3

6

2+500

0.0-30.5 33.9

S4

BC=150

SC=175

BC=100

SC=175

30.5-43.5 16.1 43.5-100 4.8

7

3+000

0.0-21.0 8.1

S4

BC=150

SC=175

BC=150

SC=175

21.0-33.3 24.1 33.3-42.6 15.6

42.6-100.0 6.2

8

3+500

0.0-32.5 8.8

S4

BC=150

SC=175

BC=150

SC=175

32.5-53.5 19.8

53.5-100.0 6.7

9

4+000

0.0-16.9 70.3 BC=100

SC=150

BC=100

SC=150

Provide

minimum

thickness of

16.9 to Below

High due

to rock


RRRSDP-2 35

Kathmandu

soling BC and SC

10

4+500

0.0-19.6 109.2

BC=100

SC=150

BC=100

SC=150

Provide

minimum

thickness of

BC and SC

19.6 below

High due

to rock

soling

11

5+000

0.0-12.5 37.8

BC=100

SC=150

BC=100

SC=150

Provide

minimum

thickness of

BC and SC

12.5-13.0 54.6 13.0-44.1 56.6

44.1 below

High due

to rock

12

5+500

0.0-27.0 46.6

BC=100

SC=150

37.0-31.3 85.3

31.3 below

High due

to rock

13

6+000

0.0-12.2 11.2

S3

BC=150

SC=250

BC=100

SC=250

12.2-68.6 3.1

68.6-100.0 5.2

14

6+500

0-11.0 71.1

S5

BC=150

SC=100

BC=100

SC=150

11.0-24.0 30.2 24.0-100.0 6

15

7+000

0.0-20.6 15 S4

BC=150

SC=175 BC=100

SC=175

20.6-98.9 5.5

16

7+500 0.0-23.6 28.6

S5 BC=150

SC=100 BC=100

SC=150

23.6-96.9 6.6

17

8+000 0.0-28.0

29.1 S5

BC=150

SC=100

BC=100

SC=150

28.0-39.6 54

18

8+500 0.0-17.1 31.1

S5 BC=150

SC=100 BC=100

SC=150

17.1-49.0 14.8

19

9+000

0.0-100.0

7.7

S4 BC=1500

SC=175 BC=100

SC=175

20

9+500

0.0-27.0

21.6

S3 for 4.1

CBR and S6 for higher

values shown

BC=150

SC=250

BC=100

SC=250

27.0-34.5 4.1 BC=100

SC=150

for higher CBR

34.5-46.9

36.2

21

10+000

0.0-10.7 58.2

S5

BC=150

SC=100

BC=100

SC=150

10.7-43.6 41.4 43.6-63.3 15.9

NB1: *SD=Surface Dressing= a wearing coat like 30 mm thick open graded Premix or Asphalt Concrete or single /double bituminous surface treatment (SBST/DBST).So it is basically meant for protection of road surface from changes in moisture and abrasion by traffic and pavement under layers and it is not normally taken into account when determining the structural thickness of the pavement.

NB2:** BC =It is to be noted that in all RRRSDP-2 roads 30 mm thick closely graded aggregates (max. nominal size should be little less than half of the total compacted design thickness) blacktopped premix carpet is provided. So, it cannot only protect but also add structural strength to take load and disburse traffic loads down to sub grade. So its thickness is additional strength and plus point and can be included as structural thickness. We propose to substitute 30 mm of Asphalt Concrete in 100 mm of base course.

NB3:***SC= According to IRC Flexible Design Procedure or Road Note 29 & 31,it is recommended that the minimum thickness of sub-base should be 150mm (15cm) for design traffic less than 1.0 msa.


RRRSDP-2 36

Kathmandu

Asphalt Concrete Plants are easily available in Kathmandu; diverted traffic to this road will be increased significantly after

completion of this road, Construction Procedure and Quality Control for Asphalt Concrete work will be comfortable

30 mm thick Asphalt Concrete pavement to Sankhu- Palubari- Nagarkot road has been proposed due to following reasons

diverted traffic to this road will be increased significantly after completion of this road,

Asphalt Concrete Plants are easily available in Kathmandu

Construction Procedure and Quality Control for Asphalt Concrete work will be more comfortable to DTO

since DTO technicians have considerable experience of premix carpeting during RRRSDP phase 1

implementation.

The cost of DBST per km is calculated about 2.2 million while the cost of asphalt concrete of 30 mm thickness is about 2.6

million. Though cost of Asphalt Concrete is slightly high than DBST, considering the benefits listed above, Asphalt

Concrete for wearing course is recommended.

8.7 Field Verification of Design / Estimate

After the production of draft/design drawing a field visit have been made to review and explore the possibility of

improvement of existing steep gradient.

Similarly, after the production of revised design drawings and cost estimate of road sub-project, joint field

verification from DTO and Consultant representative have been done to verify the result of survey, design

works with the existing ground reality and to assess whether the proposed retaining and drainage structures

are appropriate as per the field condition.


RRRSDP-2 37

Kathmandu

9. CHAPTER-IX: COST ESTIMATE

9.1. Summary

The total estimated construction cost for upgrading of Sankhu – Palubari - Nagarkot road is summarized

in the Table below, which does not, include compensation for building and land.

S. No.

Road Name Length Km

Cost Estimate NRs

Cost per km

1 Sankhu – Palubari -

Nagarkot road

10.046 NRs. 232,716,449.2

Includes contingency

and VAT

NRs. 19,968,311.16

Excludes Contingency and VAT

The details of the cost estimation are provided in Volume II of this report

9.2. Quantity Estimate

Quantity estimates are based on the cross-section designs and number & types of cross drainage structures.

The quantity of different items of work like earthwork excavation, filling etc. is calculated by using the Design

software and on the basis of standard engineering formulae. However, some minor adjustment might be

needed which would be verified during the construction phase.

9.3. Rate Analysis

During the calculation of unit rates, three major components labor, material and equipment were considered.

Unit quantities for all these three components were taken from the DoLIDAR and DoR Work Norms and

Specifications. Similarly, the cost of labor and construction materials, are based on the district rate 2072/73 of

DDC. The rate of labor, material and equipment is then increased by adding VAT of 13%.

9.4. Cost estimate

The detailed cost estimate has been prepared using the calculated quantities and unit rates,

derived from standard applicable District Rates and DoLIDAR Work Norms and DoR Norms.

Contract packaging will be suitably done for all subprojects, and respective bidding documents will

be prepared following the Standard bidding documents of PPMO and DoLIDAR practices and

frameworks.

9.5. Conclusion

Due to adaptation of higher standard road width than previous design standard (road width from 5.00 m to

6.25 m) it is rational to increase the volume of earthwork and retaining structures, which along with raised

daily wages obviously increased the per kilometer cost of road. Similarly, due to presence of high and

steep gradient and hair-pin-bends the quantity of structures increased while trying to bring it within

permissible design standard and thus resulting in per kilometer cost


RRRSDP-2 38

Kathmandu

10. CHAPTER-X: CONCLUSION & RECOMMENDATIONS

The RRRDSP-2 has proposed to upgrade this Sankhu – Palubari – Nagarkot Road to all weather blacktopped

standard. Other intervention includes widening of narrow track and improvement of longitudinal gradient to

bring it within geometric standard road of District Road Core Network. Furthermore provision of passing bays,

construction of proper drainage system including lined drain, box & pipe culverts and causeways have also

been proposed following DoLIDAR guidelines and geometric standard of Nepal Rural Road Standards.

Upgrading and improvement of this district road will improve access and mobility of large settlements of

Sankhu, Palubari and Nagarkot to market, education and service centre, health and other economic activities.

The road will play a vital role to increase cash crops, horticulture and dairy & poultry farming in the zone of

influence area by providing access to these hinterlands to dense populated market of capital. As Nagarkot is a

tourist spot and Sankhu is famous historical religious place, this road will promote and enhance internal

tourism as well.

Upgrading of the road will help the people of the area to receive better education and quick access to medical

facilities. Government‟s other services will also be delivered better as the road will encourage government

employees to visit the area and its vicinity more frequently, or extend the duration of their stay. It is expected

to reduce the travel time further after the implementation of this project inspiring to use the saved time in

income generating activities.

The total cost of the project is estimated as NRs. 232,716,449.2 for 10.046 Km of length. The unit cost per Km

is estimated at NRs. 19,968,311.16.

CONSTRAINTS:

Due to the lengthy holidays of Dashain, Tihar and Chhat festivals and also because of election of the

Constituency Assembly on November 2013, the progress of assigned detailed engineering survey, design and

estimate of this road has been severely affected. Similarly the delay in timely delivery of output happened for

following reasons:

Due to need of joint field verification of design/drawing of each road sub-project than that was in

original contract

Delayed responses and repeated comments and suggestions from districts on submitted reports it

took double time to finalize the detail design report.

Another matter that delayed the timely delivery of output is need of concentration in 20 priority roads

up to tendering process. This has interrupted in smooth progress of gross work which could be done in

mass as most time was expended in preparing, correcting, re-correcting BoQ and bid documents of 20

district.

Furthermore, there was lack of consistency in review of submitted Detailed Design Report. Each and

every district reviewed DDR in own way and shown altering and varying requirement. The late and

frequent and even day by day changing comments / demands from each district extremely consumed

lots of time in addressing such issues.


RRRSDP-2 39

Kathmandu

And the devastating earthquake that took place on 4th week of April and 2nd week of May has off course

hampered the work progress severely. However, the consultant has tried their best for timely delivery of

outputs despite of such unavoidable circumstances.

CONCLUSION

Improvement and upgrading of this road to all weather standard will enhance the increased access to markets

and social services; provide opportunity to use saved travel time for productive income generating works;

development horticulture, cash crop, diary production and other agro based industry etc, which eventually pave

the way to achieve the program goal of reduce the poverty through creating employment generation

Documents

Project Coordination Unit · So far, the construction concerns, environment–friendly approach adopted in design. The Consultant has tried their best knowledge, lesson learnt and