mbeya lwanjilo trunnnk road project report executive summary
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2008
KUNDAN SINGH CONSTRUCTION
KENSETSU KAIHATSU CONSULTANTS
4/1/2008
EXECUTIVE SUMMARY
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CONFIDENTIALITY AND © COPYRIGHT
This document is for the sole use of the addressee (Kundan Singh Construction Ltd.) and KensetsuKaihatsu Consultants. The document contains proprietary and confidential information that shall not bereproduced in any manner or disclosed to or discussed with any other parties without the expresswritten permission of Kensetsu Kaihatsu Consultants. Information in this document is to be consideredthe intellectual property of Kensetsu Kaihatsu Consultants. in accordance with Kenyan copyright law.This report was prepared by Kensetsu Kaihatsu Consultants. for the account of Kundan SinghConstruction Ltd. The material in it reflects Kensetsu Kaihatsu Consultants.’s best judgement, in thelight of the information available to it, at the time of preparation. Any use which a third party makes ofthis report, or any reliance on or decisions to be made based on it, are the responsibility of such thirdparties. Kensetsu Kaihatsu Consultants. accepts no responsibility for damages, if any, suffered by anythird party as a result of decisions made or actions based on this report.
©2008 Kensetsu Kaihatsu Consultants
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EXECUTIVE SUMMARY
ES1 Introduction
In 2004, the Government of Tanzania (GoT)
through its agency TANROADS signed a contractwith BCEOM France in association with M-
Konsult Tanzania for consulting services for
Detailed Design for upgrading of Mbeya-
Chunya-Makongolosi Road. With the intention
to upgrade the road to tarmac grade through
MoW and TANROADS, the GoT retained
BCEOM/M-Konsult Ltd. To carry out both
detailed design work including environmental
and social impact assessment and preparation
of Tender Dossier.
Fig. 1 Location Map
The Project road is about 115km long and lies
between 08025’00 – 08053’36”S and 33000’48”
– 34007’12”E. The altitude for the Project road
ranges from 1200 to 2450 metres above sea
level (m.a.s.l). The project road traverses the
highest point of trunk roads in Tanzania,
standing at 2457 m.a.m.s.l at Kawetele and
about 18km away from Mbeya Municipality.
The Works contract for the upgrading of Section
I of the Project Road was signed in August 2007
between TANROADS and Kundan Singh
Construction Ltd. Kenya (KSC). The Section runs
from Mbeya town at km 0+000 to km 36+000
and rises from 1688 masl at Mbeya to 2456
masl at km 17+625 and then drops to 2008 masl
at km 26+000. The alignment of the road
undulates along a meandering horizontal pathwith some sharp hair pin bends and several
sections lying on the edge of ridges or at times
dangerously on slopes where severe
hydrological hazards are bound to cause faults.
Fig. 2a Some problematic sections of the Project
Road
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Fig. 2b Some problematic sections of the Project
Road
Significant deficiencies in the Design leading to
seriously impacted on the engineering
feasibility leading to a decision by the
Contractor to seek consultant an independent
third opinion.
Site visit by independent consultant
One of the sections within the landslide zone
identified during the visit
ES2 Geotechnical Consultant Team
The Contractor KSC having encountered major
technical difficulties in terms of implementing
the required sound engineering standardsbased on the original design, decided to engage
the services of a highly qualified Geotechnical
Engineering Consultant with comprehensive
knowledge and specialization of the
geotechnical and hydrogeological conditions of
Africa, particularly the EA Region (including
Sudan, Burundi) and on problematic soils.
Kensetsu Kaihatsu Consultants (KKC) is a Kenyan
firm of Consultants led by a worldwide
recognized Geotechnical Engineer, Dr. JN
Mukabi who is reputed to have offered many
innovative solutions for major problematic
areas and designs. He is a recognized and highly
honored engineer/scientist with international
awards and accolades having contributed
immensely to top geotechnical, soil mechanics
and civil engineering societies and forums. It
was upon the site visit that the Consultant
advised the Contractor that Kensetsu Kaihatsu
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Consultants undertake a Comprehensive
Geotechnical Engineering Analysis and Review
of the Original Design to offer
recommendations and possible designs/method
of construction to benefit the Client by realizing
a cost-effective Value Engineeering (VE)
structure that would be durable, while being
sensitive to the environment, as well as offering
possible mitigation mesures for geohazards that
are more than likely to happen.
Kensetsu Kaihatsu Consultants therefore made
and makes an undertaking to partake this
assignment under the guidelines of geo-
professionals within the provisions of the
International Society of Soil Mechanics and
geotechnical Engineering (ISSMGE), and Sub-
Clause 2.6 of the Fourth Edition of The FIDICConditions of Contract presented in the Table
below in ES4 and ES9.
ES3 Analysis and Review Objective
The Project Area has the following factors that
contribute immensely to geohazards:
high rainfall
prone to landslides
seismic activity
Mbeya and a better part of Tanzania which lies
in the Rift receives significant seismic activity as
indicated in the above figure
Some of the factors that must be seriously
considered in design for the area include slope
failure/slope stability, slope protection, cut
versus fill, material stability,
hydrology/hydrogeological assessment/design
and environment/ppp (locals involvement).
The overall objective of the Study is to establish
the actual existing geotechnical problems
including slope stability, the hydrogeological
conditions and engineering impediments thatcould culminate in failure of the road and long-
term cost in-effectiveness rendering the
Contract non-viable.
The specific objectives of the Study are:
(1) To undertake a Comprehensive
geotechnical soil and materials study of
the Mbeya~Lwanjilo Trunk Road.
(2) To comprehensively review the original
design in relation to the soils, materials
and geotechnical engineering aspects.
(3) To determine the ground stability vide
comparative analysis of cut and fill
areas along the Project Road.
(4) To propose a cost-effective value
engineering based approach that will
realize a sound and durable road
pavement structure.
ES4 Brief Analysis of Relevant Contractual
Clauses
An analytical digest of the relevant contractual
clauses is given under Sub-section 1.1.3 of the
Main report (Comprehensive Geotechnical
engineering Analysis and Review of the Original
Design). KKC reviewed the Contract and has
noted the various Clauses/Sub-Clauses
pertaining to the process of construction and
necessity to analyze and review the design. The
implications in liability, costs and risks of both
the Client and/or the Contractor have been
analyzed and determined. The pragmatic
approach to resolving the current situation will
be both contractual and value engineering
based. KKC noted Sub-Clause 8.1 of the FIDIC
Conditions of Contract and noted that:
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ES5 Contractor’s Concern and need for
Independent Professional Consultation
The Contractor on various occasions raised the
issues of the problems encountered and
deficiencies in both the Documentation anddesign. In minutes of various Site Meetings and
that held on Thursday, 13th
March 2008, in
particular, this is noted. It was due to the
Contractor’s concern and the decision to
engage an independent expert was reached.
The copy of minutes attached as Appendix to
the Main report refers.
ES6 Strategic Direction
The decision to have a comprehensive analysis
and review has led to the compilation of the
Main Report, of which this is the Executive
Summary. A presentation is also to be made on
the scheduled date. The innovative solutions
and recommendations will lead to a cost-
effective and highly viable and beneficial
project if all parties concerned appreciate the
problems and deficiencies encountered while
agreeing mutually to accept and expedite the
implementation of the recommended
approach.
ES7 Current Design of Mbeya and Method of
Construction (Analysis)
The Original design stipulates the extensive use
of fills and gabions in construction of the road
for Section 1 (km1~km36). Considering the
topography of the existing Project Road, the
rolling hilly land, slopes and environment, the
original (current) design fails to properly
address the most appropriate, suitable and
optimum engineering solutions for a sound
design of the Project Road.
Furthermore, there is no evidence that adetailed and comprehensive study was
undertaken, as is depicted in Figure 6.1 in
Chapter 6 of the pavement Design Manual-1999
(ref. to Sub-section 4.4.4 of the Main Design
Review Report).
The overview of the review presented in
Chapter 4 of the Main Design Analysis and
Review Report. While the recently developed
State-of-the-Art methods of investigation,
study, survey, analysis and design areextensively discussed in Chapters 5, 6, 7 and 9
of the Main Review Report.
On the other hand, the Consultant who
undertook the design states, on page 4-10 of
the Detailed design Final report and page 10 of
the Bidding Documents Volume 3 under the
sub-topic “Improved Subgrade Layers” and
“Areas of Low Strength (Expansive/Dispersible)
Soils”, that:-
(1) It was established that the first 45kilometres of the Project road contain
low strength in-situ subgrade soils
(2) The remaining portion of the road has
relatively good subgrade soils, which do
not require improvement. This section
also is mainly located on cut areas.
(3) The first 45 kilometres of the Project
Road Contains Soils, which exhibit high
plasticity and low strength
characteristics. This soils are termed as
“problem soils” since they have high
shrinkage and swelling properties which
usually affects the overall performance
of the pavement structure.
Contents Brief Analytical Remarks
Clause 8.1 Contractors GeneralResponsibilitiesThe Contractor shall, with due care anddiligence, design(to the extent provided forby the Contract), execute and completethe Works and remedy any defects thereinin accordance with the provisions of theContract. The Contractor shall provide allsuperintendence, labour, materials, Plant,Contractors Equipment and all otherthings, whether of a temporary orpermanent nature, required in and for suchdesign, execution, completion andremedying of any defects, so far as the
necessity for providing the same isspecified in or is reasonably to be inferredfrom the Contract.The Contractor shall give prompt notice tothe Engineer, with a copy to t he Employer,of any error, omission, fault or other defectin the design of or Specification for theWorks which he discovers when reviewingthe Contract or executing the Works.
This Clause clearly indicates that it is the Contractorwho is liable to the proper execution of andcompletion of the Works as provided for in theContract.On the other hand in accordance with Sub-Clause8.3 part a) i) on page No.11 of the conditions ofParticular Application for this Contract, the Contractoris responsible for ensuring that sound Engineeringpractice is observed at all times and f or all aspects ofthe project.Essentially therefore paragraph 1of this Sub-clauseprovides that the Contractor takes f ull responsibility ofensuring the proper and practical implementation ofthis project.
The foregoing fact is emphasized by paragraph 2 ofthe same sub-clause, which requires that theContractor should have the ability to detect any error,omission, fault or other defect in the design orspecification for the works, upon which the Contractorhas the obligation to notify the Engineer andEmployer promptly.The main pragmatic interpretation and implicationhere is that:
1) The Contractor has the full responsibility ofreviewing the design and all other associated,corresponding and/or otherwise relevantdocuments, in the post-bidding stage (Contract
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Furthermore, the possibility of dangerous slope
failures seems to have been completely omitted
in the engineering analysis of the detailed
design. The time needed to compact some of
the high fill areas was not properly computed.
The use of gabions as slope protection in fill
areas without considering the hydrology,
seepage that must occur and instability of the
fill material is considered an engineering
oversight. The eventual collapse of the gabions
and slope from the slip that will eventually form
in the fill will prove catastrophic. Designing over
10metres of fill! should show that this is highly
unstable and a time consuming construction
method as demonstrated in figures below.
ES8 Analysis of the Effect of Moisture, Slope
failure /Landslides and Seismicity –
Geohazards Monitoring
Rainfall: Mbeya region has high rainfall that can
reach a maximum of 2700mm.
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Effect of rainfall on Landslides: Perhaps the
most common trigger of a landslide, water
reduces the friction between the bedrock and
the overlying sediment, and gravity sends thedebris sliding downhill. In sand and clay soils, a
small amount of water may increase stability.
You've likely seen this when building a sand
castle or working with clay. However, too much
water causes the sediment to flow, which is
why many landslides occur after rainstorms.
Gravity is the primary factor in a landslide. Soil on a flat surface does not
move. On a slope, gravity alone also may not t rigger a landslide. But when
another disrupting factor -- like rain -- comes into play, gravity will pull
sediment downhill.
Gravity has a very major role to play in
ground/slope stability. Flat surfaces are usually
stable while slopes have gravity force acting on
the mass. Where there is much rainfall the
tendency for the mass to creep or worse slumpis high after rain effect.
Example of slope failure (landslide) on a similarenvironment to the Project Road
A Rotational Slide or Slump
Creep
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- Effect of Moisture as analyzed from
Project road
- Permeability and Seepage
Slope failure and Gabions: The slopes at the fill
areas protected by gabions are technically at a
potential risk because of the dam effect that
the gabions will cause if there is seepage into
the fill. This has the effect of higher stress levels
and seepage forces and will lead to the
possibility of different stress-strain properties
resulting in some zones being highly stressed
than imagined.
Possible Slip failure along the Project road
CASE STUDY: Slope failure on the Goha Tsion
road in Addis Ababa.
Dam effect of gabions on the Project road
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It can be noted from the above computations
that the Factor of Safety ( ) is extremely low
implying that the gabions cannot provide the
resistance required.
- Proof Rolling Results
Seismicity: Mbeya Region lies within a highly
seismic zone of the East African Rift system. The
are is considered a goe-hazard prone area and
combined with it being flood prone too and thatthe rainfall is very high, this could eventually
lead to liquefaction.
Seismicity within and around Mbeya
ES9 – Construction Problems and Contractor’s
Liability / Client’s Liability
The Contractor’s/Client’s liability in relation to
the original (current) design problems are
Normal fault
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summarized in the Clause below and the
following table.
Clause 20.4 Employer’s risk
The employers risk are
g) Loss or damage to the extent that it is
due to the design of works, other than
any part of the design provided by the
contractor or for which the contractor is
responsible, and
h) Any operation of the forces of nature
against which an experienced
contractor could not reasonably have
been expected to take precautions.
Relevant Clauses Based On ExceptsFrom The Fourth Edition 1987 of TheFIDIC Conditions Of Contractor-Part IGeneral Conditions
ES10 – Typical Design for Mbeya Environment,
Design Development, Implementation
A design based on the Comprehensive Method
of Design is recommended. An example is given
under Chapter 9 of the main Report.
E11 – Cost – Benefit Analysis
11.1 Benefits from Structural Durability
As was demonstrated in chapters 6, 7, as well as
in sections 9.9 of chapter 9 and chapter 10, the
Employer is certainly bound to benefit
immensely if the road is constructed to
withstand the prevailing external forces and
environmental factors to a reasonably
sustainable standard, the structural durability
factor will then contribute greatly to the
sustenance of the socio – economic activities
with the regions through which the road
traverses due to the longevity of its design life.
11.2 Enhanced Road Safety
The current geometric design with section 1 of
the Project Road posses enormous dangers due
to the acute blind curves, ridges, and frequent
meandering. The re-design would have toconsider cost-effective realignments that
ensure the enhancement of road safety.
11.3 Extended Performance of the Contractor
Contractual Clauses pertaining to these issues
and the repercussions that are likely to prevail
as a result of the failure of the pavement
structure and/or slopes have been analytically
discussed under Sub-section 1.1.3 of this
Report.
11.4 Direct Cost Savings
Direct cost savings will mainly be realized
through commercial activities and social
institutions such as schools, hospitals,
community centres etc, in terms of the drastic
reduction in travel time, trade etc.
Clause/Sub-Clause: Contents Brief Analytical RemarksClause 8.1 Contractors GeneralResponsibilitiesThe Contractor shall, with due care anddiligence, design(to the extent provided forby the Contract), execute and completethe Works and remedy any defects thereinin accordance with the provisions of theContract. The Contractor shall provide allsuperintendence, labour, materials, Plant,Contractors Equipment and all otherthings, whether of a temporary orpermanent nature, required in and for suchdesign, execution, completion andremedying of any defects, so far as thenecessity for providing the same isspecified in or is reasonably to be inferred
from the Contract.The Contractor shall give prompt notice tothe Engineer, with a copy to the Employer,of any error, omission, fault or other defectin the design of or Specification for theWorks which he discovers when reviewingthe Contract or executing the Works.
This Clause clearly indicates that it is the Contractorwho is liable to the proper execution of andcompletion of the Works as provided for in theContract.On the other hand in accordance with Sub-Clause8.3 part a) i) on page No.11 of the conditions ofParticular Application for this Contract, the Contractoris responsible for ensuring that sound Engineeringpractice is observed at all times and for all aspects ofthe project.Essentially therefore paragraph 1of this Sub-clauseprovides that the Contractor takes full responsibility ofensuring the proper and practical implementation ofthis project.The foregoing fact is emphasized by paragraph 2 ofthe same sub-clause, which requires that t he
Contractor should have the ability to detect any error,omission, fault or other defect in the design orspecification for the works, upon which the Contractorhas the obligation to notify the Engineer andEmployer promptly.The main pragmatic interpretation and implicationhere is that:
1) The Contractor has the full responsibility ofreviewing the design and all other associated,corresponding and/or otherwise relevantdocuments, in the post-bidding stage (Contract
Clause/Sub-Clause: Contents Brief Analytical Remarks
8.2 Site operations and methods of
constructionThe contractor shall take full responsibilityfor the adequacy, stability and safety of allsite operations and methods ofconstruction .provided that the contractorshall not be responsible (except as stated
here under or as may be otherwiseagreed) for the design or specification of
permanent works, or for the design orspecification of any temporary works notprepared by the contractor. Where thecontract expressly provides that part of the
permanent works shall be designed by thecontractor, ha shall be fully responsible forthat part of such works, notwithstandingany approval by the engineer.
This sub-clause basically qualifies the first paragraph
of sub-clause 8.1 above and the corresponding briefanalytical RemarksIt is therefore interpreted that it is imperative for theContractor to take the initiative, which iscommensurate with his responsibilities , liabilities andobligations, to review any documents related to the
execution successful completion of the Works whereadequacy, stability and safety factors are upheld in
the design and the construction Works, failure towhich the Contractor is obligated to notify theEngineer and the Employer (client).
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11.5 Indirect Cost Savings
Indirect cost savings would mainly be as a result
of external trade and tourism activities within
the vicinity of the Project Road.
E12 – Conclusions
Detailed investigations, survey, in-situ and
laboratory testing were undertaken during this
Study. Subsequently, the results were
comprehensively analysed by adopting
powerful state-of-the-art analytical tools that
have been developed and tailored for most
tropical soils that exist within this region. Based
on the findings of this Study, the following
conclusions are made:
(1) The original (current) design was not
based on detailed and comprehensive
studies. This culminated in some serious
flaws within the Fundamental design
Concept.
(2) Contrary to the normal engineering
practice, the original (current) design
specifies the construction of high fills
and purging in problematic soil areas
instead of cutting into the hilly sides.This indeed is not only an expensive
method of construction but also
renders the pavement structure
susceptible to slope failure. The
adoption of this design would be costly
and disastrous.
(3) From the evaluation made during this
Study (Comprehensive Geotechnical
and Engineering Analysis and Review of
the Original (Current) Design for
Mbeya-Lwanjilo-Chunya-Makogolosi
Road Upgrading), it is apparent that
comprehensive Environmental and
Impact Assessment (EIA) was not made.
E13 – Recommendations
The following recommendations are made on
the basis of the results obtained in this Study.
(1) It is imperative that the pavement
structural design is reconsidered in
order to alleviate the potential Client’s
Liability problems.
(2) It would be advisable that the redesign
is based on the Comprehensive Method
of design for purposes of achieving a
cost-effective Value Engineering based
Structure that fosters sound
engineering practice.
(3) Based on the analysis of the relevant
contractual clauses during this Study, it
is highly advisable that the employer
takes expeditious action in resolving the
current design problem, contrary to
which the Project is likely to suffer
enormous losses and socio-economic
benefits or otherwise disastrous failureof the pavement structure.