Mbeya Lwanjilo Trunnnk Road Project REPORT Executive Summary

8/20/2019 Mbeya Lwanjilo Trunnnk Road Project REPORT Executive Summary

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2008

KUNDAN SINGH CONSTRUCTION

KENSETSU KAIHATSU CONSULTANTS

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EXECUTIVE SUMMARY


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Comprehensive Engineering Analysis and Review of Original (Current) Design Page 2

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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.

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