NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY

INDUSTRIAL ATTACHMENT REPORT

Submitted by

SHELTON SIMBARASHE MUZENDAN010 9662X

CIVIL AND WATER ENGINEERING DEPARTMENTFACULTY OF INDUSTRIAL TECHNOLOGY

(OCTOBER 2013-SEPTEMBER 2014)

Supervised byENG. P.I MPOFU

MRS E MANGORE

ATTACHMENT CARRIED OUT AT:

A REPORT SUBMITTED TO THE FACULTY OF INDUSTRIAL TECHNOLOGY,NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY, IN PARTIAL

FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF BACHELOR OFENGINEERING HONOURS (B.ENG HONS) IN THE FIELD OF CIVIL AND WATER

ENGINEERING.

PREPARED BY: SHELTON SIMBARASHE MUZENDAREGISTRATION NUMBER: N010 9662X

CIVIL AND WATER ENGINEERING DEPARTMENTFACULTY OF INDUSTRIAL TECHNOLOGY

NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY

DEDICATION

This report is dedicated to my sisters Gertrude and Glenda.

ACKNOWLEDGEMENTS

I would like to thank the Lord, God Almighty for the great abundance mercy, privileges, wisdomand knowledge he has given and granted me throughout my life.

My sincere gratitude is extended to my Industrial supervisor Eng P.I. Mpofu and my academicsupervisor Mrs E. Mangore for motivating and guiding me throughout my Industrial attachmentperiod.

I am greatly indebted to my parents Mr and Mrs Muzenda for their support and encouragement.

I would like to thank Mr A. Nkiwane for his assistance and encouragement during my industrialattachmement period at Stelix Civils (Pvt) Ltd.

I would like to thank Mr C.Salimu and Prophet T.B Joshua for their moral, religious and materialsupport.

I am also grateful to all the engineers, technicians and all staff of Stelix Civils (Pvt) Ltd for thesupport they gave me during my industrial attachment period.

ABSTRACT

The author of this report is a fourth year (Industrial Attachment period) undergraduate student atthe National University of Science and Technology.

The Industrial attachment period at carried out at Stelix Civils (Pvt) Ltd, a firm of CivilConsulting Engineers and Construction.

This was in partial fulfillment of the Bachelor of Engineering Honours (B.Eng Hons) Degree inCivil and Water Engineering at the National University of Science and Technology.

The attachment period was from October 2013 to September 2014.

During the attachment period the writer was exposed to the world of civil engineering. Thisreport will give a brief description of how the writer achieved the main objective of IndustrialAttachment of bridging the gap between theoretical aspects of Civil and Water Engineering withthe practical aspects currently prevailing in the real engineering world.

The work covered includes:

Sewer system design and construction. Water reticulation system design and construction. Pavement design and construction. Vertical Shaft Brick Kiln (VSBK) technology. Construction site Safety and Health. Types of Contracts. Tendering methods and procedures. Preparation of Bills of quantities. Storm water drainage system design and construction. Preparation of cost estimates for prospective projects. Production of engineering drawings for Civil and Structural work. Preparation of comprehensive weekly reports. Preparation of weekly site meetings. Inspecting day to day work on the construction site Conducting safety and health induction and first aid exercise.

The report also highlights the impact industrial attachment had on the author.

ANNOTATION

ZESA- Zimbabwe Electricity Supply Authority

BCC Bulawayo City Council

AASHTO

ADD Average Daily Demand

SHE Safety and Health Exercise

WSH- Workshop Safety and Health

ADWF Annual Dry Weather Flow

CBR California Bearing Ratio

AADD Annual Average Dry Weather Flow

ZIE Zimbabwe Institute of Engineers

ZACE Zimbabwe Association of Consulting Engineers

CONTENTS PAGE

Dedication i

Acknowledgements ii

Abstract iii

Annotation iv

Table of contents v

1.0 INTRODUCTION2.0 COMPANY PROFILE3.0 SEWER SYSTEM DESIGN4.0 WATER RETICULATION DESIGN5.0 PAVEMENT DESIGN6.0 VERTICAL SHAFT BRICK KILN (VSBK)7.0 SAFETY AND HEALTH8.0 STORMWATER DRAINAGE SYSTEM9.0 BILLS OF QUANTITIES AND COST ESTIMATES10.0 IMPACT OF INDUSTRIAL ATTACHMENT11.0 REFERENCES

APPENDICES

APPENDIX A: PROGRAMME OF WORKS FOR ROADS IN PHASE A

APPENDIX B: DRAWINGS

APPENDIX C: TYPICAL BILL OF QUANTITIES

APPENDIX D:

CHAPTER 1

INTRODUCTION

During the industrial attachment period the author participated in:

Civil engineering designs Production of Bill of Quantities Preparation of cost estimates for prospective projects Production of engineering drawings for Civil and Structural works

The author spent most of the industrial attachment period with the Civil Engineering departmentof Stelix Civils (Pvt) Ltd.

The student engineer consulted senior engineers for any help on work assigned to him. Oncompletion of the task the student engineer would take the work to the Head of department forchecking and approval.

In the report the author will make reference to selected projects he worked on to highlight designprocedures.

CHAPTER 2

COMPANY PROFILE

2.1 Brief background of the company

Stelix Investments plc trading as STELIX CIVILS ENGINEERS AND CONTRACTORS is adiversified civil and environmental engineering company. The firm has civil engineeringconstruction and consultancy services outfits operating in three Southern African Countries,Zimbabwe, Namibia and Angola. The firm was established in 2006 by Zimbabweans living inthe Diaspora, with the sole purpose of investing and working in Zimbabwe.

The diversity of the group does not make STELIX a unique one stop shop in mining andconstruction but also allows the group to effectively maximize on its synergies for both clientsand shareholders. The group is made up of the following subsidiaries:

Stexil Civils Engineers and Contractors (Pvt) Ltd Stelix Clay Industries (Pvt) Ltd Bulawayo Granite Products (Pvt) Ltd

Stelix Civils provides professional consultancy services for government parastatals, privatesector and bilateral and multilateral financing agencies in the following fields:

Civils and construction services Energy Mining Environment Tele communication Municipal engineering Land and property development

The associates of the company include economists, engineers, environmentalists and other whopull their knowledge in an integrated approach towards problem solving.

These associates enable the firm, at a very short notice, put together tailor made teams to meeteach clients unique and specific needs.

2.2 Services offered

Stelix Civils (Pvt) Ltd are able to offer client organizations the following services:

2.2.1 Civil Engineering

Water reticulation systems Sewer reticulation systems

Water and sewer treatment plants Land development Housing development Roads Traffic and transportation systems Dams and canals Industrial effluent treatment

2.2.2 Structural Engineering

High and low rise buildings Industrial buildings Bridges Reservoirs Structural steelwork

2.2.3 Construction Supervision and Project Management

Preparation of contract documents, specifications and bills of quantities Preparation and production of budgets and expenditure control Progress control in terms of quality, cost and time. Coordination and control of construction work Post-construction impact studies

2.2.4 Economic Appraisals

Project identification and formulation Feasibility studies Environmental impact assessment Socio-economic evaluations Technical and socio-economic surveys

Through its professional association with various specialists Stelix Civils (Pvt) Ltd can puttogether a project team to meet all the planning, mining, engineering, environmental andmanagerial requirements from project conception through to commissioning.

CHAPTER 3

SEWERAGE RETICULATION DESIGN

3.1 Introduction

In Zimbabwe about 85% of the fresh water supplied to a single dwelling is discharged as sewage.Determination of the Average Dry Weather Flow (ADWF) of sewage is carried out byapplication of a factor representing percentage return of sewage to the Annual Average DailyDemand (AADD) figure for fresh water supplied.

The values of Average dry weather flow (ADWF) vary from area to area, depending on local,domestic and climatic conditions.

Sewers must be designed to convey peak flows. Sewerage reticulation should be designed tocater for the Peak Wet Weather Flow (PWWF) conditions.

Peak factors shown in Table 3.1 below should be applied to the Average Dry Weather Flow(ADWF) to get the Peak Wet Weather Flow (PWWF).

Table 3.1 Peak factors (Sanitation manual)

ADWF-[l/s] Peak Factors

0 to 23 5.25

23 to 69 4.50

69 to 231 3.75

231 to 2315 3.00

2315+ 2.70

3.2 Physical design

The first step in designing a sewer system to serve a new development is to draw the layout ofsewers on a contour plan. Sewers must pass all properties that are to be sewered and shouldwherever possible follow the slope of the ground to minimize depth of excavation. All sewersshould eventually concentrate at one point.

Sewers should be deeper than all other services and should always have a separate servitude.Sewers must always be designed as straight lengths between manholes.

The primary purpose of a manhole is to provide access to the sewer for inspection, maintenanceand cleaning of blockages that sometimes occur.

Manholes are expensive to construct and should only be provided where absolutely necessary.Manholes must be provided at every junction, bend, change in grade, or change in sewerdiameter.

The smallest size of sewer that should be used is 150-mm diameter but it is permissible to use100-mm sewers where the grade is suffiently steep.

After the sewer layout has been drawn on the contour plan, ground profiles along the sewershould be drawn and manholes indicated at all bends and junctions.3.3 Hydraulic design

A sewer pipe size and gradient should be selected to flow close to full-bore at the ultimate flow,subject to also achieving self-cleaning velocities (high enough to transport silt) at least at peakdaily flow.

Sewers and manholes constructed of cement (in concrete or asbestos-cement products) can becorroded. This is indirectly caused by hydrogen sulphide, a product of septicity. In order torestrict the incidence of corrosion, slow flows or stoppages should be eliminated. Ideally sewagevelocities should be high enough to transport silt, but not so high that pipes become scoured.Minimum velocities for design, which must be achieved at least once per day at peak daily flows,are given in Table 3.2 below.

Table 3.2 Minimum velocities to be used in designs (Sanitation manual)

Type of sewer Minimum velocities[m/s]

Collector sewers 1.0

Trunk sewers 0.6

Maximum velocities, for collector sewers and trunk sewers, should not exceed 3.66m/s underany flow conditions.

3.4 Emhlangeni outfall sewer design

The author was involved in the design of outfall sewerage reticulation for 391 stands inEmhlangeni medium suburb phase 1. To highlight design procedures the project was selectedfrom the sewerage reticulation designs the author worked on during attachment period.

Design information and assumptions

Population growth rate -5% (UNICEF).

Assume that the number of people per each residential stand to be 7-people.

Assume that the water consumption per capita is 160-l/day.

Design period (t) is 20-years.

Number of residential stands is 391-stands.

Pipes to be designed to flow at 50% full (d/D=50%).

Assume that 85% of the water used is returned as sewage.

Calculations

Present population = number of stands X number of people per stand

= 391 x 7

= 2 737 people

Population growth in 20-years-time:

Using the Geometric method formula to calculate the population growth after 20-years time

F = PV (1 + i)Where F is the future population

PV is the present value of population

i is the growth rate

n is the design life

F = 2737(1 + 0.05)20

= 7 262 people (approxiamate)

Therefore the water consumption Q = 7 262 x 160

= 1 161 920 l/day

With a 85% return flow, the average dry weather flow (Q act) = % return as sewerage x waterconsumption

= 0.85 x 1 161 920

= 987 632 l/day

= 11.43 l/day

From Table 3.1 the Peak factor is 5.25

Peak wet weather flow = 5.25 x 11. 43

= 60.01 l/day

Using Mannings formula, to calculate the velocity (v):

V = 1/n. R2/3. S1/2

Where v velocity [m/s]

n Roughness constant

R Hydraulic radius

A Cross-sectional area

S Slope or gradient

D Pipe diameter (400mm assumed)

For new PVC pipes values of n are 0.009 n 0.012 and taking n = 0.012.

For pipes flowing at 50% full, R = 0.25D and A = 0.393D2.

Considering one length of the outfall sewer section and using it as an example of how the sizingand selection of gradients was done.

A gradient of 1:95 which is closer to the ground surface gradient is chosen as a first trail.

V = 1/0.012 (0.25 x 0.4)2/3 (1/95)1/2

= 1.842-m/s

A value of 1.842-m/s is greater than the self cleansing velocity in Table 6.2 for trunk sewers.

Now checking for the design discharge Q des = A x v = 0.393 D2. V

= 0.393 x (0.4)2 x (1.842)

= 0.116-m3/s

Check Q des is much greater than Q act.

See Appendix B Drawing number 3.1 for the Sewerage reticulation layout.

See Appendix B Drawing number 3.2 for the outfall sewer design.

3.5 Construction

The activities were carried out as follows:

Bush clearance Excavations Bedding, which are normally made of granular materials or concrete, serves four main

functions are: To enhance a uniform support under pipes in order to reduce the bending

moment longitudinally To increase the load-supporting strength of the pipes; For pipes with valve and socket joints, it enables pipes to be supported

along pipe lengths instead of pipe sockets. Otherwise, uneven stress maybe induced and it may damage the pipes;

To provide a platform for achieving correct alignment and level duringand after construction.

Drain laying Backfill Construction of manholes Testing and commissioning

3.6 Findings

Most of the sewer lines and outfall sewer were constructed during the wet season, thus resultingin challenges of flooding in trenches. This made it difficult to bed and lay pipes. The writersuggested introducing a water pump to help in dewatering the trenches. The construction of theoutfall were forced to stop as the area were the pipe line moved was flooded with water.

CHAPTER 4

WATER RETICULATION DESIGN

4.1 Introduction

Before commencing the detailed design of a water scheme the designer has to:

Consult an approved development plan area Collect all available historical data on the water consu,ption in the area. Establish the water resources in the area. Establish the fire risks and the level of protection to be provided for in the system.

Pipelines are used to convey water from its source through a treatment works and storageresrviors to consumers. These pipelines may be raisinig mains, carrying pumped flow or gravitymains.

Raising mains and trunk graivity mains should take the most direct routes to the point or pointswhere they connect with other works.

Reticulation pipework should be designed at peak hourly rates to serve all properties witheconomy and flexibility.

In general layouts should consists of a series of networks with major (usually larger diameter)pipes providing rings or spines from which pipes will extend.

Water demands will depend upon supply and sanitation methods selected but where a lowerstandard is initially adapted consideration should be given to any potential upgrading.

4.1 Peak factors

Consumption of water varies considerably from day to day depending on the time of the year andalso on an hourly basis during when high and low peak demands will be experienced.

The Peak daily demand is the highest daily demand within a year and research has found this tobe 1.5 x Average daily demand (Paulsen, 1985).

The Peak hourly demand is the highest hourly demand within any one day and research hasfound it to be 2 x daily demand on any given day (Paulsen, 1985).

Since design must allow for peak hourly flows during the Peak daily demand then Peak hourlydemand = 2 x peak daily demand

= 2 x 1.5 x average daily demand

= 3 x average daily demand

4.3 Emhlangeni water reticulation design

The author got involved in the design of water reticulation system for Emhlangeni mediumdensity suburb and the design will be highlighted to show the design procedures.

4.3.1 Data

Emhlangeni phase 1 has a total of 391 residential stands. Assume an average daily demand of220-l/day for each household.

4.3.2 Calculations

The total average daily demand for the whole of Emhlangeni phase 1 is:

= 220 391

= 86 020-l/day

=86.02-m3/day

Peak daily demand = peak day factor x average daily demand

= 1.5 86.02

= 129.03-m3/day

Peak hourly demand = hourly peak factor x peak demand

= 2 129.03

= 258.06-m3/day

Assuming a 12-hour day, the peak hourly demand:

= 258.06 12

= 21.51-m3/hr

= 5.97-l/s

4.3.3 Pipe reticulation system

For the transmission main the distribution zone is served by a reticulation system, whichgenerally consists of a series of loops and branches.

See Appendix B Drawing No. 4.1 for the water reticulation layout.

The gate valves and fire hydrants in the reticulation network were sited strategically to enablepart of the system to operate while part is out of commission. These were provided so that nomore than 2-valves need to be closed in order to isolate any section of the system.

4.5 Construction

The activities were carried out as follows:

Bush clearance Excavations Bedding, which are normally made of granular materials or concrete, serves four main

functions are: To enhance a uniform support under pipes in order to reduce the bending

moment longitudinally To increase the load-supporting strength of the pipes; For pipes with valve and socket joints, it enables pipes to be supported

along pipe lengths instead of pipe sockets. Otherwise, uneven stress maybe induced and it may damage the pipes;

To provide a platform for achieving correct alignment and level duringand after construction.

Drain laying Backfill Construction of manholes Testing and commissioning

CHAPTER 5

PAVEMENT DESIGN

5.1 Introduction

Definitions

Design traffic the estimated number of equivalent 80-kN single axles, which will be carried bythe lane during the design life of the pavement.

Equivalent 80-kN Axle - the standard axle load to which all heavy vehicle axles are equated inorder to estimate design traffic. Equivalent 80-kN axles are usually abbreviated to E80.

Design life a period of years for example 10, 15, or 20 selected by the designer, for which thepavement is expected to remain serviceable before requiring strengthening or reconstruction.

Design CBR the California Bearing Ratio value assigned to a subgrade and used to determinethe required pavement thickness.

Base the term given to the pavement layers.

Pavement Standard is determined by the number of E80 axles that the pavement is expected tocarry during its design life. A designation indicating the E80 axles in million is used for examplea 0.1M standard pavement is designated for a maximum of 100 000 E80 axles.

5.2 Soil grouping and classification for design purposes

Sub- grade materials are tested for grading, plasticity index and California Bearing Ratio (CBR)values of the soils.

For expansive soils an additional classification, SGE is used.

This method of classifying soils by CBR facilitates the use of standardized pavement design.

5.3 Subgrade classification, description, and comments on use

SGE: Any expansive soil.

SG3: Any non-expansive soil with a design CBR of 3 or more but less than 5. It may be used infills not exceeding 3-m height.

SG5: Any soil with a design CBR of 5 or more but less than 9. It may be used in all fills. Theupper 150-mm layer is usually compacted to 93% Mod. AASHTO.

SG9: Any soil with a design CBR of greater than 9. It requires a minimum cover on all designstandards and is preferred in all fills. The upper 150-mm layer is usually compacted to 93% Mod.AASHTO.

5.3 Subgrade treatment

The subgrade materials require different treatments to form satisfactory foundation for thepavement and the methods of treatment and preparation have been symbolized as follows:

Symbol Treatment

T5 This symbol is normally applicable to SG5 material or better.

1. Remove topsoil, scarify and compact roadbed with a Single Axle Pneumatic Roller(S.A.P.R).

2. Form up to subgrade level in local material and compact to a minimum density of 90% Mod.AASHTO in each 150-mm layer.

3. Ensure that material in the top 150-mm layer complies with the pavement designrequirements and components and compact to a minimum density of 93% Mod. AASHTO.

T3 The symbol is normally applicable to SG3 materials.

1. Remove topsoil, scarify and compact roadbed with a S.A.P.R or equivalent.2. Form up to subgrade level in local material and compact to 90% Mod. AASHTO each

150-mm layer.

TE This symbol is used only in connection with expansive formations (SGE).

1. Remove the expansive soil over the full width of the road.2. Backfill with non-expansive soil of SG3 or better and compact to a density of 90% Mod.

AASHTO.

TR This symbol is normally applicable to soils with a design CBR < 3 on main roads.

- This material is not suitable in the top layer of subgrade and must be excavated to waste.

5.4 Pavement design for Emhlangeni 15-m road

The author designed the pavement for Emhalngeni 15-m road.

The design traffic (E80) was found to be in the range of 1 to 3. 106. The subgrade material wasfound to be SG5.

The 15-m road was designed to have two Bases as follows:

150-mm Base 1 Class 2.***

150-mm Base 2 Class 2***

5.4.1 Sub-grade treatment

T5 treatment was used where by:

The topsoil was to be removed, scarified and compacted with SAPR. The sub-grade was to bethen formed in local material and compacted to a minimum density density of 90% Mod.AASHTO in each 150-mm layer.

5.4.2 Surfacing

A bituminous layer was used to provide a wearing surface to the top of the pavement.

See Appendix B Drawing number 5.1 for the 15-m road design.

5.5 Construction

The writer was assigned to supervise all road construction works in phase A.

See Appendix B Drawing number 5.2 for the road layout.

See Appendix A Program of works.

The construction exercise was as follows:

Bush clearance Scarify, mix and compact Subgrade preparation and testing Pavement layers

Fill bases

Base 2 preparation and testing

Base 1 preparation and testing Surfacing

5.6 Findings

During construction the writers duties were as follows:

making sure that the bulldozer cleared according to the designed road widths along withother specifications

making sure that the bulldozer operator did not uproot pegs

taking surveys and calculating the volume of topsoil excavated

supervising on the cutting and filling

making sure that extra excavated and bulldozed earth was not deposited into stands

There were challenges in the terrain. The area was had a lot of sand (mostly 600-mm deep) androcky (boulders) at some areas. The D6 dozer which was originally hired failed to clear the arearesulting in a D8 with rippers being brought in.

CHAPTER 6

VERTICAL SHAFT BRICK KILN TECHNOLOGY

6.1 Introduction

The Vertical Shaft Brick Kiln (VSBK) is an energy efficient and less polluting technology forthe firing of clay brick. The VSBK seeks to promote a greener and environmentally friendly wayof firing bricks than the use of firewood and coal.

The introduction of Vertical Shaft Brick Kiln (VSBK) technology aims to provide a cleaner andmore equitable solution in reducing energy consumption and diminishing gas and particulateemissions during the firing process.

The writer was honored to be part of the team of engineers that went on a site visit at LangkloofBrick, Jeffreys Bay, Eastern Cape, South Africa, to learn and understand the new green,environmental friendly brick firing method. This is the first in Africa.

The writer highlights some of the findings on the new technology.

6.2 VSBK IN SOUTH AFRICA

6.2.1 Introduction

The Vertical Shaft Brick Kiln (VSBK) is an energy efficient and less polluting technology forthe firing of clay brick. Internationally constantly improved with the support of the SwissAgency for Development and Cooperation (SDC), it has reached a higher level of efficiency inSouth Africa during the South-South technology transfer.

The SA-VSBK is a South-South Technology Transfer project implemented in South Africa bySwiss contact (Swiss Foundation for Technical Co-operation) in collaboration with SKAT(Swiss Resource Centre and Consultancies for Development). The project is funded by the SwissAgency for Development and Cooperations (SDC) and part of their Global Climate Change

Mitigation Programme, which in South Africa focuses on energy efficiency in the buildingsector.

The primary objective of the project is to introduce and disseminate the VSBK brick firingtechnology as a viable and sustainable alternative firing technology for the clay brick industry,with many positive impacts from the economic, environmental and social point of view.

The project is facilitating the transfer of the technology to the South African brick entrepreneurs,generally small and middle size family businesses enterprise.

The technology offers economic, environmental and social benefits to the clay brickmanufacturers and therefore to the South African Air Quality. The project partners come fromboth the public and private sector, with a focus on creating a suitable business environment aswell as knowledge download at various levels ensuring a successful transfer and take-up of thetechnology.

The VSBK contributes positively to climate change mitigation due to an average 50% reductionin coal consumption and therefore carbon dioxide (CO2) emissions compared to clamp kiln, thetraditional South African firing technology. Due to the vertical structure and efficientcombustion the emission of other gases and particles is also drastically reduced. Emissions arenow easily measured and are below the new South African air quality standards.

The technology brings various economic and social benefits to the employers and workers, and isa good example of a clean and sustainable development contributing to South Africasinternational climate change targets.

6.2.2What is VSBK?

The Vertical Shaft Brick Kiln (VSBK) technology is an energy-efficient updraft kiln comprisingof a vertical shaft from which bricks are loaded at the top and removed at ground level in acontinuous process. An unloading tunnel runs through the centre of each kiln allowing for accessto both sides of the shaft.

Internal body fuel is mixed into the bricks with a measured amount of external coal spreadevenly between the layers of stacked bricks to control the firing temperature.

The position of the fire in each shaft in relation to the updraft is determined by the rate the bricksare removed and loaded into the shaft. This reuses the rising heat, making it very fuel-efficient.The firing shaft is very well insulated on all four sides, so that heat loss is minimised.

Once the kiln reaches the specified temperature, the heat from the coal ignites the internal coal ofthe bricks so that very little heat is lost through exhaust gases or the kiln itself.

These exhaust gasses are used for the gradual preheating of the unfired bricks on top, thusreducing energy consumption and carbon monoxide(CO) emissions by up to 50% compared tothe more commonly used clamp kilns.

Figure 6.1: Structure of VSBK by Langkloof Brick, Jeffreys Bay, Eastern Cape, SouthAfrica.

6.2.3 The Origins of VSBK TechnologyThe VSBK technology evolved in rural China. The original version of a Chinese Vertical ShaftBrick Kiln was adapted from the traditional updraft intermittent kiln in the early 1970s. In 1985the Chinese government commissioned the Energy Research Institute to improve its energyefficiencies and by 2000, between 50 000 and 60 000 units was in operation throughout thecountry.

Through the support of SDC, the technology has since been enhanced and re-pioneered in Nepal,Pakistan, Afghanistan, India and Vietnam. In September 2011, South Africas very first SA-VSBK pilot plant was inaugurated at Langkloof Bricks, in Jeffreys Bay, in the Eastern Cape.

6.2.4 How Does the VSBK Work?

During initial firing operation, a fire (with wood and briquettes) is lit in the firebox atthe bottom of the brick setting (or charcoal top). During continuous operation, onebatch of dried green bricks is loaded in layers at the top at a time. A weighed quantity

of sized coal (5-15 mm) is spread on each layer uniformly to fill the gaps. The brickunloading is done from the bottom using an unloading trolley, which runs on railsalong the length of the unloading tunnel. Lifting and lowering of the trolley is doneusing a single screw unloading mechanism.

For unloading, the trolley is lifted so that the whole stack of bricks in the shaft rests onit. The support bars are taken out, when the load is released. The whole stack is thenlowered till the layer with openings appears, through which the support bars are thenreinserted. On further lowering, the load of the stack is taken by the support bars exceptfor the batch being unloaded which comes down along with the trolley finally restingon a pair of rails.

The trolley is later pulled out along the rails laid out on the floor of the tunnel. Thebricks subsequently unloaded and sorted out for dispatch. The next batch is loaded atthe top from the green bricks lifted onto the loading platform. The frequency ofunloading - loading varies from 90 to 150 minutes. The residence time of a batch in thekiln typically varies from 26 to 30 hours.

The skill in operation is to keep the firing zone in the middle of the shaft. The draughtof air moving up from the bottom cools the fired bricks in the cooling zone and it getsheated. Maximum temperatures of up to 10000C are attained in the central firing zone.The hot gases moving upwards dry and heat up the green bricks in the preheating zone.This recovery of sensible heat accounts for the high energy- efficiency of the VSBKtechnology.

The VSBK works on the basis of a counter current principle. When the lid is closed, the shaftand exhaust becomes an integral chimney system. The firing process of pre-heat, firing(vitrification) and cooling takes place within the shaft, as the bricksmove down the shaft. Energy efficiency is derived through theverticality of the shaft and structural thermal efficiency

Table 6.1: Comparison of average energy required for firing for themain firing technologies in South Africa.

Production Mechanism Firing Energy Required (per Kg offired brick)

Tunnel kiln 1.65 2.1 MJ/KgTransverse Arch kiln 2.0 4.0 MJ/KgClamp kiln 1.7 4.2 MJ/KgVSBK Worldwide 0.84 1.1 MJ/KgSA-VSBK (Langkloof Bricks) 0.85 MJ/Kg and still improving!

Figure 6.2 VSBK operational design

6.2.5 Benefits of the VSBK technologyThe VSBK technology covers all three pillars of sustainable development and provides thefollowing benefits:

Environmental Benefits

Each kiln will contribute to reduce by 600t per year the CO2 emissions, which with a 50% ofclamp kiln conversion to this cleaner clay brick technology as VSBK by 2020, it is estimated toachieve half a million tons CO2 reduction per year.

Economic benefits

With an energy consumption of 0.85 MJ/kg fired brick (compared to an average of 2.3 MJ/kg forclamp kiln) there is a coal saving of on average 50% reducing the embodied energy of the finalbrick and building.

Breakages in production are below 2% compared to the average of 15% allowing more finalsaleable product with the same inputs.

Social Benefits

The VSBK helps to retain jobs and requiring more skilled people it provide opportunity for skillsdevelopment.

Improved health and safety on the working place with allow to a better working condition for theemployees.

6.2.6 Challenges and barrier

Even if technology transfer has been successful and competences have been transferred to andanchored in South African local service providers and are ready to be multiplied, a wider uptakeof the technology has not taken place yet. The main reason is that other challenges and barriersbeside the technology still remain present.

These challenges and barriers are:

Access to Finance to obtain preferential green credit lines to support the investment costs; conservative mind set, cultural habit and traditional practice of business and operation; lack of knowledge of detailed single operation practices and costs; adverse investment climate due to national and international financial situation; Environmental Impact Assessment (EIA) requirements and process taking longer than

expected and discouraging these changes.

CHAPTER 7

WORKPLACE SAFETY AND HEALTH

7.1 Introduction

Occupational safety and health (OSH) also commonly referred to as occupational health andsafety (OHS) or workplace health and safety (WHS) is an area concerned with protecting thesafety, health and welfare of people engaged in work or employment. The goals of occupationalsafety and health programs include fostering a safe and healthy work environment. OSH mayalso protect co-workers, family members, employers, customers, and many others who might beaffected by the workplace environment.

The main focus in workplace health and safety is on three different objectives: The maintenance and promotion of workers health and working capacity. The improvement of working environment and work to become conducive to

safety and health. The development of work organizations and working cultures in a direction which

supports health and safety at work and in doing so also promotes a positive socialclimate and smooth operation and may enhance productivity of the undertakings.

7.2 Workplace hazards

Although work provides many economic and other benefits, a wide array of workplace hazardsalso present risks to the health and safety of people at work. These include but are not limited to,chemicals, biological agents, physical factors, adverse ergonomic conditions, allergens, acomplex network of safety risks, and a broad range of psychosocial risk factors.

7.2.1Physical and mechanical hazards

Physical hazards are a common source of injuries in many industries. They are perhapsunavoidable in many industries such as construction and mining, but over time people havedeveloped safety methods and procedures to manage the risks of physical danger in theworkplace. Employment of children may pose special problems.

Falls are a common cause of occupational injuries and fatalities, especially in construction,extraction, transportation, healthcare, and building cleaning and maintenance.

7.2.2Biological hazards

Bacteria Virus Fungi Mold Blood-borne pathogens Tuberculosis

7.2.3Chemical hazards

Acids Bases Heavy metals Lead Solvents Petroleum Particulates Asbestos and other fine dust/fibrous materials Silica

7.2.4 Psychosocial hazards

Psychosocial risks are issues such as occupational stress and workplace violence which arerecognized internationally as major challenges to occupational health and safety. Psychosocialrisks are:

Precarious work contracts Increased worker vulnerability due to globalization New forms of employment contracts Feeling of job insecurity Aging workforce Long working hours Work intensification Lean production and outsourcing High emotional demands Poor work-life balance

7.3 Hazard identification

A hazard is something that can cause harm if not controlled.

Hazard identification or assessment is an important step in the overall risk assessment and riskmanagement process. It is where individual work hazards are identified, assessed andcontrolled/eliminated as close to source (location of the hazard) as reasonable and possible.

7.4 Risk assessment

This assessment should:

Identify the hazards Identify all affected by the hazard and how Evaluate the risk Identify and prioritize appropriate control measures

7.5 Findings

The writer addressed the importance of workplace safety and health. The writer designed a safetyboard that captures data of all the accidents that occur on site, minor, major or fatal. The authormade a site safety induction exercise that sets awareness to all the workers, visitors, school andthe surrounding community. A barrier tape was placed a warning around the construction site.

The following welfare facilities were provided:

Toilets Washing area Canteen

7.5.1 Site rules

In the site safety induction the following were to be adhered to at all times:

All personnel must receive a site induction prior to commencing work on site. Noinduction, no work.

Appropriate personal protective equipment (PPE) is to be worn by all persons on site atall times.

Drugs and alcohol will not be tolerated on his site. Anyone found under the influence willbe disciplined and removed from site immediately.

No radios or other such musical equipment are permitted on this site. All food and drink is to be consumed within the prescribed welfare facilities compound. Use the rubbish bins provided and be minded not to leave scraps of food as these could

attract vermin.

The use of mobile phones is not permitted on this site, except within the site offices andcanteen. Anyone found using a mobile phone on site will be disciplined and removedfrom site immediately.

Keep all areas of the site tidy and free from discarded materials. A yellow card/red cardscheme is in operation on this site.

Ensure mechanical and electrical equipment is stored in the metal site compoundcontainers at the end of each day.

Inform site management immediately should you discover any hazardous materials oractivity.

This is a no smoking on site.

7.5.2 First Aid

The site had first aid box located in the site office.

7.5.3 Accident reporting

The writer ensured that all accidents are to be logged in the accident book. The accident book islocated in the site office.

Although the site safety inductions were conducted, the accident still occurred due to ignoranceof some workers on site. Most of the lost time during working hours was lost due to workerstaking many and unnecessary smoke breaks.

CHAPTER 8

STORMWATER DRAINAGE SYSTEM

8.1 Introduction

Initially the layout of the stormwater drains should be planned is such a way that the most directroute to the nearest water course or open space is developed.

On gravel roads the objective of the drainage system is to drain the water off the road into opendrains as soon as possible, but on the surface and kerbed roads it is usually more economical touse the roadway for short distances as a stormwater drain provided the gradients are satisfactoryand the quantity of runoff is not excessive.

8.2 Estimation of the runoff design flow

The quantity of runoff is calculated using the Rational Formula, which is expressed as follows:

Q = 0.278CiAWhere: Q = peak surface runoff rate (m3/s)

A = catchment area (ha)

C = runoff factor

I = intensity of rainfall (mm/hr)

The drainage area, A, is often determined from a map which includes the drainage area ofinterest. It may be necessary to first determine the boundaries of the drainage area using acontour map. Once the boundaries are known, the area can be determined using the map scale.

The runoff factor or coefficient (C) is the fraction striking the drainage area that becomes runofffrom that drainage area surface. The runoff coefficient reflects that part of the storm rainfallcontributing to the runoff at the outlet of the drainage area in question. The runoff coefficient isan empirically determined constant, dependent on the nature of the drainage area surface.

Table 8.1 Recommended runoff coefficient for the use with the Rational formula (source:Township roads and stormwater drainage manual)

Type of catchmentarea

Maximum percentage ofimpervious surfaces

Potential runoff

Grassed areas andparks

NIL 0.25 0.35

bare soils NIL 0.35

Low density residential 20% 0.40

Medium densitydevelopment

40% 0.60

High densitydevelopment

80% 0.80 0.90

Fully paved areas androad reserves

100% 0.95

The design rainfall intensity depends on the locality and the recurrence interval is the statisticalinterval at which a given storm intensity may be assumed to recur. The design rainfall intensityis the intensity of a constant intensity design storm with the specified design return period andduration equal to the time of concentration of the drainage area.

For a given rainfall intensity which falls continuously and indefinitely its runoff will reach topeak at the time of concentration, Tc , when all points of the watershed contribute to the flow.

Time of concentration is the time required for runoff from the farthest part of the drainage areato reach the oulet.

The size of the stormwater drain can be calculated from the amount of runoff to be drained usingMannings formula:

Q = 1/n (A x R2/3 x S1/2)Where: Q = flow in drain (m3/s)

n = Mannings coefficient

A = area covered by flow (m2)

S = slope/ gradient

R = hydraulic radius

The author worked on a number of stormwater drainage designs but the following project wasselected to highlight the general procedures.

8.3 Stormwater drainage system for Emhlangeni medium suburb

8.3.1 Introduction

Emhlangeni medium suburb is located in the northern suburb of Bulawayo close to RomneyPark. The area is to be fitted with trapezoidal stormwater drains that run along beside the roads.

8.3.2 Estimation of runoff drain sizingThe layout of stormwater drains was produced in such a way that:

All drains were laid to follow along the roads. All drains were laid to follow the general ground slope since the water is to gravitate.

Emhlangeni suburb is a medium density still developing. A value of C = 0.60 for mediumdensity development was used.

Design information and assumptionsRecurrence interval = 5-years

Rainfall = 800-mm/annum

Time of concentration = 5-minutes

Interpolated rainfall intensity = 175-mm/hr

Slope = 0.0067 = 1/150

Mannings coefficient, n = 0.01

Calculations

The catchment area for each drain was calculated.

The quantity of runoff, Q, to be drained by each drain was calculated from which the depths ofrectangular drains were calculated using Mannings formula.

For a trapezoidal drain:

Flow area A = (b + xy)y

Wetted perimeter P = b + 2y (1-x2)

Hydraulic radius R = A/P

8.5 Construction

The construction exercises were done as follows:

Bush clearance Setting out Catch pits Culverts Stone pitching

CHAPTER 9

BILL OF QUANTITIES AND COST ESTIMATES9.1 Introduction

Contracts for civil works are usually based on contract documents comprising the followingprinciple parts:

Conditions of contracts Drawings Specifications Bills of Quantities

The author was involved in the preparation of several Bills of Quantities and Cost estimatesfor prospective projects. The Bills of Quantities and Costs estimates prepared were mainlyfor:

Water reticulation works Sewer reticulation works Road works

Storm water drainage works

9.2 Bill of QuantitiesThe Bill of Quantities is a list of items giving the estimated quantities and brief description of allworks to be performed and materials to be provided under the contract. The quantities and thedescriptions being derived from the drawings and specifications.

Space is provided for the insertion of price rates against each item and the extension and totalingof the prices.

The Bill of Quantities is intended, in the first instance, to give information to tenders and toenable them, by pricing each individual item as it relates to the condition of contracts, drawingsand specifications, to arrive at the total tender prices.

When priced the Bill of Quantities affords assistance to the adjudicator in comparing the varioustenders.

After the contract has been entered into the priced Bill of Quantities provides the means wherebythe worker executed may be valued for payment, the price rates being applied to the quantities ofwork finally measured as actually carried out.

A typical Bill of Quantities is shown in Appendix C.

9.3 Cost estimates

A detailed project construction cost estimate is based on pricing the full Bill of Quantities.Operation and maintenance cost per year can be obtained expenditure from similar projects in thepast.

The prices and rates to be inserted in the Bill of Quantities are to be full inclusive prices to theEmployer for the described under the several items.

Such prices shall cover all costs and expenses that may be required in the construction of thework described and shall cover the cost of all general risks, liabilities and obligations set forth orimplied in the documents on which the tender is based.

The writer was involved in preparation of a tender document and bill of quantities for a landdevelopment project, and the bid was a success and was awarded to the company.

CHAPTER 10

IMPACT OF INDUSTRIAL ATTACHMENT

`10.1 Achievements

The writer was privileged to attain the following skills through his attachment period:

The attachment period helped to instill confidence in the author as he managed to interactwith people from different engineering generations and age groups.

The author gained a lot in experience in the application of computers in the engineeringfield as he managed to use some to carry out most of the assigned work. Most of thedesign work was made easier by the availability of computer packages like AutoCAD,Microsoft Project and Microsoft Tools.

The author constructed numerous spreadsheets in Microsoft Excel to speed up the designprocess.

The student engineer learnt to produce and interpret drawings.

Knowledge in administration issues such as the general office set-up and operation of aconstruction engineering firm was gained.

Knowledge of the roles of professional bodies such as ZIE, ZACE and CIFOZ in theoperation of consulting and construction firms was gained.

Management and Leadership Skills Compiling weekly reports Tendering methods and procedures. Types of contracts. Designing and construction of storm water drains along with the challenges faced from

different designs. Water and sewer reticulation design and construction along with the problems

encountered due to poor designs. Workplace safety and health exercise. Can perform first aid procedures. Road design and construction. Green energy technology. Brick manufacturing technology.

10.2 Challenges

The exposure that the author got during the industrial attachment period was of great benefitalthough he faced some constraints like:

Limited accesses to the Internet for the latest information on design, new constructionmaterials and design supervision techniques.

The writer was considered as top management, in charge of several sections. The peoplethat the writer was made to manage where way older than the writer. It was therefore noteasy to manage them due to the age difference.

Non co-operating workers, some workers would work without proper PPE, and otherswould not wear them on site. Most of the lost time during working hours was lost due toworkers taking many and unnecessary smoke breaks.

10.3 Recommendations

I strongly recommend that when students go on attachment, they must have strong backgroundknowledge on road designs and maintenance. They should also undergo site visits to a variety ofdifferent projects to help equip them with knowledge of the practical world and not just the

theoretical. The site visits help to install a driving moral to challenge the world and to think in

other terms.

I highly recommend that when students go on attachment, they must have strong backgroundknowledge on workplace safety and health. The department should add courses that address theissue of workplace safety and health.

The writer also recommends that for land development projects, they should be constructed onlyin the dry season to reduce the problems of flooding trenches and damage to the laid pipes.

Town planners should liaise with other service providers and government parastatals e.g ZESA,Powertel before, during, and after land development. This helps in notifying one another on theexistence of other services that are laid underground.

10.4 Conclusion

The writer found the attachment period challenging but exciting and highly educative. Theattachment helped the writer to think in other terms. Stelix Civils Engineers and Contractors

offered the writer an excellent learning environment which in cooperated a wide range of Civilengineering, mining and environmental aspects.