SASTT contact details:

Web: www.sastt.org.za

President: Michael king

Tel: (021) 417 2900Fax: (021) 417 2999

E-mail: mike.king@smec.com

Honorary director: Joop van Wamelen

Tel: (012) 567 4026 Fax: 086 668 4026

E-mail: director@sastt.org.za

FOR FURTHER INFORMATION CONTACT:Tel: (011) 206 2000Fax: 086 517 8122

Email: jacked@wkc.co.zawww.jackpipe.co.za

JACKED PIPELINES a division of WK CONSTRUCTION (PTY)LTD

PIPE JACKING AUGER BORING

"Pioneers and leaders in South African Trenchless Technologies"

YOU ARE NEVER AN

ILLUSION IN OUR WORLD

IMIESA April 2013 49

SASTT

THE AWARD WAS presented in rec-

ognition of a contract that the com-

pany undertook for the Mandela Bay

Development Agency involving the

rehabilitation of two parallel sewers located in

the heart of Port Elizabeth’s CBD.

Trenchless Technologies’ managing

member Sam Efrat says that the ISTT

Annual Project Award is the highest

accolade available worldwide in the

trenchless technology industry and

is chosen from nominations received

from companies that are members

of the 30 ISTT-affiliated trenchless

societies across the globe.

The contract was undertaken by

Trenchless Technologies in con-

junction with Afri-Coast Consulting

Engineers, Sekisui Rib Loc Australia

(part of SPR Asia), subcontractor

Tuboseal as well as consultant Pipes

and Engineering Advice and Services.

Efrat explains that this was the sec-

ond phase of a two-phase project –

phase one was completed in 2009

Local entity receives highest accoladeSubsurface pipeline construction and rehabilitation company Trenchless Technologies has been awarded the International Society for Trenchless Technology (ISTT) 2012 Annual Project Award.

ANNUAL PROJECT AWARD

and involved the reha-

bilitation of 570 m of

450DN sewer using

SPR EX technology,

as well as 560 m of

840DN sewer using

SPR PE spiral wound

technology. The pipe-

line rehabilitation

took place concurrent

with an urban envi-

ronmental upgrad-

ing project involving

decorative paving and

resurfacing works on

the surface above the

existing pipes.

Further downstream, the 450DN and 840DN

sewers increased in capacity to 525 mm and

1 000 mm in diameter. Phase two involved

the rehabilitation of these two sewers. Efrat

explains that what made this project unique

was its location – the 525DN

sewer was located beneath one

of Port Elizabeth’s busiest and

most heavily congested streets,

Govan Mbeki Avenue. Additionally,

the 1050DN sewer was located

underneath a newly constructed

Bus Rapid Transport (BRT) lane.

Considering that the BRT and road

lanes are utilised every day, only

non-destructive trenchless tech-

niques could be employed for the

rehabilitation of these pipelines.

Efrat explains that condition

assessments were carried out on

both sewers using CCTV inspec-

tion and cutting of windows from

the sewers for physical inspection.

LEFT Phase 1: 450 cast iron pipe before cleaning

ABOVE Trenchless Technologies’ managing member Sam Efrat

BELOW Phase 1 (before): 840 concrete sewer with deep sill worn away at pipe base

50 IMIESA April 2013

SASTT

Our range of services include:

• Pipe Bursting

• Horizontal Directional Drilling

• Pipe Rehabilitation

• Slip Lining

• Pipe R ming

• CCTV Inspection

• Dewatering

• Industrial Pipe Cleaning

• HDPE Welding

• Deep Excavation and Shoring

• Underground Service Detection

• Close-fi t lining: COMPACT PIPE

For more information you can contact us: +27 (0)21 761 3474 F +27 (0)21 797 1151 E info@tt-innovations.co.za www.tt-innovations.co.za

Trenchless Technology Specialists

It was ascertained that the 525DN sewer was

severely corroded around its entire circumfer-

ence due to acidic effluent with pH values

measuring as low as 3.3. The sewer’s mortar

had corroded out of the construction joints and

was no longer watertight.

Additionally, the 1050DN sewer was severely

corroded above the water line and the reinforce-

ment was exposed and corroded away at plac-

es. Particularly severe deterioration occurred

at the sides and invert of the sewer due to a

combination of corrosion and erosion along the

sections of the sewer where the fluid velocity

was high. Efrat explains that this corrosion is

typical of what occurs in a sewer downstream of

a rising main where there is an accumulation of

gas due to long retention times. He points out

that it was estimated that sections of the sewer

would collapse within 10 years.

Speaking on the technology used by

Trenchless Technologies on the project,

Efrat explains: “Altogether the project used

five different trenchless techniques: spi-

ral wound expanded to a close fit, spiral

wound in-place, ambient cured-in-place pipe

(CIPP), UV CIPP and pipe bursting. The

contract was awarded based on utilising

spiral wound technology, namely SPR EX

for the 525 sewer and SPR RO for the

1050 sewer. However, during the project

unforeseen site conditions, such as a 15 m

90-degree radius bend on the 525 pipe and

a 43 m length of 800 mm diameter pipe

was discovered where the 1 000 sewer

reduces in size, which required the intro-

duction of additional ambient cure and UV

CIPP methods. Additionally, pipe bursting of a

225DN clay lateral pipe became necessary as

a cracked and leaking lateral 225DN clay pipe

was preventing plugging and over-pumping at a

critical manhole.”

Efrat adds that the

wide range of tech-

nologies used on this

project allowed for

a complete ‘no-dig’

solution that enabled

rehabilitation to take

place entirely through

access chambers.

What’s more, the solu-

tion was design-com-

pliant and the risk was

lower as the entire

process could be

reversed in the event

of unforeseen problems. With CIPP, once the

liner cures, it is extremely difficult to remove

in the event of a failure, whereas with spiral

wound it is far easier to remove your liner if you

have a failure, thus your risk is lower.

Despite the challenges encountered, the

combined team managed to pull off the suc-

cessful rehabilitation of the two sewer pipe-

lines without any disruptions to traffic or the

public. “This project is an excellent example

of using trenchless technology options to

address unanticipated site conditions allow-

ing the project to be completed success-

fully without excavation and site disruption,”

maintains Efrat.

LEFT Phase 1: 450 cast iron pipe after cleaning

BELOW Phase 1 (after): 840 concrete pipe after relining with Rib Loc Ribline

IMIESA April 2013 51

SASTT

THE PROJECT INVOLVED the instal-

lation of four ducks of 110 mm in

diameter over a distance of 130 m

through solid rock, crossing under N1

in Centurion and under the very active Gautrain

rail lines. “Several companies had failed and

the project had been waiting for a year or

two for the right contractor,” says Robert

‘Chico’ Garcia, JCS Pipeline’s operations and

horizontal directional drilling (HDD) manager,

adding that the evidence of previous contrac-

tors’ attempts to get all the way across were

cleary visible.

Challenging conditionsThe biggest challenge on-site was the hard

rock. “South Africa has some of the hardest

rock in the world,” says Garcia. The majority

of the bore was solid rock, tested at over

300 MPa. The continuous traffic on the N1

was also challenging, according to Garcia,

as well as the fact that the drilling had to

cross under the tracks of the Gautrain line.

“All of these are very different obstacles that

not everybody can overcome, but we did,”

states Garcia.

The equipment of choice in this challeng-

ing context was a downhole hammer sup-

plied by Vermeer’s alliance partner Pioneer,

on a Vermeer D130 x 150 drill rig, which

Craig Burnie, MD at Vermeer Equipment

Suppliers, says was sourced from Vermeer’s

Beijing Factory. The rig itself was designed for

large-diameter HDD projects and, according to

Burnie, has “the features and power needed

for demanding job site conditions”.

In addition, the open-top vice increases vis-

ibility for the operator and offers the ability to

set large tooling in the vice with ease.

The hammer in this case was used to trav-

erse the approximately 130 m of solid sub-

surface rock, after the initial hole was opened

to a diameter as prescribed by the consulting

engineers. “Using the hammer was Step 1 –

the hammer is only 160 mm in diameter – but

it allowed us to get all the way across, which

then allowed us to proceed with the rest of the

project,” explains Garcia.

The entire drilling process took only 15 days

for Garcia and his team from JCS Pipelines,

with the pilot bore itself done in only a couple

of days. Several days were required for a size-

able single jump to the final 355 mm hole

opener (rock reamer). “The hammer and rig

worked very well in the South African condi-

tions,” adds Garcia.

Training essential“Not many people have the experience to use

the hammer and the related equipment. This

takes a lot of specialised skill,” warns Garcia,

adding that the hammer and rig that Vermeer

supplied were supported by training from a

Pioneer specialist from the US, with Vermeer‘s

assistance, who showed Garcia and his team

exactly what the hammer and rig were capable

of. This allowed the already highly skilled team

to push the equipment to the limits of its capa-

bilities on-site in order to deliver on time and

according to exacting specifications.

“I was very impressed with the team from

Vermeer. They always give us outstanding

service and their aftersales service is also

excellent,” concludes Garcia.

Downhole drilling successA recent drilling project crossing under the N1 in Centurion, near the active Gautrain high speed rail, proved tricky until the right contractor for the job, armed with the right equipment, managed a breakthrough.

The entire drilling process on-site took only 15 days

HORIZONTAL DIRECTIONAL DRILLING

SASTT

IMIESA April 2013 55

Trenchless versus traditional

Trenchless technology is recognised as environmentally and sociably acceptable

COMPARING COSTS

THE POTENTIAL USE and application

of trenchless technology in rehabili-

tation or renewal of water services

in Australasia is staggering, with an

This article compares costs and discusses the factors that impact a project and the environment and society that should be considered when selecting the appropriate pipeline construction methodology.By Steve Apeldoorn: Australasian Society for Trenchless Technology

estimated 96 000 km of sewer and

sewer pressure mains approaching or

exceeding their design life. This situa-

tion is akin to other western nations;

56 IMIESA April 2013

SASTT

• GRUNDOMAT soil displacement hammers for pipes up to ND 150 - extremely precise due reciprocating chisel head.

• GRUNDORAM ramming machines for steel pipes up to ND 4000 - also applicable vertically for ramming sheet piles.

• GRUNDOBURST static pipe bursting systems for the replacement of pipes up to ND 1000

• GRUNDODRILL HDD systems for steerable bores up to ND 600 - with percussive hammer for stony soils.

• FÖCKERSPERGER PIPE AND CABLE PLOWS - for trenchlessly plowing in pipes up to OD 225 and cables in open terrain.

• PRIME DRILLING - Midi & Maxi HDD rigs for pipes up to 1400 mm.

ALL THIS AND MORE ONLY FROM TT.ALL THIS AND MORE ONLY FROM TT.

TT sales partner in South Africa: Reef Trenchless Technology SA (Pty) Ltd · 19 Shamrock Road, Primrose, P. O. Box 2168 · Primrose 1416 · South Africa Phone: +27 (0)11 828 2397 · 828 5782 · Fax +27 (0)11 828 7981 · E-Mail: reefpneu@mweb.co.za · www.reeftrenchless.com

the American Society of Civil Engineers (ASCE)

estimated that it would cost US$1.3 trillion

(R12.04 trillion) over the next five years to

maintain current underground infrastructure

systems (R Mohammed et al. Oct 2008).

Growth in the use of trenchless technologies

comes as communities become more aware

of the impact of infrastructure development

and renewals on our social and ecological

environments, and as the ageing pipelines

in our built up and congested urban areas

require replacement. Trenchless technology is

recognised as an environmentally and socially

acceptable method of construction, particu-

larly in comparison with traditional open exca-

vation alternatives, but comparing the costs

between trenchless and open cut methodolo-

gies on a dollar to dollar basis can be difficult

and inaccurate when we consider the total

cost to the community. The amount of money

paid for installation or renewal of water and

wastewater pipelines by local authorities does

not represent the total cost to society, broader

consideration of all costs – both project and

social costs – should be given when selecting

the best method for constructing or renewing

piped infrastructure.

Trenchless technology eliminates disruption of services

The question: “What is the cost of trenchless

construction or renewal projects relative to

conventional open-cut methods?” is the most

frequently raised question by potential trench-

less users, but unfortunately it is also the most

difficult to answer.

The cost of both open-cut and trenchless

methodologies is affected by many factors,

such as the location of the pipeline, its depth,

size and also the local availability of the various

trenchless technology methodologies. The cost

of a pipeline construction or renewal project

can be divided into several components. The

costs fall broadly into the costs paid by the

utility as direct and indirect construction costs,

and those paid for by society at large, termed

social costs, that are a result of the project

being undertaken.

The direct and indirect costs are those most

often associated with the “project costs” or

“construction costs”, which are usually relatively

straightforward to estimate using standard esti-

mating methods and are greatly represented

proportionally by the construction cost fees ten-

dered by contractors. The cost of any particular

rehabilitation or renewal method, open-cut or

trenchless method varies significantly dependant

on the site conditions.

The variability of costs and uncertainty of

what cost items are included or not included in

project estimates, makes comparing the cost

between open-cut and trenchless methods dif-

ficult and there is little recent published data

available. A published case study in 2008

compared the potential cost of open excava-

tion versus pipe bursting to replace the sewer

network in the City of Troy in Michigan, US, con-

cluded that the trenchless method of renewal if

implemented would be 25% less expensive than

open excavation (R. Mohammed et al. 2008).

The study had a number of caveats and areas

for further research: sewer laterals and lateral

connections had not been considered as part

of the comparison study, nor had the possible

effects of ground condition variability.

Approximately 70% of the cost of open exca-

vation construction is simply excavating and

replacing the ground dug up during the process

(R. Mohammed et al. 2008). However, it does

not always necessarily translate that trenchless

technology is one third the cost of open excava-

tion. In some cases the cost of construction

using trenchless technology exceeds that of

open excavation particularly in greenfield and

shallow conditions. Trenchless technologies do,

however, have a tendency to become better

priced than the open-cut options in higher density

urban areas where access, traffic control and the

cost of reinstatement of surfaces become more

expensive per meter

of pipe and where pipe

depths are greater

requiring expensive

shoring and sig-

nificant increases in

excavation resources.

In the paper

“ M i n i m i z i n g

Environmental Impact

through Trenchless

C o n s t r u c t i o n ”

(Ariaratnam et al.

2008), it was also

concluded in the

case study that the

expected reduction

in greenhouse gas

emissions by use of

horizontal directional

drilling (HDD) was

around 97%.

Another important

social cost factor

that should also be

considered in a com-

parison is the visual

impact on the envi-

ronment. Trenchless

technology projects

have a far smaller

Trenchless technology can be up to 25% less expensive than open excavation

SASTT

IMIESA April 2013 57

impact on the project zone, not only reducing

the disruption that may be caused but also the

stress and effect on the lifestyle of the inhabit-

ing community, particularly during large and long

duration projects.