Construction World October 2016

CONSTRUCTION WORLD

OCTOBER

2016

PROJECTS AND CONTRACTS

“We are able to put a compre-

hensive skills-set to play for

clients such as Sasol, for which

the group’s divisions undertake

a broad spectrum of projects,” says Geoff

Thompson, business development director

for the Stefanutti Stocks Structures business

unit. “These capabilities, coupled with our

uncompromising policies on quality and

safety, and solid client relationships, have

made Stefanutti Stocks one of the preferred

contractors within this industry.”

Piling capabilities

After successfully completing the piling

for the Oxygen Train 16

project in 2009,

Stefanutti Stocks Geotechnical was awarded

the piling works contract for what will be the

worlds’ largest Oxygen production facility,

the new Oxygen Train 17

Plant. The scope of

works on this contract included:

• Preliminary designs at the tender stage

and further auger trial holes to verify the

founding conditions.

• Final construction design with piles

carrying loads in side-shear only,

including client’s minimum require-

ments based on the auger trial holes

information.

• Installation of 516 temporary cased

and uncased Auger-Cased In Situ (ACIS)

structural piles, with diameters ranging

between 450 mm to 750 mm.

• Installation of three 750 mm-diameter

compression-load test piles, with four

anchor piles for each test.

The production schedule was impacted by

the discovery of an unforeseen hard rock

layer of dolerite beneath 83% of the site

footprint, which needed to be drilled through

in order to achieve the minimum required

rock sockets. Also, unexpected water seepage

below eight metres deep required proper

planning for drilling, pile-base cleaning and

concrete pouring. In some of the piles, mainly

in the backfilled areas, severe water ingress

and associated side-wall collapses required

the utilisation of temporary casings.

This project had very tight milestones

and required sections to be handed over in

early January 2016, with heavy penalties

as a result of not completing on time. “Our

planning in terms of material procurement,

mobilising to site and the execution of the

works had to be very precise,” says project

manager Teboho Motaung. “We put a sound

strategy in place and completed the overall

works and sectional hand overs two weeks

ahead of schedule.”

The specification required pile compres-

sion load tests be done on three 750 mm-

diameter piles carrying a working load of

2 765 kN. The piles were loaded to 1,5 x

working load as per the testing specifica-

tions. “The main purpose for conducting the

pile compression load testing is to validate

and to check compliance with the design

specifications,” explains Motaung. “In order

to allow the application of a load to the

test pile for an extended period of time this

method of testing involved the use of a reac-

tion system, using a 500 ton jack to apply the

required test load of 4 147 kN.”

As pile-compression load testing

is regarded as temporary works, the

method and assembly of the tests were

carried out in accordance with the require-

ments of SANS1200F, British Standard and

the South African Occupational Health and

Safety (OHS) Act.

Structural, mechanical,

electrical, instrumentation

and piping (SMEIP)

Stefanutti Stocks Oil & Gas division is

undertaking the Chlorotrifluoroethylene

(CTFE) SMEIP contract for Sasol in Secunda.

The contract for the fabrication of the piping

spools, using free issue material, was also

undertaken by the division. This was under-

taken at the division’s pipe spool fabrica-

tion facility in Elandsfontein (that includes

a furnace for heat treatment). Once the

blasting and painting completed delivered to

site in Secunda.

Process plant maintenance and

construction

E&I has been undertaking the electrical and

Scope for application of

MULTIDISCIPLINARY

CAPABILITIES

By Chrissi Maria

As a multidisciplinary construction partner to the oil & gas

sector, Stefanutti Stocks offers a full-range of construction

services including geotechnical, earthworks, civils,

building, mechanical, process piping systems, electrical

and instrumentation installations, as well as structural

rehabilitation and concrete repair.

Stefanutti Stocks Geotechnical's piling rigs that were used at the Sasol Train 17th Plant site.