international
construction
may 2014
CONCRETE
32
Early involvement
Record-breaking pour
A16,300m
2
continuous concrete pour required 19 pumps
A
newWorldRecordhas been set for the largest continuous concrete pour inhistory – a
feat achievedduring foundation construction of the335mWilshireGrandhotel in
downtown Los Angeles, US.
Set to be the tallest structurewest of theMississippi when its doors open in2017, general
contractor Turner Construction startedwork in February this year. It drafted in specialist
concrete contractor ConcoConstruction to co-ordinate a fleet of 19pumps, including16
Putzmeister units, for the record-breaking16,200m
3
mat pour.
The concretewas poured into a6mdeeppit that lay between24 and29mbelow street
level, linedwith3,700 tons (3357 tonnes) of reinforcing steel.
Six pumps at street level fed six pumps, including twoPutzmeisterMX34-4placingboom
towers, two32.4m truck-mountedboompumps and one36.4mmodel, locateddeep in the
excavation. TwoPutzmeister BSA14000 trailer pumps at ground level also relayed concrete
into the pumps down inside the excavation.
Michael Marchesano, Turner’s general superintendent, said, “With a continuous pour of this
magnitude, youneed to be able to count on your equipment to keepdoing its job, evenunder
demanding conditions.”
The pour included227 readymix trucksmakingmore than2,100 trips andpouring almost
39million tonnes of concrete during an18 and-a-half hour period.
“Each truckmade10 to14 concrete drops, traveling through the night between eight
different concrete plantswithin a30 km radius,” saidMrMarchesano.
The structural engineering team, Brandow& Johnston, opted for themassive continuous
pour to ensure the foundationwould yield themaximum strength. Following the pour, a cure
blanket and a thermal control systemwere put into place for 15days.
>
Hæhre usedRMDKwikform’s 3DLocus programme to create
a steel shoring model for the project’s 28.4 m central span.
The software calculated the exact positioning and quantity
requirements for theRapidshor support system.
RMD Kwikform engineer Adam Fixter said, “By taking the
3Dmodel of the bridge andputting it intoour customised suite
of computer-aided design software, we were able to create our
own 3Dmodel of the shoring solution.
“This allowed us to work with our distributor Teknikk and
Hæhre to create a workable solution for the site, eliminating
clashes, while creating plans, sections and elevations for the site
team.This process gave them all the information theyneeded to
correctly erect the equipment.”
Theprecise adjustment of formworkwas also akeydemandon
a project to construct a new cooling tower for a coal-firedpower
plant in Krishnapatnam, Andhra Pradesh, India. Contractor
Tata Projects was tasked with constructing the 172.5 m tall
tower with a tapering diameter – the maximum diameter is
132 m at the base, reducing to 76.4 m at the centre and
increasing again at the top ring to 77.4m.
Tata Projects used Doka cooling tower formwork SK175,
which is designed for precise adjustment, for the job. Andreas
Guttenbrunner, head of the Doka Power Plants Competence
Centre said, “SK175 allows radii of up to 70m to be navigated
withoutanyadjustmentsandall commonlyoccurringgeometries
during cooling tower construction are covered.”
In total, the project used 128Doka SK175 units – a climbing
scaffold that serves as a carrier for the steel formwork, which is
transported by electromechanically-driven lifting systems from
one concreted section to the next.
Construction is also progressing in one-day cycles, thanks
to strict workflow plans created by Doka engineers. The
working platforms and scaffolding were delivered to the site in
accordance with an agreed schedule drawn up in conjunction
with the construction management team, and assembly takes
place under the supervision of aDoka formwork instructor.
Formworkmanufacturer Pilosio, meanwhile, said 70% of the
formwork it supplied to support construction of a motorway
junction north of the city of Durban, South Africa, was tailor-
made for the job.
ContractorCMC is building theN2-M41Mount Edgecombe
Interchange – a project which includes two of the longest
viaducts in the country.The first measures 947m long and 26
m high, and the second is 18m high and 443m long.
Pilosio is supplying200m
2
of P300 formwork for foundations
and trusses, 500 m
2
of steel formwork for the construction
of the viaducts’ pile shafts, 350 m
2
of steel formwork for the
construction of the pier caps, and two sets of Maximix model
formwork and custom-made products totalling 940m
2
.
In addition, it is supplying itsOmnimode shoring systemwith
customised to carry suspended work platforms which will be
used in the installation of the roadway ashlars (masonry).
RMDKwikform’s 3Dmodel technologywas central to Norwegian contractor Hæhre’s
design for the Labbdalen Bridges, key new structures in the country’s 3,140 km E6
Highway improvement programme.
The precise adjustment of formworkwas a key demand on
a project to construct a new cooling tower for a coal-fired
power plant in Krishnapatnam, Andhra Pradesh, India.
