Concrete Magazine, June 2013 Tesco, Woolwich. The £86m scheme which is developed by Spenhill (a wholly owned subsidiary of Tesco stores) will create a large mixed-use development that will house an 8,000 square metre Tesco superstore, seven further retail units, car park, police station and 259 apartments in Woolwich.

1. T
he design team consists of Sheppard Robson
Architects with Walsh Associates providing the
structural engineering input, including the post-
tensioned design. Such is the scale of the development
that Willmott Dixon is combining all three parts of
its capital works division (major contracting, house
building and interior design and fit-out) to complete
the scheme. Widely regarded as one of the largest
post-tensioned schemes in the UK today, the scheme’s
construction will see the consumption of 100,000
tonnes of concrete delivered by 5000 concrete trucks. Five
thousand tonnes of reinforcing steel will be required to
complete the frame and 85,000m3 of excavated material
will need to be removed. However, environmental
initiatives will see 50,000 tonnes of demolition material
reused.
Other initiatives have been used, including
slipforming the cores to take them off the critical path
and to improve hook time for follow-on trades, huge
pours to Level 1 and the use of precast columns to the
residential blocks. Structural Systems was involved in
grouting up the precast columns, which were dowelled
to the columns below.
Seventeen-storey project
In addition to the superstore, the 17-storey project will
house basement car parking for both Tesco customers
and residential owners. The accommodation is split
between private sale and affordable rent markets. Of
the 259 new homes, consisting of a mixture of one, two
and three-bedroom apartments, 189 will be available
for private sale, with a further 70 for affordable rent.
The 259 apartments forming the residential aspect of
the scheme are located in eight separate blocks that run
from Level 8 upwards. The tallest of these blocks, Palma,
will be eight storeys high, giving Woolwich Central a
maximum height of 17 floors. A residential roof-top
garden will sit between the blocks, with access from two
private residential entrances.
Investment
The development brings huge inward investment
to Woolwich; it is hoped this will create new jobs
and further growth with the arrival of skilled people
who will be attracted by the modern apartments in a
good location. A major advantage of the residential
development beginning seven floors above street level
is that occupants will be sheltered from much of the
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POST-TENSIONING/PRESTRESSING
Post-tensioning provides the
base for ‘Tesco Town’
Willmott Dixon is building the first of a series
of planned ‘Tesco Towns’ in south London.
The £86 million scheme being developed
by Spenhill (a wholly owned subsidiary of
Tesco stores) is to create a large mixed-use
development that will house an 8000m2
Tesco superstore, seven further retail
units, a car park, police station and 259
apartments in Woolwich. As Richard Gaskill
of Structural Systems (UK) reports, it is also
one of the largest post-tensioned projects in
the UK.
The largest
pour was on the
podium slab at
Level 8. This was
scheduled to
be done in five
pours totalling
a staggering
3267m3
❞
❝
The Tesco Extra, Woolwich is a major development by Spenhill, a wholly owned
subsidiary of Tesco, producing a residential and mixed-use development.

2. www.concrete.org.uk JUNE 2013 concrete 17
POST-TENSIONING/PRESTRESSING
London noise. West-facing apartments will have the
added benefit of balconies that front on to the roof-top
garden, while east-facing apartments will profit from
mini-winter gardens, reflecting the fact they get less
sunlight.
Structural Systems installed a variety of post-
tensioning components into the concrete frame,
including both 12.9 and 15.7mm strands in both slabs
and beams. The 12.9mm strand was mainly used on
Level 1 and the slabs on Level 2, and for the residential
blocks. All other areas used the 15.7mm strand. In total,
over 54,000m2 of post-tensioning was installed, with a
variety of slab depths ranging from 180 to 350mm deep.
In addition to the slabs, throughout the structure, over
three miles of post-tensioned beams were used, ranging
in size from 500 to 1500mm deep and up to 2000mm
wide. Within the beams, BBR VT Cona CMF anchors
were also used, having three and four strands per anchor
with up to nine tendons per beam.
Above: The basement
construction under way.
A slab-and-beam option was
used to reduce the number
of columns.
Far left: Concreting the car
park PT slab and beam, with
the PT in the beams clearly
visible.
Above: A bird’s eye view of the Tesco Store
development, which is on the edge of the town,
with the River Thames in the background.

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POST-TENSIONING/PRESTRESSING
Largest pour
The largest pour was on the podium slab at Level 8.
This was scheduled to be done in five pours totalling
a staggering 3267m3, which included 18 beams with
multi-strand BBR VT Cona CMI anchors using between
ten and 12 strands per anchor. The slab running over
the top of the beams totalled just less than 8500m2 of PT
slab. The largest pour was approximately 1400m3 and
was completed in a single day.
Such was the pace of the programme that the
concrete frame was completed within a ten-month
period from October 2011 to July 2012. The new
superstore is now open, along with the first wave of
residential units. The remainder of the development
and associated apartments will be completed in several
stages, with the whole project due to be completed and
handed over by July this year. ●
Above: The cores were
slipformed to take them off
the critical path.
Right: The Tesco Extra,
Woolwich.
Far right: A mixture
of in-situ and precast
columns (in the residential
blocks) was used to aid
programming and improve
hook times on the cranes.