The Hearts of Oak Benefit Society, which
operates within the framework of the Friendly
Societies Act, has grown from humble beginnings
in 1842 to become one of the foremost friendly
societies in the country. It is appropriate,
therefore, that the new Euston Road, London,
Headquarters building should be a prestigious
edifice and, because of the growth record, that
every available square foot of the site should be
used effectively.
A normal tower block was the ideal solution but
the height necessary to achieve the required
usable office space was unacceptable from a town
planning viewpoint because of the proximity of
St Pancras Church. The shape of the building as
dictated by the Town Planning Authorities led
the Society’s Architects to design the building
on the suspension principle so that there are
no columns intruding on the office floor space,
and with a podium of three storeys, inclusive of
basement, which further compensates for the
loss of space due to the reduction in height.
The new building is but the fourth of its type
in the UK, the other three also being in London.
Of the examples of tall suspended buildings
elsewhere in the world, the architects and
engineers visited those of the Common Market
in Brussels, BP in Antwerp and Philips in
Eindhoven. Valuable information was gained
from each but the Philips building displayed
principles most applicable to the Hearts of
Oak development. Unlike the Philips building,
however, which has the floors suspended only
from the long sides of the core, the Hearts of
Oak building has suspenders on all four sides.
This was necessary to allow the east side of the
building to overhang the existing pavement, for
which, down to third floor level, agreement was
reached with the Greater London Council. The
suspended floors thus project the same amount
on all sides from the central core to give plan
dimensions of 58ft × 106ft. The core itself is 18ft
9in × 67ft 3in.
Construction
The construction of all buildings of this type
follows the same principles. A concrete core is
built to house stairs, lifts and other services
and to act as a stiff member to transmit all
horizontal forces to the foundations. Then an
umbrella structure is cantilevered out at the
top and from the periphery, the suspenders are
hung to support the floors.
In the case of the Hearts of Oak building the
concrete core, supported on a raft surmounting
under-reamed piles reaching 40 to 50ft down
into the London clay, was built by traditional
methods with a vertical tolerance of only ±½in
in some 200ft.
30 NSC
June 19
At the top of the core, eighteen specially
constructed anchor blocks of high yield stress
steel are built into the core cap. Opposite
anchor blocks are connected with pairs of cables
each consisting of thirty four 7mm wires, post
tensioned in two stages to take loads of up to 120
tons per cable. The anchor blocks set diagonally
at each corner of the core are held back by
similar pairs of cables anchored to the core itself.
During erection, the cables are protected against
corrosion by a surface coating. They will be
L5i0s tYienagrss Ago
Reprinted from Volume 5 No. 4
June 1969
Head office for
Hearts of Oak
Benefit Society
Model showing the whole concept