C O M M E N D A T I O N SSDA 2018
FACT FILE
Architect:
SimpsonHaugh
Structural engineer:
BuroHappold
Steelwork
contractor:
William Hare
Main contractor:
Laing O’Rourke
Client: Mosley Street
Ventures Ltd
NSC
October 18 33
Two
St. Peter’s
Square,
Manchester
Two St. Peter’s Square is a
new build, Grade A office
space in the heart of
Manchester city centre,
consisting of 12-storeys
above ground and two
basement levels.
The project occupies one of
Manchester’s prime city centre
locations, opposite the Civic Centre
and facing both the Grade I listed
Town Hall and Grade II listed Central
Library.
The high civic importance, heritage
and visibility of the site resulted in an
intricate and challenging planning context,
demanding a high-quality building.
The key driver for the structural design
was to provide highly flexible column-free
accommodation that would be attractive
to potential tenants. The typical beams
are 730mm deep and, over the 18m span,
vibration was a key criterion governing
many of the section sizes.
“Only by using cellular beams could
the 18m spans be accommodated while
maintaining the required floor-to-ceiling
heights,” says SimpsonHaugh Partners
Architect Simon Critchley.
At ground floor level the architectural
intent was to provide a colonnade with
columns at 12m centres and cantilevers
of 6m at either end. Continuing this wide
spaced gird on the typical floors above was
not economic and a number of options were
considered.
Considering the buildability and cost
implications a transfer structure at the lowest
level was the chosen option. This greatly
simplified the buildability and allowed
a considerable service zone, which was
required to support the servicing strategy.
To maximise the spatial experience of the
colonnade at ground floor level the columns
are double-height, with the first floor setback
from the perimeter.
Long-span transfer beams at level
two achieve this with the first floor hung
from above. A similar arrangement is
adopted at level ten with transfer beams
that support the set-back columns above.
This arrangement provides a high value
terrace space overlooking the civic heart of
Manchester.
Supporting the façade presented a
number of engineering challenges. Each
unit was constructed in 6m wide by 4m
high mega-panels which were supported
vertically at the base and tied laterally at the
head. Mega-panels are supported by stubs
directly back to each steel column, allowing
a slender perimeter edge beam, coordinating
well with the fenestration.
The use of a structural steel framing
solution was a key element in the project’s
success as Laing O’Rourke Project Manager
Tim Brown says: “The obvious win was
speed of procurement and erection, as the
client had a deadline to get the building
open in order to secure a Blue Chip anchor
tenant.”
“Technically, by using steel the designers
were also able to create a large double-height
main entrance for the high-end reception
area.”
Summing up, the judges say this scheme
of new Grade A offices in the heart of
Manchester’s civic centre responds to the
challenge of this site of prime importance.
Not only does the glazed stone tracery
respond appropriately to the location, but
the elegant steel-framed building with 18m
clear spans provides flexible accommodation
highly attractive to tenants.
© Daniel Hopkinson
/Design
/Floor_vibrations
/Steel_construction_products#Cellular_beams
/Facades_and_interfaces
/Construction#Steel_erection
/Multi-storey_office_buildings
/Braced_frames
/Multi-storey_office_buildings#Flexibility_and_adaptability