DESIGNING FINLAND’S TALLEST TIMBER BUILDING
An innovative new office building,
called Keilaniemen Portti, will be Finland’s tallest timber building. Ramboll
is on board as engineering partner, to help Varma Mutual Pension Insurance
Company realise the ambition of creating an innovative and sustainable
structure with low environmental impact.
Keilaniemen Portti, which means “the gate of Keilaniemi”, will be located in
the fast-developing business district Keilaniemi in Espoo, Finland, which is
home to many of Finland’s largest corporations and known for its many
high-rises.
At 60 metres, Keilaniemen Portti will
be the tallest timber building in Finland – and one of the tallest timber
office buildings in the world – and add another striking high-rise to Espoo’s
city skyline.
The 17,900 m2 building will house a
number of attractive office spaces as well as a conference centre and
auditorium, a restaurant, a sauna, a scenic rooftop terrace and underground
parking spaces.
Ramboll is helping Varma realise the ambitious
project by providing structural design, geotechnical design and HVAC services
as well as designing the energy system and securing BREEAM Certification for
the building, aiming for a rating of ‘Excellent’.
Lowering the carbon footprint
Varma’s ambition for Keilaniemen
Portti is to create an innovative structure with low environmental impact and
eco-friendly materials and choosing timber as one of the primary building
materials is a key part of realising this ambition.
As timber has less than half the
embodied carbon of concrete and the ability for long-term carbon storage,
timber significantly reduces the carbon footprint of the building.
Moreover, timber is lighter and
enables more prefabrication, which can help reduce the number of deliveries to
site and result in cleaner siteworks, fewer onsite construction workers and
minimised waste on site.
Together with the choice of timber,
solar panels, a green roof and energy efficient building solutions will help
increase the sustainability of the building.
Unique architecture and innovative technical
solutions
Timber is also at the core of the
architectural vision. Combined with the sloping green roof, an organic shape
with soft curves, and the seaside location, timber will help bring a sense of
nature to the office space, with the aim to improve well-being for the tenants.
However, the complex shape of the
building sets high demands for the structural design. To meet the demands,
Ramboll designed a true hybrid structure that utilises both timber, steel and
concrete.
The building’s core shafts are made
of concrete, while the shell of the building is timber. Steel beams, which are
stronger and lower than timber beams, are fitted inside the timber floors,
making it possible to run HVAC piping straight through the building. The
overall thickness of the intermediate floor was minimized and streamlined in
the design to enable maximum utilization of the floor height.
In this design process, the Ramboll
team invented an innovative new technical solution that connects the timber and
steel elements together, allowing them to work together as one and efficiently
transfer loads to the concrete core shafts. The new connector was designed to
improve safety during installation by enabling quick and easy assembly.
The result is a structure that
utilises the strength of each material to successfully and efficiently realise
the architectural vision.
Work on the building foundation and
underground parking is planned to begin in 2021, and the building will be
completed in 2024.
Project data:
Client: Varma Mutual Pension Insurance Company
Completion: 2024
Architect: Architects Soini & Horto
Services Ramboll provided:
Structural design & engineering
Geotechnical design
HVAC
Energy systems
Environmental certification