DESIGN OF THE PILESUPPORTED
SLAB FOR THE
KIRISMÄKI INTERCHANGE
In the Kirismäki project, reinforced
concrete piles were used. Because
of the thick clay soil, the aim was to
minimize the number of piles. When
there are fewer piles, a great force
of the pile load is impacted on the
connection of the pile-supported slab,
and the pile tends to punch through the
slab. It is possible to increase the slab's
punching resistance by making the slab
thicker, using shear reinforcements, or
by changing the concrete strength.
In the pilot project, one section
of one pile-supported slab was
implemented using the PSB® Punching
Reinforcement System instead of a
mushroom slab. This was the first time
that this Peikko's System was used in
a pile-supported slab project. Peikko
provided design support as well as
guidance in the use of the Peikko
Designer® software.
"Together with the Finnish Transport
Infrastructure Agency, Peikko has
performed good work with the design
criteria," Jaakko Ingerttilä mentions.
"The punching reinforcement
dimensioning methods that are in use
in Finland are based on the Finnish
building regulations, whereas the
dimensioning of the PSB® Punching
Reinforcement System is based on
PROJECT FACTS
• DEVELOPER: FINNISH
TRANSPORT INFRASTRUCTURE
AGENCY
• STRUCTURAL DESIGNER:
WSP FINLAND OY
• MAIN CONTRACTOR: DESTIA OY
Eurocode and the ETA assessment of
the product. There are slight differences
between these and for this reason,
my understanding is that with Peikko's
PSB®, it is not possible to achieve slabs
as thin as might be possible. We have
presented Peikko with a development
idea in this area."
DESTIA COMPARES THE
BENEFITS OF PILE-SUPPORTED
SLAB STRUCTURES
In the Kirismäki interchange, both the
traditional mushroom slab and Peikko's
PSB® System were used to compare
the functioning and cost impacts of the
solutions. At Destia, the comparison of the
pile-supported slab structures is performed
by Panu Salminen, foreman:
"The punching reinforcement system
speeds up the construction of a pilesupported
slab significantly, because one
work phase, namely the holes made for
the mushroom structures and concreting
these, is eliminated. This can speed up the
work by up to a week." Installation of the
punching reinforcement was really easy
and fast according to Panu Salminen.
The use of the punching reinforcement
system does, however, require a thicker
concrete slab. In these types of projects,
the depth of a mushroom slab's concrete
slab is usually 25 cm (10 in) and at the
mushroom bulges, 53 cm (21 in). In the
case of Kirismäki punching reinforcement
system, the slab depth was 41 cm (16
in). On the basis of the pilot project's
comparison calculations, design criteria
for reducing the slab depth can be
reassessed. ●
REFERENCES
26 PEIKKO CONNECTIONS 1/2021