82
X1
Category 1: Buildings
Software: Scia Engineer, Allplan Engineering
HILASE, New Lasers for Industry and Research - Prague, Czech Republic
Description
The main objective of presented project “HILASE” is to
develop laser technology with breakthrough technical
parameters. In offering these parameters, Laser Centre
“HILASE” will be unique, not only in the Czech Republic
but also in Europe. The “HILASE” object is divided
into two parts; a monolithic two-storey laser hall and
a three-storey administrative section. The dimensions
of the laser hall are 25.9 m x 49.9 m, with a height of
8.9 m. The ceiling above the 1st floor and the roof above
the 2nd floor have a common beam formed in the 2nd
floor. The beam is broken by a number of large holes
for wiring technology lasers. The beam has a span of
25.9 m and was designed as monolithic-reinforced. The
administrative building has the dimensions of 14.7 m
x 60.0 m and a height of 11.85 m. The structure is
designed as a monolithic skeleton, while the building
edge sections are cantilevered on the second and third
storeys. The building foundation is designed on piles.
The foundation of the laser plate, located on the 1st floor
of the hall, is designed with a 420 mm thickness. The
dynamic filter is designed under the laser plate in order
to reduce the transmission of vibrations from the subsoil
into the building.
Conceptual design and structural analysis
The building was designed according to strict
technological requirements for the operation of the laser.
Especially strict are the limits for the dynamic behaviour
of the laser foundation slabs from subsoil vibration.
These vibrations are propagated from the subsoil
environment to the building structure.
The first natural frequency of the laser slabs must be
greater than 25Hz. The limit deflection of any point
structure is <Δuz,rqr = 0.2 micron in 5-50Hz, and the
maximum Δuz,rqr = 0.02 micron in 50-100Hz. These
values are very stringent and are difficult to achieve in
the design of the foundation slabs. The foundation plate
is located in the hall of the building and it is laid in bad
geological layers. To reduce vibrations transferred from
the subsoil to the foundation structure, the dynamic filter
was designed, at the boundary of both systems. The
layered structure is composed with a high and very low
bulk density and also a high and low speed of vibration
through strata. Filter efficiency was determined at a
value of 30%. The own response to dynamic exciting
(loading) was performed with the use of the spectral
analysis computing system with Scia Engineer on the
3D model. Control calculations were carried out in the
reference software. The foundation of the laser plate was
modelled as a 3D (wall-plate) structure supported by a
flexible “Winkler - Pasternak subsoil”. The values of the
soil were modelled using envelope subsoil with regard
to the fact that the control-verification was made with
the system Soilin. The vibration load was considered
as 0.00008 m/s
2
and was an expert estimate compiled
from experiences of other sites and from vibration
measurements in the locality. The ceiling above the 1st
floor (the laser hall) and the roof above the 2nd floor
have a common beam formed in the 2nd floor. The
beam is broken by a number of large holes for wiring
technology lasers. The beam has a span of 25.9 m
and was designed as monolithic-reinforced. For global
analysis several nonlinear 2D and 3D models were
created in Scia Engineer. A controlling calculation was
performed on the beam element. Crucial to the design
of the reinforcement was the “strut and tie” model, which
served for the design and control of global reinforcement
and reinforcement around the holes. It was confirmed
that this method achieved good agreement with the
nonlinear calculation made with Scia Engineer.
Conclusion
The design of the laser hall - in particular the foundation
of the laser plate - required the linking together of deep
expertise in the geotechnical and dynamic sides of
structures. Calculations that are made for structures
exposed to subsoil environment vibrations are very
complicated and require high theoretical and practical
experience. In this case, to achieve very strict limits in
regard to the dynamic responses of the foundation of the
laser plate, the dynamic filter was used at the boundary
of both systems to reduce the transmission of vibrations
from the ground to the construction. The checking of
calculations for the trusses was performed with the
“strut and tie” method. It was confirmed that this method
achieved good agreement with the nonlinear calculation
made with Scia Engineer.
