The
office building E is the very last piece of development completing the northern
part of the BB Center complex along Vyskocilova (street) and a ramp to 5.května
(street). So, towards the city centre the bldg. E closes the planned
“protection shield” against the negative impact of city highway traffic on
residential houses planned for the second phase of development. This part of
the Prague-Michle district has now been revitalized, reintroducing the urban
environment with multiple functions and restoring it the way it was before the
highway – 5.května street – completely destroyed it.
Location
of the building within the first plan facing the highway protects the future
development along Baarova (street), but at the same time calls for the necessity
to eliminate noise reverberation to the opposite residential houses. The
solution of this problem became (similar to the solution of the recently
completed Gamma building) the basic architectural concept responding to
physical principles of noise reverberation.
The
approach to this problem is very individual resulting from the specific set-up
of this particular building. A ´broken´ façade is designed facing the source of
noise – 5. kvetna street and the access ramp – with strip fenestration. Its
moulding was defined by the specific highway curve and the ramp from
Vyskocilova (street) in order to prevent reverberation of noise generated by
cars passing by towards the above-mentioned houses on the opposite side of the
highway. The designed geometry allows areas of this special envelope to bounce
noise away either to the grassed slope between the highway and the ramp
naturally absorbing it, or diverting it at a large angle upwards and diffusing
it in the open space high above. This way the façade system effectively deals
with the so-called ´non-attenuable´ parts of the façade – i.e. glazed strips of
windows and remaining solid panels that are incapable of noise attenuation due
to their physical properties. The bigger part of the facade is made from
sound-absorbing perforated steel plates.
The broken façade is a 3-D
reinforced concrete wall with window openings between loadbearing pillars
copying its geometry. To build it the contractor decided in the end to use a
combination of prefabricated elements and casting in-situ. Façade windows are
designed as fixed panels made of the façade modular structure; special
trapezium profiles were produced for this particular purpose corresponding with
the designed inclination of the façade. Glazing and fixing to the core and
shell is dealt with so that acoustic comfort is also maintained in the interior
– the assumed maximum level of acoustic pressure in each office is Laeq 45
dB. A particular type of glass for this façade was selected in respect of solar
radiation – glass panes are used preventing an increase in the heat loading;
exterior louvers complement glazed areas. These louvers can be controlled
either individually or from the central control panel.
Solid
façade sections are designed as thermally insulated with perforated sheet
panels finished by metallic coloured powder coat set in front. Perforation
(diameters and cc distances of holes) was again selected in cooperation with
sound engineer. Sheets are screwed to structural grating that also drains water
away from the façade. Due to perforation, a waterproof foil protects mineral
acoustic and thermal insulation. Window frames with plinths and boxes for
exterior louvers consist of exactly fabricated Larsen composite casing panels.
The parapets and fronts of walls set in the face of the façade on both ends of
the building are composed the same way.
A system of fixing eyes for
anchorage of the façade cleaning and maintenance staff is designed within the
façade system.
The acoustic facade forms a
hypotenuse of a triangular concept of the building; the remaining two sides
facing inwards to the area are designed as fully glazed with irregular
horizontal articulation. The envelope is designed using a system modular
façade; the additional areas on the ground floor and façade of the bay above
the entrance are standard framing with additional cladding of solid areas by
aluminium coated sheet and Larson composite panels.
The triangular footprint contains a
similar triangular atrium letting light into the interior of the seven-storied
structure. The atrium is at the same time a circulation and social centre of
the building containing green, panoramic lifts and other refreshing elements. A
glazed skylight roofs the whole atrium.
The building E also has areas
allocated for relaxation and park areas, partly designed in front of the main
entrance, partly in the form of a roof garden protected by a parapet of the
acoustic façade. A fountain is installed as a landscaping element in front of
the entrance.
The concept of the layout allows
arranging the interior areas as open-space and at the same time as individual
offices. The office areas, furnished and parted according to the particular
tenant’s needs (CEZ Group), are complemented by other facilities – a kitchen
with a staff canteen, a conference centre with a cafeteria on the ground floor,
etc. The underground garage utilises the central shape of the building and it
is designed as a four-storied helix without additional ramps.
The building E is equipped with
sophisticated forced ventilation and cooling, the so-called exact cooling – VRV
system. The building is fully sprinklered; gas fire extinguishing is designed
for server rooms and IT workplaces. Lighting of offices is also up-to-date
employing the system of mobile floor-tape luminaries allowing more even
distribution of light and better a flexibility of office organisation.