Concrete Plant + Precast Technology Betonwerk ... - BFT International

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many cases, as well as due to frequent changes in use. In
this respect, three approaches to optimization are being
pursued:
(1) Accurate documentation of required service loads: A
detailed documentation of the actual service loads acting
on the structure enables the calculation of equivalent
area loads that depend on the structural system of
the framework and on the load introduction area. This
prevents any unnecessary over-design of the structural
framework. Since the magnitude of the equivalent
area loads mainly depends on the load introduction
area, the additional material required for wide spans
can be partially compensated by an area load designed
accordingly. In addition, it is very important to identify
the loads acting on the structure accurately in order
to provide the required fl exibility of the load-bearing
structure for varying uses.
(2) Optimization of structural components: The environmental
impact of reinforced concrete components can
be optimized in a targeted fashion by adjusting their
dimensions, the strength of the concrete used and the
resulting reinforcement ratio. For point-supported
fl at fl oor slabs, the example of primary energy consumption
was used to demonstrate that a fl oor thickness
that is as low as possible provides the most favorable
environmental outcome (Fig. 2).
(3) Flexible load-bearing structures: Resource consumption
can be reduced in the long term due to a high degree
of fl exibility of use of the structural framework
that enables a long service life of the load-bearing
structure.
Subproject C3: Energy-effi cient building construction
Energy effi ciency is a key aspect of construction with a
view to achieving a higher degree of sustainability, especially
with regard to the period of use of buildings. Simulations
were carried out and used to determine the primary
energy consumption of the reference building used
in the joint project (urban module) for residential and offi
ce use and for two diff erent load-bearing structures. In
this exercise, the energy expenditure for heating, cooling,
hot water supply and lighting of the building was considered.
According to this investigation, the type of façade
used (such as a punctuated or ribbon façade or a façade
with a high amount of glazing) has a major infl uence on
energy consumption. Under the boundary conditions selected,
the most favorable primary energy consumption
was found for the ribbon façade. Amongst other benefi ts,
concrete construction enables a reduction in the amount
of cooling required, in particular during chargng and uncharging
of a structural component, for instance by nighttime
ventilation. If provided building services and thermal
coupling of the load-bearing concrete structure are
combined in an appropriate fashion, the need for an active
cooling of offi ce buildings can be eliminated completely
without having to compromise on thermal comfort.
BFT 02/2010
Primary energy consumption/Primärenergiebedarf (MJ/m 3 )
Podium 1
h [cm]
Fig. 2 Primary energy consumption per m² of fl oor slab area depending on fl oor thickness h
(fl at slab, l = 10m, q = 20 kN/m²).
Abb. 2 Primärenergiebedarf pro m² Decke in Abhängigkeit von der Deckendicke h
(Flachdecke, l = 10m, q = 20 kN/m²).
dass eine möglichst geringe Deckendicke das ökologische
Optimum darstellt (Abb. 2).
(3) Flexible Tragstrukturen: Durch einen hohen Grad an
Nutzungsfl exibilität des Tragwerks kann auf Grund
einer langen Nutzungsdauer der Tragstruktur der
Ressourcenverbrauch langfristig reduziert werden.
Teilprojekt C3: Energieeffi zienter Hochbau
Energieeffi zienz, insbesondere mit Blick auf die Nutzungsphase
von Gebäuden, ist ein wesentlicher Gesichtspunkt
des Bauwesens auf dem Weg hin zu mehr Nachhaltigkeit.
Anhand von Simulationsrechnungen wurde der
Primärenergiebedarf des im Verbundprojekt verwendeten
Referenzgebäudes (Stadtbaustein) für eine Wohn-
und eine Büronutzung sowie für zwei unterschiedliche
Tragstrukturen ermittelt. Dabei wurden die Energieaufwendungen
für die Beheizung, Kühlung, Warmwasser
sowie die Beleuchtung des Gebäudes betrachtet. Demnach
hat u. a. der Fassadentyp (Lochfassade, Bandfassade,
hoch verglaste Fassade) einen hohen Einfl uss auf den Energiebedarf.
Unter den gewählten Randbedingungen
schnitt die Bandfassade primärenergetisch am günstigsten
ab. Die Vorteile der Betonbauweise liegen in der Verringerung
des Kühlbedarfs insbesondere bei der Be- und
Entladung eines Bauteiles, z. B. durch Nachtlüftung. Bei
gezielter Kombination von Gebäudetechnik und thermischer
Kopplung der Betontragstruktur kann für Bürogebäude
auf eine aktive Kühlung vollständig verzichtet
werden, ohne dabei thermische Komforteinbußen hinnehmen
zu müssen.
Reinforcing
steel +
concrete
Bewehrungsstahl
+ Beton
Reinforcing
steel
Bewehrungsstahl
Co-Autoren
Dipl.-Ing. Thorsten Bleyer
bleyer@bgt.rwth-aachen.de
Prof. Dr.-Ing. Marten F. Brunk
brunk@bgt.rwth-aachen.de
Dipl.-Ing. Tobias Dreßen
tdressen@imb.rwth-aachen.de
Dipl.-Ing. Andreas Haas
haas@mb.bv.tum.de
Dipl.-Ing. Norbert Hanenberg
Hanenberg@
bauko.arch.rwth-aachen.de
Dipl.-Ing. Ingo Heusler
ingo.heusler@ibp.fraunhofer.de
Dipl.-Ing. Christian Mühlbauer
muehlbauer@mb.bv.tum.de
Dr.-Ing. Roland Peter Niedermeier
niedermeier@mb.bv.tum.de
Prof. Dipl.-Ing. Hartwig N. Schneider
schneider@
bauko.arch.rwth-aachen.de
Dipl.-Ing. Herbert Sinnesbichler
herbert.sinnesbichler
@ibp.fraunhofer.de
Prof. Dr.-Ing. habil. Dr.-Ing. E.h.
Konrad Zilch
k.zilch@mb.bv.tum.de
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