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Contents: Structural Concrete 4/2012 Structural Concrete 4/2012 Contents

Kurzfassung

Keine Kurzfassung verfügbar.

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Clark, Gordon Concrete, Cars, Computers and Climate Change Structural Concrete 4/2012 211-212 Editorial

Kurzfassung

Keine Kurzfassung verfügbar.

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Beckmann, Birgit; Schicktanz, Kai; Reischl, Dirk; Curbach, Manfred DEM simulation of concrete fracture and crack evolution Structural Concrete 4/2012 213-220 Articles

Kurzfassung

A two-dimensional simulation of concrete behaviour using the discrete element method (DEM) is presented in this work. The main aim of this paper is the modelling of the failure process and crack initiation. The failure process of a concrete prism during a compression test is simulated. A substructure representing the concrete components - aggregate and cement matrix - is introduced. It is shown that convex and concave concrete specimens can be treated, whereas the particle geometry always remains convex. The crack patterns of the concrete specimens resulting from the simulation are shown and compared with laboratory experiments. It is shown that the calculated peak load does not depend on the particle number used in the simulation. The ratio of lateral strain to longitudinal strain of the concrete specimen during load application is simulated and compared with experimental results.

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Al-Akhras, Nabil M. Performance of olive waste ash concrete exposed to alkali-silica reaction Structural Concrete 4/2012 221-226 Articles

Kurzfassung

This work investigates the effect of olive waste ash (OWA) on the durability of concrete exposed to alkali-silica reaction (ASR). Three OWA contents were considered in the work: 7, 15 and 22 %, with crushed Pyrex glass used as reactive fine aggregate. The other experimental parameters investigated in the study were: w/c ratio (0.4 and 0.5) and air content (non-air-entrained and air-entrained). The OWA concrete specimens were submerged in 1-N NaOH solution at 40 °C to accelerate the ASR. The ASR damage was monitored by measuring the expansion of concrete prisms and the decrease in compressive strength.
The study demonstrates that OWA concrete is more resistant to ASR deterioration than plain concrete. The durability of OWA concrete with respect to ASR damage improved with the increase in OWA content. The OWA concrete with a w/c ratio of 0.4 exhibited a better performance with respect to ASR deterioration than the OWA concrete with a w/c ratio of 0.5. The air-entrained OWA concrete exhibited better durability with respect to ASR damage than the non-air-entrained OWA concrete.

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Larsson, Oskar; Thelandersson, Sven Transverse thermal stresses in concrete box cross-sections due to climatic exposure Structural Concrete 4/2012 227-235 Articles

Kurzfassung

Spatial and temporal temperature variations in a concrete structure due to variations in the surrounding climate will produce movements which, if restrained, may induce stresses in the structure. To get a better understanding of transverse thermal stresses due to climatic effects in concrete box cross-sections, the FE simulations in this study have been performed using extensive climatic input data directly or by using simplified methods to simulate the temperature and resulting stress fields in a section of the hollow concrete arch of the New Svinesund Bridge. Studies of other cross-sections with varying depth, width and wall thicknesses have also been performed to investigate the geometrical influence. The results reveal an overestimation of the maximum thermal tensile stress when using a linear temperature differential approach compared with the direct use of climate data that includes the non-linear part of the temperature distribution. The effect of depth, width and orientation is negligible compared with variations in thickness between slabs and walls. For box sections with slabs/walls having different thicknesses, the transverse thermal stresses will be significantly larger in the thinner members, irrespective of the actual orientation and position of the member.

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Jiang, Wei; Gong, Jian; De Schutter, Geert; Huang, Yulin; Yuan, Yong Time-dependent analysis during construction of concrete tube for tower high-rise building Structural Concrete 4/2012 236-247 Articles

Kurzfassung

Vertical and differential deformations in super-high-rise buildings are extremely important during construction. In order to be able to adjust the construction process accurately, taking the deformations into account, such deformations must be calculated exactly. The analysis of the vertical deformations of the high-rise Shanghai World Financial Centre building is illustrated in this paper. The prediction models of CEB-FIP 90 are used for calculating shrinkage and creep. The fictitious degree of hydration method has been applied for calculating the creep behaviour of the early-age concrete. The influence of steel bars on the vertical deformations has been analysed based on the macroscopical modulus method. Calculation of the vertical deformations includes the pre-construction and the post-construction deformations. Finally, the differential deformation between the concrete and the mega-structure column is determined. Theoretical results for the vertical displacement of this super-high-rise building agree very well with field monitoring data.

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Bertagnoli, Gabriele; Giordano, Luca; Mancini, Simona Design and optimization of skew reinforcement in concrete shells Structural Concrete 4/2012 248-258 Articles

Kurzfassung

Nowadays, it is more and more often necessary to design two-dimensional reinforced concrete elements to satisfy both architectural demands and to comply with traffic safety requirements in the design of road and railway infrastructures. In fact, the demand for non-regular structural geometry is increasing in both cases.
As a consequence, the use of finite element analyses to model structures and calculate internal actions is constantly growing because closed-form solutions are generally unavailable for irregular shapes. Therefore, the problem of reinforcement design needs our attention because steel bars, in general, should be placed in non-orthogonal directions and can vary over the structure.
Consequently, there are two different kinds of design problem: choice of reinforcement direction and evaluation of the reinforcement ratio between the chosen directions, with the aim of minimizing the total amount.
Such problems can be easily overcome by generalizing a mechanical model consolidated in the literature for orthogonal reinforcement for skew directions. The model is set up according to the ultimate plastic behaviour of the elements. An optimization technique based on genetic algorithms is then applied to the new model to reduce the amount of reinforcement.
This paper describes both the ultimate resisting mechanism with generic reinforcement directions and the way genetic algorithms are employed to optimize the amount of reinforcement.

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fib-news: Structural Concrete 4/2012 Structural Concrete 4/2012 259-267 fib-news

Kurzfassung

Call for entries: 2014 fib Awards for Outstanding Concrete Structures
fib 2013 Symposium, Tel Aviv
Commission 9 update
70th birthday symposium for Rolf Eligehausen
BEFIB2012 - An overview
Symposium for Joost Walraven
fib bulletins
Walter Thorpe † 1928-2012
Congresses and symposia
Acknowledgement
2012 reviewers

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Contents: UnternehmerBrief Bauwirtschaft 4/2012 UnternehmerBrief Bauwirtschaft 4/2012 Contents

Kurzfassung

No Abstract.

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Schalk, Günther Gürtel und Hosenträger? 4/2012 UnternehmerBrief Bauwirtschaft 4/2012 1 Editorial

Kurzfassung

No Abstract.

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Kurz infomiert UnternehmerBrief Bauwirtschaft 4/2012 2 Kurz informiert

Kurzfassung

• Konjunkturpaket II bei Bundesbauten verpufft
• Mediationsgesetz erst einmal in der Warteschleife
• Umweltministerium: „Aktionismus am falschen Ende”

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Proske, Dirk Theorie und Praxis: Welche Rolle spielt die Sicherheit am Bau? UnternehmerBrief Bauwirtschaft 4/2012 3-11 Berichte

Kurzfassung

No Abstract.

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Kontierungsvermerk auf elektronischen Rechnungen? UnternehmerBrief Bauwirtschaft 4/2012 12 Berichte

Kurzfassung

No Abstract.

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Grunderwerbsteuer: Kunden über Musterprozess informieren UnternehmerBrief Bauwirtschaft 4/2012 12-13 Berichte

Kurzfassung

No Abstract.

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Vorsicht bei Zuschlägen für Sonntags-, Feiertags- und Nachtarbeit UnternehmerBrief Bauwirtschaft 4/2012 13 Berichte

Kurzfassung

No Abstract.

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Fuchs, Bastian; Höckmayr, Andreas Aktuelles aus der Rechtsprechung UnternehmerBrief Bauwirtschaft 4/2012 14-16 Berichte

Kurzfassung

No Abstract.

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Steuerfreie Überlassung von Software, Smartphones & Co. UnternehmerBrief Bauwirtschaft 4/2012 17 Berichte

Kurzfassung

No Abstract.

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Fotovoltaik: Vorsicht vor Nachteilen bei Gewerbesteuer UnternehmerBrief Bauwirtschaft 4/2012 17-18 Berichte

Kurzfassung

No Abstract.

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Entfernungspauschale: So wird bei einer Umwegstrecke gerechnet UnternehmerBrief Bauwirtschaft 4/2012 18 Berichte

Kurzfassung

No Abstract.

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Bürgschaft: Werbungs- oder Anschaffungskosten? UnternehmerBrief Bauwirtschaft 4/2012 18-19 Berichte

Kurzfassung

No Abstract.

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Umsatzsteuer: Aktuelle Trends, Urteile und Anweisungen UnternehmerBrief Bauwirtschaft 4/2012 19 Berichte

Kurzfassung

No Abstract.

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Schalk, Günther Mit dem Stetoskop an der Mauer? UnternehmerBrief Bauwirtschaft 4/2012 20 Buchtipp

Kurzfassung

No Abstract.

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Veranstaltungshinweise UnternehmerBrief Bauwirtschaft 4/2012 20 Veranstaltung

Kurzfassung

No Abstract.

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Inhalt: Bauphysik 3/2012 Bauphysik 3/2012 Inhalt

Kurzfassung

Keine Kurzfassung verfügbar.

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Kaase, Heinrich; Aydinli, Sirri; Gramm, Stefan; Thiel, Stefan; de Boer, Jan; Erhorn, Hans; Kuhn, Tilman; Wienold, Jan; Hillmann, Gustav; Korolkow, Margarethe; Piazena, Helmut Energieoptimierte Beleuchtung bei gleichzeitiger Verbesserung der Lebensqualität durch Nutzung von Tageslicht und neuer Lampen- und Vorschalttechnik Bauphysik 3/2012 85-100 Fachthemen

Kurzfassung

Die wissenschaftlich-technischen Arbeitsziele dieses vom Bundesministerium für Wirtschaft (BMWi) geförderten Projektes wurden in fünf Teilen erarbeitet. Die einzelnen Themen resultieren aus aktuellen Fragestellungen; sie haben dennoch einen allgemein anwendbaren Charakter. Das Konsortium hat die folgenden Teilprojekte bearbeitet:
(1) Aufbau einer Messtechnik zur Bestimmung energetischer und lichttechnischer Kennzahlen von Tageslichtbauteilen mit einem round robin test, an dem drei Institute beteiligt waren. (2) Realisierung eines detaillierten Bewertungs- und Nachweisverfahrens für die Tageslichtversorgung von Innenräumen in unterschiedlichen Klimazonen. (3) Für die Beleuchtungskontrolle privater Lebensräume wurde ein “Powerline Carrier Communication“-System evaluiert und die Vorteile gegenüber einem Funkübertragungssystem herausgearbeitet. (4) In einem Pflegeheim wurden quantitative Untersuchungen zum Wohlbefinden, zur Erfüllung von Sehaufgaben und zur Eignung zur Melatoninsuppression bei verschiedenen Szenarien der Allgemeinbeleuchtung mit zwei unterschiedlichen Farbtemperaturen der eingesetzten Lampen (“warmweißes Licht“ mit TCP = 3000 K und “kaltweißes Tageslicht“ mit TCP = 6500 K) und vertikalen Beleuchtungsstärken an den Augen der Probanden zwischen 100 lx und 700 lx durchgeführt. (5) Für zwei Schulgebäude in Berlin wurde der Endenergiebedarf der Bestandsanlage, des Referenzgebäudes sowie der Neuplanung ermittelt. Dabei wurde in beiden Beispielen deutlich, dass die Bestandsanlage im Bereich der Beleuchtung den zulässigen Wert nach EnEV 2009 mitunter weit überschreitet. Eine gute Neuplanung hingegen kann den maximal zulässigen Wert deutlich unterschreiten. Diese Untersuchungen wurden von einem einjährigen Monitoring des Energieumsatzes begleitet. Eine Querschnittsanalyse über 48 Schulen mit insgesamt 86 Gebäuden zeigt unter anderem einen erheblichen Sanierungsbedarf bei Schulgebäuden, die vor 1990 errichtet wurden.

Energy optimised lighting in buildings with simultaneous improvement of quality of life by daylight utilisation and innovative lamps and ballast techniques.
The scientific and technical goals of this project were developed in five parts. The individual topics arising from current issues, they still have a generally applicable nature. The consortium has worked on the following subprojects:
(1) Development of a measurement technique to determine energy and photometric key figures of daylight components with a round robin test with three institutes. (2) Implementation of a detailed evaluation and documentation process for daylighting of interior spaces in different climate zones. (3) For lighting control in private living areas a “Power Line Carrier Communication” system has been evaluated and the advantages of a wireless transmission system were identified. (4) In a home for elderly quantitative studies on the well-being, for the fulfillment of visual tasks and the capability of melatonin suppression at different scenarios of general lighting with two different color temperatures of lamps (“warm white” with TCP = 3000 K and “cold white daylight” with TCP = 6500 K) and vertical illuminance at the eyes of the subjects between 100 lx and 700 lx were performed. (5) For two school buildings in Berlin, the final energy consumption of the existing lighting system, the reference building and a re-planning were determined. It became clear in both examples that the existing lighting system exceeds the permitted value (EnEV 2009) by far. A good redesign, however, can be significantly less than the maximum allowed value. These studies were accompanied by a one-year monitoring of energy consumption. A cross-sectional analysis of 48 schools with a total of 86 buildings shows a substantial need for renovation of school buildings that were built before 1990.

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