Erweiterung des Hitzewarnsystems um die Vorhersage der Wärmebelastung in Innenräumen

Extending the existing heat/health warning system with indoor heat load predictions. A heat/health warning system (HHWS) was established in Germany as a climate change adaptation measure and as a direct consequence of the heat wave in 2003. The system used by the German weather service currently only provides information about outdoor conditions, i.e. no data on indoor climate – which may differ significantly from ambient conditions – are provided. This article describes an extension of the existing heat/health warning system based on a thermal building simulation model. It enables internal heat loads to be estimated based on predicted meteorological conditions. While the prediction model is limited to a worst‐case scenario for practicability reasons, the information derived from the load values can nevertheless be very useful. The technique was used during summer 2007 in parallel with the conventional system, illustrating the added value.     

Kriterien des nachhaltigen Bauens: Bewertung des thermischen Raumklimas – ein Diskussionsbeitrag

Criteria for sustainable buildings: Assessment of indoor thermal environment – a contribution to the discussion. The German federal government provides a guide book “Sustainable Buildings” [5]. The guide book contains principles for the design, construction and operation of buildings. Furthermore it provides procedures to assess economical and ecological but also sociocultural factors. The German Federal Ministry of Transport, Building and Urban Affairs is planning to enhance the guide book. This article discusses criteria for assessing the sociocultural factor “thermal comfort”. The criteria gained from a review of literature and standards are examined for their suitability as assessment criteria in the guide book. They should be applicable for residential and office buildings as well as for new and existing buildings. For the different building types feasible methods are suggested. So far standards provide several approaches to assess thermal comfort. For some of these criteria there is no simple calculation method available. Several standards exist addressing the same criterion but using different methods. There is a need to harmonize the standards. Further research is required to provide assessment methods for important factors influencing occupant's satisfaction.     

Höhepunkte im modernen Verbundbau – eine beispielhafte Entwicklungsgeschichte

Highlights in modern composite construction – an exemplary historical development. The development of the steel composite construction for buildings is pointed out. For the last forty years the milestones are described in particular, which contributed to the advancement and thus to the meaning of this building method: economic shear connectors, integrated fire protection, modern connection technology and ambitious architecture because of apparent steel surface.     

Verfüllung des Rodewischhafens in Hamburg – Zur Technik der Flächenaufhöhung auf Weichschichten

Backfilling of the Rodewischhafen in Hamburg – to the technology of land reclaiming on soft layers. Concerning the increasing need of store and transportation areas of the economy in Hamburg on the one hand and the surface scarceness in the population centre on the other hand force to extremely careful handling with the surface resources. An optimization of already in use present surfaces in Hamburg port with the goal of becoming changed requirements fairly more and more land reclamation activities are necessary on former harbor basins, which had been partly filled up with dredged mud. The coverage of these basins makes high requirements to the geotechnical design and the execution of construction due to the very low bearing capacity of the mud. In this contribution the load bearing concept is presented by using special geosynthetic reinforcement products as well as the necessary ground investigations and construction designs. The engineering design lead into recommendations regarding the application of the observation method during the execution of construction. Finally the results of the deformation observations are described.     

Höherfrequente Hämmerverfahren – Ursachen der Steigerung der Ermüdungsfestigkeit und Nachweismodell

Der Einsatz von Schweißnahtnachbehandlungsverfahren zur Optimierung wechselnd beanspruchter Stahlkonstruktionen in Hinblick auf deren Lebensdauerverlängerung oder eine Reduzierung des Konstruktionsgewichts wurde in den letzten Jahren verstärkt untersucht. Dabei erwiesen sich höherfrequente Hämmermethoden als besonders wirkungsvoll zur Steigerung der Ermüdungsfestigkeit. Der vorliegende Artikel zeigt die Potentiale der Verfahren auf und belegt deren Einfluss auf das Rissinitiierungs‐ und Rissfortschrittsverhalten von Schweißnähten. Anhand eines entwickelten Bemessungsmodells wird eine Möglichkeit der rechnerischen Erfassung der positiven Wirksamkeit der Verfahren dargelegt. Reasons and calculation of the improved fatigue life of welds treated with high frequency peening methods. The application of post weld treatment methods in order to optimize fatigue loaded steel structures in view of an extension of their service life or a reduction of the construction weight has been studied intensively in the last years. High frequency peening methods proved to be extreme effectively in order to increase the fatigue strength. The following article shows the potentials of the methods and proves their influence on the crack initiation and crack propagation behaviour of welds. With help of a developed design procedure the possibility of respecting the positive effect on the fatigue strength during the design is provided.     

Raumakustische Zielgrößen und Maßnahmen zur Optimierung der kognitiven Leistungsfähigkeit sowie des akustischen Komforts in Mehrpersonenbüros

Lärm zählt zu den häufigsten Quellen von Beschwerden an Büroarbeitsplätzen. Insbesondere Gespräche von Mitarbeitern werden als störend erlebt. Darüber hinaus beeinträchtigt Bürolärm die Leistungsfähigkeit und das Befinden der Angestellten. Richtlinien und Normen berücksichtigen kaum die besondere Bedeutung sprachlicher Hintergrundgeräusche. Der Speech Transmission Index (STI), ein Maß für die Verständlichkeit von Sprache, wird aktuell als geeignete physikalische Führungsgröße zur Gestaltung offener Büroumgebungen diskutiert. Im Rahmen einer laborexperimentellen Untersuchung wird der Zusammenhang zwischen der Darbietung von Hintergrundschallen mit unterschied licher Sprachverständlichkeit (STI) und der kognitiven Leistungsfähigkeit sowie dem empfundenen akustischen Komfort von Probanden untersucht. Dabei zeigt sich ein starker Zusammenhang zwischen der Sprachverständlichkeit und Maßen kognitiver Leistungsfähigkeit sowie akustischem Komfort. Der STI kann daher als eine geeignete physikalische Führungsgröße zur Gestaltung offener Büroumgebungen betrachtet werden. Room acoustical set values and measures for optimization of cognitive performance and acoustic comfort in open‐plan offices. Noise is among the most frequently mentioned sources of complaint in open‐plan offices. Particularly conversations of colleagues are perceived as being annoying. In addition office noise is known to impair employees’ cognitive performance and wellbeing. Standards and norms hardly account for the special role of background speech. The Speech Transmission Index (STI), a measure of speech intelligibility, is assumed to be a suitable physical set value for the acoustical design of open‐plan offices. The results of a laboratory experiment are presented investigating the relationship between presentation of background speech varying in STI and cognitive performance as well as perceived acoustic comfort. A strong relationship between speech intelligibility and cognitive performance as well as acoustic comfort is found. Therefore the STI can be assumed to be a suitable physical set value for the acoustic design of open‐plan office.     

Vom Einfluß des Analysewerkzeugs auf die Modellbildung – Zur statischen Analyse des Wiegmann‐Polonceau‐Trägers in der 2. Hälfte des 19. Jahrhunderts

On the influence of the analysis tool on the modeling – Structural analysis of the Wiegmann‐Polonceau girder in the second half of the 19th century. Motivated by the recent re‐erection of the Schrannenhalle (grain market), Munich (originally built 1851–53), we study the process of mechanical modeling of the Polonceau girder in its relation to the development of structural mechanics and computation 1850–1900.     

Simulation dynamisch‐thermischen Langzeitverhaltens in Gebäuden mittels CFD

Dynamic CFD simulation of thermal long‐term behaviour of buildings. The design of complex buildings increasingly demands the usage of simulation programmes. Actual dynamic thermal simulation programmes in use are incapable to determine the air flow and the temperature distribution in a room. One solution is to displace building simulations to a CFD platform which involves extremely long calculation times and large amounts of data. To reduce the calculation time a new freeze‐flow method was developed for ANSYS CFX‐5. It is based on the periodic freezing of the hydrodynamic equations enabling long term simulations. The CFD simulations were validated for free convection which is the dominating driving force of flow in rooms. Freeze‐flow simulations of simple test models confirmed a dramatic reduction in calculation time without any loss in accuracy compared to full dynamic CFD simulations.