Wölbkrafttorsion bei veränderlichem,offenem Querschnitt – hat die Biegezugstabanalogie noch Gültigkeit?

Warping torsion for variable, open cross sections – is the analogy for theory of beams with tensile force still valid? The difficult theory of warping torsion can be replaced by the easier second order theory for beams with longitudinal tension force by using the appropriate analogy. But it is mostly unknown, that this analogy is no longer valid if cross section is variable. For a special single‐symmetric I‐section with variable height and width all formulae for internal forces, displacements and warping stresses are developed, based on the field transfer matrix. The application is demonstrated by three examples. For the first example the results when using the mentioned analogy are also given, and it is obvious that not even the signs of secondary torsion variables are correct.     

Einfach Bauen und Schallschutz – ein Konflikt?

Building Simply and noise protection – a conflict? Investigation of the noise perception of residents using the case study of the three “Building Simply” research houses In the discussion about cost-effective construction, residential standards currently undergo a critical review, especially requirements on sound insulation. However, perception of noise from the neighborhood is rather subjective and is influenced by factors such as age and sensitivity. The ′Building Simply′ paradigm aims at streamlined, environmentally friendly construction. Three ′Building Simply′ research houses had been investigated with respect to sound insulation by measurements. All three houses meet the legally binding as well as enhanced requirements. However, the satisfaction of the residents evaluated by a survey, revealed strong variations in noise perception. Conciliatory communication with neighbors significantly influenced satisfaction,. Expecting reduced sound insulation properties in ′simple construction′ may cause discord, proven by the fact that residents had been moving due to noise impact. Current standards are inadequate for noise-sensitive individuals. Informing residents about expected sound insulation levels is crucial.     

Ist Elektrosmog eine Herausforderung für die Bautechnik?

Is Electric Smog a new challenge for the construction technology? Today electric energy is being applied extensively to every sphere of our life. Despite the measures for the peoples protection, that are been developed therefore, experts and ecologically aware citizens worry about the influence this increase could have on our healthiness. Not least because of its economic relevance the problem of electric smog is discussed controversial and with more and more polemic. Therefore this article provides specialized information for the impartial reader to support him in forming an opinion. Thereby the article concentrates on measures that determine the protection level of the human health – according to endangerments caused by electromagnetic fields – during the design and realization phase of building construction.     

Ist die Hinterlüftung von Holzfassaden ein Muss?

Nach Durchführung einer großen Schweizer Forschungsinitiative zum Thema “Brandschutz im Holzbau” sind seit 2005 Außenwandbekleidungen aus Holz unter Zuhilfenahme von bestimmten Brandschutzmaßnahmen bis zur Hochhausgrenze (22 m) möglich [1]. Dazu zählen unter anderem auch Außenwandbekleidungen, deren Hinterlüftungsraum geschossweise unterbrochen und oben verschlossen wird. Solche Fassaden weisen brandschutztechnische Vorteile auf, da sie die Brandweiterleitung hinter der Bekleidung reduzieren bzw. verhindern. In diesem Zusammenhang stellte sich die Frage, ob eine Hinterlüftung von Holzfassaden aus bauphysikalischer Sicht überhaupt notwendig ist. Im Rahmen eines Forschungsvorhabens an der Berner Fachhochschule — Architektur, Holz und Bau in Biel/Bienne wurde dieser Frage nachgegangen [2]. Is ventilation of timber façades essential? Following a major Swiss research initiative, “Fire protection in Timber Structures”, exterior timber wall claddings incorporating specific fire protection measures have been permitted up to the high‐rise limit of 22 m since 2005 [1]. This includes exterior wall claddings with a ventilation space that is interrupted and closed off from above at each storey level. Such façades have advantages when it comes to fire protection as they reduce or prevent the spread of fire behind the cladding. This has raised the question of whether the ventilation of timber façades is necessary at all from a building physics perspective. This matter was investigated as part of an Architecture, Timber and Construction research project at Bern University of Applied Sciences [2].