Berechnung von Holz‐Beton‐Verbunddecken

Evaluation of Timber Concrete Composite Slabs If timber and concrete acts together in a cross section, the carrying and deformation behaviour of this new composite section is affected by many influences e.g. geometry, material properties, connecting device, long‐term behaviour, etc. The advantages of this building method and an optimization of the cross sections only can be achieved, if these influences are known and can be taken into account in the structural design. For the proof of the short term behaviour different procedures, e. g. [1], are available. Regarding the long‐term behaviour of the timber concrete composite floors it becomes obvious that the rheological behaviour of timber concrete composite structures is not considered sufficiently by the design method in [1].     

Integration von TGA‐Installationen im Aufbeton von Spannbeton‐Elementplatten

Im Hinblick auf eine Ressourcen schonende Bauweise ist eine möglichst flexible Gestaltung der Raumaufteilung bei Wohn‐ und Geschäftsgebäuden über die erste Nutzungsperiode hinaus wünschenswert. Dazu eignen sich Spannbeton‐Elementdecken in besonderer Weise. Aufgrund dieser Bauart wird es auch möglich, eine Vielzahl von Leitungen der technischen Gebäudeausrüstung einfach auf der Fertigplatte in die Ortbetonergänzung der Decke zu integrieren. Realistische Querschnittsschwächungen wurden in Zusammenarbeit mit TGA‐Planern für den üblichen Wohn‐ und Geschäftsbau ermittelt. Die auftretenden Querschnittsschwächungen der Decke werden in statischer Hinsicht beurteilt. Untersuchungen zeigen, dass diese Querschnittsschwächungen ohne weitere Maßnahmen, allein unter Beachtung von konstruktiven Regeln in weiten Bereichen der Decke zulässig sind. Implementation of Building Services' Installations on Top of Prestressed Precast Plates at Composite Concrete Floors With regard to the sustainable use of new housing and commercial buildings, a maximum flexibility of space should be achieved providing far more than its initial conceived use. Composite floors of prestressed precast plates with an in‐situ solid concrete topping serve to meet this requirement very well. It is also easily possible to install a lot of different building services' ducts and lines on top of the prestressed precast plate on site without impact of later design modification before in‐situ concrete is cast. Firstly, the effective weakening cross‐sections from the building installations at the slab structure have been defined on the basis of the evaluation of a number of representative housing and commercial buildings. The structural impact at the slab structure resulting from defined weakening sections are analysed to define the remaining structural resistance. Based on reported research results it can be shown that the weakening resulting from the implemented normal ducts and lines is widely admissible without reduction of total structural resistance.     

Visko‐elastisches Verhalten von Holz‐Klebstoff‐Verbindungen unter zyklischer Zug‐Druck‐Belastung

Visco‐elastic behavior of bonded wood under cyclic tensile and compression loading In the present contribution, a test method is used to simulate the static, cyclic loading of adhesive joints due to swelling and shrinking of the wood and to demonstrate the plastic deformation in the low load range. For tensile shear specimens prepared from beech wood and bonded with three different adhesives (MUF, PRF, PUR), the elastic behavior under cyclic tensile and compression loading was investigated and the loss and storage of energy was determined. All tested adhesives showed viscose parts even at a very low load level of 3 MPa. At a load level of 7 MPa, the PRF joints revealed a more elastic behavior than the other. The increased loss energy determined for the PUR bonding indicates a softening of the adhesive joint.