Zum Tragverhalten von Stahlbetonplatten ohne Querkraftbewehrung mit integrierten Leitungsführungen

In der vorliegenden Arbeit wird das Querkrafttragverhalten von einachsig gespannten Stahlbetondecken mit integrierten Leitungsführungen untersucht. Anhand zahlreicher Traglastversuche an Deckenstreifen mit unterschiedlicher Öffnungsgeometrie, -lage und -gruppierung sowie variierender Deckendicken konnte die Reduzierung der Querkrafttragfähigkeit experimentell nachgewiesen werden. Die Versuche wurden mit einem zweidimensionalen FE-Modell, welches an Hand der experimentellen Ergebnisse kalibriert wurde, nachgebildet. Anschließend wurde mit Hilfe des Modells eine Parameteruntersuchung durchgeführt, worin die Parameter Plattendicke, Öffnungsdurchmesser und Lage der Öffnung im Querschnitt variiert wurden. Die Ergebnisse der experimentellen und rechnerischen Untersuchungen dienten zur Definition eines Abminderungsfaktors, der die Reduktion der Querkrafttragfähigkeit infolge der Öffnungen im Deckenquerschnitt beschreibt. Mit dem im Rahmen dieser Arbeit entwickelten Modell konnten die Grundlagen für eine ingenieurmäßige Querkraftbemessung von Stahlbetondecken mit integrierter Leitungsführung geschaffen werden.The reduction of the shear load capacity of the examined specimen was verified on the basis of numerous bearing load tests by varying opening diameter, position of openings and grouping of openings as well as structural depth. The performed load carrying tests were recalculated using a two dimensional finite element model which was calibrated on the experimental results. Using this FE-model a parameter study (sensitivity analysis) was carried out by varying the parameters slap thickness, diameter of openings and position of opening. Due to the results of the experimental and analytical investigations a factor was defined which describes the reduction of the shear load carring capacity subjected to the examined parameters. The equation for the shear load carrying capacity of concrete structures without shear reinforcement according to DIN 1045-1 was extended by this factor for the consideration of openings. Within the scope of the present investigations a design concept was developed and conclusive application rules were proposed for concrete slabs with integrated ducts and no shear reinforcement

Zum Tragverhalten von Stahlbetonplatten ohne Querkraftbewehrung mit integrierten Leitungsführungen

In der vorliegenden Arbeit wird das Querkrafttragverhalten von einachsig gespannten Stahlbetondecken mit integrierten Leitungsführungen untersucht. Anhand zahlreicher Traglastversuche an Deckenstreifen mit unterschiedlicher Öffnungsgeometrie, -lage und -gruppierung sowie variierender Deckendicken konnte die Reduzierung der Querkrafttragfähigkeit experimentell nachgewiesen werden. Die Versuche wurden mit einem zweidimensionalen FE-Modell, welches an Hand der experimentellen Ergebnisse kalibriert wurde, nachgebildet. Anschließend wurde mit Hilfe des Modells eine Parameteruntersuchung durchgeführt, worin die Parameter Plattendicke, Öffnungsdurchmesser und Lage der Öffnung im Querschnitt variiert wurden. Die Ergebnisse der experimentellen und rechnerischen Untersuchungen dienten zur Definition eines Abminderungsfaktors, der die Reduktion der Querkrafttragfähigkeit infolge der Öffnungen im Deckenquerschnitt beschreibt. Mit dem im Rahmen dieser Arbeit entwickelten Modell konnten die Grundlagen für eine ingenieurmäßige Querkraftbemessung von Stahlbetondecken mit integrierter Leitungsführung geschaffen werden.The reduction of the shear load capacity of the examined specimen was verified on the basis of numerous bearing load tests by varying opening diameter, position of openings and grouping of openings as well as structural depth. The performed load carrying tests were recalculated using a two dimensional finite element model which was calibrated on the experimental results. Using this FE-model a parameter study (sensitivity analysis) was carried out by varying the parameters slap thickness, diameter of openings and position of opening. Due to the results of the experimental and analytical investigations a factor was defined which describes the reduction of the shear load carring capacity subjected to the examined parameters. The equation for the shear load carrying capacity of concrete structures without shear reinforcement according to DIN 1045-1 was extended by this factor for the consideration of openings. Within the scope of the present investigations a design concept was developed and conclusive application rules were proposed for concrete slabs with integrated ducts and no shear reinforcement

Material-Dependent Shear Capacity of Threaded Rods

Currently, the determination of the shear capacity VRk,s0 of post installed adhesive anchors is already included in the current standardization and approval documents. Considering that EAD 330499-00-0601 allows for determining the shear resistance of a fastener only based on the characteristic steel ultimate tensile strength fuk determined from the material tensile tests, and without considering the actual ductility of the material used, this leads to a severe underestimation of the actual steel shear resistance. In order to efficiently determine the shear strength by calculation based on material characteristics, tensile and shear tests were carried out on metallic threaded rods and rebars to show their correlation with the material properties. A new correlation between tensile and shear strength is presented, which is based on the plasticity module Epl and allows a good prognosis of the shear strength

Experimental Investigation of Concrete Sandwich Walls with Glass-Fiber-Composite Connectors Exposed to Fire and Mechanical Loading

Precast concrete sandwich panels (PCSPs) are known for their good thermal, acoustic and structural properties. Severe environmental demands can be met by PCSPs due to their use of highly thermally insulating materials and non-metallic connectors. One of the main issues limiting the wider use of sandwich walls in construction is their unknown fire resistance. Furthermore, the actual behaviour of connectors and insulation in fire in terms of their mechanical performance and their impact on fire spread and the fire resistance of walls is not fully understood. This paper presents an experimental investigation on the structural and thermal behaviour of PCSPs with mineral-wool insulation and glass-fiber-reinforced polymeric bar connectors coupling two concrete wythes. Three full-size walls were tested following the REI certification test procedure for fire walls under fire and vertical eccentric and post-fire mechanical impact load. The three test configurations were adopted for the assessment of the connectors’ fire behaviour and its impact on the general fire resistance of the walls. All the specimens met the REI 120-M criteria. The connectors did not contribute to the fire’s spread and the integrity of the walls was maintained throughout the testing time. This was also confirmed in the most unfavourable test configuration, in which some of the connectors in the inner area of the wall were significantly damaged, and yet the structural connection of the concrete wythes was maintained. The walls experienced heavy heat-induced thermal bowing. The significant contribution of connectors to the stiffness of the wall during fire was observed and discussed

Experimental Investigation of Concrete Sandwich Walls with Glass-Fiber-Composite Connectors Exposed to Fire and Mechanical Loading

Precast concrete sandwich panels (PCSPs) are known for their good thermal, acoustic and structural properties. Severe environmental demands can be met by PCSPs due to their use of highly thermally insulating materials and non-metallic connectors. One of the main issues limiting the wider use of sandwich walls in construction is their unknown fire resistance. Furthermore, the actual behaviour of connectors and insulation in fire in terms of their mechanical performance and their impact on fire spread and the fire resistance of walls is not fully understood. This paper presents an experimental investigation on the structural and thermal behaviour of PCSPs with mineral-wool insulation and glass-fiber-reinforced polymeric bar connectors coupling two concrete wythes. Three full-size walls were tested following the REI certification test procedure for fire walls under fire and vertical eccentric and post-fire mechanical impact load. The three test configurations were adopted for the assessment of the connectors’ fire behaviour and its impact on the general fire resistance of the walls. All the specimens met the REI 120-M criteria. The connectors did not contribute to the fire’s spread and the integrity of the walls was maintained throughout the testing time. This was also confirmed in the most unfavourable test configuration, in which some of the connectors in the inner area of the wall were significantly damaged, and yet the structural connection of the concrete wythes was maintained. The walls experienced heavy heat-induced thermal bowing. The significant contribution of connectors to the stiffness of the wall during fire was observed and discussed