Sandwich panels with folded plate and doubly curved UHPFRC facings

Abstract

Sandwich‐structured composites represent an efficient method to establish building envelopes which concurrently satisfy several demands. Besides low self‐weight with high load‐bearing capacity, sandwich panels provide sufficient physical properties, such as heat and sound insulation. In general, sandwich panels for applications in building industry are made of flat or thin profiled metal sheets or thick concrete facings. However, standard elements are limited to short spans. In contrast, spatially shaped concrete structures with folded plate or curved geometry provide high stiffness and load‐carrying capacity even for thin elements. The application of folded plate and curved concrete structures to sandwich panels combines the advantages of both construction methods. To realize thin facings in various shapes, high performance cementitious composites are advantageous. Ultra‐high performance fiber reinforced concrete (UHPFRC) provides high compressive and tensile strengths with ductile material behavior. The application of non‐corrosive reinforcement, for example, carbon fiber reinforced polymer (CFRP), allows for filigree concrete elements with a thin concrete cover to only fulfill bond requirements. For sandwich panels with folded plate or curved facings, new production methods are necessary to account for cross‐sections in various shapes. This paper introduces the basic ideas of non‐planar concrete sandwich elements for long‐span roof structures and the developed production methods.

Calculation method for flexural capacity of high strain‐hardening ultra‐high performance concrete T‐beams

“…It is beneficial to use reinforced high strain‐hardening UHPC in structures with high demand of crack width control. Stark et al applies UHPC to design long‐span sandwich structures, which utilize high strength and high ductility to significantly increase the load carrying capacity of the sandwich unit. During a research project, Zani conducted several experimental tests to mechanically identify the individual and coupling materials that make up the innovative multilayer roof slab; experiments have shown that UHPC materials can improve the toughness and ductility of common materials.…”

Weitspannende Sandwichelemente mit vorgespannten Textilbetondeckschichten und geschäumter Kernschicht

“…Der Verbund zwischen Betondeckschichten und Kernmaterial kann durch das Einschäumen eines PUR‐Dämmstoffs anstelle herkömmlicher Herstellungsmethoden mit vorkonfektionierten Blockschäumen erheblich verbessert werden [14–16]. Nachdem bereits in [17] die Ausschäumtechnik an maximal 4 m spannenden Elementen ohne Verbundmittel erfolgreich erprobt wurde, wird im vorgestellten Projekt die Übertragbarkeit der Technik auf großformatige Elemente mit 8 m Länge überprüft. Hierbei werden außerdem linienförmige Verbundmittel aus alkaliresistentem (AR‐) Glas verwendet, welche die Sandwichtragwirkung der Elemente und den Verbund zwischen Kern und Deckschichten verbessern.…”

Stabanker für dünne Carbonbetonwände

“…Nach dem Rütteln erhärtet das Wandsystem in einem Trockenofen, wodurch die Halbfertigteile bereits nach acht Stunden ausgeschalt werden können. Nach dem Aufstellen der Wände auf der Baustelle wird der Kern mit Ortbeton vergossen, sodass der Gesamtquerschnitt nach Erhärten des Betons monolithisch trägt .…”