Pneumatic Forming of Hardened Concrete (PFHC), a new resource efficient concrete shell construction method, was invented by Professor Benjamin Kromoser at and Professor Johann Kollegger at. Concrete shells are efficient supporting structures, but the existing methods of constructing for formwork are labour and material intensive. The PFHC construction method, however, is comparatively easy. At first a flat concrete plate with wedge-shaped outlets is cast. After the concrete has hardened, an air cushion placed underneath the plate is inflated, and the post-tensioning tendons at the circumference are tensioned until the final form is reached. Glass fibre reinforced plastic rods are used as reinforcement to absorb the occurring strains in the concrete plate. If the flat plate is produced with high accuracy, the PFHC construction method allows very precise concrete shells to be built. The functionality of the complete construction method has already been tested in two large scale experiments: a spherical concrete shell 10.8 m in diameter and 3.2 m in height, and a free formed concrete shell with plan measurements of 17.6 m × 10.8 m and a height of 2.9 m; both shells had a thickness of 50 mm. Furthermore, the construction method has been practically applied for the construction of two concrete shells, an event canopy and a concrete shell bridge, on behalf of the Austrian railways. The event canopy has plan measurements of 26.5 m × 19.1 m, a height of 4.2 m and a final thickness of 150–200 mm. The bridge has plan measurements of 36.2 m × 38.7 m, and height from the top edge to the vertex is 7.6 m, with a thickness of 450 mm.

Keywords: Pneumatic Forming of Hardened Concrete, Concrete Shell, Flexible Formwork, Pneumatic Formwork, Topology Optimization, Structural Optimization

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2018 Journal article ** Kromoser, B; Kollegger, J Conceptual design, geometry optimization and calculation of the concrete shell bridge AM2 built with PFHC. BETON- STAHLBETONBAU. 2018; 113(2): 88-95. WoS FullText FullText_BOKU ** Kromoser, B; Kollegger, J; Kari, H; Gradenegger, K; Ganster, M Practical Application of an innovative concrete shell construction method: Construction of the deer pass AM2 by use of PFHC. BETON- STAHLBETONBAU. 2018; 113(3): 222-232. WoS Article in conference proceedings Kollegger, J.; Kromoser, B.; Suza, D.: (2018): Erection of bridges and shells without formwork - challenges for the computational modelling. [Conference on Computational Modelling of Concrete and Concrete Structures (Euro-C), Bad Hofgastein, 26. February - 1 March 2018] In: Meschke, G.; Pichler, B.; Rots J.G. (Eds.), Computational Modelling of Concrete Structures ; ISBN: 978-1-138-74117-1 2017 Journal article ** Kromoser, B; Kollegger, J Active Shaping of hardened Concrete Elements for the Production of spatially crushed Concrete Surfaces. BETON- STAHLBETONBAU. 2017; 112(2): 106-115. WoS FullText FullText_BOKU Article in conference proceedings Kromoser, B.; Kollegger, J.: (2017): Construction of a thin walled concrete shell event canopy. [CCC Tokaj, Tokaj, 31.08. - 1.09.2017] Kromoser, B.; Kollegger, J.: (2017): How to inflate a hardened concrete shell with a weight of 80 t. [IASS Annual Symposium 2017 , Hamburg, 25. - 28. September 2017] Schmitt, C.; Kromoser, B.; Harmening, C.; Falkner, J.; Neuner, H.-B.; Kollegger, J.: (2017): Geodetic surface based methods for applications in civil engineering. [7th International Conference on Engineering Surveying, Lissabon, 18. - 20.10.2017] In: A. Kopáčik et al. (Hrg.), Ingeo 2017, Proceedings of the 7th International Conference on Engineering Surveying 2016 Journal article ** Hawkins, W; Herrmann, M; Ibell, T; Kromoser, B; Michaelski, A; Orr, J; Pedreschi, R; Pronk, A; Schipper, R; Shepherd, P; Veenendaal, D; Wansdronk, R; West, M Flexible formwork technologies - a state of the art review. STRUCT CONCRETE. 2016; 17(6): 911-935. WoS FullText FullText_BOKU ** Kromoser, B; Huber, P Pneumatic Formwork Systems in Structural Engineering. ADV MATER SCI ENG. 2016; WoS FullText FullText_BOKU Article in conference proceedings Kromoser, B.; Kollegger, J.: (2016): Building concrete shells without formwork and falsework.
[fib Symposium 2016 , Cape Town, 21. - 23. November 2016] Pachner,T.; Kromoser, B.; Kollegger, J.: (2016): Structural Optimization of a concrete shell bridge with the Pneumatic Forming of Hardened Concrete construction method. [IASS 2016 International Symposium, Tokyo , 26.9. - 30.9.2016] 2015 Journal article ** Kromoser, B; Kollegger, J Pneumatic forming of hardened concrete - building shells in the 21st century. STRUCT CONCRETE. 2015; 16(2): 161-171. WoS FullText FullText_BOKU Kromoser B.; Kollegger J.: (2015): Application Areas for Pneumatic Forming of Hardened Concrete. Journal of the IASS, 56, 187-198; ISSN 1028-365X Article in conference proceedings Kollegger, J.; Foremniak, S.;Kromoser, B.: (2015): Egg-Graben-Brücke, Wildbrücke AM2, Lafnitzbrücke - Anwendung von neuen Bauverfahren für Brücken in Österreich.. [25. Dresdner Brückenbausymposium, Dresden, 9.3. - 10.3.2015] ; ISBN: 978-3-86780-421-9 Kollegger, J.; Kromoser, B.: (2015): Neue Tragwerke – Eine Betonkuppel zum Aufblasen. [59. Betontage Ulm, Ulm, 24. - 26.2.2015] Kromoser, B.; Kollegger, J.: (2015): Building shells from initially flat hardened concrete plates. [IASS 2015, Amsterdam , 17.8. - 20.8.2015] Dissertation Kromoser, B.: (2015): Pneumatisches Verformen Von Ausgehärtetem Beton - Die Errichtung Von Betonschalen Aus Ursprünglich Ebenen Platten . ; TU Wien, Institut für Tragkonstruktionen - Forschungsbereich für Stahlbeton und Massivbau 2014 Journal article ** Kromoser, B; Kollegger, J Manufacturing of shell structures made of concrete with the "Pneumatic Wedge Method" A new Construction Method for the Construction of Double-Curved Concrete Surface by using Pneumatic Formwork. BETON- STAHLBETONBAU. 2014; 109(8): 557-565. WoS FullText FullText_BOKU Article in conference proceedings Kollegger, J.; Foremniak, S.; Kromoser, B.: (2014): Innovations for the Design of Concrete Bridges Developed at Vienna University of Technology. [10th Japanese German Bridge Symposium in Munich,, München, 16.9. - 17.9.2014] Kollegger, J.; Foremniak, S.; Kromoser, B.: (2014): Innovative Proposal for the Construction of Concrete Bridges. [International Seminar on Long Span Bridge, Shanghai , 23.10. - 25.10.2014] Kromoser, B.; Eichwalder, B.; Kollegger, J.: (2014): Simulation of large strains in concrete specimen – centric tensile tests using steel ropes as reinforcement. [Euro-C , St. Anton, 24.3. - 27.3.2014]; ISBN: 978-1-138-00145-9 Kromoser, B.; Kollegger, J.: (2014): Building free formed concrete surfaces by using the “pneumatic wedge method. [The 10th fib International PhD Symposium in Civil Engineering , Quebec, 21.7. - 23.7.2014] ; ISBN: 978-2-9806762-1-5 2012 Article in conference proceedings Kollegger, J., Kromoser, B., Dallinger, S.: (2012): The building of ice and concrete shells by employing pneumatic formwork. [Second International Conference on Flexible Formwork, Bath, 27.6. - 29.6.2012] In: Orr, J.; Evernden, M.; Darby, A.; Ibell, T. (Eds.), Proceedings of the Second International Conference on Flexible Formwork; ISBN: 978-0-86197-184-8; S Kromoser, B.: (2012): Methods for transforming flat concrete plates to double curved shell structures.
[The 9th fib International PhD Symposium in Civil Engineering, Karlsruhe, 22.7. - 25.7.2012] ; ISBN: 978-3-86644-858-2 Kromoser, B.; Kollegger, J.: (2012): Using Ice to Build Shell Structures. [10th International Conference and Exhibition on Performance of Ships and Structures in Ice, Banff, 17.9. - 20.9.2012] ; ISBN: 978-0-9780896-3-4