Evy Verwimp

General info

Kb 117
Date of birth: 
27 februari 1988
Place of birth: 
Mechelen, Belgiƫ


Curved concrete elements, Flexible formwork, Textile reinforced cement composites


A flexible and structural stay-in-place formwork system of TRC composites for curved concrete elements.

There is an increasing demand towards the construction industry for structures with optimal structural and material efficient behaviour, and which can be built in an economical way. For concrete structures the use of curved (structural) surfaces can provide a better design. Curved elements are stronger, stiffer and more efficient than straight lined elements, but their production is questioned due to the complexity of the existing formwork methods.

Current formwork systems for curved concrete elements are timber moulds, which are very labour intensive, and foam blocks, which can be milled into every form but are wasted after use. A lot of research is performed on flexible formwork for curved surfaces. Fabric formwork is very flexible, though a certain stiffness is needed to withstand the poured concrete. Furthermore the placement of traditional steel reinforcement is difficult to integrate in these flexible formwork systems.

This research examines a new formwork method using textile reinforced cement composites (TRC) exploiting their flexibility in the wet phase and their stiffness and their strength in the hardened phase. Eventually the new formwork system will fulfil a structural and permanent role in the concrete element as the tensile reinforcement.

Every step in the process of obtaining an economical and ecological formwork in TRC step will predetermine certain goals and research questions:

1) A set of actuators, which are adjustable in height, acts as the support.  A rubber layer is placed on top of the actuators as a base for the actual TRC formwork. The first goal is to develop a numerical model that predicts/describes the curved shape.

2) The TRC composite is placed on top of the rubber layer in wet phase. Thanks to the flexibility of the composite in the wet phase, the curved shape is easily obtained.

3) After hardening of the composite, the TRC formwork is transported to the construction site.

4) On site the concrete is poured on the TRC, which acts as a permanent formwork for the curved concrete element. The second goal is the modelling of this TRC layer as formwork and the experimental validation of it.

5) When the concrete is hardened a mixed TRC-concrete section is obtained, where the composite acts as the reinforcement. The third goal is the modelling of the mixed section and the experimental validation of it.

When the 3 goals are achieved, the research question can be answered: Is the TRC element dimensioned as formwork or as reinforcement?




  • Verwimp E.Tysmans   T. and Mollaert, M. (2015). Numerical evaluation of structural stay-in-place formwork in textile reinforced cement composite, Advances in Structural Engineering. Under review.

  • Verwimp E. Tysmans T. and Mollaert, M. (2015). Influence of non-linearities on the structural behaviour of thin cement composite shells, Engineering Structures. Under review

  •  Verwimp, E., Tysmans, T., Mollaert, M. and Berg, S. (2015). Experimental and numerical buckling analysis of a thin TRC dome. Thin-Walled Structures, 94:89-97.

  • Filomeno Coelho, R., Tysmans, T. and Verwimp, E. (2014). Form finding & structural optimization: A project-based course for graduate students in civil and architectural engineering. Structural and Multidisciplinary Optimization, 49(6): 1037-1046.

Conference publications: 


  • Verwimp E., Tysmans T., Verbruggen S. and Mollaert M. (2015). Experimental and numerical analysis of textile reinforced cement composite as tensile reinforcement in concrete shells. Proceedings of 11th International Symposium on Ferrocement FERRO-11 and International Conference on Textile Reinforced Concrete 3rd ICTRC 2015, Aachen, Germany, 11p.

  •  Verwimp, E., Tysmans, T. and Mollaert, M. (2015). Improving the buckling behaviour of flexible formwork in textile reinforced concrete for concrete shells. Proceedings of the International Society of Flexible Formwork (ISOFF) Symposium 2015, Amsterdam, The Netherlands.

  • Verwimp E., Tysmans T., Mollaert M. (2014). Reinforcing concrete shells with cement composite stay-in-place formwork: Numerical analysis of a case study.  In De Wilde, W., Hernandez, S. and Brebbia, C, editor. High Performance and optimum design of structures and materials (HPSM/OPTI), Oostende, Belgium.

  • Verwimp E., Tysmans T., Mollaert M., Verbruggen S. and Cormond J. (2014). Experimental study on textile reinforced cement composites as alternative reinforcement for concrete shells. Proceedings of the IASS-SLTE 2014 Symposium "Shells, Membranes and Spatial Structures: Footprints", Brasilia, Brazil, R. Brasil and R. Pauletti editors, 8p.  

  • Verwimp E.Tysmans, Verwimp E. T. and Mollaert, M. (2013). Flexible formwork as reinforcement for curved concrete structures, In Obrebski, J.B. and Tarcewski, R., editor. Proceedings of the International Association for Shell and Spatial Structures (IASS) Symposium, Beyond limits of man, Wroclaw, Poland.

Design and implementation by aware