Tine Tysmans

Shell Elements of Textile Reinforced Concrete Using Fabric Formwork: A Case Study

Innovations in formwork solutions create new possibilities for architectural concrete constructions. Flexible fabric replaces the stiff traditional formwork elements, and takes away a limiting factor for creative designs. Combined with textile reinforcement, the production of a new range of curved and organic shapes becomes possible without the intensive labour for formwork installation. Besides a general introduction about the concepts of fabric formwork and textile reinforcement, this paper focuses on the production and structural evaluation of doubly curved shells. Creating a very interesting type of element from a structural point of view, the shape flexibility of both the fabric formwork and textile reinforcement make a perfect match to overcome practical production issues for thin shell elements. The application of shotcrete and the integration of non-metallic reinforcement allowed first of all the production of very thin concrete shell elements based on the design approach of the textile architecture. Comparing a shell structure with traditional reinforcement and one with textile reinforcement, a case study evaluates furthermore both the design and the structural performance of such a shell structure.

Stay-in-Place Formwork of TRC Designed as Shear Reinforcement for Concrete Beams

In order to reduce on-site building time, the construction industry shows an increasing interest in stay-in-place formwork with a reinforcement function after concrete hardening, such as CFRP formwork confinement for columns. The current combined systems however do not answer the demand of the building industry for a material system that is both lightweight and fire safe. High performance textile reinforced cement (TRC) composites can address this need. They can be particularly interesting for the shear reinforcement of concrete beams. This paper describes a preliminary analysis and feasibility study on structural stay-in-place formwork made of TRC. Comparative bending experiments demonstrate that a fully steel reinforced beam and an equivalent beam with shear reinforcement in TRC formwork show similar yielding behaviour, indicating that the TRC shear reinforcement system actually works. Moreover, the cracking moment of the concrete was more or less doubled, resulting in a much lower deflection in serviceability limit state than calculated. Digital image correlation measurements show that the latter is due to the crack bridging capacity of the external TRC shear reinforcement.

Numerical evaluation of structural stay-in-place formwork in textile reinforced cement composite for concrete shells

This article presents the structural evaluation of textile reinforced cement composite elements as formwork and reinforcement for concrete shells. Different shell geometries of 10 m span and a height between 2.5 and 5 m are examined. On one hand, the minimum thickness of the composite element functioning as formwork for these shells is determined when supported with a different number of supports and for different concrete sections. On the other hand, the minimum thickness of the composite functioning as reinforcement is calculated to withstand the occurring maximum bending moment. For shells with a 10 to 15 mm concrete section, a minimum composite formwork of 5–6 mm is needed to carry the load of the cast concrete, while the minimum composite reinforcement needed to withstand the maximum occurring bending moment equals 2–3 mm. Conclusively, this preliminary numerical study demonstrates the structural potential of textile reinforced cement composite stay-in-place formwork for concrete shells and indicates the dominance of the casting stage over the final stage. More specifically, local buckling of the formwork is the determining factor and should drive future work towards this issue.

An Automated Structural Optimisation Methodology for Scissor Structures Using a Genetic Algorithm

We developed a fully automated multiobjective optimisation framework using genetic algorithms to generate a range of optimal barrel vault scissor structures. Compared to other optimisation methods, genetic algorithms are more robust and efficient when dealing with multiobjective optimisation problems and provide a better view of the search space while reducing the chance to be stuck in a local minimum. The novelty of this work is the application and validation (using metrics) of genetic algorithms for the shape and size optimisation of scissor structures, which has not been done so far for two objectives. We tested the feasibility and capacity of the methodology by optimising a 6źm span barrel vault to weight and compactness and by obtaining optimal solutions in an efficient way using NSGA-II. This paper presents the framework and the results of the case study. The in-depth analysis of the influence of the optimisation variables on the results yields new insights which can help in making choices with regard to the design variables, the constraints, and the number of individuals and generations in order to obtain efficiently a trade-off of optimal solutions.

Influence of Weathering Conditions on TRC Sandwich Renovation Panels

Using large lightweight prefabricated sandwich panels for the renovation of existing dwellings facilitates the installation process and reduces the renovation time to a few days. To guarantee the performance of the panels during their entire life span it is necessary to evaluate their behaviour on the long term. During their life span the facade panels are exposed to weather conditions such as wind, snow, rain, etc. To simulate these effects 8 sandwich beams, with a span of 2.2 m were fabricated and loaded until failure, after being subjected to repeated mechanical loading and/or and heat-rain cycles. The latter were done in a climate chamber according to ETAG004.

Experimental Investigation and Benchmarking of 3D Textile Reinforced Cementitious Composites

The last couple of years, the importance and potential of textile reinforced cementitious composites (TRC’s) has been investigated and proven in literature. The research has mainly been performed on thin-layered specimens made of individual fibre textile layers impregnated by a matrix. The drawback of this manufacturing technique however is the time-consuming process. A solution is the transition towards a three dimensional, rigid fibre textile, fully immersed in the matrix, which would drastically decrease the production time and thus improve the market uptake of these materials.

Buckling Behaviour of Structural Insulating Sandwich Walls with Textile Reinforced Cement Faces

Loadbearing insulating sandwich panels with Textile Reinforced Cement (TRC) faces can combine the structural and insulating performance of a conventional wall configuration in one lightweight element. This makes them very suitable as a new type of wall element for low- and high rise residential buildings. By combining 2D and 3D textiles in the TRC faces the performance of the panels can even be improved. This paper presents a preliminary investigation of the buckling behaviour of large-scale sandwich panels with combined 3D and 2D TRC faces. The large-scale experiment is compared with an analytical model. This paper shows that further in depth investigations are needed with regard to the experimental test set-up (boundary conditions) in order to establish a better agreement with the analytical model.

Fracture monitoring by acoustic emission: recent applications of parameter-based characterization

The present paper describes a collection of fracture monitoring cases in different materials. The cases examined include bending of textile reinforced cement (TRC), hybrid concrete-TRC lightweight beams, granite, additive manufacturing metal components, combined loading of human femur bone and pull-out in reinforced concrete. In all cases the basic role is played by acoustic emission (AE). It is shown that certain waveform parameters exhibit strong sensitivity to the rate of fracture as well as the dominant fracture mode. Parameters like frequency content and the duration of the signals supply real time trends that in the present cases are verified by optical techniques. It is concluded that AE supplies important information and allows the prediction of how the material will behave based on the initial AE recordings and before serious damage is inflicted. AE shows a very broad application range; however, the contribution of combination with other techniques is highlighted in order to increase the reliability of the interpretation of AE results.