Concrete Structures

The chair of Structural Design of Concrete Structures provides education aiming to design safe concrete (and masonry) structures, carries out research and pursues strategic internal and external collaborations. The results are published in high quality scientific journals. The chair addresses structural design from a value chain type of perspective. Design, manufacturing and assembling are considered in an integral manner with a focus on innovation to work on a digital transition. Digital technologies, on all levels, are needed to improve on both construction productivity and sustainability in the sector. It is our vision that design, manufacturing and assembling should be studied in an integrated and digital manner. This explains why the chair also hosts the certificate program on construction technology.

The research is focussed on digital design, digital manufacturing and digital assembling (D3DMA). Digital design is studied on three subsequent levels. On a macro level, the structures of buildings and (small) civil structures like pedestrian bridges are designed using both parametric and generic design tools. Optimisation algorithms, like form finding and topology optimisation are incorporated to safe on natural resources and explore new shapes, always bearing the construction technology in mind. On a meso level concrete components like slabs and walls are studied numerically. Parametric design tools are being developed, based on strut and tie analysis, yield lines and the stringer panel methods. Finally, on a micro scale, discrete FEM analyses are used to study e.g. the pull-out behaviour of reinforcement and fibres. All types of analyses are supported with fundamental experimental research for matters of verification. Finally, digital manufacturing is treated in the certificate program on construction technology.

Concrete printing
All of the above-mentioned research topics come together in the research on 3D Concrete Printing (3DCP). A unique large-scale print facility has been realised and is allocated in the Structures Laboratory. The research on 3DCP comprises three goals.
The first goal is to work on the robustness of the print process itself. The materials properties of fresh concrete are studied experimentally, and the results are embedded in a finite element analysis to predict the maximum print speed to avoid (plastic) yield strains or overall instability of the printed structures.
The second goal is to improve on the materials properties by additives like fibres and accelerators and innovative types of structural reinforcement. Fibres and other additives are embedded with a special device developed at TU/e near the printer nozzle, just prior to extruding the concrete filaments. This allows for future optimization to functionally graded structures since not only concrete can be places where it is needed most, but also the concrete quality and functionality can be adjusted on demand on every position of the structure in an industrial and controlled manner. Another tool has been developed to automatically embed a reinforcement wire and research is performed to further improve this system. The third level of research is to monitor the print process by (non-destructive) sensors using e.g. ultra sound and optic eyes and work towards printers with algorithms based on deep learning (AI).
The output of recent research is already being applied in real projects, in close collaboration with industrial partners. So far, a cycling bridge has been printed, a second one is in a research phase and the first out of five houses of project Milestone will be ready for the inhabitants in June 2019. More information on 3DCP and the projects can be found on the site: TUe.nl/3DConcretePrinting.