Automated Manufacturing Process and Structural Performance of Ribbed CRC Slabs (2024-09)¶

A significant proportion of concrete in building construction is typically poured into solid slabs. The adoption of modular ribbed floor systems, consisting of ribbed columns and slabs, presents an efficient approach to substantially reduce material consumption. However, fabricating ribbed structures poses challenges, especially in terms of formwork creation and manual effort. In this regard, the emergence of innovative concrete 3D-printing technologies provides a distinct advantage, enabling the straightforward implementation of novel load-adapted concrete structures that revolutionize traditional construction practices. This paper presents a concept of a modular floor slab system, integrating topology-optimized design principles with digital manufacturing methods. The slab system consisting of two types of modules – column module and field module – which were manufactured using 3D-printing technology. This approach allows these modules to be detachably connected and mechanically assembled through post-tensioning. This modular construction results in a material-efficient floor slab that is adaptable to internal flow of forces, conversional and extensible. In this approach, slender, bi-directionally oriented ribs are 3D-printed onto a precast concrete plate that is serving as the foundation for slab modules. Carbon reinforcement protrudes from the plate, defining the trajectory along which the webs will be printed. This method facilitates the creation of free-form, material-efficient slab modules with enhanced geometrical flexibility. To optimize production efficiency, robot-assisted manufacturing steps tailored for the fabrication of modular reinforced concrete components were devised. To assess the load-bearing capacity of the modules, bending and punching shear tests were conducted. The comprehensive process, encompassing design, fabrication, and structural testing of additive-manufactured components, underscores the practicality of material-optimized, ribbed reinforced concrete structures achieved through advanced 3D-printing technologies.