Investigations on the Structural Behaviour of Prestressed Modular Concrete Beams with Dry Joint Interfaces

The construction sector lags behind manufacturing in productivity, while housing demand rises sharply. By adopting modularisation strategies, construction times can be shortened and costs reduced. This paper presents a concept for a modular construction kit for the efficient erection of widely used concrete frame structures, based on the principles of Design for Manufacturing and Assembly (DfMA). A standardised dry-joint interface has been developed, enabling fast assembly and damage-free disassembly. The joining of the modules is achieved through unbonded post-tensioning. To provide a high degree of architectural freedom, the construction kit contains nodes and intermediate components, which enable buildings with bent and curved floor plans. To investigate the structural behaviour, four modular beams were fabricated: a straight reference beam and three beams that are bent in the ground plan through the use of intermediate components of different angles (α = 10°, 20°, 30°). All beams exhibited highly ductile behaviour, characterised by the opening of the joints and high deformations. After yielding of the lower tendons, complete concrete crushing occurred towards the end of the tests. ... mehrThe structural capacity of the beams with angles α = 10° and α = 20° were only slightly reduced compared to the straight reference beam, whereas the beam with α = 30° exhibited significant losses in structural capacity and an increase in deformations. Results confirm that the use of modular concrete beams using prefabricated concrete components is feasible and that their structural capacity decreases with increasing angle in the floor plan. Ongoing work includes finite-element parametric studies to determine reasonable limits for span widths and intermediate component angles of the modular beams.