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This study investigates the influence of different printing set-ups and materials on the bond strength of reinforcement manually placed between 3D printed concrete layers. An identical experimental campaign was performed at two institutes in Switzerland and Italy. Each institute used its own printing process, which consisted either of a set on-demand mix or a high yield stress material. Two types of reinforcement (reinforcing bar Ø8 mm and a high strength steel wire Ø1 mm) and three production configurations (casting and printing with the reinforcement parallel or perpendicular to the printing direction) were investigated. The results showed high bond strength with only a limited influence of the fabrication method for the reinforcing bars. An increased bond was observed for the set on-demand approach compared to the high yield strength material. The comparison with existing models showed that the reinforcing bar bond strength of printed concrete varies slightly from conventional concrete. The high strength wires exhibited poor bond. Based on the gathered experiences, insights into the standardisation of testing for 3D concrete printing are discussed. • Inter-laboratory study comparing two 3DCP strategies in Italy and Switzerland. • Pull-out tests with conventional reinforcing bars and wire reinforcement. • Choice of printing strategy influences the bond strength. • Bond of reinforcing bars in 3DCP mortars higher than predicted by existing models. • Insights towards standardisation of bond strength tests for 3DCP. [ABSTRACT FROM AUTHOR]

The aim of using dual steel eccentrically braced frames with removable links is to reduce the repair costs and downtime of a structure hit by an earthquake. This objective is to be attained through removable dissipative members and re-centering capability of the structure. The concepts of removable dissipative members and re-centering capability are to be implemented in a dual structure, obtained by combining steel eccentrically braced frames with removable bolted links with moment resisting frames. The bolted links are intended to provide the energy dissipation capacity and to be easily replaceable, while the more flexible moment resisting frames would provide the necessary re-centering capability to the structure (the columns of the moment resisting frames are made of high strength steel in order to remain in the elastic range). The objective of the present work is to present the results of the numerical simulations and experimental tests done in order to investigate the possibility to replace bolted links within a realistic structure following significant inelastic deformations and the practical feasibility of the replacement procedure. Practical solutions regarding order in which bolted links need to be replaced are proposed. The numerical simulations mentioned above are to be used for a full scale pseudo-dynamic test performed at Ispra, Italy. [ABSTRACT FROM AUTHOR]