PSI - Issue 64

Saim Raza et al. / Procedia Structural Integrity 64 (2024) 1176–1183 Raza / Structural Integrity Procedia 00 (2024) 000 – 000

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Fig. 6. Effect of Steel/Fe-SMA reinforcement ratio on the residual drifts of segmental columns with 3D printed concrete formwork

4. Conclusion and Future Outlook This study introduced an innovative prefabrication concept for accelerated construction of segmental bridge columns. The proposed approach combines digital fabrication technology with an advanced Fe-SMA-based prestressing technique. In the proposed prefabrication approach, hollow 3DPC shells are used as permanent formwork for the columns, thereby eliminating the need for temporary formwork used in traditional construction. The viability of the concept was assessed through large-scale experiments on columns subjected to combined gravity and quasi static cyclic lateral loads. The results showed that the columns were able to withstand 5% drift without collapse and premature failure of 3DPC formwork. Furthermore, the columns showed self-centering up to a target drift of 3% due to the prestressing effect of Fe-SMA bars. It is expected that self-centering behavior could be further improved by increasing the initial prestressing level and varying the location of Fe-SMA bars within the cross-section. Given the positive results of the feasibility study, future work could investigate optimized geometries for the formwork shells of segmental columns that can be fabricated efficiently through 3D printing, thereby making the next generation of columns lightweight. This could include overall shape optimization of the 3DPC formwork shells, geometric variation between the segments, and the integration of additional functionality including printing of formwork shells with integrated ducts. Acknowledgements The authors would like to acknowledge Dr. Mateusz Wyrzykowski and Dr. Volha Semianiuk for their scientific support and the staff of the Empa Structural Engineering Laboratory for their technical support, in particular Mr. Robert Widmann and Mr. Werner Studer. The authors are also grateful to the industrial partner, re-fer AG, for providing the materials and technical support with prestress activation. The financial support of the Department of Engineering Sciences at Empa and the Institute of Technology in Architecture at ETH Zurich is also gratefully acknowledged. References Billington, S. L., Barnes, R. W., & Breen, J. E., 1999. A precast segmental substructure system for standard bridges. PCI Journal, 44(4), 56-73. Dong, Y. H., Jaillon, L., Chu, P., & Poon, C. S., 2015. Comparing carbon emissions of pre-cast and cast-in-situ construction methods – A case study of high-rise private building. Construction and Building Materials, 99, 39-53. Figg, L., & Pate, W. D., 2004. Precast concrete segmental bridges - America's beautiful and affordable icons. PCI Journal, 49(5), 26-38.