NEW DELHI: Researchers at the Indian Institute of Technology (IIT), Guwahati, have developed a framework for designing earthquake-resistant 3D-printed concrete walls, according to officials.
As it eliminates the need for labour and materials and allows structures to be made in more complex shapes, 3D printing in construction is being adopted globally. Although there has been some significant progress in producing 3D-printed buildings around the world, they have yet to gain widespread use in earthquake-prone regions.
According to Biranchi Panda, Assistant Professor, Department of Mechanical Engineering, one of the reasons behind this is the limited knowledge and understanding of how full-scale 3D-printed concrete walls will perform during multiple earthquake shakes.
“Currently, there are no standard procedures for adding steel reinforcement to 3D-printed walls that comply with current building codes. To bridge this gap, we constructed and tested three full-scale walls made of 3D-printed materials under seismic loading conditions,” Panda told PTI.
The research has been published in the Journal of Building Engineering. While the first wall was made of plain printable mortar (3DPM), the second wall was made of strain-hardening ductile concrete (3DPC-CF), a special concrete that can bend and develop many small cracks without failing.
“This special concrete was able to support the wall’s weight even after damage started. The third wall was made of modularly reinforced ductile concrete (3DPC-CFR), the same special concrete with the added feature of a modular steel reinforcement framework integrated into the wall’s structure.
“We integrated this reinforcement in such a way that it can be constructed using 3D printing without hampering the printing process and meets the safety requirements of Indian and international earthquake safety standards,” Panda said.
To test the strength and real-world usability of 3DPC-CF and 3DPC-CFR walls, the research team conducted large-scale experimental tests backed by computer simulations of their behaviour under cyclic loading conditions.
The results confirmed that using the special ductile concrete and incorporating steel reinforcement in 3D-printed walls significantly improved their earthquake resistance, thus making them suitable for the development of safe, efficient, and structurally reliable additive manufacturing practices.
“In this study, we have experimentally (full-scale) validated the enhanced seismic performance of 3D printed walls, achieved through material ductility and modular reinforcement.
"Based on numerical results, we have optimised the 3D printed wall design and predicted cyclic performance of full-scale structural building for earthquake-resistant applications,” Panda said.
To further test the real-world application of the developed framework, the team created a simple model of a full-scale single-storey 3D-printed house to analyse the entire building and found it to accurately predict the behaviour of large 3D-printed structures.
“This study also acknowledges the advantages of 3D printing, including reduced material and formwork use. The approach has a strong potential for cost optimisation as scale and technological maturity increase,” Panda said.
The developed technology can be employed in the development of faster and safer robotic/digital construction. It can also be used to analyse the behaviour of other structures exposed to earthquakes and other extreme forces, the professor said.
“We know plan to extend the framework to multi-storey buildings, investigate resistance to other hazards such as impact and blast loading, and contribute to future design standards for structural 3D printing,” Panda said.