By Kang Pu
At a sci-tech park of the Institute of Engineering Mechanics (IEM) under China Earthquake Administration in Sanhe city, north China’s Hebei province, a team of Chinese experts in intelligent construction, structural engineering, and earthquake resistance conducted an intense “destructive” experiment for a 3D-printed house model.
This 3D-printed concrete house model was brought in for testing by associate professor Sun Xiaoyan’s team from the College of Civil Engineering and Architecture at Zhejiang University.
“Are 3D-printed houses sturdy?” This is the most common question received by Sun.
The sturdiness is primarily determined by how well they can resist earthquakes. Sun had collaborated with Hangzhou Lingdong Technology Co., Ltd., an enterprise specializing in digital construction and 3D printing design based in Hangzhou, east China’s Zhejiang province, to precisely calculate the structure’s earthquake-proof performance using a 3D digital model.
Theoretical analysis suggested excellent earthquake resistance, but to confirm these findings, Sun and a team of experts from different areas decided to conduct a shaking table test.
A shaking table is a device that simulates earthquakes. The one being used for this test was a state-of-the-art six-degree-of-freedom shaking table capable of generating horizontal and vertical vibrations as well as rotational movements.
To match the dimensions of the shaking table, Sun commissioned a factory to produce a scaled-down 3D house model measuring five meters in length and just over one meter in width, which is also the maximum dimensions allowed for testing.
The experiment included six different seismic conditions, with seven tests conducted for each situation. “The goal is to keep shaking it until it breaks down – to see how strong an earthquake it can endure,” Sun said cheerfully.
“Start!”
Following the command, a buzzing sound filled the air, and the hydraulic actuators of the shaking table jolted violently – a simulated earthquake began.
After the shaking subsided, researchers quickly stepped onto the platform, meticulously inspecting every corner of the house model and marking every visible crack.
Visual inspection, however, was only part of the assessment. The model was equipped with acceleration sensors, displacement sensors, strain gauges, and an advanced optical tracking system empowered by video recognition. Additionally, four ultra-high-speed cameras positioned on either side of the structure could capture the slightest changes during the simulated earthquake.
“These ultra-high-speed cameras can capture 3,000 frames and produce 6GB of image data per second – no structural movement goes unnoticed,” said Zhu Liangying, a technician with Hefei Zhongke Junda Vision Technology Co. Ltd., the manufacturer of the cameras.
Sources say that the IEM has made significant strides in fields such as strong-motion observation and application, earthquake-resistant building engineering, earthquake risk assessment and mitigation, earthquake engineering testing technologies, and earthquake and engineering vibration measurement technologies.
In 2024, the institute spearheaded the development of a next-generation high-speed railway earthquake early warning and monitoring system, which has been deployed along more than 1,500 kilometers of railway in China and exported for use in Jakarta-Bandung High-Speed Railway in Indonesia.
As the experiment progressed, the simulated earthquake became more intensified, followed by a louder buzzing sound, and cracks started appearing on the house model.
By the time the test reached the sixth condition, even the floor beneath the observers trembled noticeably as the hydraulic actuators roared.
In real earthquakes, most casualties are caused by the collapse of buildings. According to He Huanan, associate professor with the School of Infrastructure Engineering, Dalian University of Technology, China has established three principles for earthquake-resistant construction to ensure building safety: structures should remain undamaged in minor earthquakes, sustain repairable damage in moderate earthquakes, and avoid collapse in major earthquakes.
To be specific, a minor earthquake refers to a common seismic event with a 63 percent probability of occurring within a 50-year design lifespan, where buildings should remain undamaged. A moderate earthquake corresponds to the expected seismic intensity, with a 10 percent probability of being exceeded in 50 years – some damage is acceptable, but buildings should remain functional after repairs. A major earthquake is a rare event, with only a two to three percent chance of occurring within a building’s lifespan, where the primary goal is to prevent collapse and ensure people’s life safety.
After a full day of testing, the 3D-printed house model withstood an earthquake with a magnitude of 6.0 without any structural damage. When magnitudes reached 7.0 and 8.0, cracks appeared but did not extend to the structural framework, maintaining overall stability. Even after an earthquake at a magnitude of 9.0 that caused complete cracking, the core structure remained intact without collapse or severe damage. The model successfully passed the test.
Sun explained that 3D-printed concrete buildings boast many advantages. First, they allow for rapid and precise construction through digital design, additive manufacturing, and prefabrication, and can accommodate a range of architectural forms. Second, their hollow-wall design can incorporate reinforced steel frameworks, creating a robust concrete structure with excellent anti-seismic performance and long-term durability.
“The future of 3D-printed houses is promising,” Sun said.
However, as a novel construction method, 3D-printed concrete houses still require further professional certification and practical testing. The outstanding earthquake resilience of this scaled-down house model has brought confidence in future research and wider technological adoption.
Researchers mark cracks on the 3D-printed house model at the experiment site. (Photo by Kang Pu)
