Researchers in China have successfully used a digital twin to investigate the reasons for a building collapse.
Reported in a recent edition of Advances in Civil Engineering, the researchers from Tsinghua University in Beijing and the China Southwest Architectural Design and Research Institute Corporation in Chengdu detailed their approach, starting with a real-world scenario to prove their thinking.
They chose a seven-storey building, which collapsed after welding strengthening in 2020. The building was initially of a conventional steel frame structure, but underwent many functional changes in its time, and its structure changed correspondingly – the complex retrofitting process and irregular internal structure led to complicated loading states and collapse accidents.
The researchers noted: “The complex retrofitting process makes it difficult to reveal the potential collapse mechanism using conventional analysis methods. The digital twin-based collapse investigation method can provide a comprehensive and accurate understanding of the building at each stage from construction to collapse.
“Therefore, to establish the digital twin model, we collected the necessary information about the building from construction to collapse. Based on this information, we established the corresponding digital twin models and updated the models several times from the initial state to the critical state before collapse.”
“Even if the service history of the engineering structure is complex, the digital twin model can effectively record and update the series of changes, which can assist in the analysis of complex collapse mechanisms.”
The researchers’ technique involved the development of building information models, finite element models (FEM), and physics engine models of the building to simulate its performance during operation and maintenance. Subsequently, the main causes of building collapse were analysed and expounded.
The researchers wrote: “The results indicate that defects and damage in critical regions of buildings are important factors that can cause building collapse. The rationality of the digital twin-based virtual model analysis was validated by site investigation.”
In conclusion, the researchers noted: “Via the information interaction between the physical world and the virtual world, the real cause of the accident can be revealed more reliably. In the building collapse case, the maximum compressive stress in the columns on the ground floor of the building exceeded its critical buckling stress. The welding process led to local buckling and plastic deformation of the ground floor columns, which further resulted in large flexural deformation in the columns. This caused severe disturbance to the highly loaded steel columns, which induced damage to the columns on the ground floor and the overall collapse of the structure.”
In addition, they stated: “With improvements in FEM, BIM, physics engine, and model updating techniques, the digital twin technology can be used for the collapse scenario simulation and cause investigation of structural collapse accidents. Even if the service history of the engineering structure is complex, the digital twin model can effectively record and update the series of changes, which can assist in the analysis of complex collapse mechanisms.”
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