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Hanshin Expressway Company (hereinafter “Hanshin Expressway”) and Toshiba Corporation  have developed ultra-large-scale analysis technologies for computer modeling of complex bridge structure that demonstrate bridge deformation and impacts from vehicle loads (Fig. 1). Unlike conventional models, which represent complex shapes with simplified beams, the new model dramatically improves accurate identification of stressed locations within bridge structures. It has been successfully applied to the 885m span of the Higashi Kobe Bridge in Kobe prefecture, Japan, a cable-stayed bridge on the Hanshin Expressway No. 5 Bayshore Route in Osaka Bay.

Details of the technology will be announced on 30 August at Japan Society of Civil Engineers 2018 Annual Meeting, at Hokkaido University.

Bridges and other infrastructure constructed during Japan’s period of high economic growth are aging and degrading, at the same time as an aging society is causing labor shortages. In addition, developing a realistic model meets the need to improve on the efficiency of conventional manual inspection for bridge maintenance and management, and to ensure prompt understanding of structural status if a bridge is hit by an earthquake or other natural disasters.

Hanshin Expressway and Toshiba’s goal was to realize a “Digital Twin” of the real-world bridge. This highly advanced approach to modeling aims to create a faithful reproduction of an object. In the case of a bridge, that includes the impacts of daily wear and tear and deterioration due to aging and fatigue. Realizing a digital twin of a bridge opens the way to enhancing disaster prevention by achieving greater precision in diagnosing deterioration, and to improving management and maintenance efficiency. It is also a powerful tool for quickly assessing structural soundness following a natural disaster.

Hanshin Expressway and Toshiba started to research ultra-large-scale analysis technologies for building Digital Twins of bridges in February 2017. Structural analysis technologies Toshiba has cultivated through research, design, and development of infrastructure and digital products, combined with Hanshin Expressway’s expertise in bridge maintenance and management, supported the companies in developing technologies for quickly building a three-dimensional models from the two-dimensional design drawings of the Higashi Kobe Bridge.

Conventional analysis techniques model bridges by representing their complex cross-sectional structures with simplified beams. The newly developed ultra-large-scale analysis technologies is much more precise and true to the original, and can reproduce the bridge in detail at a scale approaching 500 million degrees of freedom.^* Representing the complexity of complex real structures rather than replacing them with beams helps to realize precise analysis of where loads are applied in the structure and where deformation will occur.

Hanshin Expressway and Toshiba continue to refine the Digital Twin model. Measures that will improve its accuracy include a network of IoT sensors now being installed in the bridge, which will verify current result and allow fine tuning. Going forward a wider range of analysis functions will include bridge elongation caused by temperature rises and vibration caused by wind and vehicle.

*Approaching 500 million degrees of freedom: This represents the granularity of the model. The present Digital Twin represents the bridge as 80 million nodes, each capable of movement in six directions. This results in 80 million (nodes) × 6 (directions) = 480 million degrees of freedom.

 

 

Figure. 1: Ultra-large-scale analysis of the Higashi Kobe Bridge to model deformation

 TOP:Higashi Kobe Bridge on the Hanshin Expressway No. 5 Bayshore Route

LEFT:Deformation simulation modeling vehicle load
        Load conditions: Load due to a 24-ton truck (deformation ratio: 1000×)

RIGHT:The Digital Twin of the bridge (large-scale structural analysis model)
         A finite element model with 500 million degrees of freedom

 

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