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To ensure the safe operation of bridges, it is necessary to carry out repair and strengthening based on appropriate inspections and damage records. However, in conventional bridge maintenance, the inspection results are recorded as 2 D data, which makes it difficult to carry out appropriate repair and strengthening due to the small amount of information. Therefore, research has been conducted to utilize Building Information Modeling (BIM) for bridge maintenance to record damage in more detail, and various concepts have been proposed. However, since no concrete method has been established to automate the entire process from damage detection to linking the damage to the BIM-based model, these tasks currently have to be carried out manually. For this reason, the use of BIM in actual maintenance work has not progressed. This study proposes a method to automate the process from damage detection to linkage to a BIM-based model. In the proposed method, each damage is detected using deep learning, local location information is obtained using Structure from Motion, and the location information is integrated into the 3 D data of the entire bridge. In addition, a case study using an actual bridge is also presented to demonstrate the usefulness of the proposed method. [ABSTRACT FROM AUTHOR]

Machine learning models have been developed to perform damage detection using images to improve bridge inspection efficiency. However, in damage detection using images alone, the 3D coordinates of the damage cannot be recorded. Furthermore, the accuracy of the detection depends on the quality of the images. This paper proposes a method to integrate and record the damage detected from multiple images into a 3D model using deep learning to detect the damage from bridge images and structure from motion to identify the shooting position. The proposed method reduces the variability of the detection results between images and can assess the scale of damage or, conversely, where there is no damage and the extent of inspection omissions. The proposed method has been applied to a real bridge, and it has been shown that the actual damage locations can be recorded as a 3D model. [ABSTRACT FROM AUTHOR]

Bridge structures play a crucial role in the recovery process after an earthquake; however, the need to produce a resilient structure requires the implementation of expensive materials that are essentially limited to critical structures. To achieve a low-cost resilient system, a novel friction pendulum sliding system fabricated from only steel and concrete was experimentally evaluated. Simple concave shapes mounted transverse to one other; and spherical shapes with variable curvatures fabricated by a three-dimensional printer were evaluated. Bidirectional shaking table tests were conducted with different acceleration intensities, and the input acceleration was reduced by 50% during sliding. The spherical shapes exhibited stable hysteresis responses even when subjected to strong ground motions. The proposed friction pendulum sliding system for bridge structures provides a low-cost design solution that can ensure post-event operability. [ABSTRACT FROM AUTHOR]

For dynamic analysis in seismic design, selection of input ground motions is of huge importance. In the presented scheme, complex Continuous Wavelet Transform (CWT) is utilized to simulate stochastic ground motions from historical records of earthquakes with phase disturbance arbitrarily localized in time-frequency domain. The complex arguments of wavelet coefficients are determined as phase spectrum and an innovative formulation is constructed to improve computational efficiency of inverse wavelet transform with a pair of random complex arguments introduced and make more candidate wavelets available in the article. The proposed methodology is evaluated by numerical simulations on a two-degree-of-freedom system including spectral analysis and dynamic analysis with Shannon wavelet basis and Gabor wavelet basis. The result shows that the presented scheme enables time-frequency range of disturbance in time-frequency domain arbitrarily oriented and complex Shannon wavelet basis is verified as the optimal candidate mother wavelet for the procedure in case of frequency information maintenance with phase perturbation. [ABSTRACT FROM AUTHOR]

In civil infrastructure maintenance planning, prevention of severe accidents is essential. Toward that aim, it is necessary to consider the probability of rare events, and risk indices such as value at risk (VaR) and conditional value at risk (CVaR) are frequently employed. However, these indices are not time-consistent. A policy that was initially regarded as optimal may therefore not be optimal when one wants to evaluate the maintenance policy to reduce the probability of tail-risk events, considering policy changes in the future. To eliminate the effect of inconsistency, this study proposes a risk quantification scheme that accounts for the dynamic characteristics of infrastructure maintenance by exploiting the formulation of iterated risk measures as a framework for conventional risk indices such as CVaR. The estimation of the iterated risk measure using a Monte Carlo simulation is costly because it requires a great many samples. To mitigate this problem, the samples are divided into clusters, which enables an efficient identification of samples corresponding to tail-risk events. The performance of the proposed scheme is verified through numerical simulations of road pavement maintenance. The results show that the proposed scheme can evaluate the maintenance policy to reduce the probability of tail-risk events, with consideration for time-consistency. [ABSTRACT FROM AUTHOR]

Following the damage to infrastructure systems in the 2011 Tohoku earthquake, a new seismic design concept named the anti-catastrophe concept in seismic design framework was proposed for the resilience of infrastructure. It states that seismic damage to infrastructure could shift discontinuously from a normal to a severe level, which we refer to as the 'phase transition' of infrastructure damage. In this article, damage to a peripheral lifeline system involving buried pipes for water distribution and sewerage, and power distribution equipment was analysed surveying statistical damage data in the 2011 Tohoku earthquake. It was observed that the damage to the peripheral lifeline systems went beyond the assumption made under the previous damage measures using a relatively lower and moderate seismic intensity at which the degree of the damage became rapidly serious, thereby representing the threshold to the phase transition of infrastructure performance. Further, preferable seismic disaster response with the reduction of the 'large uncertainty of the impact' of the phase transition of infrastructure damage was discussed. Based on the discussion, implications for the resilience of peripheral lifeline systems were derived. The anti-catastrophe concept for the seismic design was introduced and conditions for the implementation of such design concept were summarised. [ABSTRACT FROM AUTHOR]