Structural monitoring of a breakwater using UAVs and photogrammetry

Sousa, Pedro J.; Cachaço, António; Barros, Francisco; Tavares, Paulo J.; Moreira, Pedro; Capitão, R.; Neves, Maria G. P. M. S.; Franco, Elsa

doi:10.1016/j.prostr.2022.01.073

Cited by 4 publications

(2 citation statements)

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“…There is an increasing number of both breakwaters in service whose original lifetime is exceeded or close to being exceeded in the coming years, and low-cost, high precision surveying techniques (e.g. UAV LIDAR for the emerged part of the breakwater); this favors the use of a variety of new breakwater monitoring schemes and surveys (see Ueno et al, 2021, Sousa et al, 2022, and Bajo, 2022. This selection of available monitoring techniques range from simple visual inspections of the emerged part and not so simple underwater visual inspections (photographs and videos) by divers.…”

Section: Upgrading Repair and Rehabilitation Of Mound Breakwatersmentioning

confidence: 99%

Breakwaters In A Living Environment

MEDINA

2024

CoastLab

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Breakwaters protecting harbors and coastal areas are key to the economic and social development of many countries, but they are also infrastructures which may result in relevant environmental and social impacts. The construction of new breakwaters in developing countries, together with the dismantling, rehabilitation or repair of old breakwaters in developed countries, should be adapted to the principles of sustainability to produce efficient and resilient systems. Global mean temperatures and sea levels are rising due to climate change, and many environmental variables and numerous ecosystems are evolving. The hypothesis of stationarity, widely assumed in the last century when estimating the wave climate for the design of maritime structures, is now questionable, and new methodologies are required to design breakwaters in this changing environment. Marine life and ecosystems are affected by construction processes and structures, but the interactions are not well known; marine growth and enhanced biodiversity are usually considered positive environmental impacts of most breakwaters but materials, carbon footprint and energy consumption are negative impacts. The two main challenges in breakwater design are (1) to develop sound design methods valid in a changing wave climate and with rising sea levels, and (2) to adapt design guidelines to build-up, to repair and to dismantle breakwaters in a living environment.

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Section: Upgrading Repair and Rehabilitation Of Mound Breakwatersmentioning

confidence: 99%

Breakwaters In A Living Environment

MEDINA

2024

CoastLab

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“…Furthermore, structural condition inspection and damage diagnosis based on the point cloud model have also been studied [37]. Te health monitoring of the structural movement can be realized by comparing the data collected by the UAV over diferent periods [38]. Te semantic segmentation of important structural components in the point cloud model can be accomplished for diferent types of structures, such as bridges [39], tunnels [40], buildings [41], and towers [42].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Accurate Point Cloud Model Reconstruction for Earthquake-Damaged Structures Using UAV-Based Photogrammetry

Shan

Zhu

2023

Structural Control and Health Monitoring

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Camera-enabled unmanned aerial vehicles (UAVs) provide a promising technique to considerably speed up the inspection and visual data collection from regions that may otherwise be inaccessible. In addition, the technology of image-based 3D reconstruction can generate a point cloud model using images captured by UAVs. However, the performance of the point cloud modeling may be affected by multiple factors, such as the modeling software, ground control points (GCPs), and UAV flight modes. In this study, three common software packages were compared, and Pix4Dmapper was considered a suitable software for point cloud modeling for earthquake-damaged buildings. The accuracy and resolution of point cloud models are usually evaluated by root mean square error (RMSE) and ground sampling distance (GSD). The effects of the main factors, including the number of GCPs, distribution of GCPs, flight manner of the UAV, and distance from the UAV to the target, were investigated on the basis of two real-world multistory earthquake-damaged structures. The influence rules of the main factors revealed that a close range, automatic flight mode of the UAV, a large number of GCPs, and a relatively wide distribution of the GCPs may generate a point cloud model with low computational costs, high accuracy, and high resolution. In the particular illustration example here, the RMSE is 6.78 mm while the GSD is 1.60 mm. Finally, rapid structural damage inspection was demonstrated using an accurate point cloud model and compared with the inspection results of a total station and terrestrial laser scanner point cloud models. The comparison of different inspection results showed that the relative errors were relatively acceptable within 4%.

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