Imaging a safer future - No 21 - March 2020
NEXCO provides imaging services for structures from the inside-out. A recent project conducted in the state of Connecticut demonstrated the efficacy of scanning of all bridge members in "one fell swoop" because we were able to generate full structural crack maps that pinpointed exactly where cracks were occurring and how they were propagating. The project further bolstered our ability to represent crack conditions in accessible formats and served as a representative example of how this technology benefits long-term monitoring.
The bridge featured box girders, complex piers, and a deck top. The box girders and piers were both imaged from the exterior and interior, and the correlation between crack patterns was overlapped to observe through-cracks and the direction of crack patterns. Accurate mapping and the study of significant crack patterns were the main focus of the project, but with the use of hand-held IR cameras, we were also able to notate delamination and leakage as well. In the very same deliverables, leakage could be viewed alongside cracks, spalls, patching, and so forth.
The selection of adequate test methods and standard procedures generate comparable results, aid the classification of the different deterioration degrees and the urgency for corrective or preventive interventions. Adequate inspection and evaluation criteria conducted periodically assures reliable and representative data ensuring the maintenance plan of bridges in a safe and economic way for the public. Two years down the road, end-users will be able to refer to this comprehensive dataset and see how fast cracks are propagating. They will be able to measure the total length cracks traveled, and the width they took on. Also, using the previous biannual inspection report, we were able to validate the results of the scanning data by comparing the past and present conditions of cracking. The validation showed over a 90% accuracy rate.
The Cincinnati Union Terminal underwent major renovations under the management of GBBN Architects. The work involved structural repair in a historical preservation context.
To gain a better idea of the condition of structural components and surfaces, a 3D laser scanning technology and photogrammetry provider offered their services to create a digitized copy. The team of architects and structural engineers involved in the renovation work put this digital record to use by expediting their work by reducing back-and-forth between the office and site.
We applaud this wonderful demonstration of how visual imagery was taken of a structure can lead to long-term benefits for repair and rehabilitation efforts. Now, the agency owner and future contractors can refer to this complete and detailed record for their planning purposes without setting foot on the site. NEXCO is also projected to begin an interior subway station scanning project in the near future and will enable owners to access the scanned data remotely.
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