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Au Sable Lighthouse, MI – With a goal of improving how historic structures are managed and advancing the role of technology for historic preservation, a collaborative team of experts completed a field experiment at the Au Sable Lighthouse in Michigan's Upper Peninsula. The team, which included researchers from the U.S. Army Engineer Research and Development Center's Construction Engineering Research Laboratory (ERDC-CERL), University of Wisconsin-Madison (UW-Madison) and National Park Service (NPS), is integrating advanced fiber optic technology and 3D scanning to enhance structural health monitoring.
“It is truly exciting to see research that UW-Madison and ERDC-CERL have been working on for several years culminate in this first field experiment to innovate how the government monitors and manages its historic structures,” said Dawn Morrison, ERDC-CERL Team Lead for the Assess and Monitor Historic Structures Initiative. “We are really grateful to the NPS for supporting this project and making the Au Sable Lighthouse available.”
This groundbreaking project is pushing the boundaries of structural health monitoring for cultural resources management. The field work at the Au Sable Lighthouse is the first time the project has implemented the innovative technology for real-world data gathering and monitoring.
“As an early career researcher, it’s invigorating to be involved in an innovative project that has the potential to transform the field of historic preservation,” said Madison Story, an architectural historian at ERDC-CERL. “I’m so honored to have the opportunity to learn about engineering technologies and how they can be leveraged to improve the management of and preserve our nation’s cultural resources.”
For this initiative, UW-Madison Professor Jesse Hampton is spearheading a team of graduate students to equip the lighthouse with fiber optic technology developed by UW-Madison for structural health assessments. This technology will enable the team to monitor the lighthouse's response to weather loading and environmental impacts.
“We are incredibly excited to combine ongoing research with the educational mission of UW-Madison where I was able to lead a group of ten graduate students within my Nondestructive Evaluation course to this beautiful location and introduce them to remote sensing and the possible impact of damage on culturally important sites,” Hampton said.
“We are collecting four types of fiber optic sensing at this site: distributed strain, distributed temperature, distributed acoustic and high-resolution distributed strain. Integrating both high- and low-frequency measurements of strain will help us understand how the structure is responding to the environmental stresses it experiences, such as diurnal temperature variations, strong wind events, or stress waves from people walking within or near the structure,” Hampton explained.
With long-term monitoring, the team says they will be able to understand if the structure is beginning to respond differently to similar loadings and possibly invert for the changes in physical properties producing those differences.
“This is an exciting area for the intersection of damage mechanics, remote sensing, and structural health monitoring,” Hampton said.
The fiber optic data will be combined with 3D scanning data collected by ERDC-CERL's Cultural Resources team and UW-Madison graduate students. Carey Baxter, an archeologist and 3D scan lead, said the scans will help create an augmented virtual reality that allows for assessments of the lighthouse in response to environmental and weather affects.
“The 3D scans that we collected of the lighthouse site are so detailed that we clearly recorded the fiber optic cables that UW-Madison attached to the lighthouse tower. Any time the sensors detect any changes in the lighthouse tower, the scan data will allow them to determine exactly where that event happened,” Baxter explained. “They will be able to use the scan data to create 3D computer models of the entire site and be able to recreate and analyze digitally what their sensors recorded in the real world.”
“It is exceptionally important to know the orientation of the fiber optic cables, as they are only sensitive to strains in the direction of the cable and this information can help interrogate the observations in three-dimensional space,” Hampton added.
Baxter said an added benefit of the scanning is that if any portion of the light station is damaged or destroyed in the future, the team now has the data needed to reconstruct or replicate any portion of the buildings or site.
Story said collecting data on the lighthouse was an incredible experience, explaining that she “witnessed and participated in the application of emerging engineering technologies to a marvel of historical engineering.”
“Being able to learn from both Ms. Baxter and Dr. Hampton while also communicating the history of the site and the importance of preserving heritage structures to students graduate-level engineering students was extremely rewarding,” Story said.
The Au Sable Lighthouse is a historic beacon that has guided ships through the waters of Lake Superior since its construction in 1874. Standing at 86 feet tall, the lighthouse played a crucial role in maritime navigation. The lighthouse became fully automated in 1958 and transferred from the U.S. Coast Guard to the NPS in 1968. Today, it remains a significant landmark and a symbol of maritime heritage.
“The Au Sable Light Station is such an amazing site since it was the first “Poe-style” light tower designed by Orlando Poe, the District Engineer for the Eleventh Lighthouse District in the early 1870s. Visiting the site also clarifies the importance of light stations in the late 19th century—I couldn’t have truly understood the extremely remote, foggy, and windy nature of the site, and therefore both the dangers facing ships on Lake Superior and the value of this site for structural health monitoring, without having been there myself,” Story shared.
The main objective of this first field experiment was to evaluate the sensitivity and effectiveness of the fiber optic technology and its integration with 3D scanning data. The insights gained are expected to enhance methods for preserving historic structures and will be provided to NPS and ultimately the Department of Defense.
| Date Taken: | 10.15.2024 |
| Date Posted: | 10.17.2024 10:45 |
| Story ID: | 483130 |
| Location: | UPPER PENINSULA, MICHIGAN, US |
| Web Views: | 1 |
| Downloads: | 0 |
This work, ERDC partners with UW-Madison and NPS to advance historic preservation, by Sophia Espinosa, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
