nected to the original library building. Comparing that data to the lack of movement picked up by sensors at other parts of the site confirmed that the column in question was moving. Contractors developed a plan to stabilize the column, thus preventing significant damage and ensur - ing the building’s integrity. Finally, monitoring plans and schedules must remain flexible. As con - struction progresses, different areas of a site will become more or less sensitive to movement. Adjust sensor locations and sight lines to corre- late with the shifting zone of influence. For example, the team monitored the horseshoe area of the Alderman Library for movement for approxi- mately nine months. As the project moves to new phases, ATS units will be placed in and around the building’s courtyard because this area will be more sensitive to movement in this new phase. Having a detailed plan in place will help the team anticipate and manage these changes. Movement monitoring is all about safety. Key work decisions are connected to potential movement at a site, such as slowing work for
shutting down a site. Before making these major calls, contractors need collaborating evidence. Utilizing real-time data from sensors placed strategically around a construction site is crucial. A lack of proper monitoring can risk site safety and the integrity of a building, especially a historic structure. Fortunately, new sensors and software provide the clearest view yet of any movement happening during construction. Structural engineers and surveyors who work together can leverage these tools to monitor movement closely and ensure issues are ana- lyzed and addressed quickly.
CHERYL STOCKTON is a Survey Team Leader at Draper Aden Associates, a Mid- Atlantic engineering, surveying, and environmental services firm. Based in Charlot - tesville, VA, she has over 30 years of experience providing surveying services to a wide array of projects. She can be contacted at cstockton@daa.com.
Into the Woods Technology helps researchers manage forests By Mary Jo Wagner
Forest management in the Canadian province of Quebec is serious business. With forest landscapes that cover an area twice the size of Sweden, Quebec’s forest industry is valued at around $10 billion CAD ($7.8 billion US), the second largest amount of any Canadian province, and employs about 65,000 people. Managing Quebec’s forests is also serious business. Although forest managers have used geospatial tools such as aerial photography, optical satellite imagery and GIS software to assess their properties, the process of classifying forest land and delineating forest stands, i.e., a contiguous group of trees that are sufficiently homo - geneous in species, density and size, has typically been a laborious combination of photogrammetry and drawing features by hand. “Standard practice is to manually delineate forest species at the stand level, which is time consuming and subject to misinterpretation,” says Mathieu Varin, head of the Centre D’enseignement et de Recherche en Foresterie de Sainte-Foy (CERFO) remote sensing laboratory. “Au- tomizing that process and scaling it down to classify individual trees would allow managers to individually oversee specific tree species and develop targeted silviculture and harvesting plans.”
As an applied research center, Quebec City’s CERFO has been a key supporter of the forestry business. Working with partners and forest managers, CERFO develops tools to help owners better manage, as- sess, and inventory their present-day holdings in order to develop long- term operational strategies. In his work at CERFO, Varin has spent considerable focus on using satellite imagery and object-oriented image analysis (OBIA) technol- ogy to build an automated forest classification and mapping solution that would target mapping trees at the individual tree level. Antoine Desrochers stands with his Trimble GPS receiver in a cluster of American Basswood trees.
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DECEMBER 2021 csengineermag.com
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