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Burlington, MA, United States

Moser P.,Fay | Moaveni B.,Tuft University
Mechanical Systems and Signal Processing

Continuous monitoring of structural vibrations is becoming increasingly common as sensors and data acquisition systems become more affordable, and as system and damage identification methods develop. In vibration-based structural health monitoring, the dynamic modal parameters of a structure are usually used as damage-sensitive features. The modal parameters are often sensitive to changing environmental conditions such as temperature, humidity, or excitation amplitude. Environmental conditions can have as large an effect on the modal parameters as significant structural damage, so these effects should be accounted for before applying damage identification methods. This paper presents results from a continuous monitoring system installed on the Dowling Hall Footbridge on the campus of Tufts University. Significant variability in the identified natural frequencies is observed; these changes in natural frequency are strongly correlated with temperature. Several nonlinear models are proposed to represent the relationship between the identified natural frequencies and measured temperatures. The final model is then validated using independent sets of measured data. Finally, confidence intervals are estimated for the identified natural frequencies as a function of temperature. The ratio of observed outliers to the expected rate of outliers based on the confidence level can be used as a damage detection index. © 2010 Elsevier Ltd. All rights reserved. Source

Gould J.,Fay | Clancy G.,Office of Community Development
Journal of New England Water Environment Association

The low-lying Winn's Brook Area is in the northeast section of Belmont, Mass. For years, residents in this area have experienced periodic sanitary sewer overflows and backups into the basements of their homes during large storm events. Using four basic concepts-increased capacity, flow diversion, system storage, and isolation and pumping-the town developed 13 overflow mitigation alternatives to address this problem. Hydraulic modeling was used to rank the alternatives based on lowering the hydraulic grade line and reducing peak discharge. This process required close collaboration with neighboring communities and the Massachusetts Water Resources Authority (MWRA) to ensure the project created no detrimental downstream effects. The winning combination includes diverting flow through a 2,800-foot-long (853-meter-Iong) storage conduit along with new sewers and diversion structures to redirect flow to an off-line pump station. Once the pumping station is activated, the Winn's Brook Area is isolated from the general sewer system. Source

Szymczakiewicz D.P.,Springfield Water and Sewer | Chapman S.A.,Fay | Ditullio III W.A.,Fay
Journal of New England Water Environment Association

The Springfield Water and Sewer Commission (SWSC) is conducting a collection system assessment program of its combined wastewater collection system within the city of Springfield, Mass. This involves performing National Association of Sewer Service Companies' (NASSCO) inspections of collection system assets and inserting that data into a risk and criticality model. This model indicated that the sewer main within Pine Street, between Maple Street and Central Street, was in failure mode and highly ranked in criticality to the collection system as well as risk associated with failure. This section of 1.60-meters-high by 1.07-meters-wide (63-inch-high by 42-inch-wide) egg-shaped brick combined sewer was constructed in 1882, is 408 meters (1,340 feet) long and has an average depth of about 14 feet to invert. In March 2011, SWSC began to review information, collect supplemental information, evaluate viable alternatives, and design the replacement or rehabilitation of the Pine Street combined sewer. Source

Varney J.C.,Fay | Lee S.D.D.,Fay
Structures Congress 2014 - Proceedings of the 2014 Structures Congress

The Duck Bridge is a five-span, double-intersection, Warren-type through-truss bridge carrying Union Street over the Merrimack River in Lawrence, Massachusetts. Constructed in 1888 by Boston Bridge Works (Cambridge, MA), it is the oldest of its type in the state of Massachusetts. The structure underwent a $15.6M rehabilitation between September 2008 and March 2013, during which components of the substructure and superstructure were repaired or replaced. While the rehabilitation project was driven by the need to address safety concerns from structural deficiencies found in the bridge superstructure, it was important to maintain the historic nature of the truss bridge. The Duck Bridge has long been a significant part of the surrounding community, past and present. It is one of the primary features of the North Canal Historic District, which was added to the National Register of Historic Places in 1984. © 2014 American Society of Civil Engineers. Source

Harrington P.F.,Fay | Khalil R.Y.,Fay | Varney J.C.,Fay
Structures Congress 2014 - Proceedings of the 2014 Structures Congress

This paper describes the rehabilitation of the historic Anderson Memorial Bridge which carries North Harvard Street over the Charles River in Boston and Cambridge, Massachusetts. The structure is a vital transportation link that accommodates significant volumes of vehicular, pedestrian and bicycle traffic. The bridge is classified as an Urban Arterial, and it is listed on the State and National Registers of Historic Places as an integral component of the historic Charles River Basin. The Anderson Bridge, completed in 1915, is a three-span, earth-filled, concrete arch bridge with notable brick and granite aesthetic treatments adding to its appeal. Deterioration of the spandrel walls, parapets, brick arch rings and concrete arches necessitated bridge rehabilitation, and a $20 million project began in the Spring of 2012 to address these issues as part of the MassDOT $3 billion Accelerated Bridge Program. The project incorporated input from the public along with the interests of 18 stakeholders. © 2014 American Society of Civil Engineers. Source

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