Measuring Deflection of a Road Surface

Résumé du livre

Due to an event known as the frost-thaw cycle, roadways in colder climates are susceptible to damage caused by heavy vehicles driving on asphalt supported by soft, water-logged soil. The soft road underbed is unable to properly support the asphalt, and cracks may form leading to further road damage. Civil engineers attempt to prevent some damage by implementing Seasonal Load Restrictions (SLRs) on heavy trafficked roads when weather conditions predict the soil may become too soft under roads. To assist civil engineers in assessing the accuracy of weather-impacted predictions, a sensor system designed to measure the temperature gradient underneath roadways was developed by a team of graduate students at the University of Massachusetts Dartmouth, under a federal Department of Transportation grant awarded to Dr. Paul Fortier of the College of Engineering Electrical and Computer Engineering Department. During the development stage of this project, the desire arose to directly measure the impact heavy vehicles have on vulnerable roadways. It is to this end that the development of a sensor capable of measuring roadway deflection was commissioned. By directly measuring the movement of asphalt when a vehicle passes over it, the efficacy of an SLR could be quantified, leading to refinements of the methods used in determining the conditions necessary to warrant an SLR, which can have an impact on local travel and commerce. Utilizing micro-electromechanical systems (MEMS) components and low-power microcontrollers allows integration of a deflection sensor into the existing temperature-measuring system with little need for reconfiguration of the prebuilt systems.