Analysis of Load Pulse Durations for Marquette Interchange Instrumentation Project

The loading frequency is an important input for determining the stiffness of asphalt materials on the basis of their dynamic modulus data. This stiffness relationship is used in the Mechanistic-Empirical Pavement Design Guide (MEPDG) to calculate a pavement's structural response to loading. This response-typically maximum horizontal strain and vertical pressure-is then used to estimate the number of load repetitions to failure. The Marquette Interchange Perpetual Pavement Instrumentation Project Is a research effort carried out by the Transportation Research Center at Marquette University. The project implemented different pavement sensors to provide researchers with a complete set of pavement response data for calibration of local design variables and to provide insight Into the structural behavior of a perpetual pavement opened to live urban freeway traffic. An analysis of the strain and pressure data recorded from the project was conducted to measure the length of strain and pressure pulse durations. The load pulse durations for each axle were then analyzed and compared with models contained In the MEPDG software. The analysis showed that the models may broadly fit actual load durations, but the surrounding assumptions may not be adequate for all axle and load configurations.