Runway instrumentation and response measurements

This paper presents ongoing research to measure the in situ response to airplane traffic of flexible pavement on a runway at Cagliari-Elmas Airport in Italy. Understanding how pavement materials respond to traffic and environmental loading is fundamental to designing pavements and assessing their performance. The pavement material behavior is affected by many factors (i.e., load magnitude, material properties, and environmental conditions). The influence of these factors can be simultaneously taken into account by measuring in situ stresses and strains using embedded instruments. The pavement layers of the Cagliari-Elmas runway were equipped with 149 instruments: 36 linear variable differential transformers, 36 pressure cells, four time domain reflectometers, 28 T-thermocouples, and 45 hot-mix asphalt strain gauges. The instrumented area, 55 m2, allows measuring the responses during three main loading maneuvers: taking off, landing, and taxiing. The preliminary data acquired during and after the runway's construction and before its opening to airplane traffic and its analysis show that the instrumentation process was a success. The instrument response testing includes falling weight deflectometer, truck, and airplane loading of various types, magnitudes, and speeds. The collected data were successfully compared with preliminary numerical simulations. Further data collection and research will be performed, particularly involving airplane traffic data. Data analysis will include the effect of the environmental data (i.e., moisture and temperature) and airplane configuration and speed. The collected data will be used to validate advanced pavement modeling and predict pavement runway performance. In addition, data resulting from this research have the potential to support and improve runway pavement design and to improve the evaluation process for new and existing runway pavement performance and damage prediction.