Identifying Modal Characteristics of Reinforced Concrete Bridges Using Smartphones

Abstract

This paper explores the use of smartphones as vibration measurement device to identify modal properties of reinforced concrete (RC) bridges. Two in-service RC bridges are instrumented with both conventional accelerometers and smartphone accelerometers. One of the tested bridges is a simply supported RC T-beam bridge structure and the other one is a simply supported RC slab bridge with a skew angle of 15 degrees. The vibration testing includes both traffic-induced ambient excitations and impact hammer excitation. The natural frequencies of the bridges are identified from operational modal analysis using the data obtained from both conventional and smartphone accelerometers at a single point and a peak-picking technique. In addition, the modal properties of two bridges are extracted using data obtained from a dense network of sensors and by employing enhanced frequency domain decomposition method. To assess the correlation between the modal properties identified from smartphone data and data obtained from traditional sensor, statistical analyses are conducted. Results show that there is a good agreement between the modal characteristics extracted from smartphone and reference sensor data as well as those obtained from a dense instrumentation.