Study On Experiment Of Step Forces Based On Insole Pressure Measurement System

Induced by pedestrian forces light and long-span pedestrian structures will often vibrate excessively, it makes people worried and panic even in normal case and catastrophic events will occur in extreme case, such as structural collapse, stampedes and so on. As pedestrian step forces is the really excitation source of structural vibration, establishing accurate load model is the foundation of study on human-induced vibration. Therefore, researching on measurement of step forces has great significance to vibration assessments and design of long-span footbridges, staircases, floors, corridors and so on. To sum, based on resistance strain pressure sensors an insole step forces measurement system is developed. Meantime, this paper carried out many tests with two kinds of operating conditions:single piaffe and single walking, and analyzed the texts’temporal and spatial parameters of gait and step forces. The main research methods and achievements are as follows:(1) Based on pedestrian forces measurement test method, this paper summarizes the existing pedestrian force measurement test method and its research results at home and abroad. By analyzing the measuring devices’ structure and working principle of various measurement methods, insole step force measuring device was made.(2) By analyzing the performance characteristics of various types of sensors, the resistance strain type pressure sensor was designed and produced with the existing laboratory conditions. Depend on the structural style of the sensor, the three-dimensional model of pressure insoles was designed and established, and pressure insoles were made by using 3D printer quickly and accurately. Combined with dynamic strain measurement technology, an insole pressure device was realized based on pressure sensor which was composed of resistance strain gauge, and its performance indicators was measured at last.(3) This paper carried out many tests with two kinds of operating conditions:single piaffe and single walking by using the above measurement device. Depending on the frequency of walking, each test was carried out respectively under the frequency of 1.5 Hz,2.0 Hz,2.5 Hz and freely frequency with 5 subjects, and each working condition repeat 5 times. The test got the parameters of the five subjects under the four frequencies, which including the stress time-history curve about the single piaffe, the single walking and both feet on the ground. The result showed that the step length is related to testers’ height, the step length was reduced with the increase of the frequency, but walking speed is increased. At the same time, the peak of vertical force was proportional to the subjects’ body weight, and vertical force peak was increased with the addition of frequency.