In the Field Validation of Human Induced Loads Measuring Technique

Human induced vibrations on civil structures is a key problem in comfort and security design. The estimation of loads due to human motion is a critical and still unsolved problem, but it is fundamental for a correct design of new buildings and proper monitoring of existing. This work presents a validation of an imaged based measuring technique of these loads. The test-bed is the Meazza Stadium in Milan. The validation of the proposed technique is done as follows: some volunteers jump on a stand and the induced vibration is acquired; a video recording of the jumping crowd is acquired simultaneously. The video is analyzed using a digital image correlation (DIC) code in order to obtain a motion estimation and, starting from the DIC results, induced loads are predicted. Using the frequency response function of the stand, previously estimated through a dynamic characterisation of the structure, it is now possible to forecast the induced vibration and compare it with the acquired one. The results show a very high correspondence between the measured and estimated accelerations and, above all, the performances do not degrade increasing the number of volunteers.