A MULTICAMERA DISPLACEMENT MEASURING SYSTEM FOR BOUNDARY LAYER WIND TUNNEL TESTS

摘要

This work deals with the long span bridge dynamics due to turbulent wind using wind tunnel testing. In particular bridge model vibrations during wind tunnel tests have been performed by means of a new photogrammetric system. This is made up of three infrared cameras, the lightening system and a PC which synchronizes the cameras and processes the acquired images. This system is able to overcome the typical limits of the techniques, like those based on laser triangulation transducers and on accelerometers, traditionally used to measure large displacements in wind tunnel tests.rnThe bridge model displacement information was combined with the aerodynamic forces measurements. The aim is twofold: finding out its aerodynamic behaviour and validating numerical models simulating fields of aeroelastic forces acting on civil structures. The measurement system as well as the test methodology are described, then some main results are illustrated and commented.