Laminated Glass Beams Subjected to Artificial Solar Radiation

In the long run laminated glass interlayers are sensitive to weather conditions. Several studies have been carried out that aim at understanding the consequences of moisture and solar radiation on adhesion to glass and on the mechanical response of the composite pane. In particular, solar radiation seems to produce the strongest effects on the bulk properties of PVB, modifying the coupling capability of laminated glass plates exposed to the direct sunlight. Such problem has been already studied by the authors via dynamic tests on small laminated glass specimens subjected to artificial UV light; however, due to the methodology of these mechanical tests, it was not possible to repeat the experiment on the same specimens subjected to different exposition times, and it was not possible to investigate the laws of accumulation of the consequences of weathering actions. In fact, solar radiation could produce different effects on the structure of material, but only superimposed consequences can be observed. In order to better understand the time progression of the phenomenon, creep tests were performed on laminated glass beams subjected to four-point bending; the specimens were tested in correspondence of definite time intervals of UV exposure. The total amount of time will be defined according to the observed variation of test results with respect to the total exposure. The effects of UV radiation are highlighted directly comparing the displacement history diagram and successively evaluated analyzing the mechanical parameters that describe the rheological behavior.