Dieter Callewaert

Experimental investigation of unconventional canopy prototypes, suspended by adhesive bonds

In this contribution the performance of an adhesively bonded glass to metal connection with a carefully selected epoxy adhesive is investigated experimentally. Deliberately pushing the limits of conventional safety concepts for the sake of the experiment, laminated glass canopies were suspended on stainless steel local point-fixings, adhesively bonded to the upper glass sheet only. Subsequently, the suspended system was subjected to a ball-drop test, a uniform load and a hammer impact. Different glass types and canopy arrangements have been tested in this way. Depending on the design parameters, several compositions demonstrated surprisingly good residual structural safety: even after 24 hours of full loading in broken conditions, the heat-strengthened canopy configurations did not collopse.

Experimental investigation of the influence of temperature on local bridging behaviour in laminated glass elements in post-breakage state

The assessment of the post-breakage performances of laminated safety glass elements used in construction needs to take into account the sensitivity to the temperature of the mechanical behaviour and properties of the product, in particular of the interlayer material. After a general problem statement, an overview is given of tests at different scales, with typical observations and results for two different interlayer materials. Through the different presented experimental scales, the mechanisms ruling the bridging behaviour in cracked laminated safety glass are explained, highlighting the difficulty of assessing the mechanical properties to be used in practical design calculations.

TORSIONAL STIFFNESS OF LAMINATED GLASS ELEMENTS IN STRUCTURAL APPLICATIONS — INFLUENCE OF A ELASTO-VISCOPLASTIC IONOMER INTERLAYER ON THE PRE-BREAKAGE BEHAVIOUR

To investigate the mechanical behaviour of laminated glass with the elasto-viscoplastic ionomer interlayer SentryGlas® by DuPont, an experimental program was executed on full-scale glass laminates. The results of this research improved the insight in the complex mechanical behaviour of this stiff interlayer. More specifically, a clear influence of load duration and temperature could be observed for both creep and relaxation setups during bending experiments. The stiffness reduction due to the load duration and the temperature raise was most significant for the smaller specimens - with a span of 1 m - while for the largest specimen - with a span of almost 3 meter - the reduction remained less than 25 % of the monolithic bending stiffness, even after a load duration of 48 hours at 65 °C.