Towards a More Consistent Design of Laminated Glass

Global glass design standards vary significantly in their treatment of laminated glass. This is especially true with respect to the design of laminated glass to resist loads of different durations. Because the method of accounting for interlayer shear transfer differs across standards – from no transfer in DIN 18008, to fixed transfer coefficients in prEN 13474-3, to calculated values in ASTM E1300 – not only does the glass strength vary from standard to standard, but so does the structural system itself. This can lead to sometimes drastically different results for identical systems when calculated according to different standards.

This paper therefore proposes a more rational method for laminated glass design that takes into account the load duration on both the shear transfer coefficient and the glass strength. It is proposed to use utilization rates for each of the individual loads. In this way each load is resisted by a glazing laminate with the appropriate resistance and strength, and the total utilization is a summation of the individual loads according to the appropriate partial load factors. Design examples from each current standard are included to illustrate the differences across codes and these are compared to the methodology proposed in this paper.