Laminated Glass Units Under Uniform Lateral Pressure

Laminated flat glass is gaining popularity as an architectural glazing product. Despite its increased use as a cladding material, its structural properties are not well known. Research undertaken to advance understanding of the behavior of laminated glass units under lateral pressure representing wind loads is reported. Laminated glass units are comprised of two layers of glass connected by a thin interlayer of polyvinyl butyral. The material properties of the interlayer are very different from the properties of the glass plates which it joins together; its modulus of elasticity in shear is only about 1/10,000th that of glass. Experimental stress analyses were conducted on several laminated glass units to ascertain whether their behavior was similar to a monolithic glass plate of the same nominal thickness, or to a layered glass unit consisting of two glass plates with no interlayer. At room temperature the laminated glass unit behaves much like a monolithic glass plate of the same nominal thickness. At elevated temperatures [170 °F (77 °C)] the behavior changes, and approaches that of a layered glass unit with no interlayer. Results of the experimental stress analyses are compared with theoretical stress analyses designed to characterize the behavior of monolithic glass plates and layered glass units.