Glass Struct. Eng. https://doi.org/10.1007/s40940-021-00156-8 RESEARCH PAPER Cantilevered laminated glass balustrades: the Conjugate Beam Effective Thickness method—part I: the analytical model Laura Galuppi · Adam J. Nizich Received: 21 January 2021 / Accepted: 22 June 2021 © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021 Abstract The proper assessment of shear coupling is necessary for the evaluation of laminated glass perfor- mance between the bounding layered and monolithic limits. The most common simplified design approach consists in defining the effective thickness, i.e., the thickness of a monolithic section with equivalent flexu- ral properties. Cantilevered laminated glass balustrades are common applications of structural glass. However, the use of existing effective thickness methods presents strong limitations for their design. Here, the conju- gate beam effective thickness (CBET) method is pre- sented, based on the conjugate beam analogy recently proposed to evaluate the response of inflected lami- nates formed by external elastic beams bonded by an adhesive ply. The conjugate beam analogy, applied to laminated glass beams, allows accurate evaluation of the shear stress transmitted by the interlayer, based on the response of a monolithic conjugate beam, with the option to constrain relative sliding of plies at a beam end. Once the shear coupling is known, the effective thickness may be evaluated with the proposed CBET model by comparing the maximum stress and deflec- tion of the laminated beam with a monolithic Euler– Bernoulli beam. The CBET method’s formulas can be L. Galuppi Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy A. J. Nizich (B ) Simpson Gumpertz and Heger Inc., 1625 Eye Street NW, Suite 900, Washington, DC 20006, USA e-mail: ajnizich@sgh.com readily applied to evaluate the maximum stress and can- tilever free-end deflection for different load and bound- ary conditions, representative of cantilevered laminated glass balustrade supported in a U-profile. Keywords Laminated glass · Balustrades · Glass design · Effective thickness · Analytical methods Abbreviations CBET Conjugate Beam Effective Thickness EET Enhanced Effective Thickness PVB Polyvinyl butyral (a safety glass inter- layer) Geometric and material parameters L Length of the the cantilever span a Length of simply-supported span b Beam width d Distance from free end of cantilevered span i = 1, 2 Glass ply numbering h i Thickness of the i th glass ply t Thickness of the interlayer x , y , z Axial, through-the-thickness and lateral beam directions E Young’s modulus of glass G Secant shear modulus of the interlayer ν Poisson’s ratio 123