Designing Bolt-Fixed Lamina ted Glass with Stress Concentration Factors

Abstract

A general method for determining stress con centration factors for l aminated glass balustrades with two plus two bolt fixings with var iable positions is developed. It is demonstrated how the stress concentration factors can be presented graphically in design charts and representative charts are displayed for the case of a more specific bolt-fixed balustrade type. In general, the use of simple formulas and design charts allows the maximu m principal stresses of the balustrade to be determined for any relevant combination of variable geometry parameters involved.also advantageous from the perspective of using material efficiently.Design of glass structures can be performed using tables and graphs contained in design standards as far as common geometries and loading conditions are concerned. For more complicated geometries and support conditions, for instance bolt fixings, a more detailed computational analysis is often required. 4 In lamin ated glass structures with bolt fixings, the traditional method for predicting stress distributions is to use three-dimensional models in finite element analyses. However, the large models that are required for accurate stress pre dictions make this type of analyses practically im possible from a computational perspe ctive. Consequently, there is a need for strength design methods with a strong scientific and technical base for laminated glass struc tures with bolt fixings. In a previous work, a solid-shell element 5 suitable for stress predict ions of large laminated glass structures with multiple b olt fixings was implemented. 6 The computational efficiency was increased while the accuracy of the stress predictions was preserved. However, the use of this method requi res advanced knowledge of finite element analysis. In the present work, the solid-shell element is used in finite element analysis in order to develop a method for determining stress concentration factors for laminated glass balustrades with two plus two bolt fixings. With the use of stress concentration factors, the maximum of the largest principal stress of the balustrade can be determined for arbitrary combinations of the variable geometry pa rameters. The computed s tress values could be used in the strength design of the balustrade.Strength design methods in terms of formulas, tables, or graphs are particularly rare, although not nonexistent, when it comes to bolt-fixed laminat ed glass design. A comprehensive overview of the current state of knowledge is given in Ref. [4]. Existing design methods for vertical bolt-fixed glass are typically constructed for the case of a uniformly distributed wind load and fixed positions of the bolts. In this work, simple formulas and charts are developed for balustrades subjected to a uniform line load and with variable positions of the bolt fixings. The charts constitute a graphical representation of the stress concentration factors that are determined. The aim is to make the strength design of this type of boltfixed laminat ed glass balustrades possible without performing...