Design and dimensioning of a complex timber-glass hybrid structure: the IFAM pedestrian bridge

Abstract

Research has repeatedly pointed out the suitability of adhesive bonding to substitute to "traditional" joining techniques for numerous materials and loads, including timber to glass. Practitioners, however, are still reluctant to implement them into their designs. Adhesion as a method of joining, particularly in the context of hybrid structures, presupposes knowledge of all involved materials, including codes and procedures; most practitioners however tend to be focused on just a subset of materials. While such specialization is not unusual, it makes it challenging to implement novelty (i.e. new materials or techniques). Additionally, when it comes to adhesion where most of the knowledge has been generated by chemists, the lines become even more blurred. Taking the example of a pedestrian timber-glass bridge, this research shows how design and dimensioning of complex bonded hybrid structures can be performed in accordance with "traditional" engineering practice. The paper guides through every step, from the first concepts to the final design, including the manufacturing, of a relatively complex structure, in which timber and glass act together as equivalent members. The compliance of this process with engineering models is emphasized, and the embedment into existing codes and standards is sought after to ensure acceptancy by practitioners.

Can confined mechanical metamaterials replace adhesives?

“…Firstly, in all cases presented in Figs. 4-5-6 part (a), we observe that the deflection of the lever arm in the DCB configuration manifests two regions: (i) ã0 ≤ x < 1 + ã0 (size 1, scaling with λ i , given our choice of normalisation), where the foundation is subject to tension; and (ii) x ≥ 1 + ã0 , for when the metamaterial interface is under compression. Notice that the largest deflection is set by ε (t) i .…”

“…In fast-growing industrial sectors for infrastructure engineering, such as transportation and energy, drives for efficiency and functionality inevitably rely on a deep understanding of confined materials and adhesive joints [1,2]i.e, joining or sealing two similar or dissimilar materials is paramount to progress. Examples are found in glass fibre composite (GFRP) parts of a wind turbine rotor blades [3], trending glass bridges connected to metallic or wooden frames [4], and timber construction with in-rod mounting [5]. In many of these instances, the assumption of idealised and seamless joints are commonly far from ideal to be considered in calculations, and disregarding their intrinsic characteristic dimensions and constitutive behaviour is more often than not leading fundamental design flaws.…”

A novel concept for a reinforced glass beam carrying long term loads

“…Timber/glass and concrete/glass have been suggested in the literature (e.g. Ber et al 2016;Freytag 2004;Vallee et al 2016). However, most work have been published for Glass/steel composites which have shown that a ductile, safe mechanism of failure can be achieved by bonding steel to the glass analogously to reinforced concrete (Bos et al 2004;Louter 2011;Nielsen andOlesen 2007, 2010;Ølgaard et al 2009;Veer et al 2003;Wellershoff and Sedlacek 2003).…”