Mechanical behaviour of adhesively bonded GFRP and glass composites for high-performance façade applications

Aluminium-framed unitized curtain wall systems are widely used in high-rise buildings due to modern architectural trends. With the growing demand for minimalist designs, there is an increasing need for highly structurally efficient glazed façade systems. However, current non-composite façade systems are structurally inefficient arising from the absence of composite action, especially when relying on structural silicone glazing (SSG). Further, the current technologies are vulnerable to corrosion in saline conditions while also being thermally inefficient. These shortcomings raise critical questions about the long-term durability and sustainability of conventional aluminium-based façade systems.

This research investigates the feasibility of using pultruded glass fibre-reinforced polymer (GFRP) as an alternative framing material for unitized curtain wall systems. The primary objective is to determine whether adhesively bonded GFRP-glass composite assemblies can address the structural limitations of conventional systems.

A comprehensive experimental programme was conducted, comprising three main phases: adhesive characterization through lap shear testing to identify suitable adhesives, flexural testing of composite beams under both monotonic and long-term loading to evaluate composite action and medium-scale testing of GFRP-glass panels to assess flexural performance at the panel level. These investigations enabled a detailed assessment of load-bearing capacity, deformation characteristics, and long-term response under sustained loading. Complementing these experimental data, finite element models were developed which were subsequently used to investigate alternative design configurations.

The findings highlight the potential of glass–GFRP composites as a structurally efficient alternative to non-composite aluminium systems for curtain wall applications. The study confirms that the use of high-stiffness adhesives significantly enhances composite action and overall structural performance. However, the research also revealed limitations of the system, including a direct correlation between ambient temperature fluctuations and long-term creep behaviour, indicating the need for further investigation.

Overall, this research contributes to the advancement of knowledge in façade engineering by providing a systematic evaluation of bonded GFRP-glass composite systems as a replacement for traditional non-composite systems. The outcomes support the development of structurally efficient, thermally superior, and more sustainable curtain wall technologies for modern buildings.