The use of hybrid and composite solutions for structural applications represents a common approach for the development of safe design principles. Consolidated examples exist for concrete, steel and masonry structures. As a general rule, materials are combined so as to obtain an enhanced redundancy, strength and/or (lateral) stiffness for these systems. In this paper, structural laminated glass (LG) beams including reinforcement rods are investigated, and special attention is spent on the effect of embedded rod features, consisting of GFRP, CFRP or stainless steel reinforcement tendons. The examined embedded solution, as shown, can offer a certain benefit to the bending performance of traditional LG beams, including positive effects on stiffness, resistance and redundancy. The intrinsic properties of rods can otherwise largely affect the overall observations. To this aim, unpublished experimental tests are first briefly summarised for a set of 1 m span LG beams. Support for the preliminary discussion of the examined design concept is also derived from simple analytical calculations. Finite-Element (FE) numerical simulations are then presented, reporting on major expected behaviours due to variations in the geometrical/mechanical features of the rods, with respect to the experiments. A key role in the FE models is given by the reliable description of mechanical properties and interactions between the structural components. Comparative results are hence discussed for the post-fracture assessment of beam specimens. As shown, even a limited presence of reinforcing rods (≈100-to-400 the explored range for the ratio of glass-to-rods cross-sectional area) can provide ductility and redundancy to the LG beams. Maximum benefits (+30% residual resistance) are given by ductile steel rods, while positive effects can also be achieved with GFRP and CFRP tendon rods.@en

Architectural trends to include transparency in structural systems lead to the implementation, in the last decades, of structural glass load-bearing components able to substitute traditional construction materials like timber, steel, concrete. In this paper, the structural bending performance of post-tensioned, glass-FRP hybrid beams is evaluated by means of advanced Finite-Element (FE) numerical analyses. To this aim, a concise recapitulation of existing research on several typologies of glass-FRP hybrid beams is first provided. Based on earlier experimental and preliminary FE research outcomes, further detailed discussion is then proposed for the specific concept of glass-FRP post-tensioned glass beams. FE parametric simulations for quasi-static bending loading configuration and room temperature are compared for such systems, typically including a laminated glass (LG) cross-section and an adhesively connected, post-tensioning FRP tendon. As shown, several aspects should be properly taken into account when investigating the overall performance of these systems, as far as both their elastic and post-cracked performance are highly sensitive to various mechanical and geometrical input parameters. A sensitivity FE study is hence presented, aiming to better explore their typical performance.@en

In this paper, a Finite-Element (FE) numerical investigation is carried out on laminated glass beams with Carbon Fibre Reinforced Polymer (CFRP) adhesively bonded post-tensioning tendons. Taking advantage of past four-point bending experimental test results available in literature, a refined full 3D FE numerical model is calibrated and validated. A key role is given to a multitude of aspects, including the implementation of damage models for materials as well as the appropriate mechanical interaction between the beam components, in order to properly reproduce the expected effects of post-tensioning as well as the overall bending behavior for the examined structural typology.@en

Purpose: Glass material is largely used for load-bearing components in buildings. For this reason, standardized calculation methods can be used in support of safe structural design in common loading and boundary conditions. Differing from earlier literature efforts, the present study elaborates on the load-bearing capacity, failure time and fire endurance of ordinary glass elements under fire exposure and sustained mechanical loads, with evidence of major trends in terms of loading condition and cross-sectional layout. Traditional verification approaches for glass in cold conditions (i.e. stress peak check) and fire endurance of load-bearing members (i.e. deflection and deflection rate limits) are assessed based on parametric numerical simulations. Design/methodology/approach: The mechanical performance of structural glass elements in fire still represents an open challenge for design and vulnerability assessment. Often, special fire-resisting glass solutions are used for limited practical applications only, and ordinary soda-lime silica glass prevails in design applications for load-bearing members. Moreover, conventional recommendations and testing protocols in use for load-bearing members composed of traditional constructional materials are not already addressed for glass members. This paper elaborates on the fire endurance and failure detection methods for structural glass beams that are subjected to standard ISO time–temperature for fire exposure and in-plane bending mechanical loads. Fire endurance assessment methods are discussed with the support of Finite Element (FE) numerical analyses. Findings: Based on extended parametric FE analyses, multiple loading, geometrical and thermo-mechanical configurations are taken into account for the analysis of simple glass elements under in-plane bending setup and fire exposure. The comparative results show that – in most of cases – thermal effects due to fire exposure have major effects on the actual load-bearing capacity of these members. Moreover, the conventional stress peak verification approach needs specific elaborations, compared to traditional calculations carried out in cold conditions. Originality/value: The presented numerical results confirm that the fire endurance analysis of ordinary structural glass elements is a rather complex issue, due to combination of multiple aspects and influencing parameters. Besides, FE simulations can provide useful support for a local and global analysis of major degradation and damage phenomena, and thus support the definition of simple and realistic verification procedures for fire exposed glass members.@en

Laminated glass components are usually realized by bonding glass plates using interlayer polymers that develop adhesion forces during lamination. Recently, these adhesion forces have been used also to realize special adhesive connections for structural glass components and assemblies. The typical example of such a joining technique is conventionally known as “embedded laminated connection” where a metal insert is encapsulated in multi-ply laminated glass components. In this study, careful consideration is paid for the investigation of the mechanical behaviour of embedded laminated connections with thick metal insert. To this aim, small-scale laboratory tests, Finite Element (FE) numerical models and analytical considerations are presented. Firstly, the results of experimental investigations at different temperatures are discussed, giving evidence of the geometrical and mechanical parameter effects on the so observed performances. It is observed, in particular, that the temperature affects not only the maximum load carrying capacity but also the failure mode of the studied connection typology. Non-linear numerical simulations are then developed in ABAQUS on FE models, able to account for the geometrical and mechanical properties of the reference connection specimens. Further analytical considerations are also presented, in support of the observed experimental findings. It is shown, in particular, that as far as high temperatures are not attained, the mechanical performance and failure mode of the examined connections is strictly related to glass breakage. In addition, it is also observed that at high temperature, failure mode (i.e. bubble formation) and failure location are in line with the expectations. Rather close correlation can be also found for the same embedded connections between test results, FE numerical simulations and analytical assumptions.@en

In this paper, careful consideration is paid for structural glass elements under fire loading. In particular, a thermo-mechanical Finite Element (FE) numerical investigation is carried out in ABAQUS on small-scale structural glass elements exposed to fire. Taking advantage of past literature efforts, major thermal effects on the material properties are taken into account in the form of key input parameters for numerical simulations. Further validation of the so calibrated FE models is then carried out towards past small-scale experimental fire tests on monolithic glass panels. A sensitivity FE study is hence proposed, giving evidence of major influencing parameters on the thermo-mechanical performance of the same structural glass elements, including variations in the fire exposure, thermal-to-mechanical loading ratio, geometrical and mechanical features of the specimens.@en

This paper investigates the structural response of laminated glass beams under combined fire-exposure and sustained in-plane loading. This is done by means of experimental testing and Finite Element (FE) numerical modelling. Firstly, small-scale (1 m long) laminated glass beams are tested under thermal exposure and in-plane loading on a small fire resistance test furnace. From the test results it can be seen that laminated glass beams are able to sustain an imposed in-plane load for a time of 34–51 min before failing according to the limiting rate of deflection as defined in EN 1363–1:2012. It should be noted, however, that the observed failure times are strictly related to the boundary conditions applied in the test, i.e. the magnitude of mechanical loads (in this study a relatively small load of P = 1.15 kN was applied) and the presence of an inherent top zone protection, which may have positively affected the results. Secondly, additional FE thermo-mechanical simulations are performed to further investigate the mechanical response of the laminated glass beams under thermal exposure, with a focus on the effects of the top zone protection and the load magnitude on the performance of the examined laminated glass beams. From the FE study it can be seen that reducing the top zone protection (from 40 mm to 0 mm) results in a reduction in failure time from 45 min to 20 min, while increasing the load with a factor 5 (taking 30 mm top zone protection as a reference) results in a reduction of failure time from 32 to 18 min.@en

This paper investigates the structural response of laminated glass beams under combined fire-exposure and sustained in-plane loading. This is done by means of experimental testing and Finite Element (FE) numerical modelling. Firstly, small-scale (1 m long) laminated glass beams are tested under thermal exposure and in-plane loading on a small fire resistance test furnace. From the test results it can be seen that laminated glass beams are able to sustain an imposed in-plane load for a time of 34–51 min before failing according to the limiting rate of deflection as defined in EN 1363–1:2012. It should be noted, however, that the observed failure times are strictly related to the boundary conditions applied in the test, i.e. the magnitude of mechanical loads (in this study a relatively small load of P = 1.15 kN was applied) and the presence of an inherent top zone protection, which may have positively affected the results. Secondly, additional FE thermo-mechanical simulations are performed to further investigate the mechanical response of the laminated glass beams under thermal exposure, with a focus on the effects of the top zone protection and the load magnitude on the performance of the examined laminated glass beams. From the FE study it can be seen that reducing the top zone protection (from 40 mm to 0 mm) results in a reduction in failure time from 45 min to 20 min, while increasing the load with a factor 5 (taking 30 mm top zone protection as a reference) results in a reduction of failure time from 32 to 18 min.@en

Due to their increasing use in contemporary architecture, the lateral torsional buckling performance of laminated structural glass beams represents a topic of great interest for researchers. Although several analytical models and design approaches have been recently proposed, various aspects complicate the realistic prediction of this phenomenon. Based on experimental results of a large campaign of lateral torsional buckling tests (55 laminated beams), the paper investigates analytically the effects of various mechanical (e.g. the stiffness of interlayer) and geometrical properties (e.g. initial twist, production tolerances) on the typical lateral torsional buckling response of laminated glass beams.@en

Due to their increasing use in contemporary architecture, the lateral torsional buckling performance of laminated structural glass beams represents a topic of great interest for researchers. Although several analytical models and design approaches have been recently proposed, various aspects complicate the realistic prediction of this phenomenon. Based on experimental results of a large campaign of lateral torsional buckling tests (55 laminated beams), the paper investigates analytically the effects of various mechanical (e.g. the stiffness of interlayer) and geometrical properties (e.g. initial twist, production tolerances) on the typical lateral torsional buckling response of laminated glass beams.@en

Due to their increasing use in contemporary architecture, the lateral torsional buckling performance of laminated structural glass beams represents a topic of great interest for researchers. Although several analytical models and design approaches have been recently proposed, various aspects complicate the realistic prediction of this phenomenon. Based on experimental results of a large campaign of lateral torsional buckling tests (55 laminated beams), the paper investigates analytically the effects of various mechanical (e.g. the stiffness of interlayer) and geometrical properties (e.g. initial twist, production tolerances) on the typical lateral torsional buckling response of laminated glass beams.@en

Taking advantage of past full-scale experimental test results, the bending performance of laminated glass beams with post-tensioned, adhesively bonded steel tendons is explored via refined Finite-Element (FE) models. As far as the primary advantage of the post-tensioned glass beam concept is to provide an initial state of compressive stresses in glass, a marked enhancement of the expected structural performance is expected (i.e. increase of the initial fracture load and redundancy), compared to typically brittle, unreinforced laminated glass beams. Several key aspects can affect the overall performance of such beam typology, first of all the adhesive joint providing the structural interaction between the glass beam and the steel tendon, as well as the geometrical and mechanical properties of each beam component, in relation to the amount of initial post-tensioning force. Based on a first validation of a reference full 3D FE model towards the available past full-scale experimental test results, an extended parametric study is presented in this paper, giving evidence to the effects of several mechanical and geometrical parameters (i.e. steel tendon section, level of the applied post-tensioning force, adhesive joint type and size, etc.) in the bending performance of post-tensioned laminated glass beams at room temperature under quasi-static load.@en

Taking advantage of past full-scale experimental test results, the bending performance of laminated glass beams with post-tensioned, adhesively bonded steel tendons is explored via refined Finite-Element (FE) models. As far as the primary advantage of the post-tensioned glass beam concept is to provide an initial state of compressive stresses in glass, a marked enhancement of the expected structural performance is expected (i.e. increase of the initial fracture load and redundancy), compared to typically brittle, unreinforced laminated glass beams. Several key aspects can affect the overall performance of such beam typology, first of all the adhesive joint providing the structural interaction between the glass beam and the steel tendon, as well as the geometrical and mechanical properties of each beam component, in relation to the amount of initial post-tensioning force. Based on a first validation of a reference full 3D FE model towards the available past full-scale experimental test results, an extended parametric study is presented in this paper, giving evidence to the effects of several mechanical and geometrical parameters (i.e. steel tendon section, level of the applied post-tensioning force, adhesive joint type and size, etc.) in the bending performance of post-tensioned laminated glass beams at room temperature under quasi-static load.@en

SentryGlas®(SG)-laminated reinforced glass beams are numerically investigated. This innovative structural typology consists of a composite section in which the typical brittle behaviour of glass is overcome by means of stainless steel sections able to provide significant post-cracked residual strength and ductility. The structural interaction between the components is then provided by thermoplastic SG-foils. Based on earlier studies, exploratory numerical investigations are performed by means of 2D and 3D FE-models and large series of parametric studies are discussed, in order to highlight the influence of various geometrical and mechanical parameters. As shown, although further extended studies and advanced numerical developments are required, interesting numerical predictions are found for the examined beams.@en

SentryGlas®(SG)-laminated reinforced glass beams are numerically investigated. This innovative structural typology consists of a composite section in which the typical brittle behaviour of glass is overcome by means of stainless steel sections able to provide significant post-cracked residual strength and ductility. The structural interaction between the components is then provided by thermoplastic SG-foils. Based on earlier studies, exploratory numerical investigations are performed by means of 2D and 3D FE-models and large series of parametric studies are discussed, in order to highlight the influence of various geometrical and mechanical parameters. As shown, although further extended studies and advanced numerical developments are required, interesting numerical predictions are found for the examined beams.@en

The bending performance of laminated glass (LG) beams with Glass-Fibre-Reinforced-Polymer (GFRP)-embedded rods is numerically assessed in this paper, based on earlier experimental investigations. Compared to existing literature efforts related to reinforced glass beams – typically including external steel or FRP tendons and/or reinforcement sections adhesively bonded to glass edges in tension – careful consideration is given to the still rather innovative concept of traditional LG beams that contain pultruded GFRP rods embedded within the interlayer foils. Taking advantage of past experimental results and preliminary Finite Element (FE) outcomes for hybrid glass beams, the quasi-static bending performance at room temperature of several geometrical configurations of LG beams with GFRP-embedded rods is compared. These geometrical configurations include variations in number, size and position of rods. The effects and possible benefits due to initial pre-stressing forces for the GFRP rods are also investigated. As shown for some selected configurations only, GFRP-embedded rods can provide active contribution to traditional LG beams, both in terms of post-cracked resistance and ductility. At the same time, given a reference geometry, a certain level of initial pre-stress can further exploit the potential of the same GFRP rods, acting as pre-tensioned tendons thereby enhancing the initial fracture strength. Several aspects should be properly taken into account to assess and optimize the overall performance of these systems, however, since both their elastic and post-cracked performance are highly sensitive to various mechanical and geometrical input parameters.@en

The bending performance of laminated glass (LG) beams with Glass-Fibre-Reinforced-Polymer (GFRP)-embedded rods is numerically assessed in this paper, based on earlier experimental investigations. Compared to existing literature efforts related to reinforced glass beams – typically including external steel or FRP tendons and/or reinforcement sections adhesively bonded to glass edges in tension – careful consideration is given to the still rather innovative concept of traditional LG beams that contain pultruded GFRP rods embedded within the interlayer foils. Taking advantage of past experimental results and preliminary Finite Element (FE) outcomes for hybrid glass beams, the quasi-static bending performance at room temperature of several geometrical configurations of LG beams with GFRP-embedded rods is compared. These geometrical configurations include variations in number, size and position of rods. The effects and possible benefits due to initial pre-stressing forces for the GFRP rods are also investigated. As shown for some selected configurations only, GFRP-embedded rods can provide active contribution to traditional LG beams, both in terms of post-cracked resistance and ductility. At the same time, given a reference geometry, a certain level of initial pre-stress can further exploit the potential of the same GFRP rods, acting as pre-tensioned tendons thereby enhancing the initial fracture strength. Several aspects should be properly taken into account to assess and optimize the overall performance of these systems, however, since both their elastic and post-cracked performance are highly sensitive to various mechanical and geometrical input parameters.@en