The Museum of Anthropology is one of Arthur Erickson's most famous designs and an outstanding example for Brutalism Architecture in Canada. Due to seismic issues of the original concrete framing, the Great Hall of the Museum was to be renovated. The original primary concrete structure could not be adequately strengthened, and it was decided to re-build this particular portion of the building on a base-isolated platform. As part of the re-build, the authors re-imagined and engineered a new structural glazing system that maintains the original design developed by Pilkington for Arthur Erickson, but employs today’s design principles for structural glass. The structural glazing landscape has evolved vastly over the five decades since the museum’s initial construction. Higher wind and seismic loads along with requirements to provide safer glazing systems have been met with advances in glazing technology, including larger format panels and stiff interlayers. Maintaining the original shape and size of the glass fittings while accommodating seismic drifts of the Great Hall and existing adjacent wing required innovative thinking, especially at the inside glass corners. Glass fins nearing 12 m tall required careful consideration of site conditions and installation tolerances. The large-scale Performance Mock-Up (PMU) was replaced by a series of smaller ‘micro PMU's’ that represent key elements of the facade. The authors and hardware manufacturer developed a set of three small scale test assemblies to verify strength, drift accommodation and water tightness.
Current standards suggest characterizing the distribution of glass fracture strength using co-axial double-ring standardized tests. While several international standards do not specify a minimum test number, ASTM C1499-19 recommends conducting at least 30 valid tests (defined as tests where fracture initiates in the inner ring). In practice, the results of invalid tests are often discarded. However, the invalid tests still hold information on the fracture strength, and neglecting them can lead to a biased estimation of the latter. This study proposes a Bayesian inference approach to extract and incorporate such information in glass strength characterization. The approach is applied to existing datasets at ambient and elevated temperatures, examining how the test number influences the coefficient of variation of the characteristic fracture strength used for design. The results show that discarding invalid tests may bias glass strength estimates. Furthermore, for the considered dataset at elevated temperatures, incorporating invalid tests enables achieving the same precision level as implied by the standard with fewer tests. These results show that the proposed approach can improve testing efficiency and refine characteristic fracture strength predictions. Finally, the study quantifies the impact of incorporating invalid tests on the structural reliability of a slab under different load ratios. Results show that ignoring invalid tests leads to an overestimation of the reliability index. This finding highlights that invalid tests should be considered for more robust reliability evaluations of glass structures.
In 2017, a client approached Old Town Glass, a California glass contractor, with a project: A cliffside home with a curved facade featuring 50 m of cold-bent glass with an inflection pane bridging concave and convex sections. With the foundation already built, they needed a cold-bent laminated, s-curve insulated glass unit (IGU) to minimize anisotropies and optical distortions for their unobstructed view of the Pacific Ocean. Cold-bent laminated glass requires panes of glass to be individually bent and laminated together in the autoclave, allowing them to hold shape without structural silicone, supporting framework, or significant heat required for hot-bending. Unlike typical single-radius cold bending, this project required double curvature, demanding new calculations beyond existing FEMs to predict rebound and final geometry. Tight tolerances were critical as minor deviations could misalign the inflection area, leading to inaccuracies and structural stress. To ensure precision, the team created a full-width mock-up and used 3D point-cloud scanning, 3D-printed templates, and overlays to refine adjustments before fabrication. The rugged coastal job site location added complexity. Custom seismic brackets were needed, truck deliveries navigated narrow highways, and installation required careful planning to account for unpredictable weather, long commutes, and logistical disruptions from COVID-19. Despite these challenges, the s-curve glass was successfully installed in June 2023, following over six years of collaboration among sedak’s R D team, EOC’s facade engineers, Sky-Frame, Old Town Glass, and others. This project demonstrates the feasibility of cold lamination bent glass with double curvature and expands the understanding of what can be achieved with this fabrication method, informing future research and applications in complex curved glass design.
Assessing the potential for reusing glass from existing windows and façades requires a systematic understanding of the systems, glazing assemblies, glass types, and glass dimensions that were applied over the years, as well as the requirements these systems had to fulfil. Existing façade and window systems largely determine the feasibility and effort required for disassembly, as well as the possibility to recover reusable or recyclable components or materials. Glazing assemblies and glass types from end-of-life façades and windows might limit the possibilities for further processing, while element dimensions might impose constraints on future façade designs based on reuse. This paper presents a systematic investigation of the glazing from nine educational and research buildings with metal-framed façades or windows, constructed or refurbished between 1967 and 2013. The available amount of glass was documented with respect to number, dimensions, assembly, and layer thicknesses. In-situ measurements of thermal and light transmittance were conducted and compared with software-based calculations. Furthermore, the structural performance of selected glazing assemblies was evaluated in relation to current design standards. The results provide a representative basis for assessing the reuse potential of existing glazing in metal-framed façades and identify key characteristics and challenges expected to influence disassembly, separation processes, and future circular façade design strategies.
Historically, flat glass production was a handcrafted process, resulting in glass elements with optical imperfections that altered the clarity of the view through windows – this is a decisive aesthetic feature today. In contrast, modern glass used in building industry is predominantly produced through the float glass process. Since its development in the 1960s, it enabled the mass production of fully transparent glass free of irregularities. Thereby, traditional flat glass production methods, such as the cylinder-blowing or rolled-glass processes, were displaced to both economic and quality improvements. However, with the discontinuation of older methods, the authenticity of historical buildings was also diminished. To preserve authenticity, contemporary projects aim to incorporate glass produced using traditional techniques, embracing the inherent optical irregularities of handcrafted glass. One challenge is that mouth-blown glass lacks standardization in terms of product specifications, with no established values for geometric tolerances or strength. The primary objective of the presented research is to characterize the load-bearing capacity of contemporary produced mouth-blown glass in comparison with float glass which will lead to a method for determination of strength in the future. Additionally, the study explores the effects of thermal treatment of mouth-blown glass. The research involves geometrical and photoelastic analysis of 63 samples of mouth-blown glass with 2 mm thickness. Afterwards, the four-point-bending-test (EN 1288-3 (2020)) is adapted to test samples to fracture, to evaluate the load-bearing capacity and fracture pattern. The samples were produced in 2024 using the traditional cylinder-blowing method . The results of the study confirm and quantify significant thickness tolerances in mouth-blown glass. But the results also demonstrate considerable potentials for the use of mouth-blown glass in the building industry. The load-bearing capacity of modern mouth-blown glass was found to be comparable to modern annealed glass. Thermally toughening did not reach strength levels of fully tempered float glass. The paper also discusses the importance of considering thickness tolerances when estimating realistic glass strength values.
Following London (1985), Vancouver (1985), Lisbon (1998), Dubai (2008), Dushanbe (2009) and Toronto (2014), the Ismaili Center Houston was established in 2025. Commissioned by the Aga Khan, spiritual leader of the Shia Ismaili Muslims, and designed by Farshid Moussavi Architecture, the Center functions as both a place of worship and a venue for educational, cultural and social events. The architectural envelope—designed, engineered and built by Josef Gartner—stands out for its combination of traditional Persian architecture (including ceramic mosaics and stone screens) and contemporary façade technology (such as glass fins and light steel). One of the most remarkable features is the 610 m2 folded plate glass façade, spanning up to 9 m on the eastern elevation and working as a folded structure. Folded structures are self-supporting, three-dimensional structures made up of flat panels that are joined together. They are highly dimensionally stable and enable slender constructions. However, challenges lie particularly in the design of the corner details and the supports. This article presents an overview of the project, including the folded plate glass façade and its details, from the initial concept to the final installation.
Advancing circular economy practices in the construction sector require the development of reuse and remanufacturing pathways for high-quality building materials such as architectural glass. This study investigates the technical feasibility of remanufacturing float glass reclaimed from insulating glass units (IGUs) through the application of functional coatings. Uncoated double IGUs were dismantled, and the reclaimed glass panes were reprocessed and coated with solar control layers using industrial-scale magnetron sputtering at a production site in Germany. The coated samples underwent various testing methods as part of the plant production control, assessing their optical, mechanical, and spectral properties in comparison with reference coatings applied to new float glass. The results demonstrate that reclaimed float glass can be successfully reintroduced into industrial coating lines, achieving comparable performance to conventional substrates. The paper presents experimental results and outlines the critical processing steps and conditions required for successful coating application. Furthermore, it discusses the technical challenges associated with remanufacturing at scale and provides a baseline for future studies aiming to define a set of criteria for successfully coating reclaimed glass substrates. The findings confirm the technical viability of this approach and highlight its potential to significantly reduce raw material demand, energy use, and embodied carbon in future closed-loop glass production systems.
The glass industry is increasingly exploring remanufacturing as an alternative to the recycling of reclaimed glass cullet. Remanufacturing insulated glass units (IGUs) offers the potential to preserve valuable materials and their embodied carbon, accelerating the shift towards a circular and climate-neutral economy. However, technical uncertainties continue to impede the large-scale adoption of remanufactured IGUs. This study addresses these barriers by developing strategies for a comprehensive technical assessment of 30-year-old IGUs extracted from two office buildings. A range of standardized tests are conducted to evaluate critical factors influencing IGU reusability, including the overall visual surface quality, sealant and desiccant integrity, and surface flaws that may compromise glass strength. Additionally, the assessment considers the type of installation as well as relevant external factors that occur during the IGUs’ service life and could potentially affect their performance and viability for future applications. By establishing a technical evaluation framework aligned with European product standards, the findings aim to support best practices in IGU reuse and remanufacturing.
By improving the insulation value of glazing, the glass industry contributes successfully to reduce global heating demand in the built environment. However, as temperatures are increasing and heat waves are more frequently occurring, increased insulation values of glazing also contribute to the vast growing cooling demand. Therefore, the glass industry is evolving further with smart glazing to reject solar heat entrance during summer seasons, while allowing it to heat up indoor spaces during winter seasons. This paper presents a photochromic window film with a unique combination of optical properties compared to other smart glass technologies. The film has a high visible light transmission in the transparent state (88
The fracture behaviour of glass has been studied for quite some time mainly with the focus on deriving strength or fracture mechanical properties. While such quantities are critical for the design assessment in facade engineering and structural glazing, this research investigates the fracture pattern from a geometrical point of view for different levels of thermal pre-stress, different glass thickness and a bedded support condition, to calibrate statistical predictive models for e.g. fragment count, fragment shape parameters, homogeneity of the fracture pattern etc. As this research is inherently data-driven, we first present the conduction of experiments and the collection of corresponding data. In a subsequent step, we employ computer vision and Bayesian quantification algorithms to identify and model several key quantities of the fracture geometry. The results indicate our models consisting of both special spatial point processes and simplified tessellation algorithms to significantly capture main statistical properties, and the method serves as a template framework for future data-driven methods to predict fracture patterns.
Previous research has shown that the adhesion between Polyvinyl Butyral (PVB) interlayers and glass plies is a key energy absorbing mechanism in blast resistant glazing systems. Both the work done in overcoming the bond at the PVB-glass interface and the stretching of PVB between glass fragments contribute to the post-fracture resistance of glass panes. To support the future development of numerical models that capture adhesion, interlayer stiffness, and delamination behaviour, a structured series of instrumented through-crack tensile (TCT) tests on laminated glass samples incorporating PVB types of differing adhesion levels (B100MR, V108, HR100) and thicknesses (0.76 mm and 1.52 mm) at actuator speeds between 1 m/s and 5 m/s were conducted. Additionally, similarly instrumented uniaxial tensile tests were undertaken on PVB-only samples. Complementary uniaxial tensile tests were also undertaken on PVB-only samples, and compressive shear strength (CSS) and pummel test results were obtained through Kuraray’s Performance Monitoring Program. The aim of this study is to generate a controlled, repeatable dataset suitable for the calibration of engineering numerical models, particularly bilinear traction–separation laws used to simulate glass–PVB delamination in blast and impact analyses. The results demonstrate clear relationships between adhesion level, interlayer thickness, strain rate and the likelihood of achieving progressive delamination under TCT loading. HR100 exhibited negligible delamination at all rates, whereas B100MR and V108 showed ductile behaviour except for thin (0.76 mm) interlayers tested at 5 m/s. These findings indicate that adhesion level strongly governs whether delamination occurs, while the force measured in samples during delamination is influenced by the interaction between stiffness, thickness and adhesion. The dataset provides a structured experimental basis for future development and calibration of traction–separation models and offers insights into the engineering relevance, and limits, of CSS values in predicting high-rate delamination behaviour.
Adhesive bonding has gained in popularity within the construction sector for its capacity to bond dissimilar materials and distribute stress. Silicone bonded facades (silicone structurally glazed), when reached their end of life, can be disassembled using cutting tools. However, to improve glass-frame separation and enable circularity, this study examines, for the first time, the debonding-on-demand potential of a structural silicone adhesive modified with Thermally Expandable Particles (TEPs). This research evaluates the mechanical performance and triggered disassembly of glass-aluminium joints focusing on a 10 wt
Laminated safety glass (LSG) is widely recognized for its superior impact energy absorption, retention of structure, and minimization of injury due to shard fragments. This feature makes it one of the essential materials in automotive and construction applications. This paper reports on an experimental-numerical investigation of LSG under impact loadings by systematically varying the layer configurations while keeping the same total thickness of the laminate. We have studied three specific configurations: 2-layer, 3-layer and 5-layer glass configuration. The total glass thickness is kept the same in all these configurations (12 mm), with an overall interlayer thickness of PVB set at 3.04 mm. Ball drop tests were numerically simulated using ABAQUS/Explicit. In the simulation, glass was modeled with brittle cracking behavior to capture fracture patterns under impact loading. A user-defined VUMAT subroutine defined the brittle response of glass, and crack propagation was represented by element deletion based on a fracture energy threshold. The simulated fracture pattern was compared with experimental results on the two-layer glass configuration for validation. This study highlights the modeling techniques employed in the simulations and examines the influence of key numerical parameters on the results. The findings provide valuable insights into the impact response of LSG, supporting the design of optimized configurations that improve safety and post-impact integrity. The results show that increasing the number of layers enlarges the central fracture zone and shortens the energy absorption duration, indicating a more efficient energy dissipation mechanism and enhanced impact resistance without a significant weight increase.
The prevailing global political circumstances and the concomitant increase in security concerns give rise to heightened expectations regarding the building envelope.Transparent areas in façades are essential for daylight entrance and the interaction between the interior and the external environment but represent a risk to building occupants in the case of blast events or attack with firearms. Conventional glazing such as monolithic glazing and laminated safety glass lack resistance to bullet attack due to their brittle fracture behaviour. Glass shows favourable properties in terms of scratch resistance and strength. While the lamination of numerous layers of glass panes provides enhanced resistance against bullet attack, higher dead weights result, necessitating thicker frames and fittings. Due to the higher ductility of polymers, the integration of glass with polymeric glazing material effectively reduces the total dead weight and nominal thickness of security glazing with a resistance against bullet attack. The classification of bullet-resistant glazing is determined in accordance with European standard EN 1063. A test specimen is subjected to a series of three shots fired in a triangular configuration using specified types of weapons and ammunition. The present paper focuses on the topic of bullet resistance by glass panes, plastic sheets and composite panels. In initial experimental tests, monolithic test specimens of annealed glass, toughened safety glass, polycarbonate sheets and polymethylmethacrylate sheets are investigated. The thicknesses of the materials are in a range that will cause a bullet to penetrate. This enables to measure the velocity before and after penetration of the test specimen, as well as to calculate the absorbed energy. Finally, the materials can be characterised in the context of ballistic impact. By recording the mass of the outgoing fragment and the projectile using ultra-high-speed imaging, it is possible to analyse the effect of the materials on velocity reduction. The combination of individual layers with and without lamination by thermoplastic polyurethane interlayers allows for the recommendation of a favourable composition in the cross-section. As result of the research, bullet-resistant glazing with reduced nominal thicknesses can be predicted and processed to slim insulated glazing with high thermal insulation.
This research paper focuses on identifying material model parameters for the EVA interlayer which serves as a binding element in laminated glass structures. EVA is a product that contains certain perturbations in its chemical composition due to production processes or manufacturing recipes. Here, we test whether a certain range of chemical composition can be observed through the general material model of the EVA interlayer. To test this assumption, uniaxial tensile tests were conducted, at a fixed room temperature and constant strain rate, on crosslinked specimens of two EVA types with varying vinyl acetate content. Based on experimental results a mathematical formulation for a material model is established in the frame of a modified Mooney–Rivlin hyperelastic model. The function for fitting all samples is derived from the equation for strain energy density W according to invariants for the uniaxial test. Nine parameters were defined for each group, and the model was verified through numerical simulations in Ansys software. The confirmation of the defined material model is done by comparing the numerical results with the experimental results. Regarding different groups of EVA interlayer, it is proven that for a value of strain up to 170
Switchable liquid crystal glazing presents several advantages over conventional glass facades by seamlessly incorporating shading functions directly into the glass structure. This technology eliminates the need for mechanical components, enhancing reliability and reducing environmental impact. It also features rapid response times, within fractions of a second, and allows for variable shading levels, enabling precise adaptation to individual needs, thereby improving thermal and visual comfort. However, the design of these systems presents challenges, particularly with regard to the heating of the glass panes due to the absorption of solar radiation, especially when shading. Since the liquid crystals are embedded directly within the pane arrangement of the glazing unit, heat is transferred to the glass, causing uneven heat distribution, specifically in the clamped, shaded edge areas, which increases the risk of thermal stress fractures. Two types of glazing, double and triple, were installed and tested under real weather conditions in a facade test building to measure and assess the temperature behavior within the glass pane structure over a period of three years using various shading scenarios. The study revealed temperature extremes ranging from -9.9 ^∘ C to 79.9 ^∘ C for triple glazing units (TGU) and -7.3 ^∘ C to 77.2 ^∘ C for double glazing units (DGU). Critical temperature differences between center and edge areas reached up to 47.9 ^∘ C (TGU) and 46.5 ^∘ C (DGU), exceeding the 40 ^∘ C resistance limit specified for float glass in DIN EN 572-1. Multiple linear regression analysis demonstrated that 78.7
Flat and cylindrically curved glass panels are part of modern architecture. Such panels must be able to withstand, among other loads, accidental human impacts. The proof against soft body impact can be carried out using the pendulum test with a twin-tire impactor. Experimental proofs are time-consuming and expensive, whereas numerical proofs can only be carried out using suitable software and a validated model. The present investigations aim to provide an easy-to-use, yet accurate, method for calculating the pendulum test on such glass panels. Therefore, an extensive numerical parameter study has been conducted on concave, flat, and convex glass panels with different glass thicknesses, impact energies, and impact points. Polynomial data fitting would result in a significant loss of accuracy; therefore, neural networks are used. Based on the results of the parameter study, eight neural networks were trained for different glass thicknesses and impact energies. It is demonstrated that neural networks can reproduce the pendulum test with high accuracy, serving as a simple alternative to complex calculations. In contrast to numerical simulations, the application of neural networks is straightforward and can be done with nearly any software, as it requires only basic matrix operations. The primary results are the maximum principal stresses and maximum deformations of the glass panels, which can be used for the proof of single glass units and insulating glass units according to the standard in use. The neural networks are provided as freely accessible and easy-to-use Python code as supplemental data to this paper.
It is evident that glass, a highly regarded building material, has already become a prominent feature in building construction, not only in the context of façades but also as a load-bearing element. Nevertheless, the use of increasingly larger glass elements in these prestigious buildings demonstrates that glass is not merely the external finish of the building. Glass beams or glass fins serve as the façade’s substructure. This means that glass must be considered in the building's fire protection concept to maintain structural integrity. However, prior research has demonstrated poor fire resistance of conventional glass beams. Therefore, a concept of an enhanced fire-resistant glass beam was developed. Conventional glass beams were encased in a fire protection system comprising fire-retardant gel and sacrificial glass panes. Their functionality was tested in fire tests. This paper presents the development of the novel fire protection system, as well as the planning, execution and evaluation of the fire tests. To check and ensure comparability and reproducibility, the experimental setup and results are compared with those reported in the literature. The results demonstrate, that the use of a proper fire protection system significantly enhances the fire resistance of mechanically loaded glass beams compared to conventional reference structures. We found an increase of fire resistance time of over 200% allowing for classification of R30.
This paper is a review of methods to determine optical distortion in architectural glass, with a focus on the methods described in the current available standards and guidelines. Examples from building projects are used as reference points in the review of the methods. In addition to the review initials measurement studies are performed in a laboratory to determine the physical phenomena behind the optical distortion. The paper concludes on the different types of optical distortion seen, the methods which were used for the survey and how it corresponds to the current standards and guidelines, with a proposal for future research directions. Based on the findings in this paper it is suggested that the best method to determine optical distortion is to measure the changes in milli diopters, based on the current methods utilized for monolithic glass when measured in transmission. However, this method would need to be expanded to laminated glass, IGUs and potentially to curved glass, as well as a method to measure optical distortion in reflection. These methods will have to be developed through further research to better understand the causes behind the different optical phenomena.
Glass in facades and roofs is usually used as infill elements to provide daylight supply in buildings. The load is typically transferred via a substructure. This leads to resource-intensive constructions, whereby usually the static potential of the glass panes is not taken into account. In a research project, this missing efficiency was investigated, resulting in a linear metal edge fitting that enables load-bearing glass structures by transferring tensile and compressive forces as well as bending moments. The fittings are laminated into safety glass while the use of Insulated Glazing Units (IGU’s) provides thermal performance. Since insulating glass is typically not used as a primary load-bearing structure, the entire process chain had to be redesigned and developed, from 3D planning and form-finding to design and structural analysis, manufacturing, testing and assembly. The paper focuses on the structural performance of the developed fitting. Analytical models were used to approximate the rotational stiffness of the fitting, followed by parameter studies to understand the influence of key geometric and material variables. This revealed the importance of flange thickness on the overall rotational stiffness of the linear fitting. A full-scale mockup (approximately 7 m × 3 m) was assembled to assess buildability under real-world conditions, revealing both the practical viability and current limitations of the system. Mechanical testing on specimen with fitting dimensions used in the mockup led to a bending stiffness of 6 kNm. Among the identified challenges are the precision of the lamination process, control of welded seam quality, and long-term performance under environmental influences. Additionally, aspects related to thermal performance/building physics requirements and durability require further investigation before the system can be considered for broader application.
