Redundancy of reinforced glass beams : temperature, moisture and time dependent behaviour of the adhesive bond

The most important aspect of the reinforced glass beam concept, which provides ductility and redundancy for structural glass beams, is the adhesive bond between glass and reinforcement. To guarantee structural safety, this adhesive bond has to service under all conditions. The effects of elevated temperature, moisture exposure and load duration on the adhesive bond, have separately been investigated through three series of bending tests on 1.5 m reinforced glass beam specimens. A first series has been tested at 60 C; a second series has been tested after 8 weeks of salt-water-spraying; and a third series has been loaded until initial failure whereupon it has been left statically loaded for at least 72 hours. The results show that the reinforced glass beam concept is a redundant system which shows, dependent on the applied adhesive, a significant residual strength even at extreme temperature and moisture conditions, and for a significant period of time

Digital Microscopy as a Tool to Understand Glass Fracture

Microscopy has been an indispensable tool for science since the 17th century. It has been used to study glass fractures for decades. The main problem with conventional microscopy is that you can only see a complete image if all aspects of the image are in the same geometrical plane of focus. Digital microscopy is a critical advance since it can combine information in different geometrical planes into a single image. With a transparent material such as glass this opens up new perspectives in that by using the right combination of transmission and reflective lighting both internal defects and complicated 3D surface defects can be imaged. In the field of float glass this allows for the study of edge and surface defects pre-fracture and the damage visible post-fracture. In the field of cast glass this allows for studying the -often complex- network of defects in the bulk. The ability to view and study such internal defects supports research efforts towards the characterization and application of recycled glass. The paper will show the critical aspect of using the right lighting and lenses and the settings needed to obtain high quality images of complex 3D damage. This will be demonstrated based on the microscopic analysis of multiple float and cast glass specimens tested in 4 point bending at the TU Delft Glass lab. Using proper lighting and technique provides a new insight into the fracture processes of glass

Sound absorbing glass: transparent solution for poor acoustics of monumental spaces

Monumental buildings are demolished when they lose their traditional function. These historical monuments can be maintained by repurposing them for modern use, like lectures and musical events. This results in a demand for different acoustic conditions. However, monuments are subject to strict building intervention regulations; any intervention concerning changes to the original elements are often prohibited. This creates a demand for demountable and adaptable product design, repurposing monumental buildings by alleviating acoustical problems without distorting the view towards the monumental elements. This research focused on developing sound absorption panels based on the micro-perforation principle: manufacturing these in thin glass panels, evaluating their influence on strength and transparency, optimizing sound absorption (perforation diameter and ratio) using a tailor-made computational model, and creating a pattern of perforations that optimizes strength

Sound absorbing glass: transparent solution for poor acoustics of monumental spaces

Monumental buildings are demolished when they lose their traditional function. These historical monuments can be maintained by repurposing them for modern use, like lectures and musical events. This results in a demand for different acoustic conditions. However, monuments are subject to strict building intervention regulations; any intervention concerning changes to the original elements are often prohibited. This creates a demand for demountable and adaptable product design, repurposing monumental buildings by alleviating acoustical problems without distorting the view towards the monumental elements. This research focused on developing sound absorption panels based on the micro-perforation principle: manufacturing these in thin glass panels, evaluating their influence on strength and transparency, optimizing sound absorption (perforation diameter and ratio) using a tailor-made computational model, and creating a pattern of perforations that optimizes strength

Restorative glass: reversible, discreet restoration using structural glass components

The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and aesthetical integrity. Concurrently, the material’s unique mechanical properties enable the structural consolidation of the monument. As a proof of concept, the restoration of Lichtenberg Castle is proposed. Solid cast glass units are suggested to complete the missing parts, in respect to the existing construction technique and aesthetics of the original masonry. Aiming for a reversible system, the glass units are interlocking, ensuring the overall stability without necessitating permanent, adhesive connections. This results in an elegant and reversible intervention

Restorative glass: reversible, discreet restoration using structural glass components

The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and aesthetical integrity. Concurrently, the material’s unique mechanical properties enable the structural consolidation of the monument. As a proof of concept, the restoration of Lichtenberg Castle is proposed. Solid cast glass units are suggested to complete the missing parts, in respect to the existing construction technique and aesthetics of the original masonry. Aiming for a reversible system, the glass units are interlocking, ensuring the overall stability without necessitating permanent, adhesive connections. This results in an elegant and reversible intervention

Southeast of What? Reflections on SEALS\u27 Success

In epidemiologic studies, measurement error in dietary variables often attenuates association between dietary intake and disease occurrence. To adjust for the attenuation caused by error in dietary intake, regression calibration is commonly used. To apply regression calibration, unbiased reference measurements are required. Short-term reference measurements for foods that are not consumed daily contain excess zeroes that pose challenges in the calibration model. We adapted two-part regression calibration model, initially developed for multiple replicates of reference measurements per individual to a single-replicate setting. We showed how to handle excess zero reference measurements by two-step modeling approach, how to explore heteroscedasticity in the consumed amount with variance-mean graph, how to explore nonlinearity with the generalized additive modeling (GAM) and the empirical logit approaches, and how to select covariates in the calibration model. The performance of two-part calibration model was compared with the one-part counterpart. We used vegetable intake and mortality data from European Prospective Investigation on Cancer and Nutrition (EPIC) study. In the EPIC, reference measurements were taken with 24-hour recalls. For each of the three vegetable subgroups assessed separately, correcting for error with an appropriately specified two-part calibration model resulted in about three fold increase in the strength of association with all-cause mortality, as measured by the log hazard ratio. Further found is that the standard way of including covariates in the calibration model can lead to over fitting the two-part calibration model. Moreover, the extent of adjusting for error is influenced by the number and forms of covariates in the calibration model. For episodically consumed foods, we advise researchers to pay special attention to response distribution, nonlinearity, and covariate inclusion in specifying the calibration model

Re^3 Glass: a Reduce/Reuse/Recycle Strategy

The applicability of glass in structures is continuously ascending, as the transparency and high compressive strength of the material render it the optimum choice for realizing diaphanous structural components that allow for light transmittance and space continuity. The fabrication boundaries of the material are constantly stretching: visible metal connections are minimized and glass surfaces are maximized, resulting to pure all-glass structures. Still, due to the prevalence of the float glass industry, all-glass structures are currently confined to the limited forms and shapes that can be generated by planar, 2D glass elements. Moreover, despite the fact that glass is fully recyclable, most of the glass currently employed in buildings is neither reused nor recycled due to its perplexed disassembly and its contamination from coatings and adhesives. Cast glass can be the answer to the above restraints, as it can escape the design limitations generated from the 2-dimensional nature of float glass. By pouring molten glass into moulds, solid 3-dimensional glass components can be attained of considerably larger cross-sections and of virtually any shape. These monolithic glass objects can form repetitive units for large all glass-structures that do not buckle due to slender proportions and thus can take full advantage of the stated compressive strength of glass. Such components can be accordingly shaped to interlock towards easily assembled structures that do not require the use of adhesives for further bonding. In addition, cast glass units–due to their increased cross section– can tolerate a higher degree of impurities and thus can be produced by using waste glass as a raw source

Re^3 Glass

The applicability of glass in structures is continuously ascending, as the transparency and high compressive strength of the material render it the optimum choice for realizing diaphanous structural components that allow for light transmittance and space continuity. The fabrication boundaries of the material are constantly stretching: visible metal connections are minimized and glass surfaces are maximized, resulting to pure all-glass structures. Still, due to the prevalence of the float glass industry, all-glass structures are currently confined to the limited forms and shapes that can be generated by planar, 2D glass elements. Moreover, despite the fact that glass is fully recyclable, most of the glass currently employed in buildings is neither reused nor recycled due to its perplexed disassembly and its contamination from coatings and adhesives. Cast glass can be the answer to the above restraints, as it can escape the design limitations generated from the 2-dimensional nature of float glass. By pouring molten glass into moulds, solid 3-dimensional glass components can be attained of considerably larger cross-sections and of virtually any shape. These monolithic glass objects can form repetitive units for large all glass-structures that do not buckle due to slender proportions and thus can take full advantage of the stated compressive strength of glass. Such components can be accordingly shaped to interlock towards easily assembled structures that do not require the use of adhesives for further bonding. In addition, cast glass units–due to their increased cross section– can tolerate a higher degree of impurities and thus can be produced by using waste glass as a raw source