Double-lap shear test on laminated glass specimens under diverse ageing conditions

Laminated glass is a composite laminate obtained from combining two or more glass layers with a polymeric interlayer. The adhesion between glass and interlayer, as well as the shear strength and stiffness of the interlayer, are key factors to evaluate the cohesive behaviour of laminated glass. Glass is a very durable material, while polymeric interlayers can be deteriorated by exposure to weathering factors. A double-lap shear test was carried out on laminated glass specimens, with four different interlayer materials (PVB BG-R20, Saflex DG-41, SentryGlas, and EVASAFE), after different ageing tests (unaged, thermal cycles, humidity, and UV radiation). The material selection affected the shear behaviour of the bond between glass and interlayer, and so did the previous exposure to certain ageing factors. Since the polymeric interlayers are viscoelastic materials, and therefore its mechanical properties are time- and temperature-dependant, the results here presented should be complemented with dynamic and static tests at different temperatures.The work was partially funded by CRISTEC with CDTI funds (IDI-20160588). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. Xavier Centelles would like to thank University of Lleida for his research fellowship.Peer ReviewedPostprint (author's final draft

Bending behaviour of laminated glass panels with different polymeric interlayers: experimental testing and simulation

Laminated glass combines glass layers, which provide strength and durability, with transparent polymeric interlayers, which provide coupling between glass layers and prevent glass shards from scattering in case of breakage. The main goal of this paper is to present, through COMSOL Multiphysics simulations, how the mechanical performance (bending stiffness and stress distribution) of laminated glass plates is affected by the shear stiffness of the interlayer material. The simulation results were validated with experimental tests. The laminated glass specimens presented a linear elastic behaviour until glass breakage, and its mechanical performance was affected by the interlayer material selection, as well as the load duration and the working temperature.The work was partially funded by CRISTEC with CDTI funds (IDI-20160588). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. Xavier Centelles would like to thank University of Lleida for his research fellowship.Peer ReviewedPostprint (published version

Experimental study and comparison of different fully transparent laminated glass beam designs

Laminated glass beams without metallic or polymeric reinforcements generally lack post-breakage strength and ductility. This paper aims to perform a comparative study by testing five different fully transparent laminated glass beam designs in order to see how parameters such as the number and thickness of glass sheets (3 x 10 mm or 5 x 6 mm), the interlayer material (PVB Clear or SentryGlas), and the thermal treatment of glass (annealed or heat-strengthened) affect the pre-breakage performance and post-breakage safety. A buckling analysis is also performed using a numerical model with ABAQUS CAE. The study includes a comparison between the results of different experimental mechanical tests on laminated glass beams, including the tests presented in this paper, as well as other tests found in the literature. All designs presented a linear elastic behaviour until initial breakage. The interlayer material mainly affected the crack shape of laminated glass beams. Beams with five sheets of annealed glass had a more progressive breakage, and therefore a safer behaviour, than beams with three sheets of annealed or heat-strengthened glass.The work was partially funded by CRISTEC with CDTI funds (IDI-20160588). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. The financing support given by the Spanish Ministry of Economy and Competitiveness through the project BIA2014-53774-R is gratefully appreciated. Xavier Centelles would like to thank University of Lleida for his research fellowship and to the University of Oviedo for hosting his secondment during 2019. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

Local buckling of cold-formed steel trapezoidal sheets: data for finite element model validation

Data is provided from a validation example for a finite element model of a cold-formed steel trapezoidal sheet. The sheet is subjected to bending, failing due to local buckling. The numerical model and the validation procedure are carried out according to the new Eurocode 3 prEN1993-1-14 Design assisted by finite element analysis. Detailed information concerning all aspects needed to reproduce the example is included: (i) the nominal and measured values of the sheet geometry; (ii) the measured material properties of the steel; (iii) the test setup of the validation experiments; (iv) the experimental results; (v) a complete description of the finite element model and solution procedure; and (vi) the finite element results. Additionally, data related to sensitivity studies on the numerical model is also presented, including the effect of the model domain, meshing, and imperfections (shape, magnitude, direction and combinations). Overall, the article aims to provide data and guidance to designers and researchers validating similar numerical models.This research has been funded by the Agència Valenciana de la Innovació (AVI) of the Generalitat Valenciana, project INNCAD/2021/103- A46265526. This support is gratefully acknowledged.Postprint (published version

Polymeric interlayer materials for laminated glass: A review

Laminated glass is obtained by bonding two or more glass layers using a polymeric interlayer. Compared to monolithic glass, laminated glass is beneficial in terms of post-breakage safety, security against breakins, and acoustic insulation, among others. That is why laminated glass is being used for a wide variety of constructive solutions. Polymers such as PVB, ionomers, EVA and TPU are used as interlayer materials in laminated glass. This review aims to describe the most common polymeric interlayers, outline its characterization techniques, and give a general overview about the recyclability of the interlayers. There are two main properties used to characterize the interlayer materials: mechanical properties and resistance to ageing factors. Main mechanical tests found in the literature are summarized, and the properties studied in each of them are listed. Most experimental studies regarding ageing resistance consider mainly three weathering agents: humidity, UV radiation, and temperature.The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREiA and DIOPMA (2017 SGR 1537 and 2017 SGR 118, respectively). GREiA and DIOPMA are certified agents TECNIO in the category of technology developers from the Government of Catalonia. Aran Solé would like to thank the Ministerio de Economía y Competitividad de España for Grant Juan de la Cierva FJCI-2015-25741. Xavier Centelles would like to thank University of Lleida for his research fellowship. This work is partially supported by ICREA under the ICREA Academia programme

Anàlisi estructural per a la construcció d’un complex comercial d'estructura metàl·lica situat a França

L’objectiu principal d’aquest treball és documentar el procés de disseny, càlcul i dimensionament de l’estructura metàl·lica d’un complex comercial format per dos edificis, amb una superfície total de 6355,5 m2. Un dels edificis, de 1447,7 m2, està format per un únic mòdul, i l’altre, de 4907,8 m2, està format per quatre mòduls, cadascun amb una estructura independent. El projecte també inclou un estudi de les fonamentacions i la protecció al foc de l'estructura. Es tracta d’un espai on es requereixen grans llums sense pilars entremitjos. El client ha optat per l’estructura metàl·lica perquè permet obtenir pòrtics més lleugers, resistents i econòmics en comparació amb altres materials de construcció. El disseny de l’estructura s’ha realitzat partint d’una proposta inicial de la propietat i s’han fet les modificacions que s’han cregut necessàries, tot respectant els condicionants urbanístics, les característiques de l’entorn i les necessitats del client. Prèviament a la realització del càlcul s’han obtingut les accions a tenir en compte, segons la normativa europea EN-1991: Accions en estructures, classificades com a permanents (pes propi dels elements estructurals i no estructurals), variables (neu, vent i tèrmiques) i accidentals (impacte, sisme i foc). El càlcul i dimensionament de l’estructura s’ha realitzat amb el programa de càlcul Diamonds, en conformitat amb l’EN-1993: Projecte d’estructures d’acer. Les forces i els moments obtinguts en les unions, extrets del Diamonds, han permès realitzar el dimensionament de les unions i les plaques base amb el programa de càlcul Powerconnect. El projecte inclou una anàlisi de l’impacte mediambiental de les construccions d’estructura metàl·lica, i en concret de l’edifici objecte d’estudi. També s’ha realitzat un pressupost de l’estudi realitzat. Un dels punts indicats en el full de registre era un reportatge fotogràfic, però unes modificacions en els terminis d'execució previstos inicialment han fet que, a data d'entrega d'aquest projecte, encara no hagi finalitzat la construcció de l'estructura. Així doncs, les fotografies de l'obra es substitueixen per recreacions digitals del resultat final. Aquest treball s’ha realitzat sota la direcció d’una persona externa a l’ETSEIB amb titulació superior: el Sr. Jaume Castells Gómez, i amb un ponent al centre: el Sr. Frederic Marimon Carvajal

Structural glass in buildings: study of the deflection, durability, and breakage of laminated glass elements and polymeric interlayers

Aquesta tesi doctoral avalua el comportament estructural del vidre laminat mitjançant la recerca bibliogràfica, assajos experimentals i simulacions. Alguns dels assajos experimentals duts a terme es centren en lˇestudi de les deformacions abans de la ruptura inicial del vidre, mentre que en altres sˇassoleix la ruptura per tal dˇavaluar la seguretat port-ruptura. A més a més, es fa especial èmfasi en el material intercalari que uneix les làmines de vidre entre elles, per la seva importància en el comportament global del vidre laminat. Els resultats mostren com, malgrat que el vidre és fràgil, els elements estructurals de vidre laminat poden resistir càrregues elevades i complir amb els requeriments de seguretat. No obstant, és fonamental triar els paràmetres de disseny adequats, com el tipus de vidre, el número i gruix de les làmines de vidre i el material intercalari, perquè poden tenir molta rellevància, especialment en cas de ruptura accidental.Esta tesis doctoral evalúa el comportamiento mecánico del vidrio laminado mediante un estudio bibliográfico, ensayos experimentales y simulaciones. Algunos de los ensayos llevados a cabo se centran en el estudio de las deformaciones, mientras que en otros se alcanza la rotura para evaluar también el comportamiento post-rotura. Se presta especial atención al intercalario polimérico que se usa para unir las láminas de vidrio entre ellas, por su rol determinante tanto antes como después de la rotura del vidrio. Los resultados muestran cómo, a pesar de que el vidrio es frágil, los elementos de vidrio laminado pueden resistir cargas elevadas y cumplir con los requerimientos de seguridad. Sin embargo, es esencial elegir los parámetros de diseño adecuados, como el tipo de vidrio, el número y grosor de láminas de vidrio y el material intercalario, porque pueden tener un gran impacto en el comportamiento mecánico, especialmente en caso de rotura accidental.This PhD evaluates the structural performance of laminated glass through literature research, experimental testing, and numerical simulation. Some of the conducted experimental tests focus on the deformational study before initial glass fracture, while in others the failure of the specimens is reached in order to evaluate the post-breakage safety as well. Special attention is paid to the polymeric interlayer that creates a bond between glass sheets, because it plays a key role in both the pre- and post-breakage stages. The results of this thesis show that, although glass is brittle, laminated glass elements can resist high loads and comply with safety regulations. However, it is essential to choose the right design parameters (e.g., type of glass, number of glass sheets, and interlayer material), because these can have a high impact on the mechanical behaviour, especially in case of accidental breakage

Long-term loading and recovery of a laminated glass slab with three different interlayers

The mechanical behaviour of laminated glass plates and beams is affected in different ways by the shear stiffness of interlayer materials. Polymeric interlayers are viscoelastic materials, and therefore experience creep when subjected to long-term loading. In this paper, three laminated glass panels, each with a different interlayer material (PVB Clear, PVB ES, and SentryGlas), were placed between two laminated glass beams. A uniformly distributed load was applied during four months to study the effect of creep, and then was removed to see the deflection recovery during one month. The midspan vertical displacement of the two laminated glass beams remained almost constant over time, with a small variation that was attributed to the rubber sheets placed in the supports. The plate with SentryGlas had the lowest elastic deformation, creep, and residual deformation. The plate with PVB Clear had the highest elastic and total deformation. The plate with PVB ES had a similar initial deflection as SentryGlas, but was the one that experienced the highest creep. At the end of the test the plates still had a small residual deflection, which could be due to an incomplete deflection recovery. The flexural behaviour of the three laminated glass plates was simulated using a Finite Element Model, representing the loading, the creep, the unloading, and the deflection recovery stages.The work was partially funded by CRISTEC with CDTI funds (IDI-20160588). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. The financing support given by the Spanish Ministry of Economy and Competitiveness through the project BIA2014-53774-R is gratefully appreciated. Xavier Centelles would like to thank University of Lleida for his research fellowship and to the University of Oviedo. for hosting his secondment during 2019Peer ReviewedPostprint (published version