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Abstract: V prispevku so predstavljeni namen in program raziskovalnega projekta Strateške podlage za zmanjšanje potresne ogroženosti stavb pravosodja v Sloveniji ter bistveni dosedanji rezultati. Opisu značilnosti obravnavanih 76 stavb sodišč v Sloveniji in kratkemu povzetku uporabljenih metod sledi predstavitev rezultatov izdelanih ocen potresne ogroženosti obravnavanih stavb s komentarjem. Stavbe so raznolike glede na tip konstrukcije, število nadstropij, starost in potresno nevarnost lokacij, na katerih stojijo. Razvrstitev stavb je bila izvedena glede na dva kazalnika potresne ogroženosti. Prvi je razmerje med ocenjeno vrednostjo koeficienta potresne odpornosti SRCu-np in vrednostjo koeficienta projektne potresne obtežbe BSCd, ki upošteva zahteve standarda Evrokod 8 in Novo karto potresne nevarnosti iz leta 2021. Drugi kazalnik pa je z modelom POTROG ocenjena verjetnost, da bo stavba v primeru potresa po Karti intenzitete iz leta 2011 utrpela poškodovanost kategorij 3, 4 ali 5 (tj. najmanj kategorije 3) po Evropski potresni lestvici EMS-98. Istih pet stavb je prepoznanih kot potresno najbolj ogroženih po obeh parametrih. Vseh pet je zidanih in zgrajenih pred uveljavitvijo prvih potresnih predpisov. Dve najbolj ogroženi armiranobetonski stavbi sta na 11. in 23. mestu po prvem oziroma na 15. in 16. mestu po drugem parametru. Druga od njiju je bila zgrajena pred uvedbo prvih potresnih predpisov, prva pa po njej. V zadnjem delu prispevka so kot del predstavitve metodologije projekta na primeru stavbe konkretnega sodišča predstavljeni rezultati podrobnih potresnih analiz izbrane stavbe, to je potisnih analiz, izvedenih na podlagi podrobnega pregleda in preiskav stavbe, ki služijo za natančno oceno potresne odpornosti stavbe v obstoječem in različnih variantah utrjenega stanja.
Keywords: potresna ogroženost, stavbe sodišč, model POTROG, in situ preiskave, potisna analiza, ocena stroškov utrditve
Published in DiRROS: 13.01.2026; Views: 168; Downloads: 110
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Abstract: A reliable determination of the embedment strength and foundation modulus of timber elements is critical for the design and safety assessment of joints in timber structures. However, the existence of various test configurations for characterising the embedding properties of large diameter steel fasteners in timber elements poses challenges in directly comparing and utilising available test data. This paper aims to provide an insight into the influence of embedment property test methods, comparing experimental results from different test setups within the guidelines of the EN 383 and ASTM D 5764-97a standards for European softwood species, Scots pine wood (Pinus sylvestris) and Norway spruce (Picea abies). In addition to the test guidelines, the thickness of the specimen and the application of the load was evaluated within the protocols. A comprehensive statistical analysis was performed to identify statistically significant differences between the groups evaluated. The results of the analysis revealed disagreement between the standards in the evaluation of the strength of the embedding, highlighting the potential bias inserted by the experimental setup and protocol. Furthermore, it was proven that the thickness of the specimens influences both the embedding strength and the foundation modulus of the wood species tested. Finally, no distinctions were observed between tensile and compressive loading within the guidelines of the EN 383 standard.
Keywords: embedment strength, foundation modulus, dowel-type connections, test methods
Published in DiRROS: 15.04.2024; Views: 1224; Downloads: 795
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Abstract: In cross-laminated timber (CLT) buildings, in order to reduce the disturbing transmission of sound over the flanking parts, special insulation layers are used between the CLT walls and slabs, together with insulated angle-bracket connections. How-ever, the influence of such CLT connections and insulation layers on the seismic resistance of CLT structures has not yet been studied. In this paper, experimental investigation on CLT panels installed on insulation bedding and fastened to the CLT floor using an innovative, insulated, steel angle bracket, are presented. The novelty of the investigated angle-bracket connection is, in addition to the sound insulation, its resistance to both shear as well as uplift forces as it is intended to be used instead of traditional angle brackets and hold-down connections to simplify the construction. Therefore, monotonic and cyclic tests on the CLT wall-to-floor connections were performed in shear and tensile/compressive load direction. Specimens with and without insulation under the angle bracket and between the CLT panels were studied and compared. Tests of insulated specimens have proved that the insulation has a marginal influence on the load-bearing capacity; however, it significantly influences the stiffness characteristics. In general, the experiments have shown that the connection could also be used for seismic resistant CLT structures, although some minor improvements should be made.
Keywords: CLT connection, equivalent viscous damping, experimental shear tests, polyurethane sound-insulation, steel angle bracket
Published in DiRROS: 19.07.2023; Views: 1916; Downloads: 782
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Abstract: Due to their comparable fire characteristics and surface preparation, light-frame timber panels using cement-particle boards (CPB) as a sheathing material present a potential alternative to gypsum-fibre boards. An experimental campaign was conducted to evaluate the behaviour of CPB light-frame-timber panels under in-plane lateral loading. Monotonic and cyclic in-plane shear tests were conducted on full-size panels, following preceding tests on the stapled sheathing-to-timber connections used in the panels. The influence of the boards’ thickness and staple geometry on the response of connections and panels was studied, also on panels with an asymmetrical CPB layout, which proved not to have a negative influence on the panels’ lateral load-bearing capacity. Furthermore, in order to improve the seismic response, panels, which had almost twice the number of staples compared to the basic panel, were tested; one variation with two rows of staples, and the other with the staples spaced closer together, such that the spacing distance was halved. The tests revealed a significant, though not proportional, increase in lateral resistance in the strengthened panels. Fastening the CPB with two rows of staples proved the better option, since subsequent failure of the CPB along the connections, as opposed to ductile failure of the staples in the basic panels, proved not to reduce the panels’ deformation capacity. The paper also compares the test results of the connections and panels to analytical results according to Eurocode 5 (EC5), the European code provision for the design of timber structures.
Keywords: light-frame timber panels, cement-particle board sheathing, cyclic shear tests, sheathing-to-timber connection, asymmetrical panel, staple spacing distance, EN 1995–1-1, open access
Published in DiRROS: 31.05.2023; Views: 1853; Downloads: 978
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Abstract: This study investigates timber connections with flexible polyurethane adhesives, which prove to have the po-tential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental re-sults on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.
Keywords: flexible adhesive, timber connection, polyurethane, double lap-shear, cyclic loading, energy dissipation, open access
Published in DiRROS: 19.05.2023; Views: 1790; Downloads: 969
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