1. Efficiency of FRPU strengthening of a damaged masonry infill wall under in-plane cyclic shear loading and elevated temperaturesPetra Triller, Konrad Kwiecień, Arkadiusz Kwiecień, Uroš Bohinc, BogusŁaw Zając, Marcin Tekieli, Magdalena Szumera, Theodoros Rousakis, Vachan Vanian, Ahmet Tugrul Akyildiz, Alberto Viskovic, 2024, izvirni znanstveni članek Povzetek: This paper presents results of in-plane shear tests carried out at the ZAG laboratory in Ljubljana (Slovenia) on a RC frame with masonry infill made of clay blocks (KEBE OrthoBlock). The frame was loaded with constant vertical loads at the top of the columns and then by gradually increasing horizontal cyclic loads at the top beam level. Acquired forces and measured displacements allowed capturing hysteretic behavior for determination of dissipation energy. In addition, two Digital Image Correlation (DIC) systems, Aramis and the CivEng Vision, were used to visualize the behavior of the tested specimens, with an emphasis on computing locally required information about the behavior of highly deformable interfaces. Three types of specimens were tested in-plane: the reference specimen in form of plain RC frame, the reference specimen with constructed masonry infill without any strengthening and the specimen, previously damaged and then strengthened on both sides using glass mesh bonded to the infill and the RC frame using flexible adhesive made of polyurethane matrix (Glass Fiber Reinforced PolyUrethane - GFRPU system). The strengthening process, allowed the specimen to withstand additional cyclic loads, reaching a maximum drift of 3.6 % without serious damage disqualifying the structure from further exploitation. The GFRPU strengthening system was found to be highly effective in preventing infill collapse of damaged masonry infill wall during in-plane loading. Additionally, the results of extended thermal analysis of PU are presented as polymers are, in general, a material, poorly resistant to heat. However, the analyzed PU manifested stable properties up to 200 degrees Celsius, which makes this material promising in civil engineering applications at elevated temperatures. Ključne besede: masonry blocks, damaged infill, fiber Reinforced PolyUrethane, external composite strengthening, in-plane shear, thermal tests, DIC measurements Objavljeno v DiRROS: 14.08.2024; Ogledov: 22; Prenosov: 7
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2. Comprehensive permanent remote monitoring system of a multi-span highway bridgeAndrej Anžlin, Uroš Bohinc, Doron Hekič, Maja Kreslin, Jan Kalin, Aleš Žnidarič, 2021, objavljeni znanstveni prispevek na konferenci Povzetek: As part of the reconstruction of a multi-span viaduct on a Slovenian highway, a permanent remote monitoring system with over 200 sensors was established. Several parameters are monitored on different parts of the viaduct by means of temperature sensors, accelerometers, strain gauges, long-gauge deformation and Fibre Bragg Grating (FBG) sensors. In this way strains, frequencies and temperatures on external prestressed beam cables, carbon fibre rebarsused for the flexural strengthening of a deck overhang, pier caps and prestressed beams are measured and stored into the on-site central data acquisition system. This paper presents architecture of the permanent bridge monitoring system and preliminary results of the measurements. Ključne besede: permanent monitoring, structural health monitoring, bridge WIM, sensors, viaduct Objavljeno v DiRROS: 22.01.2024; Ogledov: 520; Prenosov: 236
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3. Getting more out of existing structuresMartín-Sanz Henar, Konstantinos Tatsis, Domagoj Damjanovic, Irina Stipanović, Aljoša Šajna, Ivan Duvnjak, Uroš Bohinc, Eugen Brühwiler, Eleni Chatzi, 2019, izvirni znanstveni članek Povzetek: Ultra-high-performance fiber-reinforced cement-based composite (UHPFRC) has been increasingly adopted for rehabilitation projects over the past two decades, proving itself as a reliable, cost-efficient and sustainable alternative against conventional methods. High compressive strength, low permeability and high ductility are some of the characteristics that render UHPFRC an excellent material for repairing existing aged infrastructure. UHPFRC is most commonly applied as a surface layer for strengthening and rehabilitating concrete structures such as bridge decks or building slabs. However, its implementation with steel structures has so far been limited. In this work, the UHPFRC strengthening of a steel bridge is investigated both in simulation as well as in the laboratory, by exploiting a real-world case study: the Buna Bridge. This Croatian riveted steel bridge, constructed in 1893, repaired in 1953, and decommissioned since 2010, was removed from its original location and transported to laboratory facilities for testing prior to and after rehabilitation via addition of UHPFRC slab. The testing campaign includes static and dynamic experiments featuring state-of-the-art monitoring systems such as embedded fiber optics, acoustic emission sensors and digital image correlation. The information obtained prior to rehabilitation serves for characterization of the actual condition of the structure and allows the design of the rehabilitation solution. The UHPFRC slab thickness was optimized to deliver optimal fatigue and ultimate capacity improvement at reasonable cost. Once the design was implemented, a second round of experiments was conducted in order to confirm the validity of the solution, with particular attention allocated to the interface between the steel substrate and the UHPFRC overlay, as the connection between both materials may result in a weak contact point. A detailed fatigue analysis, based on updated FEM models prior to and after strengthening, combined with the results of a reliability analysis prove the benefits of adoption of such a solution via the significant extension of the structural lifespan. Ključne besede: bridge, steel, UHPFRC, structures Objavljeno v DiRROS: 21.12.2023; Ogledov: 407; Prenosov: 179
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4. Računski model za opis temperaturnega vpliva na meritve deformacijUroš Bohinc, 2022, izvirni znanstveni članek Povzetek: V prispevku je predstavljen izviren način za napoved odvisnosti izmerjenih deformacij od temperature okolice. Izhaja iz poenostavljenega fizikalnega modela, ki je umerjen s pomočjo niza obstoječih meritev, ki pokrivajo časovni razpon enega leta. Spremljanje konstrukcijskega stanja zvonika stolnice sv. Anastazije v Zadru je bilo opravljeno z namenom, da bi zanesljivo določili morebitne dolgotrajne trende obnašanja in tako omogočili pravočasno ukrepanje. Za uspešno določitev dolgotrajnih trendov je ključna ločitev temperaturnega vpliva na meritve. Rezultati kažejo, da je mogoče na predstavljeni način dokaj dobro izločiti temperaturni vpliv na meritve in tako izboljšati zaznavo morebitnih dolgotrajnih trendov. Ključne besede: meritve deformacij, modeliranje temperaturnega vpliva, spremljanje konstrukcijskega stanja Objavljeno v DiRROS: 04.12.2023; Ogledov: 411; Prenosov: 185
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