Browsing by Author "Rosales, Victor"

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    Assessing Treatments to Mitigate End-Face Cracking in Air-Dried Acacia dealbata Logs
    (2024) Suazo-Uribe, Manuel; Salvo-Sepulveda, Linette; Rosales, Victor; Montero, Claudio; Louzada, Jose L.; Branco, Jorge M.
    Acacia dealbata Link, known as Mimosa in Portugal, is an invasive hardwood species with potential for construction use, but research is limited. The available stock of small-diameter juvenile wood logs can help reduce this gap, but tangential cracking at log ends challenges fastener connections. This study evaluated different treatments to control and reduce end-face cracking in small wood logs during air drying, an economical and environmentally friendly procedure. The extreme two-thirds of sixteen Mimosa logs were subjected to two treatments: one with longitudinal kerfs 15 mm deep along the length (two and three kerfs) and the other with a hollow in the center up to half the length (16 mm and 30 mm diameters). Over 219 days of air drying and compared with the central part, kerfing treatments significantly reduced outer-wood tangential cracking (p < 0.001), with the three kerfs also reducing crack numbers (p < 0.05) but increasing significantly cracks near the pith (p < 0.01). The 30 mm central hollow significantly reduced central perforation cracking (p < 0.05). Prospectively, the results suggest that a combined treatment approach involving cross-cuts could help reduce and/or control end cracking, thereby improving the suitability of wild Mimosa logs for construction use.
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    Economic and technical analysis of CLT production facilities: an application to small and emerging markets
    (2022) Benedetti, Franco; Rosales, Victor; Jelvez, Arnaldo; Nunez, Mario; Rebolledo, Alonso; Jara-Cisterna, Alan
    The CLT market is quickly growing and developing in different regions of the world. However, the production and consumption are highly concentrated in Central Europe (Austria, Germany, Italy, and Switzerland). Due to the elevated levels of personalization required for the construction projects, the CLT manufacturing process involves costly and specialized equipment that represents an entry barrier for domestic producers in markets where the demand is small and incipient. This work discusses a production model and supply chain integration for the development of the CLT industry in emerging environments where the product and its properties are not well-known. Furthermore, a comprehensive economic analysis is performed for three small capacity mills designed according to SMEs capabilities. Findings suggest that CLT manufacturing with low-capacity plants (less than 10,000 m(3)/yr) is profitable but high levels of integration are required. The most influential variables in the economic results are the lumber cost and production volume; therefore, special attention must be paid to the efficiency of the process. Despite the small size of the studied plants promoted by the proposed production and plant design model, the sale price is attractive and competitive.
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    Feasibility of Bonding High-Moisture-Content Wood Using Nothofagus chilean Species
    (2023) Rosales, Victor; Rodriguez-Grau, Gonzalo; Galarce, Carlos; Montero, Claudio; Alvarado, Claudia; Munoz, Lisa; Pommier, Regis
    Appraising and protecting forests requires a management plan and the creation of innovative products for the market. The development of the green gluing technique could add value to native timber. However, there is a lack of knowledge concerning the response and the productive process of Nothofagus species using this technique. This work investigated the viability of implementing the green gluing method using three types of Nothofagus. Wood pieces were made using a one-component polyurethane adhesive. Delamination, shear tests, morphological characterization, and bond line thickness analysis tested their capacity. The results showed a variable response depending on the Nothofagus type, where the surface treatment could improve the green gluing performance. The findings highlight the relevance of increasing knowledge about the essayed species and their preparation to maintain their natural moisture condition.
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    The Adhesion Performance in Green-Glued Finger Joints Using Different Wood Ring Orientations
    (2024) Rodriguez-Grau, Gonzalo; Cordonnier, Pierre-Louis; Navarrete, Benjamin; Montero, Claudio; Alvarado, Claudia; Pommier, Regis; Rosales, Victor; Galarce, Carlos
    Structural lumber is designed to meet the technical standards that ensure safety, cost-effectiveness, and sustainability. However, some tree species face limitations in their growth, which restricts their widespread use. An example of this is Nothofagus alpina, which has excellent mechanical properties but is not utilized much due to the challenges in extracting its timber and poor utilization, mainly because of the length of the wood. There is little information concerned with the uses and better management of small pieces using Nothofagus species, but it is still insufficient. This study investigates the adhesion performance of green-glued finger joints with varying wood ring orientations and moisture contents ranging from 21% to 25% using Nothofagus alpina. The primary aim is to assess how ring orientation and wet timber affect the green gluing process for creating larger wood pieces than sawn wood. The resulting products could meet the standards for wood serviceability number three for native Chilean wood. The findings indicate that finger joint performance improves with higher timber moisture levels. However, the orientation of the wood fibers did not significantly affect the performance under the tested conditions. It is important to note that this effect may become more significant near the fiber saturation point. These findings emphasize the need for a detailed protocol on the green gluing technique for Nothofagus alpina and the associated drying and surface processes in finger joint construction.
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    Vibration-based monitoring of a cross-laminated timber building in a high seismicity zone
    (2024) Jara-Cisterna, Alan; Benedetti, Franco; Rosales, Victor; Almazan, Jose Luis; Opazo-Vega, Alexander
    Cross-laminated timber (CLT) buildings have emerged as an alternative to make more sustainable and resilient cities. However, very few cases of vibration-based monitoring of these buildings have been reported. This paper discusses the variation of the dynamic properties of a 5-story cross-laminated timber (CLT) building through vibration-based monitoring over 23 months. The building combines different construction systems, is relatively slender for its type, and was built in a high seismicity zone. The monitoring strategy included periodic measurements of the dynamic properties during construction, reference measurements with high-sensitivity accelerometers, and 10 months of continuous measurements with low-cost equipment. In addition, continuous measurements allowed the analysis of the dynamic properties during special events associated with wind gusts and moderate-intensity earthquakes. During the construction stage monitoring and reference measurements, up to 5 modal shapes of the building with their respective vibration frequencies and damping ratios were detected. These dynamic properties allowed the calibration of a simplified numerical model of the building. Subsequently, during the continuous monitoring phase of the building, it was observed that the first two translation frequencies varied by up to 8% due to changes in climatic conditions and the moisture content of the timber. Finally, monitoring during a 5.4 Mw earthquake showed that vibration frequencies temporarily decreased by up to 15% and returned to their initial value after the seismic event had passed. The results of this research will contribute to the knowledge of the dynamic response of this type of building and the updating of their structural design codes.