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This chapter aims to present a comprehensive report on the reinforcement of historic timber roofs, focusing on their main characteristics, advantages and disadvantages, which would help professionals select and define the design of reinforcement solutions. Cultural heritage issues are taken into consideration. Reinforcement can be done via different methods—traditional and modern—using simple or sophisticated techniques. An overview of the main materials and the techniques used for selected case studies are presented, illustrating how various reinforcement methods are implemented in practice.
Eleftheria Tsakanika; Jorge M. Branco. Reinforcement of Historic Timber Roofs. Bio-aggregates Based Building Materials 2021, 195 -220.
AMA StyleEleftheria Tsakanika, Jorge M. Branco. Reinforcement of Historic Timber Roofs. Bio-aggregates Based Building Materials. 2021; ():195-220.
Chicago/Turabian StyleEleftheria Tsakanika; Jorge M. Branco. 2021. "Reinforcement of Historic Timber Roofs." Bio-aggregates Based Building Materials , no. : 195-220.
This chapter focuses on the reinforcement of traditional timber carpentry joints according to different standards, recommendations, case studies, as well as analytical, numerical and experimental research works. The aim of the review is to present the state-of-the-art methodologies that can be at the disposal of carpenters, architects and engineers. In order to understand how traditional carpentry joints, work and their failure mechanisms, such as compressive crushing, shear and tensile cracks, six geometrical typologies of such joints are discussed. Finally, for the above typologies, several reinforcement strategies are presented by defining their objectives, methodologies, traditional and contemporary techniques, performance criteria and applicability areas. When assessing and reinforcing traditional carpentry joints, some challenges may come up, namely their design, based on the ratios of stiffness and load-bearing capacities. These challenges should thus be a focal point for further research in the near future.
Jorge M. Branco; Maxime Verbist; Eleftheria Tsakanika. Reinforcement of Traditional Carpentry Joints. Bio-aggregates Based Building Materials 2021, 247 -271.
AMA StyleJorge M. Branco, Maxime Verbist, Eleftheria Tsakanika. Reinforcement of Traditional Carpentry Joints. Bio-aggregates Based Building Materials. 2021; ():247-271.
Chicago/Turabian StyleJorge M. Branco; Maxime Verbist; Eleftheria Tsakanika. 2021. "Reinforcement of Traditional Carpentry Joints." Bio-aggregates Based Building Materials , no. : 247-271.
Every year earthquakes cause damage and destroy a sizeable portion of the building stock across the globe. Among traditional constructions, those built with timber are considered the most effective earthquake-resistant structures, provided that the continuity in the load path is not compromised, the joints are intact, and moisture-induced problems are kept at bay. However, the high costs and difficulties involved in the execution of interventions that meet the safety requirements prescribed by current building codes act as a deterrent to the continued use and reuse of these structures. Therefore, it is important to identify the inherent seismic-resistant features, as well as the deficiencies, of traditional timber constructions and to review the various strengthening, retrofitting and upgrading measures that have been developed to enhance the safety of such structures. The effectiveness of different strengthening techniques has been proven on the basis of results from experimental tests carried out on components of timber structures, such as joints and beams, full-scale shear walls, roof trusses and floor slabs. The successes and failures of past interventions also play an instrumental role in identifying effective and economical strengthening solutions for traditional timber structures.
Chrysl A. Aranha; Jorge M. Branco. Seismic Reinforcement of Traditional Timber Structures. Bio-aggregates Based Building Materials 2021, 133 -156.
AMA StyleChrysl A. Aranha, Jorge M. Branco. Seismic Reinforcement of Traditional Timber Structures. Bio-aggregates Based Building Materials. 2021; ():133-156.
Chicago/Turabian StyleChrysl A. Aranha; Jorge M. Branco. 2021. "Seismic Reinforcement of Traditional Timber Structures." Bio-aggregates Based Building Materials , no. : 133-156.
Wood and engineered wood products, herein also referred to as timber, have been used as structural building material for centuries and countless examples demonstrate its longevity if properly designed, built, maintained and assessed [1, 2]. The more recent development of new engineered wood products, connector systems and growing awareness about sustainability in the construction sector have led to legislative changes in the building sector and as a consequence also a significant widening in the range of structural applications of timber [3, 4].
Thomas Tannert; Philipp Dietsch; Jorge Branco. Reinforcement of Timber Elements in Existing Structures. Bio-aggregates Based Building Materials 2021, 1 -6.
AMA StyleThomas Tannert, Philipp Dietsch, Jorge Branco. Reinforcement of Timber Elements in Existing Structures. Bio-aggregates Based Building Materials. 2021; ():1-6.
Chicago/Turabian StyleThomas Tannert; Philipp Dietsch; Jorge Branco. 2021. "Reinforcement of Timber Elements in Existing Structures." Bio-aggregates Based Building Materials , no. : 1-6.
Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves.
Carlos Cunha; Marina Tenório; Daniel Lima; Arthur Rebouças; Luís Neves; Jorge Branco. Mechanical Characterization of Iroko Wood Using Small Specimens. Buildings 2021, 11, 116 .
AMA StyleCarlos Cunha, Marina Tenório, Daniel Lima, Arthur Rebouças, Luís Neves, Jorge Branco. Mechanical Characterization of Iroko Wood Using Small Specimens. Buildings. 2021; 11 (3):116.
Chicago/Turabian StyleCarlos Cunha; Marina Tenório; Daniel Lima; Arthur Rebouças; Luís Neves; Jorge Branco. 2021. "Mechanical Characterization of Iroko Wood Using Small Specimens." Buildings 11, no. 3: 116.
Despite the growing use of cross-laminated timber (CLT) panels in the construction industry, their behaviours under weather conditions, especially cyclic moisture which generated additional strains, requires further investigation. To address this gap, an extensive experimental campaign was carried out to evaluate CLT elements, in which strains are measured, under cyclic moisture changes, using Digital Image Correlation (DIC). In this way, the effects of cyclic humidity changes on amplitude and distribution of strains on four different configurations of CLT panels, divided based on the free flow direction of moisture, are explained. Regarding RH cycle tests, CLT specimens were conditioned in climatic chambers for 324 days at constant temperature 20 (ºC) with a humidity cycle varying every 21 days between 30% and 90%, getting constant at 65% after the first 142 days. Results show that, in the main face, drying periods present tensile strain while wetting periods present compressive strains in the longitudinal direction. But, in the tangential direction, restrained strains tend to reduce significantly from first to last drying cycles for all test configurations. Moreover, in the lateral face, drying periods present tensile strains while wetting periods present compressive strains in the tangential direction. Experimental results confirmed that the ratio between tangential and longitudinal directions tends to decrease with the number of RH cycles, and successive RH cycles do not cause cumulative strains on CLT panels.
Catarina Silva; Jorge M. Branco; Zabih Mehdipour; José Xavier; Arthur S. Rebouças; Paulo B. Lourenço. Strain variation analysis of cross-laminated timber elements under cyclic moisture. Journal of Building Engineering 2021, 41, 102373 .
AMA StyleCatarina Silva, Jorge M. Branco, Zabih Mehdipour, José Xavier, Arthur S. Rebouças, Paulo B. Lourenço. Strain variation analysis of cross-laminated timber elements under cyclic moisture. Journal of Building Engineering. 2021; 41 ():102373.
Chicago/Turabian StyleCatarina Silva; Jorge M. Branco; Zabih Mehdipour; José Xavier; Arthur S. Rebouças; Paulo B. Lourenço. 2021. "Strain variation analysis of cross-laminated timber elements under cyclic moisture." Journal of Building Engineering 41, no. : 102373.
A structure may be totally destroyed due to a fire, but often it is only partially damaged and parts of it may still be salvaged and reused. For buildings with significant historic and cultural value, it is of utmost importance that these elements, which were only partially damaged, can still be recovered as to preserve the authenticity of the structure. In the case of timber elements after a fire, it is common to find damage on the cross-section exterior part, whereas the inner part presents still a non-damaged section. Therefore, the element is often found with an exterior irregular shape, either due to its original shape prior decay or due to the exposure to fire, that does not coincide with the inner residual cross-section. Moreover, it is essential to perform a preliminary safety analysis to verify which elements can be preserved and to what extent interventions could be needed. The objective of this work is to apply a methodology that allows to calculate the residual cross-section of partially burnt timber elements structures as to calculate the resistant and apparent sections for geometry assessment and to implement that information in three-dimensional structural models. For this purpose, this work proposes a methodology based on a combination of drilling resistance tests together with laser scanner measurements. The methodology was first tested and calibrated within a controlled laboratory environment and then validated onsite using elements from a building exposed to a past fire. The Casa de Sarmento (Sarmento's House) in Guimarães (Portugal) was used as case study, where various structural damages due to a past fire were found.
Manuel Cabaleiro; Carlos Suñer; Hélder S. Sousa; Jorge M. Branco. Combination of laser scanner and drilling resistance tests to measure geometry change for structural assessment of timber beams exposed to fire. Journal of Building Engineering 2021, 40, 102365 .
AMA StyleManuel Cabaleiro, Carlos Suñer, Hélder S. Sousa, Jorge M. Branco. Combination of laser scanner and drilling resistance tests to measure geometry change for structural assessment of timber beams exposed to fire. Journal of Building Engineering. 2021; 40 ():102365.
Chicago/Turabian StyleManuel Cabaleiro; Carlos Suñer; Hélder S. Sousa; Jorge M. Branco. 2021. "Combination of laser scanner and drilling resistance tests to measure geometry change for structural assessment of timber beams exposed to fire." Journal of Building Engineering 40, no. : 102365.
The palafitic timber constructions of the central Portuguese coastline are an example of the adaptation to site-specific conditions (climate and sand landscape morphodynamics) using the available endogenous resources. Thus, in a context of environmental awareness and climate change, it is relevant to understand their features/strategies and how they perform. This work analyses the energy performance and thermal condition evaluation of a vernacular timber building–palheiro–from Praia de Mira, through in situ measurements, subjective analysis and energy simulation provided by DesignBuilder/EnergyPlus. The results show a good or satisfactory thermal performance during most of the seasons by passive means only. Despite, it was not possible to guarantee thermal comfort conditions for the occupants during winter. In the energy performance analysis, five scenarios, with different external walls, were compared. In the two scenarios that satisfy the maximum U-value for the climate zone, the current conventional building had a slightly better performance on heating and cooling (less 1.1 and 1.4 kWh/m2, respectively) than the timber building. However, the difference between the two construction solutions is not substantial in the annual energy demand (2.5 kWh/m2, 7.3%), indicating that timber structures are suitable in this mild climate area.
Jorge Fernandes; Ricardo Mateus; Helena Gervásio; Sandra Silva; Jorge Branco; Manuela Almeida. Thermal Performance and Comfort Conditions Analysis of a Vernacular Palafitic Timber Building in Portuguese Coastline Context. Sustainability 2020, 12, 10484 .
AMA StyleJorge Fernandes, Ricardo Mateus, Helena Gervásio, Sandra Silva, Jorge Branco, Manuela Almeida. Thermal Performance and Comfort Conditions Analysis of a Vernacular Palafitic Timber Building in Portuguese Coastline Context. Sustainability. 2020; 12 (24):10484.
Chicago/Turabian StyleJorge Fernandes; Ricardo Mateus; Helena Gervásio; Sandra Silva; Jorge Branco; Manuela Almeida. 2020. "Thermal Performance and Comfort Conditions Analysis of a Vernacular Palafitic Timber Building in Portuguese Coastline Context." Sustainability 12, no. 24: 10484.
Dowel-type timber joints made of wood are of particular interest for interventions on built heritage because such heritage buildings often involve timber structures. Wooden dowels offer a lower cost when compared with other connectors and conform to the tendency for using wood-based solutions to retrofit timber structures. However, there is a significant lack of information regarding the modelling of these wooden connectors’ responses, in terms of analytical expressions as numerical models. Therefore, this paper presents the results of an extensive experimental campaign of timber-to-timber joints using wooden dowels. Two wood species were considered: Chestnut as a hardwood and Spruce as a softwood. The wooden dowels were always made of massaranduba, a Brazilian hardwood. The aim of the experimental campaign was to obtain and analyse the response of this type of connection, and then to compare it with the load-carrying capacity accessed through the available analytical expressions to verify its accuracy. The test results highlighted the advantages of using wooden dowels in timber joints. Moreover, it became clear that further analysis and research studies are needed to suggest new expressions that are in accordance with the behaviour of the connection.
Ioana Teodorescu; Bárbara Pereira; Caroline D. Aquino; Jorge M. Branco. Experimental evaluation of dowel-type timber joints with wooden dowels. Proceedings of the Institution of Civil Engineers - Structures and Buildings 2020, 173, 927 -938.
AMA StyleIoana Teodorescu, Bárbara Pereira, Caroline D. Aquino, Jorge M. Branco. Experimental evaluation of dowel-type timber joints with wooden dowels. Proceedings of the Institution of Civil Engineers - Structures and Buildings. 2020; 173 (12):927-938.
Chicago/Turabian StyleIoana Teodorescu; Bárbara Pereira; Caroline D. Aquino; Jorge M. Branco. 2020. "Experimental evaluation of dowel-type timber joints with wooden dowels." Proceedings of the Institution of Civil Engineers - Structures and Buildings 173, no. 12: 927-938.
Due to fast delivery and convenience on site, prefabricated modular structures are increasingly present in the context of civil construction. Regarding the advantages of these systems, it has been addressed in the literature the potential of wood for the design of prefabricated houses with modular characteristics, resulting in optimization of costs, product quality and sustainability. When a new construction system is proposed, it is of extremely importance to understand its mechanical behavior and structural performance before its implementation. Therefore, this research aims to contribute, based on an experimental campaign, to the characterization of a new modular wall construction system made of Cryptomeria wood (Cryptomeria japonica). The experimental campaign comprehended the evaluation of the glued connection between wood elements of the unit and the load carrying capacity of a single and connected modular units. Besides, since the proposed system is constituted of an interior layer of insulated corkboard, the effect of its presence in mechanical terms was evaluated. The results showed the potential of this prefabricated modular systems in terms of resistance and identified the critical parameters to a safety design.
Caroline D. Aquino; Jorge M. Branco. Experimental evaluation of a modular timber unit filled with insulated corkboard. Journal of Building Engineering 2020, 32, 101725 .
AMA StyleCaroline D. Aquino, Jorge M. Branco. Experimental evaluation of a modular timber unit filled with insulated corkboard. Journal of Building Engineering. 2020; 32 ():101725.
Chicago/Turabian StyleCaroline D. Aquino; Jorge M. Branco. 2020. "Experimental evaluation of a modular timber unit filled with insulated corkboard." Journal of Building Engineering 32, no. : 101725.
Portuguese forests have changed in recent years. These changes were mainly boosted by the wildfires that affected a significant percentage of the softwood area. Eucalyptus is actually the dominant wood species in Portuguese forests. This is not a native hardwood, but is being planted mainly for pulp and paper production, and its availability and mechanical performance have made it very present in timber construction in the last 50 years. Within the discussion to substitute imported raw materials, mainly from softwoods, with local hardwoods for the production of engineered wood products, the study of the ability to glue eucalyptus has become a necessity. This paper presents experimental works aimed to assess the ability to glue eucalyptus elements for the production of glued laminated timber (GLT) and cross-laminated timber (CLT). Since this wood species has been known for being difficult to dry, a preliminary study on the dimensional stability under moisture content variation was performed. Then, shear strength tests were made in accordance with ASTM D143. The objective was to correlate those results with the tests performed in the following research step. In this further stage, shear strength tests of the bond line were performed following EN 14080 and EN 16351. The results obtained in all the experiments show that eucalyptus has the potential to be glued and therefore the production of GLT and/or CLT using this local undervalued wood species is potentially of high industrial interest.
Aiuba Suleimana; Caroline S. Sena; Jorge M. Branco; Aires Camões. Ability to Glue Portuguese Eucalyptus Elements. Buildings 2020, 10, 133 .
AMA StyleAiuba Suleimana, Caroline S. Sena, Jorge M. Branco, Aires Camões. Ability to Glue Portuguese Eucalyptus Elements. Buildings. 2020; 10 (7):133.
Chicago/Turabian StyleAiuba Suleimana; Caroline S. Sena; Jorge M. Branco; Aires Camões. 2020. "Ability to Glue Portuguese Eucalyptus Elements." Buildings 10, no. 7: 133.
Filipe T. Matos; Jorge M. Branco; Patrício Rocha; Nuno Mendes; Thomas Demschner; Paulo B. Lourenço. Corrigendum to “Quasi-static tests on a two-story CLT building” [Eng. Struct. 201 (2019) 109806]. Engineering Structures 2020, 212, 110530 .
AMA StyleFilipe T. Matos, Jorge M. Branco, Patrício Rocha, Nuno Mendes, Thomas Demschner, Paulo B. Lourenço. Corrigendum to “Quasi-static tests on a two-story CLT building” [Eng. Struct. 201 (2019) 109806]. Engineering Structures. 2020; 212 ():110530.
Chicago/Turabian StyleFilipe T. Matos; Jorge M. Branco; Patrício Rocha; Nuno Mendes; Thomas Demschner; Paulo B. Lourenço. 2020. "Corrigendum to “Quasi-static tests on a two-story CLT building” [Eng. Struct. 201 (2019) 109806]." Engineering Structures 212, no. : 110530.
Una malla estructural de madera es un tipo especial de estructura que establece un nuevo marco para la construcción ligera. Es posible crear una amplia variedad de formas y geometrías, garantizando así una enorme libertad arquitectónica. Sin embargo, dada la variedad de formas y la complejidad que pueden presentar es necesario utilizar diferentes herramientas e información para avalar este complejo proceso. El presente trabajo explora la interacción entre la información y las diferentes herramientas utilizadas por arquitectos e ingenieros durante el proceso de diseño y construcción de una malla elástica de madera, presentando un caso de estudio real con 42m2 (6,5mx6,5m), después de la elevación, construida con la intención de explorar el diseño y el proceso constructivo junto con métodos de integración de “form finding”. En el trabajo, los objetivos de optimización tanto del arquitecto como del ingeniero se realizan sobre el mismo caso de estudio. Se presentará el proceso de diseño y se describirá la construcción de la malla elástica.
J. G. Fernandes; J. M. Branco; J. P. Barroso; P. H. Kirkegaard. Mallas elásticas de madera - Estructuras con un diseño integrado. Informes de la Construcción 2020, 72, 328 .
AMA StyleJ. G. Fernandes, J. M. Branco, J. P. Barroso, P. H. Kirkegaard. Mallas elásticas de madera - Estructuras con un diseño integrado. Informes de la Construcción. 2020; 72 (557):328.
Chicago/Turabian StyleJ. G. Fernandes; J. M. Branco; J. P. Barroso; P. H. Kirkegaard. 2020. "Mallas elásticas de madera - Estructuras con un diseño integrado." Informes de la Construcción 72, no. 557: 328.
Among biological agents, insect attacks may cause severe degradation of timber structures in the service life of buildings which leads to lower mechanical performance and, thus, maintenance problems over time. Additionally, compression perpendicular to the grain always features a weak spot with respect to the long-term mechanical performance of timber members and joints. In the present work, the respective strength and elastic modulus were thus investigated for insect deteriorated wood. Following a standardized geometry, small samples degraded by anobiids were extracted from beams made of sweet chestnut wood (Castanea sativa Mill.) that were removed from service. Visual assessment of the external wood surfaces was then performed to identify areas infested by insects. Afterwards, destructive monotonic compression tests were carried out perpendicularly to the grain on the damaged area to determine the loss of compressive strength and elastic modulus. The experimental results showed that the loss of compressive strength and elastic modulus might be linearly correlated to the wood density loss for small samples infested by insects. Nonetheless, future work should focus on determining accurately the density loss in the insect-deteriorated part through non- or semi-destructive tests, in order to establish stronger relationships with the mechanical properties loss investigated.
Maxime Verbist; Jorge M. Branco; Lina Nunes. Characterization of the Mechanical Performance in Compression Perpendicular to the Grain of Insect-Deteriorated Timber. Buildings 2020, 10, 14 .
AMA StyleMaxime Verbist, Jorge M. Branco, Lina Nunes. Characterization of the Mechanical Performance in Compression Perpendicular to the Grain of Insect-Deteriorated Timber. Buildings. 2020; 10 (1):14.
Chicago/Turabian StyleMaxime Verbist; Jorge M. Branco; Lina Nunes. 2020. "Characterization of the Mechanical Performance in Compression Perpendicular to the Grain of Insect-Deteriorated Timber." Buildings 10, no. 1: 14.
A two-story full-scale CLT platform-type building of 4.5 m × 9.1 m in plan, with a height of 5.04 m, was tested under quasi-static monotonic and cyclic loading. The main objectives were to evaluate the global response of the structure, the performance of the shear walls, the behaviour of the connectors (hold-downs and angle brackets) and the frequency response of the structure during the tests. Lateral loads were applied on the storeys inducing torsion to the building. Loading procedure, number and disposition of connectors varied between tests. However, it is important to note that, in order to avoid a possible overlap of effects, the metal connectors hold-downs and angle-brackets only have been placed in CLT shear walls in each loading direction. In terms of performance, longitudinal direction presented a stiffer behaviour when compared to the transverse, where it was possible to verify greater sliding in the longitudinal direction and global rocking in the transverse direction. The results of this experimental campaign will be used for further analytical and numerical analyses, in order to help to implement more detailed seismic analysis, namely pushover, of CLT constructions.
Filipe T. Matos; Jorge M. Branco; Patrício Rocha; Thomas Demschner; Paulo B. Lourenço. Quasi-static tests on a two-story CLT building. Engineering Structures 2019, 201, 109806 .
AMA StyleFilipe T. Matos, Jorge M. Branco, Patrício Rocha, Thomas Demschner, Paulo B. Lourenço. Quasi-static tests on a two-story CLT building. Engineering Structures. 2019; 201 ():109806.
Chicago/Turabian StyleFilipe T. Matos; Jorge M. Branco; Patrício Rocha; Thomas Demschner; Paulo B. Lourenço. 2019. "Quasi-static tests on a two-story CLT building." Engineering Structures 201, no. : 109806.
Before coming up with any important decision of intervention in the restoration process of existing buildings, the assessment of the conservation state is required as regards heritage timber structures and especially for those that suffered a lack of maintenance in their service life. In that context, three timber roof structures from the Convent of Christ in Tomar, Portugal, were selected and investigated. To this end, a research methodology was introduced and applied to these case studies into four main steps: (1) visual inspection; (2) non-destructive wood diagnosis; (3) structural safety evaluation; (4) prevention and intervention measures. For the visual inspection, every element and joint constituting the roof structures received scrutiny through assessing the wood species, the different construction stages and, last but not least, their respective geometry. As regards the encountered pathologies, structural disorders (e.g. accidental failure, serviceability defects…) and wood deteriorations due to biological agents (e.g. wood-destroying fungi or insects), which ineluctably leads to a likely decrease of the mechanical performances of the roof structure, were reported. To estimate the residual element cross section and elastic modulus, wood diagnosis was carried out using three relevant non-destructive tests: (1) ultrasonic pulse velocity; (2) drilling resistance; (3) impact penetration. From the collected data, the three timber roof structures were modelled on a commercial software to check their safety and integrity. Based on those outcomes, some prevention and intervention measures haves been lastly proposed case by case.
Maxime Verbist; Filipe T. Matos; Jorge M. Branco. Structural and health assessment of historic timber roofs from the Convent of Christ in Tomar. Journal of Civil Structural Health Monitoring 2019, 9, 491 -511.
AMA StyleMaxime Verbist, Filipe T. Matos, Jorge M. Branco. Structural and health assessment of historic timber roofs from the Convent of Christ in Tomar. Journal of Civil Structural Health Monitoring. 2019; 9 (4):491-511.
Chicago/Turabian StyleMaxime Verbist; Filipe T. Matos; Jorge M. Branco. 2019. "Structural and health assessment of historic timber roofs from the Convent of Christ in Tomar." Journal of Civil Structural Health Monitoring 9, no. 4: 491-511.
Existing timber structures often present elements with different levels of decay and the choice to maintain them comes from the structural assessment, made by a civil engineer on the basis of the results coming from the on-site survey. The choice may also rely on visual inspection combined non-destructive tests. In that case, the choice to maintain an element will greatly depend on the accuracy and reliability of the results obtained through these tests. This work aims to assess the properties of timber elements through non-destructive tests, using resistance drilling, pin penetration, ultrasound, and acoustic emission tests. The tests were carried out on three timber elements from two old timber roof trusses. The results are analysed regarding the specimen size and the use of multiple non-destructive test parameters. Decay was initially identified by means of visual inspection and different levels of decay were identified taking into account their influence on the non-destructive test results and on the predictability of models based on single and multiple regression analysis. Moreover, the obtained classification was found to increase the reliability on the prediction of density.
Taoyi Yu; Hélder S. Sousa; Jorge M. Branco. Combination of non-destructive tests for assessing decay in existing timber elements. Nondestructive Testing and Evaluation 2019, 35, 29 -47.
AMA StyleTaoyi Yu, Hélder S. Sousa, Jorge M. Branco. Combination of non-destructive tests for assessing decay in existing timber elements. Nondestructive Testing and Evaluation. 2019; 35 (1):29-47.
Chicago/Turabian StyleTaoyi Yu; Hélder S. Sousa; Jorge M. Branco. 2019. "Combination of non-destructive tests for assessing decay in existing timber elements." Nondestructive Testing and Evaluation 35, no. 1: 29-47.
Timber-framed architecture is an important heritage common of many countries. However, this is being lost due to natural decay but also climatic changes and natural hazards. To preserve it, it is important to understand the influence of such actions. Timber joints significantly affect the mechanical performances of timber-framed buildings, being the weakest element. In this paper, results are presented from cyclic pull-out test conducted on traditional timber joints subjected to wind driven rain and flood, both unreinforced and retrofitted, and a comparison is made with those obtained from sound specimens. Wetting-drying cycles mainly influence the stiffness and dissipation capacity.
Elisa Poletti; G. Vasconcelos; J.M. Branco; B. Isopescu. Effects of extreme environmental exposure conditions on the mechanical behaviour of traditional carpentry joints. Construction and Building Materials 2019, 213, 61 -78.
AMA StyleElisa Poletti, G. Vasconcelos, J.M. Branco, B. Isopescu. Effects of extreme environmental exposure conditions on the mechanical behaviour of traditional carpentry joints. Construction and Building Materials. 2019; 213 ():61-78.
Chicago/Turabian StyleElisa Poletti; G. Vasconcelos; J.M. Branco; B. Isopescu. 2019. "Effects of extreme environmental exposure conditions on the mechanical behaviour of traditional carpentry joints." Construction and Building Materials 213, no. : 61-78.
Heritage timber structures are found worldwide evidencing intricate configurations, not only due to the arrangement between elements, which sometimes leads to complex connections with hidden elements, but also due to elements with variable cross-sections and often with signs of decay. Due to its historical value, the structural safety of these structures must be assessed periodically and the conservation state verified. The presence of decay and the resulting reduction of effective cross-section must be assessed both at the present time as well as its probable evolution in the future if no intervention is made. Due to this need, in the present work, a methodology is proposed to analyse the structural safety of timber structures using tridimensional parametric models where the geometry of the cross-section of each element is a variable regarding the presence of decay. The model allows to determine the structure’s volume more accurately, to identify the present condition of the structure and make predictions of possible future decay scenarios. Information obtained by laser scanner and drilling resistance tests are considered as prior information for the model. As to demonstrate the validity of the proposed methodology, the creation of a tridimensional parametric model is applied to a case study corresponding to the timber ceiling structure of the Knights’ Room of the Convent of Christ in Portugal.
Jaime Cuartero; Manuel Cabaleiro; Hélder S. Sousa; Jorge Branco. Tridimensional parametric model for prediction of structural safety of existing timber roofs using laser scanner and drilling resistance tests. Engineering Structures 2019, 185, 58 -67.
AMA StyleJaime Cuartero, Manuel Cabaleiro, Hélder S. Sousa, Jorge Branco. Tridimensional parametric model for prediction of structural safety of existing timber roofs using laser scanner and drilling resistance tests. Engineering Structures. 2019; 185 ():58-67.
Chicago/Turabian StyleJaime Cuartero; Manuel Cabaleiro; Hélder S. Sousa; Jorge Branco. 2019. "Tridimensional parametric model for prediction of structural safety of existing timber roofs using laser scanner and drilling resistance tests." Engineering Structures 185, no. : 58-67.
Despite the fact that, from the mechanical point of view, there is no ageing issues of timber elements when they are properly used, many old timber structures require important interventions because of changes in uses (which modifies the regulating rules for example), of material decay (misuse of timber) or possibly of a faulty design or construction. In particular, timber floors in old structures often present large deflections and most the time had been designed for a maximum load much lower than the one prescribed by contemporary rules. After an introduction about timber floors and a short review about the reinforcement technics that exist, the present paper presents a new proposal for their reinforcement. The solution developed in the present paper uses a Cross Laminated Timber (CLT) panel screwed over the existing floor, keeping a small gap between the panel and the existing joists. In this way, the new “composite” floor presents higher stiffness and the gap is used for horizontal line runs. For the design of such a “composite floor”, modified Johanssen’s equations (including the gap between the CLT panel and the joists) are proposed and their application on a case study is presented.
Bertrand Roensmaens; Laurent Van Parys; Jorge Branco; Thierry Descamps. Proposal of a CLT Reinforcement of Old Timber Floors. RILEM Bookseries 2019, 1575 -1584.
AMA StyleBertrand Roensmaens, Laurent Van Parys, Jorge Branco, Thierry Descamps. Proposal of a CLT Reinforcement of Old Timber Floors. RILEM Bookseries. 2019; ():1575-1584.
Chicago/Turabian StyleBertrand Roensmaens; Laurent Van Parys; Jorge Branco; Thierry Descamps. 2019. "Proposal of a CLT Reinforcement of Old Timber Floors." RILEM Bookseries , no. : 1575-1584.