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Introduction
Publications
Publications (110)
El patrimonio industrial se ha convertido recientemente en un recurso turístico y cultural, sin olvidar su aspecto social. En España desde el año 2000, existe un Plan Nacional de Patrimonio Industrial (PNPI) que identifica elementos industriales que son de interés patrimonial. Sin embargo, eso no les otorga automáticamente una protección ni existe...
El cuerpo normativo de los Eurocódigos está en fase de desarrollo de una segunda generación que será publicada previsiblemente en 2025. En el borrador del documento dedicado a la madera, en la parte 1-1 del proyecto de norma Europea EN 1995, el capítulo 6º trata de la durabilidad, incluyendo la madera y los herrajes. Su contenido representa un avan...
Si bien la madera ha sido un material muy utilizado en el ámbito industrial en época preindustrial y principios de la Revolución Industrial, en épocas más recientes, el acero y el hormigón desplazaron notablemente a la madera en dicho ámbito. Sin embargo, se siguió y se sigue utilizando madera en algunas aplicaciones industriales debido a las venta...
En un contexto de cambio climático, se espera que los eventos extremos asociados a procesos hidrológicos incrementen su frecuencia y magnitud, aumentando los posibles daños y pérdidas a infraestructuras y personas. Existe una necesidad de proponer soluciones innovadoras que permitan mitigar los peligros y riesgos futuros. En este sen-tido, las solu...
The use of wood in construction requires knowledge of the mechanical properties and the particularities that wood presents in comparison with other materials used for structural purposes such as steel, concrete, brick, or stone. The introduction mentions the environmental advantages that justify the use of wood today. The orthotropy of wood is one...
Wood-based sandwich panels are building products composed of two skins attached to a lightweight continuous core in which at least one skin is made of wood-based products, contributing to the use of renewable forest goods. Since the connection between the skins and the core is often provided by adhesive bonding, its characteristics affect the mecha...
En este artículo se presenta un estudio sobre la influencia de la rigidez de las uniones en pórticos a dos aguas de acero. Se combinan doce valores diferentes de rigidez de placa de anclaje, hombro y cumbrera. Se combinan diez geometrías (8- 20 m de luz, 3.5-10 m de altura de pilares y 10-20% de pendiente de cubierta). Se consideran tres niveles de...
The modulus of elasticity and bending strength of 45 structural Salzmann pine timber pieces with nominal dimensions of 150x200x5400 mm³ from an existing 18th century structure were estimated by semi-destructive density estimation probing method (drilling chips extraction) and acoustic wave velocity (stress and ultrasound wave). Bending strength, mo...
Natural hazards remain recurrent processes that often disrupt the status quo of communities and put the future welfare of people at risk. In the Pyrenees, extreme events related to floods, rockfall, landslides or snow avalanches have recurrently affected transport corridors and human settlement. Coping with such impacts in future requires paradigm...
The timber structural members of a seven-story building from the end of the 18th century were evaluated following a procedure based on previous research works. The structure consisted of timber-framed brick walls and heavy timber floors with mortar filling. Non-destructive measurements were taken in 13 sampling areas of the floors and framed walls....
In-situ assessment of timber members by acoustic measurement usually requires specific procedures (indirect and semidirect measurement) compared with those used in the laboratory (direct) and over longer distances. This research aims to determine which procedure is the most suitable. Acoustic Non-Destructive Testing measurements were taken in 21 15...
Many buildings in Spain constructed with "pitch pine" beams are, nowadays, under rehabilitation processes. In some cases the decision on maintaining, or not, the existing timber structure is a key issue. The commercial name "pitch pine" comprises several species in the group of Southern Yellow Pines, being the "Longleaf pine" or "Georgia pitch pine...
This work establishes the main guidelines to produce high-performance Eucalyptus globulus Labill fingerjointed solid timber and glued laminated timber laths and analyse their potential for application in mul-tilayer strained gridshells. To this end, a proposal for strength grading of eucalyptus solid timber is firstly provided, combining visual and...
![Figure 4. Bending test. (a) Diagram of EN 408 test [14] to determine...](profile/Luis-Esteban-2/publication/343047252/figure/fig4/AS:914671439736832@1595086073234/Bending-test-a-Diagram-of-EN-408-test-14-to-determine-modulus-of-elasticity-F-load_Q320.jpg)
Canary Island pine (Pinus canariensis C.Sm. ex DC) is a species endemic to the Canary Islands (Spain) that was for centuries overexploited for its wood and resin. Due to the state of the pine forest, more than 10,000 hectares were reforested in the middle of the 20th century. Now, under the silvicultural management plan, thinning operations have al...
We carried out morphological and dimensional analysis of the detritic elements deposited in the galleries of two termite species of the Kalotermitidae family present in Spain known as drywood termites (Cryptotermes brevis (Walker, 1853) and Kalotermes flavicollis (Fabricius, 1793)). This was in order to gauge the possibility of differentiating the...
Nondestructive testing (NDT) includes several highly efficient techniques for the estimation of the physical and mechanical properties of structural timber. Apart from visual grading, scientific research using Nondestructive testing on timber has been used in Spain since the 1990s. Nondestructive testing can be used for two different purposes: timb...
Nondestructive testing (NDT) includes several highly efficient techniques for the estimation of the physical and mechanical properties of structural timber. However, NDT results are affected by several factors [moisture content (MC), temperature, specimen dimensions, sensor positioning and grain angle, timber-sensor coupling, etc.], of which wood M...
The frequent highly irregular geometry of the elements in existing timber structures complicates the structural verification of members and influences the use of non-destructive testing (NDT), affecting the inspection time, cost and results obtained. This process therefore needs to be improved. The main aim of this paper is to analyse
how to obtain...
Timber elastic gridshells represent a promising solution for medium and long span lightweight roofs featuring free or modular geometries. This technique enables the construction of large simple or double curved shells by bending standard timber elements on site, incorporating potential for a high degree of industrialization and standardization.
Dou...
Plank timber vaulting is a constructive system that uses vertically laminated timber arches. It was developed in Europe in the seventeenth century to adapt existing buildings to the Baroque style. A survey was undertaken in the city of Madrid, Spain, to make an inventory of this type of vaults in seventeenth to nineteenth century buildings. 22% of...
Visual strength grading is widely used to estimate mechanical properties of structural timber. National visual grades are allocated to strength classes according to European standard EN1912. The recent discussion about the proper function of visual strength grading standards and the assignment of strength classes shows the need for further research...
Deconstruction and demolition waste are a concern today because many timber components have a high resource value, providing both environmental and economic motivations for recovery and reuse. Reclaimed timber is therefore an important potential source of timber for new construction, and one for which nondestructive techniques have a key role to pl...
The use of non-destructive techniques (NDT) to estimate physical-mechanical timber properties is an effective way of assessing and conservation of built heritage. Some research works have applied NDTs in different species with different piece’s dimensions and have showed good correlations between timber properties and the Time-of-Flight (ToF) with...
Physical and mechanical properties of the timber structure of a seven-story building from the end of 18th century, located in Madrid, Spain, were estimated using nondestructive techniques. These consisted of stress wave measurements and probing tests based on needle penetration depth and drilling residue collection, to estimate the modulus of elast...
La aplicación de las técnicas no destructivas (TND) en la estimación de las propiedades físico-mecánicas de la madera presenta resultados efectivos en la inspección y conservación del patrimonio construido. Diversos trabajos de investigación han mostrado buenas correlaciones entre las propiedades de la madera y la velocidad obtenida a través del ti...
The density of 45 structural Salzmann pine timber pieces with nominal dimensions of 150 × 200 × 5000 mm ³ from an existing 18th century structure was estimated using the following non-destructive methods: needle penetration resistance (NPR), screw withdrawal resistance (SWR) and drilling chips extraction (DCE). Non-destructive testing (NDT) measure...
Time-of-flight (ToF) measurements were conducted on twelve 76×226-mm ² in cross-section, 4.52-m long specimens of Norway spruce timber pieces from a dismantled 19 th -century building in Barcelona (Catalonia, Spain). Two commercially available acoustic devices were used: the USLab ultrasound device with conical 22 and 45 kHz sensors and the MicroSe...
Timber lattice shells are multi-layered structures of great interest for medium and long span lightweight solutions in structural and aesthetic terms. They are constructed by bending initially straight laths. This curving process can lead to high initial stresses in the laths and the possibility of overstressing under service loads. However, these...
Needle penetration resistance (NPR), screw withdrawal resistance (SWR), core drilling (CD) and drilling chips extraction (DCE) are nondestructive and semi-destructive techniques used to estimate density in timber structures. In most of the previous studies, these techniques were tested in clear sawn timber and clear specimens. The goal of the prese...
Density values are essential for the characterization of wood elements in existing structures. A new method for the in-situ density estimation of timber pieces is proposed based on weighting the residue generated by conventional drilling. This research includes the design and development of a residue collector device coupled to a conventional drill...
Non-destructive techniques (NDTs) are well suited for rapid estimation of timber properties, but NDT results are affected by several factors, the most important of which is the moisture content (MC) of wood. Much of the research in this context was limited to ultrasound measurement of a few wood species, mainly to Norway spruce. The present paper i...
Different methods, including bending tests and small and medium size shear tests, were used to assess the skin to stringer glue line shear strength of Radiata Pine Cross-Laminated Timber Derived Stressed-Skin Panels (CLT SSP). Bending test shear strengths were estimated using the mechanically jointed beam theory (gamma method) for Cross-Laminated T...
En este estudio se analizan las singularidades de la aplicación de las técnicas no
destructivas en piezas de madera de gran longitud procedentes de estructuras
existentes. Actualmente, se trata de un proyecto en desarrollo, por lo tanto, este
documento se centra en las particularidades geométricas de madera estructural
procedente de la rehabilitaci...
The mechanical properties of timber can be estimated from wave propagation velocity by measuring wave time-of-flight (ToF). However, a time-lag complicates the measurements, which produces an apparent velocity dependency on length and this species and instrument dependent property is also influenced by knottiness. This research is dealing with time...
This paper presents a simplified method of analysis and design for the repair of deteriorated timber beam ends using glass fiber–reinforced product (GFRP) bonded rigid plates. It assesses the load-bearing capacity of the plate-timber connection and assumes two failure modes: shear stresses at the bonding interface and in the timber piece. An experi...
Mechanical properties of timber can be estimated from wave propagation velocity by measuring the wave time of flight. A time lag is observed in wave time of flight depending on the species-knottiness and device, usually obtained by end to end measurements at different distances. The aim of this research is the determination of that time lag by mean...
The traditional regression method was compared with an artificial neural network for obtaining the static modulus of elasticity (MOEstatic) of Pinus radiata timber using the dynamic modulus of elasticity determined by ultrasound in the first case and ultrasonic wave propagation velocity in the second case.
Whereas the regression model is capable of...
The effect of timber length on Time-Of-Flight acoustic longitudinal measurements was investigated on the structural timber of four Spanish species: radiata pine (Pinus radiata D. Don), Scots pine (Pinus sylvestris L.), laricio pine (Pinus nigra Arn.), and maritime pine (Pinus pinaster Ait.). Time-Of-Flight longitudinal measurements were conducted o...
The use of large cross-section timber for structural purposes has increased in Spain, and knowledge of its properties is strategically necessary. The Spanish visual strength-grading standard UNE 56544 (2011) efficiency applied to large cross-section structural timber was analyzed using a sample of 363 specimens of radiata pine (Pinus radiata D. Don...
The stress distribution of timber tenoned scarf joint subjected to tension force was analysed by means of finite element method. This analysis was compared and validated with results from an experimental work on 42 specimens of Scots pine wood (Pinus sylvestris L.) with 48 × 148 mm in cross-section and 1932 mm, in length, manufactured with a tenone...
The structural behaviour of halved and tabled tenoned scarf joint subjected to tensile stresses was experimentally analysed to find the different failure modes. A total of 42 specimens of Scots pine wood (Pinus sylvestris L.) were made. Specimens were divided into 8 groups corresponding to different joint geometries. Three different failure modes w...
Historic timber structures are composed of a large variety of carpentry joints; which normally have the most influence over their structural performance. Such diversity is principally related to the function, type, structural behaviour and shape of the joints. Furthermore, structurally distinct variants of the same type of joint were locally develo...
Detailed morphological and dimensional analysis of the detritus deposited in the galleries of woodboring insects was performed for some of the most common xylophagous insect larvae in timber construction in Spain. The samples studied belong to six species of four common families of borers:
Cerambycidae, Anobiidae, Curculionidae and Lyctidae. The sa...
A group of databases making a total of approximately 9300 sawn timber pieces from Spanish coniferous species, tested according to European standards and visually graded mainly according Spanish standards were analyzed. The percentiles ratio 20th/5th of bending strength, modulus of elasticity and density distribution were obtained for different comb...
The main objective of this paper is to define the reference conditions and to propose modification factors to standardize the variables recorded by different nondestructive techniques. This practice will make it possible to generate consistent practical data while developing a procedure for the standardization of timber structure assessment.
The no...
Both non-destructive and semi-destructive tests can potentially be very efficient methods for the assessment of structural timber density. This paper describes an investigation into the suitability of three techniques: core drilling, probing, and screw withdrawal. It presents the results after testing 150 pieces of large cross-section (80 mm × 120...
Three samples of sawn Radiata pine (Pinus radiata D. Don) timber, consisting of 150 pieces with dimensions of 80 mm × 120 mm × 2400 mm, 80 pieces with dimensions of 150 mm × 200 mm × 4500 mm, and 75 pieces with dimensions of 150 mm × 250 mm × 5600 mm, were visually graded according to the Spanish standard UNE 56544 (2011) to analyze the influence o...
This presents an exploratory analysis of a method for the determination of elastic constants using strain gauges in compression tests. The elastic constants of Scots pine (Pinus sylvestris L.) wood from the “Valsaín” sawmill (Segovia, Spain) were obtained. Compression tests were performed on small clear specimens, varying grain direction with respe...
In this study the static (μe) and kinetic (μd) coefficients of friction were obtained for Pinus sylvestis L. sawn timber of Spanish origin. Friction between transverse surfaces sliding perpendicular to the grain (tangential direction) and radial surfaces sliding parallel to the grain was analyzed. A specifically designed device was used for tests,...
Bending properties have been determined by mechanical testing [modulus of elasticity (MOE) and modulus of rupture (MOR)] and by means of longitudinal (L) and transverse (T) vibration nondestructive methods on 150 sawn timber pieces of Pinus radiata D. Don, with the dimensions of 80 x 120 mm cross-section and 2500 mm long, from Catalonia, Spain. The...
In the present study, non-destructive parameters and mechanical properties have been measured on the principal structural Spanish sawn timber species, Scots pine (Pinus sylvestris L.). Non-destructive testing and three-point bending tests according to DIN 52-186 1978 were conducted on 216 specimens. Specimens were studied at six different temperatu...
Ultrasonic sound velocity measurements with hand-held equipment remain due to their simplicity
among the most used methods for non-destructive grading of sawn woods, yet a dedicated
normalization effort with respect to strength classes for Spanish species is still required.
As part of an ongoing project with the aim of definition of standard testin...
This paper presents a simplified method of analysis and design for repair using bonded rigid plates of timber beams with localized damage. This method assesses the load-bearing capacity of the connection between plate and timber and proposes two failure modes: shear stresses at the bonding interface and in the timber piece. An experimental campaign...
Bending strength, modulus of elasticity and density were obtained for 981 specimens of Spanish Sweet Chestnut (Castanea sativa Mill.) sawn timber from 5 provenances. Four-points bending tests were made three sizes (40x100x2500, 40x150x3500 and 70x150x3500 mm) according to EN 408 (CEN EN 408:2011).Visual
grading criteria were established, resulting...
The finite element method was used to investigate the influence of size and position of
cylindrical knots on load capacity considering the elasticeplastic constitutive law of Scots
pine timber. A finite element model for a four points bending test was generated considering
four different knot conditions in the beams: without knot; knot as a hole; l...
The purpose of this study is to determine the stress distribution in the carpentry joint of halved and tabled scarf joint with the finite element method (FEM) and its comparison with the values obtained using the theory of strength of Materials. The stress concentration areas where analyzed and the influence of mesh refinement was studied on the re...
The non-destructive testing (NDT) of timber using the longitudinal vibration method is based on the natural frequency of wood which is in relation to its quality. In the present paper, the suitability of this tool is investigated and the results of grading 395 pieces are presented. Structural timber of Radiata pine (Pinus radiata D. Don.), Scots pi...
The physical and mechanical properties (density, modulus of elasticity, and modulus of rupture) of standard and humidityresistant types of particleboard and fiberboard were determined by standardized test and wave propagation velocity, obtained from the natural frequency in a nondestructive longitudinal vibration test. Four batches of 66 specimens...
A finite element model was used to simulate timber beams with defects and predict their maximum load in bending. Taking into account the elastoplastic constitutive law of timber, the prediction of fracture load gives information about the mechanisms of timber failure, particularly with regard to the influence of knots, and their local grain deviati...
![Fig. 3. Tetraedro cuadrático TETRA 10 [2].](profile/Jose-Aira-Zunzunegui/publication/278829772/figure/fig1/AS:652226846547968@1532514406000/Tetraedro-cuadratico-TETRA-10-2_Q320.jpg)
![Fig. 4. Contacto sin penetración nodo a nodo [2].](profile/Jose-Aira-Zunzunegui/publication/278829772/figure/fig2/AS:652226846547969@1532514406016/Contacto-sin-penetracion-nodo-a-nodo-2_Q320.jpg)
The purpose of this study is to determine the stress distribution in the joint carpenter of halved and tabled joint with the finite element method and its comparison with the values obtained using the theory of Strength of Materials. The stress concentration areas where analyzed and the influence of mesh refinement was studied on the results in ord...
La simulación numérica de cualquier material requiere del conocimiento de sus propiedades. En el caso de las uniones tradicionales, el coeficiente de rozamiento del material es fundamental en el comportamiento de la misma y habitualmente su valor es tomado de bibliografía de referencia. En el presente trabajo se diseñó un ensayo de determinación de...
This paper describes the design of a procedure for the upgrading of timber floor joists with decayed ends using steel profiles connected to timber from the upper side of the flooring. The reinforcement consists on a steel S275 U cold formed shape with a plate inserted into timber and connected by means of screwing into the wood.
For the experimenta...
The bonding quality of epoxy glued timber and glass fibre reinforced polymers (GFRP) was evaluated by means of compression loading shear test. Three timber species (Radiata pine, Laricio pine and Oak) and two kinds of GFRP (plates and rods made with polyester resin reinforced with mat and roving glass fibre) were glued and tested using three epoxy...
RESUMEN El principal objetivo de este estudio es evaluar la influencia de las fendas de secado en las propiedades mecánicas de vigas de madera. Para esto, se utilizan 40 vigas de Pino silvestre (Pinus sylvestris L) de 4200 mm de longitud y 150x200 mm de sección que fueron ensayadas según norma EN 408. Las fendas se registran detalladamente atendien...
This paper describes the design of a procedure
for the upgrading of timber floor joists
with decayed ends using steel profiles connected
to timber from the upper side of the
flooring. The reinforcement consists on a
steel S275 U cold formed shape with a plate
inserted into timber and connected by means
of screwing into the wood.
For the experimenta...
Detailed measurements of drying fissures were carried out on 28 pieces of gross cross-section structural Scots pine timber. Different parameters have been proposed to measure their magnitude: length, depth, thickness and slope of grain, as well as an index of area in the neutral axis plane (ratio of effective to total surface). The parameters of fi...
A procedure for the reinforcement of timber floor joists in ancient buildings using steel U shape cross sections screwed to timber from the upper side is described. Bending tests of 3 groups of 10 beams were carried out obtaining the stiffness and load carrying capacity. The first one was composed by pieces of glued laminated timber of Spruce with...
