Properties Of Timber Research Articles

Optimization of Synergetic Seismic and Energy Retrofitting Based on Timber Beams and Bio-Based Infill Panels: Application to an Existing Masonry Building in Switzerland

This paper presents an optimization process for the design of a novel synergetic seismic and energy retrofitting strategy that combines the favorable mechanical properties of timber and the attractive thermal insulation properties of bio-based materials. The novel method, defined as Strong Thermal and Seismic Backs (STSB), comprises the attachment of timber frames and bio-based thermal insulation panels on the vertical envelope and the facade walls of existing masonry buildings, thus improving both the seismic behavior and the energy performance of these buildings. This strategy is integrated and visualized in a novel synergetic framework for the holistic evaluation of the seismic behavior, the energy performance and the carbon footprint of existing buildings, defined as the Seismic and Energy Retrofitting Scoreboard (SERS). The benefit of the novel retrofitting strategy is quantified based on the numerical simulation of the seismic behavior of an unreinforced masonry building located in Switzerland, an assessment of the energy performance of the building and an evaluation of the carbon footprint of the proposed retrofit solution. Three retrofitting alternatives are investigated for the synergetic seismic and energy retrofitting of the building, comprising timber beams and two different bio-based materials for the thermal insulation of the vertical envelope of the building: cork and recycled natural grass. The optimal seismic and energy retrofitting strategy for the building among the alternatives assessed in this study is chosen based on a Multi-Criteria Decision Making (MCDM) procedure.

Shaking table investigation of a low-cost and sustainable timber-based energy dissipation system with recentering ability

SummaryThe aim of this paper is to demonstrate the efficiency of a low-cost and sustainable timber-based energy dissipation system with recentering ability, which can be used as a seismic isolation system or a tuned mass damper for the seismic protection of structures in developing or developed countries. The system, defined as Dovetail with SPrings (Dove-SP), utilizes the attractive properties of timber to store CO2, thus reducing the carbon footprint of the existing energy dissipation systems: It comprises two timber slabs that are designed to slide against each other in a motion that is restrained by a dovetail sliding joint. Two sliding interfaces that allow this sliding motion at an attractively low friction coefficient are experimentally investigated: A PVC sand-wich (PVC-s) sliding interface, comprising a thin layer of sand that is sand-wiched between two PVC layers and a timber sand-wich sliding interface consisting of a thin layer of sand encapsulated between two beech timber surfaces. A set of low-cost steel springs is designed and installed on both sides of the dovetail joint to recenter the structure back to its original position after the end of an earthquake ground motion excitation. A novel, low-cost and deformable wood material fabricated from delignified balsa wood is used to reduce the pounding effects before the activation of the steel springs. The seismic behavior and the recentering ability of the novel timber-based energy dissipation system subjected to an ensemble of recorded earthquake ground motion excitations was experimentally investigated through a large-scale shaking table investigation at ETH Zurich.

Grain angle determination of silver birch by laser light scattering and tensile fracturing

Reliable non-destructive methods for grain angle determination are essential for the evaluation of mechanical properties of timber. In the present study, the detection of grain angle by means of laser light scattering patterns is investigated on small-scale specimens and timber boards of silver birch, along with the relationship to fracture angle and tensile strength. Results on small-scale specimens indicate applicability of laser scattering method, as the detected grain angles and the fracture angles show a strong correlation, r = 0.94. Three-dimensional grain angles, derived from surface grain angles, show a well defined relationship to strength, which can be described with wood-based failure criteria from literature. Furthermore, the paper presents new findings regarding the detection of flame wood through laser scattering. It was shown that small-scale specimens with flame wood tend to have higher grain angles, higher density, and lower strength, relative to specimens without. Nevertheless, for timber boards, the influence of flame wood on the strength was insignificant.

Modeling the tensile mechanical properties of silver birch timber boards

In this paper, the variability of tensile mechanical properties of silver birch timber is investigated and models for the prediction of tension strength and stiffness are developed. Through visual inspections and non-destructive tests, various strength and stiffness related indicators are identified. Destructive tension tests are subsequently performed for the determination of strength and stiffness. On each timber board, strains are measured at four localized regions, whereby, the stiffness of knot sections and clear wood sections are determined. Variability in strength, stiffness, density, knots, grain angle, and annual ring width are investigated along with the relationships between them. A hierarchical model is developed for the prediction of timber board stiffness and the reduction of stiffness due to knots. Models for the prediction of timber board strength and knot cluster strength are developed according to equality and inequality information of the failed specimens, by means of censored regression analysis. Results indicate suitable global and local predictions for silver birch timber, given the dynamic modulus of elasticity, median slope of grain, and knot geometries.

Drying Schedule and Effect of Seasoning on Physical and Mechanical Properties of Three Available Timber Species in Bangladesh

Drying schedules for seasoning of Gmelina arborea (Gamar), Swietenia macrophylla (Mahagony) and Mangifera indica (Mango) timber with minimum drying defects were developed. The effects of the drying on physical and mechanical properties of timber of these species were studied. New drying schedules for these three species were compared with an accelerated drying schedule. Physical properties i.e., density, water absorption and thickness swelling, as well as mechanical properties i.e., modulus of elasticity (MOE), modulus of rupture (MOR) of the wood of these species seasoned by new drying schedules and accelerated drying schedule were tested. Lower water absorption and thickness swelling were found for G. arborea, S. macrophylla and M. indica wood dried with new drying schedules of A, B and C respectively. MOE and MOR of wood of G. arborea, S. macrophylla and M. indica were significantly higher when seasoned with new drying schedules compared to those of green wood, and seasoned with accelerated drying schedule. Though seasoning was slower by using new drying schedules compared to accelerated drying schedule, the former resulted in no drying defects.

Evaluation of the bending properties of novel cross-laminated timber with different configurations made of Australian plantation Eucalyptus nitens using experimental and theoretical methods

Eucalypt species dominate the majority of hardwood plantations in Australia. Although fast-growing eucalypt plantation is not milled commercially for structural purposes due to forestry management procedures applied based on pulp and woodchips production, finding value-added use and developing mass-laminated timber products from this resource could be a sustainable alternate for the timber industries and construction sectors. The objectives of this study were to: (1) evaluate mechanical properties of CLT panel configuration with different combinations of grades from novel species fibre-managed Eucalyptus nitens (E. nitens) and (2) assess the applicability existing theoretical methods developed with typical feedstock and applying dynamic modulus of elasticity (MOEdyn) through acoustic wave velocity (AWV) in those methods to predict the properties of the CLT panels The timber boards graded and laminations were sorted into high, medium and low classes based on static MOE. Based on laminate MOE, twelve, three-layers CLT layups as High-Low-High, Medium-Low-Medium, Medium-Low-High, Medium-High-Medium bonded with polyurethane adhesive were manufactured. The results showed that the bending stiffness and apparent MOE appear to have significant differences among the configurations. The panels with high-grade boards in the top and bottom layers showed the highest average bending stiffness (3.29 × 1011 N.mm2) and apparent MOE (15.6 MPa). The panel configuration with the lowest MOE and MOR exceed the loading requirements for performance and commercial application. The collected experimental and numerical results reveal an overall good behaviour of heterogenous hardwood CLT panels and an excellent performance of novel heterogeneous configuration, with a great opportunity on construction applications.. It was also concluded that theoretical prediction using MOEdyn through AWV with an average accuracy of 96%, could be a potential method to evaluate the mechanical properties of the heterogeneous E. nitens CLT panel without mechanical testing. The heterogenous hardwood panel demonstrates a great opportunity for the employment of locally grown timber species for structurally efficient CLT panels. The results of this study an important insight into developing the high-value Australian-made CLT from pulpwood E. nitens timber resource.

Role of Cultural Values on the Consumption of Timber for Architectural Purposes

Cultural values play a unique role in consumption decision of goods and services in general. This study aimed to identify the impact of cultural values on consumption decision of timber for the architectural purposes, especially on house construction in Sri Lanka and dilemma between physical properties of timber and cultural values. The sample included a range of professional carpenters (12), contractors of housing projects (08), timber stores owners (05) and consumers (30) engage in house construction. Story telling exercise was performed with aged and experienced carpenters, timber stores owners and contractors to obtain the insights on cultural values associated with the selection of timber for architectural purposes. Semi-structured interviews were conducted by telephone with individuals selected for relevant practical knowledge of cultural values associated with various types of timber. All interviews were audio recorded and then transcribed into qualitative tool. Local knowledge, traditions and experience were key tools in interpretation of various cultural values attached to the types of timber. Cultural histories, stories, experiences and recommendations of adults and the trustworthy carpenter heavily influence the purchase intention of the consumers. Intangible benefits such as religious, social, and cultural values associated with different timber types were influential in consumer decision. Moral and spiritual wellbeing were influential compared to economic benefits. Little or poor consumer knowledge on identification of timber types and heavy dependency on carpenters and contractors on identification of timber pushes consumers towards irrational purchase decisions. Super luxury, luxury and special class timber were usually replaced by the substitutes.
 Keywords: Architectural purposes, Cultural values, Timber consumption

Density profile of alkaline-treated and densified 3-layered Paraserianthes falcataria composites

Wood densification is one of the wood modification methods that had been invented in the 1900s. However, this method was discontinued due to lack of knowledge to completely understand the process. Findings indicated that the procedure of wood densification had been remediated in recent years due to increase competition in construction materials and the needs of quality structural materials. In this study, low-density plantation timber, Paraserianthes falcataria was pretreated with alkaline before undergoing densification process. The aim of this paper was to determine the density profile of the treated and untreated densified 3-layered P. falcataria composites. Alkaline pretreatment using NaOH was done according to soda pulping method to remove partially lignin from the timber used. Wood densification was done according to hot-pressing mathematical modelled by previous researchers, to enhance the properties of timber, such as density, by compressing the timber cell wall structure to eliminate voids between walls. In this study, 3%, 6% and 9% NaOH were used with 0% NaOH as control and the results for density profile showed that densified composites treated with 6% NaOH has the highest density profile, while densified composites treated with 0% NaOH (control) has the lowest density profile.

Quebracho-Based Wood Preservatives: Effect of Concentration and Hardener on Timber Properties

Tannin polyphenols are produced by plants to protect themselves against natural decay. It is expected that impregnating low-durable timber with tannin extracts of more durable species such as quebracho (Schinopsis balansae) will enhance the durability of the specimens. This biomimetic approach combined with the in situ polymerization of quebracho–hexamine formulations can be a valid alternative to synthetic wood preservatives. In this work, we aim to evaluate the impregnation mechanism as well as the impact of tannin and hardener concentration on the mechanical and leaching resistance properties of treated wood. Compression resistance, surface hardness and leaching resistance of four different common non-durable wood species: spruce (Picea abies), pine (Pinus spp.), poplar (Populus alba) and beech (Fagus sylvatica) impregnated with different concentrations of extract and hexamine are presented. The results show that the mechanical properties of tannin-impregnated timber are enhanced, especially for timber with lower densities. Tannin and hardener concentrations tendentially do not contribute significantly to further increase MOE (modulus of elasticity), MOR (modulus of rupture) and Brinell hardness. Similar results are also obtained when the specimens are tested against leaching: tannin is significantly more water-resistant when cured with hexamine, but higher amounts of hardener do not further improve its water resistance. These findings suggest that quebracho tannin–hexamine formulations are already effective at low concentrations (5 to 10% extract with 2.5 to 5% hexamine).

Assessment of Different Measurement Methods/Techniques in Predicting Modulus of Elasticity of Plantation Eucalyptus nitens Timber for Structural Purposes

The mechanical properties of plantation Eucalyptus Nitens timber are currently assessed by applying visual stress grading (VSG) designed for the sawn timber from the mature plantation and do not represent the actual characteristics of the resource. However, the well-known limitation of VSG application for this resource led to the discovery of other methods to grade the timber to its relevant structural grade. There is potential for hardwood plantations in Australia to supply wood to the timber industry and be used in structural applications. However, it is necessary to employ criteria to evaluate the structural properties of this resource before it could be satisfactorily used for structural purposes. This research aimed to assess the use of non-destructive technique (NDT) through acoustic wave velocity (AWV), machine stress grading (MSG), and multiple linear regression (MLR) model to predict the modulus of elasticity (MOE) as a grade-determining factor. The results showed that there was a strong correlation (R2 = 0.88) between the dynamic MOE (MOEdyn) and static MOE (MOEs) of the boards, proving the NDT as a reliable method for the MOE estimations of E. nitens timber. The results from the MLR model also showed that the density and AWV are effective parameters and their combination can be practical to estimate the MOE. There was a high correlation between the MOE obtained from MSG and MOE obtained from four-point bending, demonstrating that the MSG method through the flat-wise bending can be a suitable method for fast grading. The results also indicated that the measured MOE in the edgewise direction correlates with both the flatwise and longitudinal directions. The results also showed that the E. nitens timber resource has the potential to be used in structural applications with a wide range of MOE from 7 GPa to 21 GPa.

Development of high-performance timber-concrete composite floors with reinforced notched connections

Timber-concrete composite floors with notched connections utilize the complimentary material properties of timber and concrete and exhibit a high level of composite action between two layers. However, due to the low tensile strength of concrete and stress concentration at the notched corners, cracks often develop in concrete at the service load level and can cause the brittle shear failure of concrete notches before the bending strength of timber or concrete is reached. This study presented a novel and efficient reinforcing solution in the notched connections to strengthen the concrete and restrict the crack opening in concrete. Three mass timber panel-concrete composite floors with different levels of reinforcement in the notched connections were fabricated and tested under four-point bending to examine the efficiency of the reinforced notched connections. Test results, including effective bending stiffness, peak loads, and failure patterns were compared with the composite floors without reinforcements in the notches. It was found that the reinforced notched connections improved the ultimate bending stiffness and load-carrying capacity of the composite floors, while the serviceability bending stiffness of the floors was at the same level as the unreinforced floors. The timber members in three reinforced floor specimens failed due to bending while the notched connections only experienced minor damages. With a controlled failure pattern, the use of the reinforced notched connections allows a more accurate prediction of the ultimate load-carrying capacity of the composite floors based on linear elastic analysis.

Dynamic modulus of elasticity in flexural vibration tests of Pinus sylvestris sawn timber obtained with fundamental resonant frequency and overtones

Abstract The use of resonant frequency is presently one of the most used non-destructive testing (NDT) methods to predict the mechanical properties of sawn timber. In most cases, only the first vibration mode is used to estimate the static modulus of elasticity (MOES). The use of other vibration modes (overtones) can improve the predictive capacity of this NDT. In this study, the dynamic modulus of elasticity (MOEdyn) obtained from the fundamental flexural resonant frequency and overtones of 38 structural size samples (2000 × 100 × 70 mm3) of Pinus sylvestris were analysed. The study was complemented with 16 small size samples (1000 × 20 × 8.7 mm3) of the same species to know the shear effect in samples with a very high length-to-depth ratio. For the structural size samples, a 6% decrease in the MOEdyn was detected each time the vibration mode increased. Using the second or third vibration mode offered lower errors in the prediction of the MOES than the fundamental resonant frequency. The lowest MOES prediction errors were obtained combining various vibration modes through power regression. This regression turned out to be a simple alternative to avoid the shear effect in the calculation of the MOEdyn.

Calibration and Validation of a Linear-Elastic Numerical Model for Timber Step Joints Based on the Results of Experimental Investigations.

The paper is dedicated to the numerical analysis of a single-step joint, enabling the prediction of stiffness and failure modes of both single- and double-step joints. An experimental analysis of the geometrically simplest version, the single-step joint, serves as a reference for the calibration of the subsequent finite element model. The inhomogeneous and anisotropic properties of solid timber make detailed modelling computationally intensive and strongly dependent on the respective specimen. Therefore, the authors present a strategy for simplified but still appropriate modelling for the prediction of local failure at certain load levels. The used mathematical approach is based on the linear elasticity theory and orthotropic material properties. The finite element calculations are performed in the environment of the software Abaqus FEA. The calibrated numerical model shows a good conformity until first failures occur. It allows for a satisfactory quantification of the stiffness of the connection and estimation of the force when local failure begins and is, therefore, recommended for future, non-destructive research of timber connections of various shapes.

Assessment of machine learning algorithm-based grading of Populus x euramericana I-214 structural sawn timber

The efficiency of visual grading standards applied to structural timber is often inappropriate, and timber properties are either under or over-graded. Although not included in the current UNE 56544 visual grading standard, machine learning algorithms represent a promising alternative to grade structural timber. The general aim of this research was to compare the performance of machine learning algorithms based on visual defects, non-destructive techniques and sawing systems (“cut type”) with UNE 56544:1997 visual grading in order to predict the qualifying efficiency of Populus x euramericana I-214 structural timber. Visual evaluation, ultrasound and vibrational non-destructive testing, and sawing systems register (radial, tangential and mixed) were applied to characterize 945 beams. In addition, in order to retrieve actual physical-mechanical values, density and static bending destructive testing (EN-408:2011 + A1:2012) was also carried out. Several machine learning algorithms were then used to grade the beams, and their predictive accuracy was compared with that of visual grading. To do so, three scenarios were considered: a first scenario in which only visual variables were used; a second scenario in which “cut type” variables were also included; and a third scenario in which additional non-destructive variables were considered. Results showed a poor level of performance of UNE 56544:1997, with an apparent mismatch between the strength values assigned for each visual grade (established by the EN 338 standard) and the actual values. On the opposite, all algorithms performed better than visual grading and may thus be deemed as promising timber strength grading tools.

PROPRIEDADES DA MADEIRA LAMINADA CRUZADA COLADA COM ADESIVO À BASE DE TANINOS DA CASCA DAS ÁRVORES DE Mimosa Tenuiflora

ABSTRACT This study aimed to determine the concentration of condensed tannins in the bark of Mimosa tenuiflora (Willd) Poir trees. Additionally, the physical-mechanical properties of cross-laminated timber (CLT) panels bonded with an adhesive based on M. tenuiflora tannins were assessed. Bark was collected from five trees. The adhesive formulation was synthesized by mixing powdered tannins, paraformaldehyde, and water at 50 °C under continuous stirring. Bark tannins extract in its pristine state without any previous chemical treatment or modification was employed to synthesize the adhesive. Viscosity, pH, solids content, and gel time of the adhesive formulation were determined. CLT panels were manufactured with Eucalyptus spp. wood. The bonding performance was assessed by determining the physical (apparent density and water absorption) and mechanical (modulus of elasticity – MOE, modulus of rupture – MOR, and shear strength) properties of the CLT panels. Condensed tannins content in the M. tenuiflora bark was 23.4%. Adhesive properties were pH = 3.93, TS of 50.64%, gel time of 460 s, and 6,000 cP for viscosity. Values of MOE, MOR and shear strength were 4,411, 16.18, and 1.06 MPa, respectively. The M. tenuiflora tannins are promising for the formulation of adhesives to bond CLT.

Effect of Microstructure on the Permeability and Sorption of Wood of Sterculia rhinopetala and Albizia ferruginea

This paper sets to find out the effect of the microstructure of wood on the permeability and sorption of the wood of Sterculia rhinopetala and Albizia ferruginea. Permeability, the way of ingress of water into wood mass, is one of the most variable properties of timber and it further influences nearly all the physical properties of wood. Wood exposed to high humidity conditions or to liquid water during use may be subjected to biological deterioration which makes equilibrium moisture content of wood very important. Equilibrium moisture content is the moisture level where the wood neither gains nor loses moisture since it is at equilibrium with the relative humidity and temperature of the surrounding environment. Sixteen randomly sampled specimens of each of the wood of Sterculia rhinopetala and Albizia ferruginea species (heartwood and sapwood) with dimensions 3 cm x 3 cm x 3 cm were exposed at various relative humidity conditions of 30 %, 45 %, 60 %, 75 % and 90 % in a temperature and humidity-controlled climate chamber. The order of water uptake in terms of percentage volume is arranged from the lowest to the highest. Sterculia rhinopetala heartwood had the lowest uptake per volume with a value of 0.31 %. On the uptake per weight Sterculia rhinopetala heartwood again had the lowest uptake whilst Albizia ferruginea had the highest with a value of 6.77 %. The sapwood of Sterculia rhinopetala had a relatively higher uptake per volume value of 0.53 % and a value of uptake per weight of 0.72 % compared to the heartwood. The equilibrium moisture content values of Sterculia rhinopetala suggests that it can have minimal dimensional changes when used in both the Southern and the Northern parts of Ghana.

Wood moisture monitoring and classification in kiln‐dried timber

Different mass timber structures require a specific range of wood moisture. Thus, moisture monitoring is a crucial quality control task during timber drying that impacts the properties and quality of the subsequent timber structures. Variations in the average and distribution of the final moisture can result in significant variations in the timber properties and thus negatively affect performance in service. This necessitates rigorous moisture monitoring and timber grading during and after kiln drying. This study aims to estimate the kiln-dried population final moisture distribution based on green timber characteristics and machine learning. This will facilitate the timber grading process by reducing the variation in the mechanical properties of the kiln-dried timber, as timbers with a higher chance of moisture variation will be identified before the drying process. Timber initial moisture, initial weight, basic density, and target moisture were used to train machine learning models. Linear discriminant analysis and decision tree were used for moisture classification. Principal component and variable clustering analysis were performed to study the critical parameters affecting the timber overdrying and underdrying. The results indicated that initial moisture level and weight are the essential variables, while density had the least significant effect on the performance of classification models. The decision tree approach exhibited better performance than discriminant analysis with ~91% classification accuracy proving the effectiveness of using initial timber properties for quality control and grading of kiln-dried timber.

Investigation of rolling shear properties of cross-laminated timber (CLT) and comparison of experimental approaches

The structural behaviour of a cross laminated timber (CLT) system is dictated in-part by the rolling shear properties (both strength fr and modulus Gr) of its laminates. To investigate the rolling shear properties of CLT, short-span four-point bending tests, modified planar shear (MPS) tests with timber sandwich plates, and MPS tests with steel sandwich plates were conducted on Australian grown Eucalyptus nitens and radiata pine, as well as European grown Norway spruce. A strong positive relationship between aspect ratio and strength was found, which agrees with previous research. However, the annual ring orientation distribution rather than the aspect ratio was shown to have the most pronounced effect on the shear modulus. The load direction, which has not been accounted for by researchers, was shown to have a substantial effect on the measured rolling shear strength. When the applied load direction was parallel to the annual rings, the Eucalyptus nitens, radiata pine and Norway spruce specimens exhibited rolling shear strengths of 4.1, 2.7 and 1.7 MPa respectively. These average recorded strengths were found to decrease by 16%, 40% and 52% respectively when the load direction was changed to run perpendicular to the rings instead. By directly measuring the shear deformations of two specimens tested under different MPS approaches using Digital Image Correlation (DIC), the impact of the plate material on the recorded shear modulus was isolated. This revealed that the MPS tests with steel plates recorded average rolling shear modulus values which were as much as 42% higher than their counterparts with timber plates, as well as identifying substantial errors in laser and LVDT-like measurement tools. It is recommended that a DIC approach is employed to complement or replace a UTM or laser sensor deformation measurement approach to mitigate these potential errors.

Mechanical and Physical Properties of Cross-Laminated Timber Made from Batai using Different Glue Spread Amounts

This study aimed to determine the mechanical and physical properties of the Cross-Laminated Timber (CLT) glued with different amounts of glue. Cost of glue is the outmost importance where it will help in reducing the CLT manufacturing cost. Four different amounts of glue spread were used where the glue that used was phenol-resorcinol formaldehyde (PRF);150, 200, 250 and 300g/m2. The testing of the CLT was conducted by following BS EN 408:2010, BS EN 16351:2015, ASTM D 2718 method B, ASTM D 143-94 and Japanese Agricultural Standard (JAS) 1152:2007. The analysis of physical tests that have been carried out are density, moisture content, shrinkage and swelling of the CLT’s thickness. Meanwhile, the mechanical tests were compression parallel and perpendicular to the grain, three-point bending test (flatwise and edgewise of CLT) and shear test. The highest density was shown by the CLT that using 300 g/m2 which the value was 316.41 kg/m3. Whereas the highest moisture content was shown by CLT that used 250 g/m2 with 15.49% in value. The highest thickness shrinkage percentage was 2.50%, CLT with 200g/m2 while the highest thickness swelling percentage was 5.60% which the CLT used 150 g/m2. For the flatwise bending test, it shows that the CLT that used 300 g/m2 has the highest MOE and MOR value which were 510.63N/mm2 and 8.39 N/mm2. The MOE and MOR value for edgewise bending also shows that CLT that used 300 g/m2 was the best with 1528.70 N/mm2and 13.48 N/mm2. In compression perpendicular to grain test, the CLT with 150 g/m2 shows the highest value of MOE which was 5.89 N/mm2 while CLT that used 200 g/m2 has the highest value of compressive strength with 9.10N/mm2. However, for compression parallel to grain test, the CLT that used 300 g/m2 shows the best performance with 1002.78 N/mm2 and 13.75 N/mm2 of MOE and compressive strength value. Lastly, for the shear test, the highest shear strength value was 0.39 N/mm2 which belongs to CLT that used 150 g/m2. Thus, CLT that used 300 g/m2 of glue spread amount is the best CLT which, the more the amount of glue, the better the performance of the CLT.

Estimation of compression and shrinkage properties of Brazilian tropical timber through porosimetry analysis by mercury intrusion

Wood is a natural material with properties that are strongly influenced by anatomical characteristics, so studies that aim to correlate properties through empirical equations in search of simplification to obtain the values of their characteristics are essential. In this context, this work aims to generate multiple regression models to estimate the properties of shrinkage and compression parallel and normal to the grain of Brazilian tropical woods as a function of the values of porosity, density, and for both properties, with porosity being obtained by mercury intrusion porosimetry. As a result, the radial (RRT) and total tangential (RTT) shrinkage could be estimated through porosity. However, it was not possible to estimate them considering only density as an independent variable. All the models that were used were able to accurately estimate the modulus of resistance and modulus of elasticity values (fc,0, Ec,0, fc,90, and Ec,90).