Oriented Strand Board Research Articles

Measurements of water vapour permeability of oriented strand boards

Oriented strand boards (OSB) are one of the most used elements in modern timber-based buildings. An important property is their permeability to water vapour. It is commonly characterized by the diffusion resistance factor (μ-value). It is not a constant, but a moisture-dependent function that is most often determined using the cup method. However, results found in the literature have large variance. This paper presents the results of carefully performed laboratory measurements using the cup method. Measurements were made at different sorption moisture contents of OSB. The measured μ-values ranged from 40 for samples with high moisture content to 160 for samples with low moisture content. The measured values were used to derive moisture-dependent functions that cover the entire hygroscopic range. They can be used in hygrothermal modelling of building envelopes containing OSB.

Experimental and numerical study on seismic performance of a novel type of cold-formed steel shear wall with built-in sandwich panels

The purpose of this paper is to study the seismic behavior of the cold-formed thin-walled steel composite wall with built-in honeycomb sandwich and analyze its failure mechanism. A total of 13 monotonic and cyclic loading tests of wall specimens were completed in this paper, including four for observing the force and failure mode of the built-in sandwich of cold-formed steel (CFS) frame specimens, and nine specimens sheathed with double-sided oriented strand board (OSB). The mechanical performance indicators such as shear bearing capacity, stiffness, ductility, energy dissipation capacity and stiffness degradation of the honeycomb sandwich and other sandwich CFS shear walls were compared and analyzed. The experimental results demonstrate that the failure mode of the wall specimens is mainly ductile failure, including chord stud buckling or tearing, screw tilted, sank into the panel, or cut off at the connection between the honeycomb sandwich and the track. The built-in honeycomb sandwich can play a better role as a skin, which can significantly improve the shear bearing capacity and stiffness of the composite wall, but reduce the ductility. The sheathing and studs can effectively limit the out-of-plane buckling deformation of the sandwich panel and give full play to the properties of the sandwich material, thereby improving the shear bearing capacity, stiffness and energy dissipation capacity of the wall, as well as improving the ductility. The effects of wall aspect ratio and sandwich thickness on the seismic behavior for the built-in honeycomb sandwich CFS shear wall were analyzed by finite element analysis (FEA) and compared with the flat steel plate sandwich and OSB plate sandwich wall. And the nonlinear simplified analysis model of the composite wall under cyclic loading was established by SAP2000.

Water vapour transmission properties of uncoated and coated wood-based panels

ABSTRACT Knowing the properties of wood-based building materials is essential for their proper use. Moisture transfer properties of building materials are crucial to proper building design and the prevention of moisture-related problems. In selecting materials for the building, it is important to know their water vapour transmission properties. In this research the water vapour transmission properties of uncoated and coated particleboard, oriented strand board (OSB) and birch plywood were studied using wet cup method and a moisture gradient in the samples was additionally measured. The water vapour transmission rate of free films of three commercial transparent coatings was also studied. Results showed that particleboard had the highest water vapour permeability and that the coatings reduced the water vapour permeability of all tested wood-based panels. Moreover, sanding increased the water vapour permeability of uncoated particleboard and OSB. The moisture gradient in all tested wood-based panels was linear. The highest water vapour transmission rate was recorded for acrylic water-borne coating, followed by polyurethane water-borne coating and the lowest for polyurethane solvent-based coating.

Numerical Assessment of the Seismic Performance of a Timber Retrofit Solution for Unreinforced Masonry Buildings

ABSTRACT This paper presents the results of a numerical study about the effectiveness of a new multi-component timber retrofit solution for unreinforced masonry buildings in seismic regions. The proposed retrofit consists of timber frames fastened to the internal surface of masonry piers, with oriented strand boards eventually nailed to the frames. This technique aims at improving both in-plane and out-of-plane capacities of masonry piers as well as wall-to-diaphragm connections. Numerical models were built and calibrated against experimental data from quasi-static cyclic shear-compression tests on two isolated piers and dynamic shake-table tests on two full-scale buildings, in bare and retrofitted conditions. The building prototype represented the end-unit of a cavity-wall terraced house. A strategy to include the retrofit contribution in equivalent-frame masonry models is proposed. Starting from the calibrated models, two additional strengthening schemes were numerically generated to investigate the influence of increasing retrofit levels on the building performance. For each model, a cloud nonlinear time-history analysis was performed using 250 ground-motion records to derive damage-state fragility functions. The numerical outcomes can assist in the selection of an optimal level of the proposed retrofit solution, balancing structural and economic goals.

Withdrawal Resistance of T-Nuts in Various Furniture Materials

T-nuts are factory installed in the holes of the ready-to-assemble furniture components. There is a risk that the t-nut spontaneously falls out during transport or storage and get lost; the t-nut can also be pushed into inaccessible spaces during assembly. These complications can make furniture assembly impossible. For this reason, sufficient force to hold the t-nut in the hole is essential. The article presents the test results of the forces holding the t-nuts in five furniture materials (softwood, Oriented Strand Board, plywood, and particleboard in two variants). The M6 t-nuts with four prongs were installed in predrilled 8 mm holes. The resistance to withdrawal of the t-nuts was measured with a universal testing machine. The tested materials could be divided into three groups in terms of the risk of the t-nut falling out: softwood and plywood – low risk, F = 1113.2-1158.0 N; OSB and particleboard – moderate risk, F = 592.3-645.5 N, particleboard with a pad – high risk, F = 645.5 N. The results show that the withdrawal resistance is not correlated with the density of the wood material, and that it decreased with the degree of wood material processing – the less processed the material, the greater the resistance to withdrawal of the t-nuts.

Physical and Mechanical Properties of Bamboo Oriented Strand Board Under Various Post-Thermal Treatment Duration

Post-treatment of bamboo-oriented strand board (BOSB) through thermal modification can be an alternative to improve BOSB quality. This study aimed to analyze the effect of post-thermal treatment duration on the physical and mechanical properties of BOSB. Three-layers BOSB with a target density of 0.7 g/cm3 was made with the core layer perpendicular to the surface and bonded with 8% phenol-formaldehyde resin. The BOSB produced was then thermally-modified at 160°C for 1, 2, and 3 h. The physical and mechanical properties of BOSB were determined based on JIS A 5908-2003 standard. The results showed that the physical properties of the thermally-modified BOSB increased while the mechanical properties decreased compared to the untreated BOSB. The moisture content (MC), water absorption (WA), and thickness swelling (TS) of BOSB decreased with the increase in post-thermal treatment duration. The decrease in MC, WA, and TS of the thermally-modified BOSB reached 38.60%, 11.92%, and 33.26%, respectively. In addition, the decrease in modulus of elasticity (MOE), modulus of rupture (MOR), and internal bonding of the thermally-modified BOSB reached 19.18%, 23.15%, and 53.51%, respectively. The results showed that TS, MOE, and MOR of the thermally-modified BOSB still could meet the 0437.0 standards for commercial OSB (Grade O-1). Keywords: bamboo-oriented strand board, Dendrocalamus asper, physical and mechanical properties, post-thermal treatment, treatment duration

Surface Wettability and Colour Change of Betung Bamboo Strands Treated with 1% NaOH under Various Immersing Times

Bamboo was a material with enormous potential to be used as raw material for various purposes. This material has good properties for structural purposes such as buildings and furniture or converted to a composite product such as bamboo oriented strand board (BOSB). This study was aimed to determine the wettability properties and the colour change of Dendrocalamus asper bamboo strands after alkali immersing treatment with 1% NaOH solution. The treatments were carried out for 1, 2, and 3 hours, respectively. The wettability of surfaces is quantified by computing the value of the K parameter or the contact angle change rate constant. Meanwhile, the colour change parameter of bamboo strands was quantified by portable colour difference meter CDX – 105 to determine the brightness intensity of a combination of red–green and blue-yellow. The results show that the wettability properties of bamboo strands were getting better after the treatments. On the other hand, the bamboo strands' colour was darker due to the alkali immersion treatment. The optimum duration of alkali immersing treatment with 1% NaOH was 2 hours.

Effects of strands geometry on the physical and mechanical properties of oriented strand boards (OSBs) made from black spruce and trembling aspen

Black spruce is widely used for lumber production in Eastern Canada, and it has the potential to replace trembling aspen and paper birch for oriented strand board (OSB) manufacturing. This study evaluated the bending modulus of elasticity (MOE) and modulus of rupture (MOR), the internal bond (IB), and the thickness swelling (TS) of OSB panels made from black spruce and trembling aspen strands and how they were affected by strand geometry. All the panels met the CSA O437 (1993) standard for class O-2 properties except for the TS. The strand thickness had a significantly negative effect on the bending properties but a significantly positive effect on the IB and TS properties. The strand length had a significantly positive effect on the parallel bending properties but a significantly negative effect on the perpendicular bending properties and the IB, except for the TS. The OSB panels made from aspen obtained better bending properties, while the IB and TS properties were lower than those of the OSB black spruce panels. The results indicate that black spruce strands obtained from the Eastern Canadian softwood lumber industry are suitable for OSB production, but more work is required to reduce the TS.

Evaluating Log Stiffness Using Acoustic Velocity for Manufacturing Structural Oriented Strand Board

Oriented strand board (OSB) is an engineered panel product formed by layering strands of resinated wood in specific orientations into a mat, then pressing the mat at a high temperature to form a panel of desired strength and stiffness. OSB manufacturing facilities utilize small diameter logs from thinning operations and waste from harvesting. Considerable variation exists in the wood properties of the raw material and ideally the OSB industry would take advantage of such variation, however, it lacks the technology required to rapidly assess log quality on-site. Non-destructive evaluation (NDE) techniques based-on acoustics have the potential to rapidly segregate logs in the field, however the influence of acoustic-based log segregation on OSB panel properties is unknown. The aims of this project were to determine if log quality affects panel properties and if acoustic NDE technology is a satisfactory tool for determining log stiffness prior to entering the manufacturing process. It was found that low velocity (stiffness) logs produced panels with low stiffness while high and medium velocity (stiffness) logs produced panels with similar properties. The Director HM 200 was a satisfactory tool for determining log stiffness. Further studies are required to determine how to incorporate NDE tools into the manufacturing process.

Shear Property and Uniform Vertical Load Capacity of Bamboo I-Beams

Bamboo oriented strand boards (BOSB) are very suitable for application in construction structures because of their excellent mechanical properties. This research investigated the shear performance of bamboo I-beams composed of BOSB to verify the structural performance of I-beams. Short beam shear tests and uniform vertical load capacity tests were performed to investigate the effects of various factors on the properties of bamboo I-beams. The results showed that shear bearing capacity and uniform vertical load capacity of bamboo I-beams exceeded the requirements for performance-rated I-Joists in APA PRI-400-2021. The shear bearing capacity, stiffness, and failure types of bamboo I-beams were determined by the web materials, flange–web joint type, and beam depth. Increasing the bamboo I-beam depth without changing the flange dimensions had no significant effect on the shear bearing capacity and stiffness of bamboo I-beams. The shear bearing capacity and stiffness of wooden orientated strand board webbed I-beams were almost half of those of bamboo I-beams with the same depth. The shear bearing capacities of specimens calculated based on the shear bearing capacity calculation formula of I-beams recommended in the Canadian standard were reasonably close to the experimental results. The uniform vertical load capacity of bamboo I-beams gradually decreased as the depth of the bamboo I-beam increased from 300 mm to 500 mm.

Physical and Mechanical Properties of Oriented Strand Board Made from Eastern Canadian Softwood Species

This study aims to investigate the feasibility of producing OSB from softwood species used in the Eastern Canadian softwood lumber industry in the context of the overcapacity of softwood chips traditionally produced for the pulp and paper industry. Balsam fir, black spruce, and jack pine logs were used to make 15 mm thick OSB panels with a target density of 600 kg/m3. The panels were manufactured at a temperature of 210 °C during a pressing cycle of 300 s. Strands with different thicknesses were used to obtain a constant specific surface of 6.7 m2/kg for the three species. The bending modulus of the rupture and modulus of elasticity, internal bond, and thickness swelling of the OSB panels were determined and compared to the CSA standard requirements. The species significantly affected the physical and mechanical properties of OSB. The bending properties of OSB decreased with an increase in the species wood density. The internal bond strength of OSB increased with the increase in species wood density. The panels made from softwood species showed physical and mechanical properties exceeding the standard requirements, except for high thickness swelling. The combination of softwood and aspen strands significantly improved the thickness swelling of softwood-based OSB. The reduction in the surface layer density could also be explored to reduce the thickness swelling of the OSB made from the softwoods considered in this study.

A Sustainable Approach to Build Insulated External Timber Frame Walls for Passive Houses Using Natural and Waste Materials

This paper presents structures of timber-framed walls designed for passive houses, using natural and waste resources as insulation materials, such as wool, wood fibers, ground paper, reeds (Phragmites communis), and Acrylonitrile Butadiene Styrene (ABS) wastes. The insulation systems of stud walls composed of wool–ABS composite boards and five types of fillers (wool, ABS, wood fibers, ground paper, and reeds) were investigated to reach U-value requirements for passive houses. The wall structures were designed at a thickness of 175 mm, including gypsum board for internal wall lining and oriented strand board (OSB) for the exterior one. The testing protocol of thermal insulation properties of wall structures simulated conditions for indoor and outdoor temperatures during the winter and summer seasons using HFM-Lambda laboratory equipment. In situ measurements of U-values were determined for the experimental wall structures during winter time, when the temperature differences between outside and inside exceeded 10 °C. The results recorded for the U-values between 0.20 W/m2K and 0.35 W/m2K indicate that the proposed structures are energy-efficient walls for passive houses placed in the temperate-continental areas. The vapour flow rate calculation does not indicate the presence of condensation in the 175 mm thick wall structures, which proves that the selected thermal insulation materials are not prone to degradation due to condensation. The research is aligned to the international trend in civil engineering, oriented to the design and construction of low-energy buildings on the one hand and the use of environmentally friendly or recycled materials on the other.

Optimization of castor oil polyurethane resin content of OSB panel made of <i>Dendrocalamus asper</i> bamboo

This work presents a study of the optimization of castor oil polyurethane (PU) resin content for the production of Oriented Strand Boards (OSB) using bamboo (Dendrocalamus asper). For this study, medium-density (650 kg/m3) OSB panels were produced with different resin contents (8%, 10%, 12%, and 15%). The bamboo particles were characterized through physical, chemical and anatomical analyses, identifying the potential of this product as a raw material for OSB panels. Subsequently, the physical and mechanical properties of OSB panels were evaluated. The results indicated that bamboo and castor oil PU are suitable for the production of OSB panels, and all the conditions met the minimum requirements of the European standard EN 300 (2002), for OSB type 1. In particular, the best overall properties were obtained by the panels with a resin content of 12%, achieving the minimum requirements for applications as a structural panel (type 4), opening new opportunities for formaldehyde-free engineered bamboo materials for the built environment.

Fast Pyrolysis Bio-Oil-Based Epoxy as an Adhesive in Oriented Strand Board Production.

The objectives of this study were to utilize bio-oil-based epoxy resin in oriented strand board (OSB) production and investigate the effect of bio-oil substitution in epoxy resin as an adhesive for OSB production. Bio-oil was produced by the fast pyrolysis (FP) process using southern yellow pine (Pinus spp.). Bio-oil-based epoxy resin was synthesized by the modification of epoxy resin with FP bio-oil at various substitution levels. Acetone extraction using a Soxhlet process indicated a superior cured reaction of bio-oil and epoxy resin at 20% bio-oil substitution. FTIR spectra corroborated the Soxhlet extraction with the removal of the epoxide peak signature within the cross-linked polymer. Images from the scanning electron microscopy suggested bulk phase homogeneity. OSB panels were tested according to ASTM D1037-12. The modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength, and water resistance (thickness swell and water absorption) properties of the OSB panels were feasible at bio-oil substitution up to 30% in the epoxy resin system.

Evaluation of some mechanical and physical properties of ‘Oriented Strand Board (OSB/3)’ following cyclic accelerated aging tests

Evaluation of some mechanical and physical properties of ‘Oriented Strand Board (OSB/3)’ following cyclic accelerated aging tests

Modeling of Wood Surface Ignition by Wildland Firebrands

The probability of structural ignition is dependent both on physical properties of materials and the fire exposure conditions. In this study, the effect of firebrand characteristics (i.e., firebrand size, number of firebrands) on wood ignition behavior was considered. Mathematical modeling and laboratory experiment were conducted to better understand the conditions of wood ignition by a single or group of firebrands with different geometry. This model considers the heat exchange between the firebrands, wood layer and the gas phase, moisture evaporation in the firebrands and the diffusion gases of water vapor in the pyrolysis zone. In order to test and verify the model, a series of experiments to determine probability and conditions for ignition of wood-based materials (plywood, oriented strand board, chipboard) caused by wildland firebrands (pine twigs with a diameter of 6–8 mm and a length of 40 ± 2 mm) were conducted. The experiments investigated the firebrand impact on the wood layer under different parameters, such as firebrand size and quantity, wind speed, and type of wood. The results of experiments showed that the increase in wind speed leads to the increase in probability of wood ignition. Based on the received results, it can be concluded that the ignition curve of wood samples by firebrands is nonlinear and depends on the wind speed and firebrand size as well as their quantity. At the same time, there is no ignition of wood samples in the range of wind speed of 0–1 m/s. The ignition of wood is possible with a decrease in the distance between the firebrands with a decrease in the firebrand length. This result agrees more closely with the model.

Lignin-Glyoxal: A Fully Biobased Formaldehyde-Free Wood Adhesive for Interior Engineered Wood Products

In this study, a biobased phenolic adhesive was successfully developed by entirely substituting both petroleum-based phenol and formaldehyde with an unmodified corn stover biorefinery lignin and glyoxal (a biobased dialdehyde), respectively. Lignin-glyoxal resins were synthesized using an alkaline catalyst with a molar ratio of lignin to glyoxal of 1:2. Chemical, thermal, and mechanical properties of the lignin, lignin-based resins, and final adhesives were assessed following appropriate standard test methods. The analysis of lignins and lignin-based resin molar mass was performed using gel permeation chromatography. The lignin-glyoxal resin was found to have a 3-fold higher average molecular weight than the starting lignin, demonstrating the successful integration of lignin into the polymeric resin network. The curing of the formulated adhesives was studied using differential scanning calorimetry and dynamic mechanical analysis. Although the lignin-glyoxal resin had a higher curing temperature (167 °C) than a conventional phenol-formaldehyde resin (142 °C) and the formulated lignin-formaldehyde resin (146 °C), the rate and degree of cure were similar or better than the other two resins. The adhesion strengths of the formulated adhesives were determined using single-lap-joint veneer samples cured according to recommended press parameters for commercial adhesives. The lignin-glyoxal adhesive had a relatively high dry adhesion strength (3.9 MPa), with over 90% wood failure, but failed the wet adhesion test (boiling water test). Although the formulated lignin-glyoxal adhesive failed the boiling water test, it had excellent stability at room temperature water, remaining intact after 1 week during the water immersion test. The high dry adhesion strength makes this class of lignin-based formaldehyde-free adhesives a unique biobased glue for the production of interior grade plywood and oriented strand boards.

Ecotoxic emissions generated by illegal burning of household waste

The practice of burning household waste including different types of plastic is illegal in Hungary, still an existing problem. As environmental consequences are hardly known, this study attempts to give an initial estimation of the ecotoxicity generated during controlled combustion of different waste types. These samples included polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PU), oriented strand board (OSB) and rag (RAG). Ecotoxicological profiling was completed using the following test battery: Vibrio fischeri bioluminescence inhibition assay, Daphnia magna immobility test and the seedling emergence assay. Also, genotoxicity of plastic waste samples was assessed using the SOS Chromotest. Concerning main pollutants in the samples, the samples could be distinguished as ‘PAH-type’ and ‘heavy metal-type’ samples. PVC, PU and PS samples showed the highest toxicity in the Vibrio and Daphnia assays. The PVC sample was characterized by an extremely high cadmium concentration (22.4 μg/L), PS, PP and PU samples on the contrary had high total PAH content. While Vibrio and Daphnia showed comparable sensitivity, the phytotoxicity assay had no response for any of the samples tested. Samples originating from the controlled burning of different plastic types such as PU, PVC, PS and PP were classified as genotoxic, PS sample showed extremely high genotoxicity. Genotoxicity expressed as SOSIF showed strong correlation with most of the PAHs detected.

Интеграция анкерных линий на кровлях зданий в проектные решения

Ensuring safety during work at height is the most important task in the context of the development of a modern construction complex. Falling from a height occupies one of the first places in terms of the number of victims among all the traumatic factors, based on the statistical data, and its share among other traumatic factors is 28 %. Works at height include construction works, in which there are risks associated with a possible fall of an employee from the height of more than 1.8 m. The employer is obliged to ensure the implementation of measures to reduce injuries at the construction site in accordance with the current legislation. Protective measures when working at height include personal and collective protective equipment, including the use of anchor lines on the building roofs. The article provides for a comparative analysis of five options for the installation of anchor lines suitable for wooden, concrete, metal, and green roofs. For the analysis, a flexible anchor line using a metal cable, a rigid anchor line on high supports, a rigid anchor line on low supports, a flexible anchor line with weights for use on the roofs with landscaping and a flexible anchor line with supports were selected. All the selected anchor line systems comply with the international safety requirements and can be used by one or more workers. The advantages of each system of the anchor lines are revealed, a wide variety of roofing materials are considered: metal seam, made of polyvinyl chloride, with oriented strand board and thermoplastic polyolefin reinforced membrane, which is a high-tech polymer roofing material. All the anchor lines have a variability in terms of the shape and can be used on the roofs of any configurations in the building design without additional efforts and search for the complex solutions on the part of the designer.

Bending Behaviour of Different Types of Timber I-Joist

Engineered wood I-joist is a structural system that comprises of flanges and web elements, and utilised as beams in buildings. Both elements must work together as a structural system to fit and meet the strength behaviour of a solid wood beam. The main objective of the study was to determine the bending strength behaviour of I-joist which produced from three types of jointed technique (finger, L-butt and nail plate) of oriented strand board (OSB) web element with two types of flange element (Keruing solid wood and laminated veneer lumber (LVL)). A total of 18 specimens of I-joist were tested to determine the bending behaviour, especially the modulus of elasticity (E) and modulus of rupture (MR). From the result of testing, LVL flanges specimen were obtained almost as strong as the specimens with solid wood flanges. Additionally, either solid wood or LVL flange was shown non-significant variances in bending strength behaviour because the MR values of the I-joist were insignificantly affected by flange element material. The I-joist specimen with finger jointed web was observed to be the strongest specimen when compared with other joints. Furthermore, the weakest joint among the three types of joints were fabricated with nail plate jointed web. The failures mode of the I-joist specimens were observed to fail due to tension or compression.