Oriented Strand Board Research Articles

The Effect of Surface Finishes on Rising Damp in Oriented Strand Board

It is known that oriented strand board (OSB) is prone to water absorption. This characteristic of OSB is undesirable, it can have a negative impact on the physical and mechanical properties of the material and it can also make it prone to attack from wood-destroying insects, rot or mould. The research follows previous work of the authors related to optimisation of surface finishes for OSB in order to increase its moisture resistance. The aim of the research is to compare the rise of dampness in test specimens with different types of coating, spray, primer and waterproofing under predefined conditions. The paper contains a definition of the basic material, test specimens and test methods, and covers 8 different types of surface finish materials selected for application to the test specimens. The results include graphs showing rise of dampness in the test specimens for each day of observation. The results are also discussed and in the conclusion the results are evaluated. The results of the experiments confirm the assumption that the choice of surface finish has a significant effect on slowing down the rise of dampness in OSB.

Hygrothermal Monitoring of Two Pilot Prefabricated Exterior Energy Retrofit Panel Designs

NRCan undertook a proof-of-concept project to retrofit a small building with prefabricated wall panels in 2017 in Ottawa, Canada. The retrofit used two wall panel designs: nailbase and woodframe. The Nailbase panel consisted of fiberglass batt, an expanded polystyrene (EPS) core, oriented strand board (OSB) sheathing, a rainscreen, and cladding. The Woodframe panel also featured OSB sheathing and included a 90 mm stand-off gap filled with dense-packed, fibrous insulation. A side-by-side comparison of cost, constructability, and performance was performed. The wall assemblies were instrumented to monitor the temperature, relative humidity, and moisture content of sensitive layers. The data was used to evaluate the hygrothermal performance, moisture accumulation, and risk of associated problems such as mould growth. This paper presents the monitored hygrothermal data from 2017 to 2021, compares the two approaches and assesses their feasibility. During construction, some of the fibrous insulation may have been wetted by wind-driven snow before completion. The data showed that this moisture was able to dissipate without significant risk. The sheathing of the Woodframe panel experienced a higher peak moisture content during the dry-out period. Otherwise, both panel designs showed limited potential for mould growth on monitored surfaces over the monitored period.

The European Yield Model (EYM) for laterally loaded timber connections with smooth nails

ABSTRACT The European Yield Model (EYM) is a commonly accepted procedure to calculate the capacity of laterally loaded connections with dowel type fasteners. The standard procedure is specified in EC5 (EN 1995-1-1 2004) and uses characteristic values as input parameters for the calculation of characteristic values of the resistance of the connection. These characteristic values are the basis for an engineering design of structures. Nevertheless, there are situations, e.g. the design of a test set-up or a pushover analysis in earthquake engineering, when mean values of the resistance of a timber connection are needed. In this context, analytical equations and mechanical models were assessed on two levels by comparing theoretical values to experimental results. The first part of the research considered all the input parameters. The mechanical definition of the plastic moment proved to be more appropriate than the definition of a modified plastic moment according to EC5 for the determination of the yield moment of nails. On the other hand, it was confirmed that the embedment strength of Norway spruce softwood can be predicted reliably and slightly conservatively according to code regulations given by EC5. The definition for the withdrawal strength according to EC5 also seems to define a conservative lower boundary. The situation is not so clear for the embedment strength of oriented strand board (OSB). Test results are very scarce and do not account for the inhomogeneity regarding the thickness of the boards with higher density at the surfaces, which is the section where contact forces are transferred. In the second part, over 110 specimens considering eight different types of nailed connections were tested to assess different calculation procedures. The study focused on nailed connections with OSB and solid timber. This combination together with smooth nails as fasteners is very common in Europe for light-frame structures, especially in areas of low and medium seismicity because they exhibit large deformation capacity without losing strength. On the level of mean values, relationships are found between 1.00 and 1.47 for experimental results over calculated resistance, and it was found that the EYM is more conservative when the thickness of the sheathing is 10 mm instead of 18 mm, which means, that the expected failure mechanism changes from one to two plastic hinges. The findings are approximately the same if the relationship is studied on the level of characteristic values. Here, the relationship of values from experimental investigations over analytical calculation lays between 1.27 and 1.58 for a mechanism with one plastic hinge and between 0.90 and 1.12 for a mechanism with two plastic hinges. Based on these results, the question arises, if the EYM is the appropriate tool to predict the capacity of laterally loaded connections if comparatively large deformations occur between the connected parts. This question should be studied more detailed in the future.

Waste Rose Flower and Lavender Straw Biomass-An Innovative Lignocellulose Feedstock for Mycelium Bio-Materials Development Using Newly Isolated Ganoderma resinaceum GA1M.

In this study, for the first time, the potential of rose flowers and lavender straw waste biomass was studied as feeding lignocellulose substrates for the cultivation of newly isolated in Bulgaria Ganoderma resinaceum GA1M with the objective of obtaining mycelium-based bio-composites. The chemical characterization and Fourier Transform Infrared (FTIR) spectroscopy established that the proximate composition of steam distilled lavender straw (SDLS) and hexane extracted rose flowers (HERF) was a serious prerequisite supporting the self-growth of mycelium bio-materials with improved antibacterial and aromatic properties. The basic physico-mechanical properties of the developed bio-composites were determined. The apparent density of the mycelium HERF-based bio-composites (462 kg/m3) was higher than that of the SDLS-based bio-composite (347 kg/m3) and both were much denser than expanded polystyren (EPS), lighter than medium-density fiber board (MDF) and oriented strand board (OSB) and similar to hempcrete. The preliminary testing of their compressive behavior revealed that the compressive resistance of SDLS-based bio-composite was 718 kPa, while for HERF-based bio-composite it was 1029 kPa and both values are similar to the compressive strength of hempcrete with similar apparent density. Water absorbance analysis showed, that both mycelium HERF- and SDLS-based bio-composites were hydrophilic and further investigations are needed to limit the hydrophilicity of the lignocellulose fibers, to tune the density and to improve compressive resistance.

Wood-based boards mechanical properties and their effects on the cutting process during shredding

In order to design effective shredding machines dedicated to shredding wood-based waste, information about the mechanical properties of materials subjected to shredding is necessary. A number of mechanical properties of particleboard, oriented strand boards, and medium-density fibreboards in the aspect of shredding process have been experimentally determined in the article. The influence of material type, blade geometries, and cutting depth on cutting force and elasticity coefficient were analysed. Blade geometries reflect different phases of rotation of the cylindrical wood chipper’s knife. It has been shown that a knife with the most favourable geometry is characterized by the lowest values of the stiffness coefficient for each of the materials. This is the geometry of the cylindrical wood chipper’s knife exactly halfway into the cutting process. By contrast, the least favourable geometry is characterized by a knife corresponding to the beginning of the cutting process. Among the tested materials, the medium density board requires the most energy to change its structure, and the laminated particleboard requires the least. The presented results can be a set of input data necessary to model the work required to implement the cutting process, but also enable validation of existing cutting models.

New Waste-Based Composite Material for Construction Applications.

The global demand for fiber-based products is continuously increasing. The increased consumption and fast fashion current in the global clothing market generate a significant quantity of pre-and post-production waste that ends up in landfills and incinerators. The present study aims to obtain a new waste-based composite material panel for construction applications with improved mechanical properties that can replace traditional wood-based oriented strand boards (OSB). The new composite material is formed by using textile wastes as a reinforcement structure and a combination of bi-oriented polypropylene films (BOPP) waste, polypropylene non-woven materials (TNT) waste and virgin polypropylene fibers (PP) as a matrix. The mechanical properties of waste-based composite materials are modeled using the Taguchi method based on orthogonal arrays to maximize the composite characteristics’ mechanical properties. Experimental data validated the theoretical results obtained.

Performance Comparison of Wood, Plywood, and Oriented Strand Board under High- and Low-Velocity Impact Loadings

Abstract In this article, the behavior of wood, plywood, and oriented strand board (OSB) under high- and low-velocity impact loadings was investigated experimentally. For the high-velocity impact test, limit velocity (Vbl) and impact energy absorbed (Eab) were determined by subjecting the material to different impact loading by conical nose projectile. For the low-velocity impact test, the materials were subjected to four levels of energy—10, 39, 78, and 98 J—and the time history responses of velocity, energy, load, and displacement were obtained. Additionally, quantitative data for damage size are presented. The results show that in comparison with OSB and solid wood plates, plywood presents better characteristics in response to both high- and low-velocity impact loadings.

Experimental investigation on composite panels of cold-formed steel and timber

Timber panels and cold-formed steel sheeting are widely used in the construction industry, especially in prefabricated structures, temporary housing and informal settlements. This is because these materials are widely available, can be cut and fixed with hand tools, and their lightweight makes them easy to transport and build with. When used together, there is a potential for composite action developing between the timber panels and the underlying steel sheeting, which is currently ignored in design. A composite panel of oriented strand boards and cold-formed steel sheeting is proposed herein and its overall structural behaviour is experimentally investigated. Based on results obtained from material, push-out and flexural tests, its mechanical properties are determined and the predominant failure modes are highlighted. The feasibility of mobilising composite action between the components of the proposed system is proven and the derived benefits, both in terms of load carrying capacity and stiffness, are quantified. It is demonstrated that harnessing the beneficial influence of composite action can lead to substantial improvements of the overall structural performance of the proposed composite panel, offering the potential to improve significantly the quality of housing in informal developments and rapidly urbanising areas.

Experimental and numerical studies on the thermal performance of structural insulated panel splines

This paper presents the experimental and numerical studies on the thermal performance of structural insulated panel (SIP) splines. Typical SIPs are comprised of two structural facings of oriented strand board (OSB) and an insulation layer of expanded polystyrene (EPS). Splines with steel nails used to connect the panels reduce the thermal performance of the SIP wall. The thermal transmittance of three types of splines commonly used in SIP wall was measured experimentally. Then the finite element model of an affected area unit of the spline was established, and a parametric study was conducted to investigate the effect of the materials' thermal conductivity, insulation layer thickness, nail spacing, and nail diameter on the thermal performance of the spline. The insulation layer was found to be the most significant factor on the thermal performance of the spline, and weakened the effect of the thermal bridge caused by nails. The nail had only a slight effect on the thermal performance of the spline. The thermal performance of the spline could be improved by reducing the materials’ thermal conductivity, increasing the thickness of the insulation layer and the nail spacing, and reducing the nail diameter.

Evaluation of Balsa wood (Ochroma pyramidale) waste and OSB panels with castor oil polyurethane resin

ABSTRACT This research presents an advanced characterization of Balsa wood waste to evaluate its potential use as raw material for Oriented Strand Board (OSB) panel. For that, chemical, thermal and microstructural characterization of the Balsa wood particles were performed followed by the production and characterization of OSB agglomerated with castor oil polyurethane resin (Pu-Castor oil). The results indicated that the lignin content of the Balsa wood waste was lower than the content found in Pinus spp. wood, used in the industrial production of OSB panels, demonstrating the need for higher resin contents to ensure a perfect agglomeration of the particles. Microstructural analysis indicated that the Balsa wood presented characteristics to be used as a constituent raw material of OSB with Pu-Castor oil. The physical-mechanical characterization indicated that the material can be classified as OSB type 1 in accordance with the EN 300:2006 guidelines and is suitable for application in internal environments.

Numerical modelling of fire test with timber fire protection

PurposeThe purpose of this paper is to present a complex pyrolysis computational fluid dynamics (CFD) model of timber protection exposed to fire in a medium size enclosure. An emphasis is placed on rarely used temperature-dependent thermal material properties effecting the overall simulation outputs. Using the input dataset, a fire test model with oriented strand boards (OSB) in the room corner test facility is created in Fire Dynamics Simulator (FDS).Design/methodology/approachSeven FDS models comprising different complexity approaches to modelling the burning of wood-based materials, from a simplified model of burning based on a prescribed heat release rate to complex pyrolysis models which can describe the fire spread, are presented. The models are validated by the experimental data measured during a fire test of OSB in the room corner test facility.FindingsThe use of complex pyrolysis approach is recommended in real-scale enclosure fire scenarios with timber as a supplementary heat source. However, extra attention should be paid to burning material thermal properties implementation. A commonly used constant specific heat capacity and thermal conductivity provided poor agreement with experimental data. When the fire spread is expected, simplified model results should be processed with great care and the user should be aware of possible significant errors.Originality/valueThis paper brings an innovative and rarely used complex pyrolysis CFD model approach to predict the behaviour of timber protection exposed to fire. A study on different temperature-dependent thermal material properties combined with multi-step pyrolysis in the room corner test scenario has not been sufficiently published and validated yet.

Experiments on sheathed cold‐formed steel beam‐columns

AbstractAn experimental study on sheathed cold‐formed steel C‐lipped columns (studs) with service holes in the web subjected to compression and major axis bending is presented in this paper. A total of 17 experiments was performed with both oriented strand board (OSB) and plasterboard used as the sheathing material and with varying connector spacing employed between the sheathing and the steel members. Material tests and geometric imperfection measurements were also undertaken. The tested specimens comprised a single 2.4 m long cold‐formed steel member sheathed on both sides and secured at its ends to top and bottom tracks. Eight pure compression tests with plasterboard and OSB sheathing and with the spacing of the connectors varying between 75 mm and 600 mm were initially performed. Specimens with OSB were then tested under pure bending and also under combined loading, by first applying a compressive load corresponding to the 75%, 50% or 25% of the predetermined axial resistance and then laterally loaded until failure. Reducing the spacing of the connectors from 600 mm to 75 mm resulted in up to 20% and 30% increases in capacity for the studs sheathed with OSB and plasterboard respectively.

Experimental investigation into the performance of cold‐formed steel walls sheathed with OSB and cement‐based panels

AbstractCold‐formed steel (CFS) structures are developing fast in both seismic and not seismic areas for their high degree of prefabrication, high structural performance and the good energy performance. In the last decades, many research groups around the world have focused on the analysis of seismic behaviour of CFS structures and the development of design procedures that still need to find their full implementation in many international codes, first of all in the Eurocode. Therefore, the development of CFS system still requires, very often, the adoption of large experimental testing, in particular, when sheathing braced design methodologies are applied. This paper presents, for the first time, the in‐plane tests of CFS walls sheathed on one side with oriented strand boards (OSB) and cement based panels (CP). In particular, a set of two full scale tests of ledger walls having 2400mm width and 2926mm height, sheathed with OSB3 and CP, and a set of two tests on ledger walls having dimensions (2400mmm x 2974mm) sheathed with OSB3 panels are presented and discussed. The tests have been carried out in accordance to the BS EN 594:1996. The results confirm in agreement with literature studies that the collapse is governed by the failure of the screws between panels and steel profiles. And, more importantly it shows that, when both OSB and CP are present the collapse is governed by the failure of the screws between cement panels and steel profiles. When comparing the two sets of walls those sheathed only with OSB panels have lateral resistance which is about 1.5 time higher than when also CP are present.

Numerical modeling for adjustment of the equivalent moduli of elasticity of OSB layers estimated from experimental flexural rigidity

Oriented strand board (OSB) panels are well-known for their many applications and as a complex multi-layer composite, which elastic properties are commonly obtained by testing the specimens for the longitudinal and transverse directions of the panel. This study aimed to establish a method to obtain the equivalent moduli of elasticity to each panel layer. For this purpose, OSB panels were manufactured from balsa wood waste and castor oil polyurethane resin. Based on the flexural rigidity for each panel direction and considering the geometric and elastic parameters, a system of the equations was established to obtain the equivalent moduli of elasticity of each layer. The method proposed was validated using the finite element method. The experimental results showed that the elastic-linear behavior was quite accurate for up to approximately 60% of the ultimate stress, and thereafter the non-linearity was better fitted by a multi-linear model. The load-deflection curves, both for the longitudinal and transverse directions, for the elastic phase were precisely represented with the equivalent moduli of elasticity. For non-linear segments, there was a strong dependence on the parameters adopted in the model. The results obtained in this study showed that the equivalent moduli of elasticity of layers of OSB panel can be obtained based on the results of bending test of specimens manufactured with the full thickness of the panel, providing properties for more detailed applications in the modeling with of this layered wood-based product.

Contribution of OSB Sheathing to Racking Capacity of Cold‐Formed Steel Frames

AbstractIn recent years, new innovative systems to ensure high structural and environmental performance have emerged in constructional steel practice. Among others, modular construction using cold‐formed steel (CFS) frames which offer some advantages over conventional structural system counterparts, such as high strength‐to‐weight ratio, controlled material quality and sustainability. Wood‐sheathed shear wall is one of the lateral load resisting systems adopted in CFS modular construction. It is composed of CFS C‐shaped framing members (chord studs, studs and tracks) attached to wood sheathing using fasteners. The resistance capacity of these shear walls, when subjected to in‐plan lateral loads, is governed by the connections between the frame and the sheathing board. It is therefore crucial to quantify the shear capacity of sheathing‐to‐frame fasteners. In this context, a testing rig was developed consisting of two CFS lipped channels facing back‐to‐back connected on the flanges by oriented strand board (OSB) and loaded such that the 8 connecting fasteners experience shear. The prevailing role of sheathing thickness and fastener type is highlighted in the results. The experimental results are summarized for further use in the analysis of shear walls under lateral load.

Lateral loading performance of end narrow panel reinforced light wood frame shear walls

PurposeThe sheathing panels of traditional light wood frame shear walls mainly use oriented strand board (OSB) panels, and the damage of the traditional walls is mainly caused by the tear failure at the bottom corner of the OSB panel. In order to improve the lateral performance of the traditional light wood frame shear wall, a new type of end narrow panels reinforced light wood frame shear wall is proposed.Design/methodology/approachThe monotonic loading tests and finite element analysis of nine groups of walls, with different types of end narrow panel, types of fasteners used on the end narrow panels and the end narrow panels edge fastener spacing, are carried out. The effects of different characters on lateral performance of light wood frame shear walls are reported and discussed.FindingsThe failure modes of the wall reinforced by parallel strand bamboo narrow panels with 150 mm edge nails spacing are similar to the traditional wall. Conversely, the failure modes of other groups of walls reinforced by end narrow panels are the tears of the bottom narrow panel or the bottom beam. The end narrow panel reinforced light wood frame shear wall can make full use of the material property of sheathing panels. Compared with the lateral performance of traditional walls, the new-type end narrow panels reinforced walls have better lateral performance.Originality/valueA new type of end narrow panels reinforced light wood frame shear wall is proposed, which can enhance the lateral performance of the traditional light wood frame shear wall. The new-type walls have advantages of convenient operation, manufacture cost saving and important value of engineering application.

Investigation of pore size distribution by mercury intrusion porosimetry (MIP) technique applied on different OSB panels

Mercury intrusion porosimetry (MIP) is a technique used to characterize the pore size distribution and resin penetration in lignocellulosic materials, such as oriented strand board specimens (OSB), a multilayer panel utilized in structural applications. The method is based on the isostatic injection, under very high pressure, of a non-wetting fluid (mercury) into the porous material to determine parameters such as pore size distribution and percentage of porosity of the specimens. In this study, five different OSB were analyzed; they contained different wood species, resin type, and resin content. The panels manufactured with castor oil polyurethane resin showed porosity values in the range of 54.7 and 27.8%. This was a promising result compared with those obtained for panels made with phenolic resins, which are currently commercialized in Brazil.

Development of a pyrolysis model for oriented strand board: Part II—Thermal transport parameterization and bench-scale validation

Oriented strand board is a widely used construction material responsible for a substantial portion of the fire load of many buildings. To accurately model oriented strand board fire response, kinetics and thermodynamics of its thermal decomposition and combustion were carefully characterized using milligram-scale testing in part I of this study. In the current work, Controlled Atmosphere Pyrolysis Apparatus II tests were performed on representative gram-sized oriented strand board samples at a range of radiant heat fluxes. An automated inverse analysis of the sample temperature data obtained in these tests was employed to determine the thermal conductivities of the undecomposed oriented strand board and condensed-phase products of its decomposition. A complete pyrolysis model was formulated for this material and used to predict the mass loss rates measured in the Controlled Atmosphere Pyrolysis Apparatus II experiments. These mass loss rate profiles were predicted well with the exception of the second mass loss rate peak observed at 65 kW m−2 of radiant heat flux, which was underpredicted. To further validate the model, cone calorimeter tests were performed on oriented strand board at 25 and 50 kW m−2 of radiant heat flux. The results of these tests, including both mass loss rate and heat release rate profiles, were predicted reasonably well by the model.

Hygrothermal Behaviour of Inorganic Binder-Based Board Materials

Currently, the use of board materials as a material intended for the dry construction of building structure cladding in the building industry has become widespread. The most common types of board materials include wood-based boards (particle, fibre, laminated / plywood, oriented strand boards [OSB]), cement-bonded particleboards and gypsum plasterboards or gypsum fibre boards. In the case of board materials based on inorganic binders, these are most often represented by boards in which the fillers used are bonded by plaster or cement. Wood can then be used as filler, which is predominantly an assortment of inferior-quality trees or comes from a short rotation coppice, treated by various technological processes. Microstructure and material composition have the greatest influence on the physical and mechanical properties of the boards. The use of the boards in the internal or external environment is determined by their individual properties. Another indicator for the possible use of boards is the form of moisture with which the board comes into contact after installation into the structure. For the external environment, the boards have to withstand mainly liquid moisture; in contrast, in an internal environment, the boards come into contact mainly with air humidity. The diffusion properties of the individual products are also crucial for the overall design and use of the boards for structure cladding.

The Impact of Post-Manufacture Treatments on the Surface Characteristics Important for Finishing of OSB and Particleboard

Oriented strand board (OSB) is a commonly used structural wood-based panel for walls and roof siding, but recently the industry has become interested in OSB as a substrate for indoor and outdoor furniture. Particleboard is mainly used in furniture productions and has become popular as a construction material due to its numerous usage possibilities and inexpensive cost. Moisture is one of the most important factors affecting wood-based panel performance and the post-treatment conditions affected their affinity to water. When OSB and particleboard are used as substrates for coatings, their surface characteristics play an important role in determining the quality of the final product. Furthermore, roughness can significantly affect the interfacial phenomena such as adsorption, wetting, and adhesion which may have an impact on the coating performance. In this research particleboard and OSB panels were sanded, re-pressed and IR heated and the influence of surface treatments on hardness, roughness, wetting, water, and water vapour absorption was studied. Results showed that sanding improved the wetting of particleboard and OSB with water. Moreover, studied surface treatments increased water absorption and water penetration depth of OSB panels, and re-pressing had a positive effect on reducing the water vapour absorption of particleboard and OSB panels.