Oriented Strand Board Sheathing Research Articles

Numerical evaluation of shear strength of CFS shear wall panel with OSB sheathing

Outside of the American Iron and Steel Institute AISI S400-15 limitations of Shear Wall Panel (SWP) height-to-width (h/w) aspect ratio, the present paper puts forward a sufficiently detailed Finite Element Modeling (FEM) using “Abaqus” software, capable to evaluate with a reasonable precision the shear strength of Cold Formed Steel (CFS) SWP with Oriented Strand Board (OSB), under lateral load. In terms of nonlinear response, shear strength and failure modes, the numerical results of the SWP with and without an opening are validated against available experimental data, accounting for nonlinear mechanical and geometrics characteristics, as well as the nonlinear behavior of connection. Subsequently, the conducted comprehensive parametric studies have revealed that the variation of the screw spacing, from 50.8 mm up to 152.4 mm, provides a nonlinear variation of shear strength that cannot be extrapolated for different screw spacings. In addition, the shear strength of a two-sided OSB-sheathed SWP is less than twice one-sided OSB-sheathed SWP. Furthermore, the door’s and window’s openings’ position between the center and the edge of the SWP provide the best performance in terms of shear strength up to 33 % and 24 % than the center and edge openings’ positions respectively.

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.

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.

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.

Experimental study of sheathed cold-formed steel beam–columns

An experimental study of sheathed cold-formed steel C-lipped wall studs, with service holes, subjected to compression and major axis bending is presented in this paper. A total of 17 experiments were performed with both oriented strand board (OSB) and plasterboard used as sheathing and with varying connector spacing employed between the sheathing panels and the steel members. The tested specimens comprised a single 2.4 m long column sheathed on both sides and secured at the ends to top and bottom tracks. The member tests were complemented by material tests, stub column tests and initial geometric imperfection measurements. The specimens were tested in a dual-actuator rig where axial compression was applied by means of a vertical actuator through the top track, while bending was applied through the application of four lateral point loads. Eight pure compression tests with both plasterboard and OSB sheathing and with the spacing of the connectors varying between 75 mm and 600 mm were initially performed. Specimens with OSB sheathing were then tested under pure bending and combined loading. The full load–deformation responses and failure modes of the member test specimens are reported. The compressed studs connected to the plasterboard sheathing at wider spacings exhibited pull-through failure of the connectors, followed by flexural torsional buckling, while the specimens with denser connector spacings, failed by local buckling at the member ends. The OSB sheathed specimens under pure compression failed by local and distortional buckling, those under combined loading exhibited local failure at the service openings, while for those under pure bending, local buckling and stud-to-track connector failure occurred. 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.

Influence of cover splices on the stress-strain state of plate-ribbed wood-composite panels

Wooden-composite plate-ribbed bent panels with structural plywood and oriented strand board sheathing with breaks are considered. An overview of studies researching and improving the effectiveness of different types of panels is presented. On the basis of the theory of calculation of composite rods by A.R. Rzha- nitsyn, a mathematical model has been compiled, which makes it possible to calculate the stress-strain state of these structures, taking into account the pre- sence of breaks in the sheathing and the flexibility of the mechanical fasteners of the sheathing and ribs. An equation for finding the coordinates of the most dangerous section of wooden ribs in the presence of breaks in the sheathing, which may not match with the middle of the span, is obtained. Panels with sheathing in a compressed zone with different locations of joints, symmetrically relative to the middle of the panel span are considered. Panels without joints in the skin are considered to compare the results. The graphs of the dependence of the maximum tensile stresses in the ribs in the most dangerous section and the maximum vertical displacements from the stiffness coefficient of the shear ties and the location of the breaks in the sheathing are presented. The values of the coefficients for the engineering design of panels, taking into account the decrease in the strength and deformation characteristics of the composite section of panels with breaks in the sheathing, as compared to panels with a solid sheathing, are obtained. The conclusions and recommendations, based on the results of the investigations, which can be used in the design of wooden-composite plate-ribbed structures, are formulated.

Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation

The transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering analysis software. In the presented approach, a timber-frame structure with polyurethane (PU)-foam insulation and OSB (oriented strand board) sheathing was exposed to dynamic excitation. The results were then used to generate a numerical 3D model of the wooden frame element. The process of creating the 3D model is explained with the necessary steps to reach validation. The details of the model, material properties, boundary conditions, and used elements are presented. Furthermore, the authors explain the technical possibilities for simplifying the numerical model in used software. Simplifying the model leads to a substantial reduction of calculation time without the loss of accuracy of results. Such a simplification is especially useful when conducting advanced numerical calculations in the field of seismic and dynamic resistant object design.

Fire Resistance of Exterior Wall Assemblies for Housing and Small Buildings

This paper presents the fire resistance results of 6 full-scale exterior wall assemblies study conducted at the National Research Council of Canada jointly with the North American construction industry and other Canadian government departments. The parameters investigated include: cavity insulation types (rock, glass and cellulose fibre) in exterior wall assemblies with oriented strand board sheathing; cavity insulation types (glass fibre and cellulose fibre) in exterior wall assemblies with Type X gypsum glass mat sheathing; and assemblies with different screw spacing of standard 400 mm o.c. and non-standard 200 mm o.c. for attaching the Type X gypsum board on the fire-exposed side and glass mat sheathing board on unexposed side to wood studs using glass fibre insulation in wall cavity. The impact of the investigated parameters on the fire resistance of exterior wall assemblies is discussed. Also, Further research recommendations on design changes to enhance the fire resistance of exterior wall assemblies are proposed. Results of the parameters studied showed that the effect of insulation types on the fire resistance of exterior wall assemblies with OSB sheathing can be considered significant when gypsum board on the fire-exposed side is attached to wood studs with screws spaced at 406 mm o.c., however, the effect insulation types on fire resistance when the gypsum board on fire-exposed side and gypsum glass mat sheathing are attached to wood studs with screw spaced at 203 mm o.c. can be considered insignificant. Also, results showed the use of non-standard screw spacing at 203 mm o.c. for attaching the gypsum board on the fire-exposed side increased the fire resistance by 37% compared to screw spacing at 406 mm o.c. Therefore, the effect of screw spacing on the fire resistance of exterior wall is significant.

REMOVAL NOTICE: Field research study for investigating wetting and drying characteristics in wood-framing walls subjected to cold climate

A field research study was conducted to investigate the wetting and drying characteristics in three 2 × 6 wood-framing wall specimens when they were subjected to different heat, air, and vapor flow transmission. The stud cavity of the wall specimens were filled with glass-fiber insulation having a nominal thermal resistance of R-20. The three wall specimens consisted of an exterior oriented strand board sheathing of 11-mm thick, spun-bonded olefin membrane, and vinyl siding. To investigate the effect of air/vapor barrier on the moisture performance, the first and second wall specimens, referred in this paper as “W1” and “W2,” included a 6-mil polyethylene sheet that was installed on the interior side of the stud cavity, behind a painted drywall. However, in the third wall specimen, referred as “W3,” the interior side of the stud cavity was closed by painted drywall without air/vapor barrier. To investigate the effect of the exterior insulation on the moisture performance of wood-framing walls with an air/vapor barrier, an insulation board made of extruded polystyrene (XPS) (50 mm thick and having a nominal thermal resistance of R-10) was installed in the wall specimen W2 on the exterior side of the spun-bonded olefin membrane. With and without air/vapor barrier, and with and without exterior insulation, this research study accounted for different parameters that may affect the wetting and drying characteristics in the wall specimens. These parameters included the pressure differential across the wall specimens, indoor humidity, outdoor cold climates, and air leakage as a result of creating deficiencies that provided a path for air leakage in the wall specimens. A test protocol was developed in this study that permitted investigating the effects of these parameters on the hygrothermal performance of wood-framing wall systems.

Experimental and numerical study of OSB sheathed-LVL stud wall with stapled connections

This paper presents the results of an experimental and a numerical study on the OSB-LVL joints and light OSB sheathed-LVL stud walls. The joints and the walls were comprised of Laminated Veneer Lumber (LVL) studs and/or joists with 6 mm thick oriented strand board (OSB) sheathings stapled on both sides. First, monotonic static and cyclic tests were performed on the stapled OSB-LVL joints to study influence of the thin OSB panels, length of the staples and their edge distance on the failure mode, loading capacity and ductility of the OSB-LVL joints. Then, three full-scale OSB sheathed-LVL stud walls with pull-down rods were tested under monotonic static gravity and lateral loads and cyclic lateral loads to evaluate the failure load, ductility and energy dissipation capacity of the walls. The well-known CASHEW load-slip model was calibrated against the results of stapled OSB-LVL joints and the calibrated model was used in conjunction with a simple mechanistic model to predict the cyclic response of the light LVL stud walls with OSB sheathing. The wall behaviour under vertical and lateral loads were also simulated with a 3D nonlinear finite element (FE) model to further demonstrate advantages of the simplified models over advanced nonlinear FE models.

A simplified method to evaluate the flexural capacity of lightweight cold-formed steel floor system with oriented strand board subfloor

Lightweight floors built with cold-formed steel C-shape joists and oriented strand board sheathing is one of the primary floor systems in cold-formed steel residential construction. In order to investigate the flexural capacity with accounting for the composite action of the floor system, two tests on the flexural capacity of the floor system were carried out. The test results indicated that the load-carrying capacity of the floor system was significantly affected by the spacing of the screws that connect the joist and oriented strand board sheathing. The primary failure mode of the floor system was the local buckling at the critical section of the C-shape joist although there was tendency of lateral-torsion buckling of the joist. The wavelength of the buckling mode was approximately equal to the screw spacing. A finite element mode was established to simulate the structural behaviour of the floors by commercial software ANSYS and it was found that the numerical results agreed well with the test data. Parametric studies were carried out based on numerical analysis to investigate how the flexural capacity of the floors was influenced by different factors such as screw spacing, joist spacing and sheathing thickness, etc. Finally, based on the test data and numerical analysis results, a simplified design method was proposed to predict the flexural capacity of the floors with accounting for the composite action. The results obtained from the proposed method were validated by both experimental and numerical investigations of two full-scale lightweight floors built with cold-formed steel C-shape joist and oriented strand board subfloor.

Finite-element analyses of light timber-framed walls with and without openings

The static responses of timber-framed shear walls with and without openings of variable dimensions and locations were numerically investigated using the finite-element (FE) method. The lateral load resistance capacities and general load–displacement behaviours of the timber-framed shear walls were investigated. In the FE study, the frame elements were modelled as beams, plates were modelled as shells and nails were modelled as spring elements. The plastic behaviour of the materials was modelled using experimental stress–strain relationships of the materials. For timber frames and oriented strand board (OSB) panels, uniaxial stress–strain curves were experimentally obtained under tensile and compressive loading. From the experimental materials models it was found that spruce exhibited non-linear behaviour under both tensile and compressive stress. In contrast, the OSB sheathing layer used in the analyses exhibited non-linear behaviour under compressive stress and linear behaviour under tensile stress. The numerical results were verified using experimental load–deflection relationships obtained from a previous study. Good agreement was found between the analytical and experimental results. To further examine the applicability of the experimentally verified numerical model, four different timber-framed shear walls were simulated with FE models.

Heat Capacity and Its Variation with Moisture Content for Plywood and Oriented Strand Board Sheathing Produced by North American Mills

Abstract The heat capacity of panels used for house sheathing is an important property that allows the hygrothermal modeling of thermal mass and the calculation of heating and cooling rates of certain types of walls. To our knowledge, this article presents the first data in over four decades for the measurement of heat capacity across a range of moisture content values. Although some estimates of panel heat capacity exist, few, if any, have been reported for mills across North America and across a range of moisture contents. The data clearly show the dependence of heat capacity on moisture content. They also show that solid wood and panel heat capacity values are similar at low moisture contents but diverge as moisture content increases. The variation in heat capacity with moisture content is large enough so that it should be considered when determining hygrothermal efficiency in walls containing plywood or oriented strand board or when developing hygrothermal models.

Moisture Performance of Energy-Efficient and Conventional Wood-Frame Wall Assemblies in a Mixed-Humid Climate

Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB) structural panel sheathing were measured over a period from mid-November 2011 through March 2013 in both north- and south-facing orientations in test structures near Washington, DC, USA. Wall configurations varied in exterior cladding, water-resistive barrier, level of cavity insulation, presence of exterior continuous insulation, and interior vapor retarder. The combination of high interior humidity and high vapor permeance of painted gypsum board led to significant moisture accumulation in OSB sheathing during winter in walls without a vapor retarder. In contrast, wintertime moisture accumulation was not significant with an interior kraft vapor retarder. Extruded polystyrene exterior insulation had a predictable effect on wall cavity temperature but a marginal impact on OSB moisture content in walls with vinyl siding and interior kraft vapor retarder. Hygrothermal simulations approximately captured the timing of seasonal changes in OSB moisture content, differences between north- and south-facing walls, and differences between walls with and without an interior kraft vapor retarder.

The effect of drying on timber frame connections post flooding

Timber structures face a unique risk from flooding. Elevations in moisture content due to prolonged wetting will lead to a reduction in the mechanical properties of the building. Despite recent growth of timber construction in the UK and a known increased risk from flooding, little research has been conducted into its effects on light frame timber construction and the most efficacious drying method. This paper presents the results of experiments to determine the optimum drying conditions for light timber frame construction with oriented strand board sheathing after simulated flooding. A series of specimens were wetted for 5 d to simulate flooding before exposure to different environments. The specimens were load tested and values of ultimate strength, yield strength and stiffness were compared to those of un-wetted control specimens. It was found that the optimum drying condition for recovery of the maximum pre-wetting mechanical properties was an environment of 38°C and 40% relative humidity. Although this is an optimal setting there is still a permanent reduction in the mechanical properties of approximately 40% for strengths and 20% for stiffness. Stiffness is dependent on grain orientation; however, strength was found to be independent of grain orientation, as it is governed by the oriented strand board failure.

Performance Evaluation of Midply and Standard Corner Joints of Wood Portal Frames

AbstractExperimental results to determine the moment-resisting capacity of wood portal frame corner joints are presented in this paper. Two types of corner joints (standard and MIDPLY) were tested with different configurations. An L-shaped corner joint including a narrow braced wall segment and header was used as a test specimen. A total of 37 corner joints were tested. Test results showed that the installation of metal strap or the adding of exterior oriented strand board (OSB) sheathing, while using high-density wood product (LVL, LSL) as header increased the moment-resisting capacity of corner joints. Furthermore, the MIDPLY corner joint had higher moment capacity than the standard corner joint. The moment-carrying capacity of corner joints could be further increased by applying fiber-reinforced polymer (FRP) on top of exterior OSB sheathing. A detailed finite element (FE) model of a corner joint is presented. The FE model predictions correlated well with the experimental results.

Lateral Load Carrying Capacity of Laminated Bamboo Lumber and Oriented Strand Board Connections

Laminated bamboo lumber (LBL) is regarded as an alternative framing material for the construction industry. However, there is limited knowledge of its behavior in connection with commonly used sheathing material, such as oriented strand board (OSB). This study characterized the lateral load carrying capacity of LBL-OSB connections and studied the applicability of the yield models presented in the national design specifications to LBL connections. Two different connection geometries, edge and plate, which were representative of those present in a wall, were analyzed. The strength of the connections was characterized using monotonic testing. After the destructive testing, portions of the framing and sheathing materials from the samples were further evaluated for dowel bearing strength. Experimental results indicate that the LBL-OSB connections have similar lateral load carrying capacity as conventional Douglas fir-OSB connections. No statistical significance was observed in the strength differences of edge and plate connection geometries. The results further indicated that existing yield models used for design of nailed connections can predict the capacity and the mode of yielding for edge connection geometry between OSB sheathing and LBL framing members of grade and dimensions considered in this study, provided that the dowel bearing capacity of the materials is known.

Behavior of cold-formed steel wall panels under monotonic horizontal loading

This paper summarizes the findings of an experimental study on cold-formed steel (CFS) wall panels with oriented strand board (OSB) sheathing. Static lateral load tests were conducted on a total of thirteen full-scale wall panel specimens to investigate the performance of CFS walls utilizing primarily the construction details used in Turkey. Experimental results revealed that the geometry of hold-down attachment used at the base of CFS wall panels to transfer tensile forces has a major effect on the overall behavior of the panels. Extensive damage was observed to occur in the hold-down attachment and in part of the bottom track adjacent to the hold-down, which prevented the wall panels to exhibit the stiffness associated with the main load resisting mechanisms. Tilting of the screws connecting the OSB sheathing to the CFS boundary framing members, as well as the separation of sheathing from the framing members were other commonly observed deformation modes. Existence of diagonal struts inside CFS frame was determined to cause a slight increase in load capacity and initial stiffness of the panels. It is also shown that the measured load capacity of wall panels can be predicted with an acceptable accuracy using design equations available in the literature.

Temperature driven inward vapor diffusion under constant and cyclic loading in small-scale wall assemblies: Part 1 experimental investigation

Important heating of a wet cladding due to solar radiation can induce a significant inward water vapor flow through the building wall, especially when the indoor space is air-conditioned to a cooler temperature. Such inward vapor transport in wood frame walls, often used in North America, may lead to an undesired wetting of wooden components in the wall and the gypsum board. In order to systematically document temperature driven inward vapor transport, an experimental test method is developed to produce precise measurements of the wetting and drying behavior of the different components of the wall, when a wetted brick veneer is subjected to a temperature loading protocol. Eight different wall assemblies are tested consisting of: a brick veneer, two variants of weather resistive membrane (spun-bonded polyolefin or building paper), an oriented-strand board (OSB) sheathing, glass fiber insulation, a gypsum board and two variants of interior finish (acrylic paint or vinyl wall covering). The test method is one-dimensional, but, in a two-dimensional variant, the influence of the wood stud on the wetting/drying behavior is also studied. It is found that, due to the temperature gradient, an important vapor flow is generated towards the inner side of the wall, wetting the OSB sheathing and the gypsum board. The vapor permeance of the interior finishing determines the wetting of the gypsum board. A vapor tight vinyl wall covering leads to significant wetting of the gypsum board and to very low drying rates during drying.

OSB as substrate for engineered wood flooring

Oriented strand board (OSB) is a commodity product subject to market fluctuation. Development of a specialty OSB could lead to a better, and more stable, market segment for OSB. It was demonstrated in a previous study (Barbuta et al. in Eur. J. Wood Prod. 2010), that OSB may be designed to obtain a high bending modulus of elasticity in the parallel direction, close to Baltic Birch Plywood (BBP) in its strongest direction. This study focused on the use of such specialty OSB in the manufacturing of engineered wood flooring (EWF) prototypes, a product that widely uses BBP as substrate in Canada. The performance of these two prototypes (aspen/birch and ponderosa pine) was studied. Five types of substrates: BBP, sheathing OSB, web stock OSB and the two specialty OSB prototypes were used to manufacture EWF. A 3-mm thick sugar maple plank was selected as the surface layer for all constructions. A polyvinyl acetate (PVA) type I adhesive was used to bond the components. The tests in conditioning rooms showed that BBP substrate constructions present the lowest distortion between humid and dry conditions as well as aspen/birch specialty OSB, according to ANOVA. The construction with OSB sheathing, OSB web stock and ponderosa pine OSB substrates showed higher distortion. The PVA type I adhesive led to weak bonding with high-density OSB surface. The results of this study demonstrate the potential of OSB panels to be used as substrate for EWF.