Timber-framed shear walls play a crucial role in providing stiffness and resistance to timber buildings subjected to horizontal forces induced by wind or earthquakes. Enhancing the load-carrying ...capacity of a timber-framed shear wall subjected to horizontal forces, is achieved most effectively by reinforcing the connection between sheathing and framing members. Since however, the shear resistance of such a wall is determined by the resistance of the individual wall elements, strengthening the sheathing-to-framing connection is possible only to an extent where the shear resistance is not limited by the resistance of the sheathing panel.
This study presents experimental investigations of the shear resistance of OSB/3 panels, when used as sheathing material in timber-framed shear walls, which revealed that the shear resistance of the OSB/3 sheathing was reduced in comparison to the shear strength of the OSB/3 panels themselves. The reduction is attributed to additional stresses in the panel, and is accounted for in design rules specified in the German National Annex of Eurocode 5 (DIN EN 1995-1-1/NA:2013-08) and in the CEN Enquiry (ENQ) draft of Eurocode 5 (prEN 1995-1-1:2023-09). The results of the investigations confirm the reduction factor which is proposed in prEN 1995-1-1:2023-09, for wall elements with one-sided sheathings. However, the reduction factor specified for the design of wall elements with two-sided sheathings could not be confirmed. The results of this study performed with comparably massive and rigid timber framing revealed no difference in the reduction factor for timber-framed shear walls with one- or two-sided sheathings.
•Tensile and shear tests on OSB/3 panels of thicknesses 12 mm, 15 mm, 18 mm and 25 mm.•Investigation of the load-carrying capacity of OSB/3 sheathed timber-framed walls.•Evaluation of the limit of OSB/3 panels in the application as sheathing material.•Comparison of results from experiments with design rules given in Eurocode 5.
The embedment strength and stiffness of wood products are key parameters in the design of timber structures using dowel-type connections. The embedment behaviour of layered wood products such as ...hybrid cross-laminated timber (HCLT) will result from a combination of the behaviours of the multiple layers. In this paper, half-hole embedment tests according to ASTM D5764–2013 are presented, evaluating the embedment performance of HCLT made of fast-growing Chinese fir and OSB with self-tapping screws (STS). Six prediction models proposed by current standards and other scholars are compared with the measured data for strength, and two modified models are proposed to predict embedment strength for HCLT. Specimens loaded parallel to the grain of longitudinal layers had a higher bearing capacity, yield and ultimate embedment strength. An increase of STS diameter improved the bearing capacity of specimens but had a negative influence on the embedment strength. The modified models proposed here achieved more accurate prediction of the experimental characteristic values for HCLT than the existing methods, both for yield and ultimate embedment strength. The findings of this study represent progress towards the safe and economical structural design and wider application of innovative CLT products in the construction industry.
•Fabrication and investigation of hybrid CLT.•Summary of current embedment models.•Proposal of two modified prediction models.•Comparison between current models and our proposed models.
A leaky-wave antenna (LWA) based on split-ring-shaped spoof surface plasmon polaritons (SSPPs) is designed, simulated, and measured. We proposed a double-periodic patch-loaded method to suppress the ...open-stop band (OSB) effect and introduced an SSPP power divider with a 180° phase shift for the anti-phase excitation to enhance the gain in the main radiation direction of the antenna. Both methods are analyzed and verified. The investigated results show that both S 11 and S 21 are less than -10 dB in 7-11 GHz and no bulge is observed around the broadside radiation frequency of 10 GHz, demonstrating good OSB suppression (S 11 < -26 dB, S 21 < -45 dB). Furthermore, the LWA also demonstrates good performances with a wide-angle (-48° to +15°), high scanning rate (1.57°/%), high gain (10 dBi), and high average efficiency (97%). This work provides a new way to realize efficient OSB suppression for LWA designs.
RESUMO Este trabalho foi desenvolvido com objetivo de avaliar a influência da orientação das partículas “strand” e inclusão laminar sobre as propriedades físico-mecânicas das chapas. Foram fabricadas ...chapas com densidade de 0,70g/cm3 e composição face:miolo de 50:50, utilizando resina fenolformaldeído. Os valores de MOE e MOR das chapas com partículas orientadas foram significativamente superiores em comparação às chapas com partículas não-orientadas. A inclusão laminar em chapas com partículas não-orientadas contribuiu para o aumento nos valores de MOE e MOR na direção paralela ao plano da chapa e redução na direção perpendicular. Para as chapas com partículas orientadas, a inclusão laminar não contribuiu significativamente para o incremento nos valores de MOE e MOR. A orientação ou não das partículas e o reforço laminar não influenciaram nos valores de absorção de água. A inclusão laminar contribuiu para a redução nos valores de inchamento em espessura das chapas.
In this article, a deployable Coplanar Waveguide (CPW) coaxial colinear (CoCo) antenna is proposed with full coverage in H-plane. The antenna features an ultra-thin profile of only 0.1 mm with ...excellent deployability. The proposed antenna consists of eight units which are connected through metal crossover lines. The top and bottom metal layers alternate as the inner and outer conductors of the CPW. Metal bridges are introduced to mitigate the open stopband (OSB) phenomenon which also eliminate the undesired CPW slot mode. A planar choke is designed to eliminate the effects of unbalanced coaxial feeding, ensuring consistency between the measured and simulated results. The antenna was fabricated using flexible printed circuit (FPC) technology. Within the target 4.8-4.9 GHz band, the measured S11 is below -10 dB and the efficiency is about 80%. The average gain in the H-plane is 5.8 dBi. The antenna shows great potential for applications in unmanned aerial vehicles (UAVs) and other mobile communication devices.
•CCB did not influence the mechanical properties of OSB.•CCB improved water absorption and thickness swelling of OSB.•The percentage of castor-oil based polyurethane adhesive (8% to 12%) did not ...change the properties.
Oriented strand board (OSB) consists of wood particles glued by resins, whose composite can be deteriorated by organisms due to construction uses in aggressive conditions. To improve the panel resistance against these organisms, especially when low natural durability woods are used, the panel treatment is necessary. This study evaluated physical and mechanical properties of OSB manufactured with Paricá (Schizolobium amazonicum), native low-density forest wood, whose strands were also treated by chromated copper borate preservative (CCB) and glued (8%, 10% and 12% content) with castor-oil based polyurethane adhesive. Panel performance was evaluated using the EN 300 and ABNT NBR 14810–2 requirements. From analysis of variance (5% significance level), the use of CCB promoted a significant reduction in the values of physical properties (thickness swelling and water absorption) and did not promote reduction in the mechanical properties of the manufactured panels. All composites manufactured showed highly satisfactory performance requirements. As the levels of adhesive resulted and composites with physical and mechanical properties statistically equivalent to each other, it can be concluded that the panels produced with 8% adhesive content and treated with CCB resulted in the best treatment, since it reaches the minimum standard with a smaller amount of resin (more economical).
In this paper, we propose an approach to realize substrate integrated waveguide (SIW)-based leaky-wave antennas (LWAs) supporting continuous beam scanning from backward to forward above the cutoff ...frequency. First, through phase delay analysis, it was found that SIWs with straight transverse slots support backward and forward radiation of the -1-order mode with an open-stopband (OSB) in between. Subsequently, by introducing additional longitudinal slots as parallel components, the OSB can be suppressed, leading to continuous beam scanning at least from -40° through broadside to 35°. The proposed method only requires a planar structure and obtains less dispersive beam scanning compared with a composite right/left-handed (CRLH) LWA. Both simulations and measurements verify the intended beam scanning operation while verifying the underlying theory.
The structural behaviour of sheathed cold-formed steel lipped channel section columns (studs) subjected to combined compression and major axis bending is investigated herein by means of numerical ...modelling. Finite element (FE) models of single studs, set in tracks and connected to oriented strand board (OSB) and gypsum plasterboard sheathing under varying combinations of axial compression and horizontal loading were developed in ABAQUS and validated against experimental results reported in the literature. The developed numerical models incorporated cross-sectional and global geometric imperfections, while geometrical and material nonlinearities for both the steel and the sheathing were considered in the analyses. Particular emphasis was given to replicating the “as-built” boundary conditions at the ends of the columns, controlled by the screws connecting the column to the track and by the column–track contact interaction. The interaction between the sheathing and the column, as well as the behaviour of the fasteners connecting the two components, were also explicitly modelled. Both the shear and pull-through characteristics of the fasteners were considered and simulated based on experimental findings. Following successful validation of the finite element models, parametric studies were conducted. The results showed that substantial structural performance benefits can be achieved by the addition of sheathing to cold-formed steel members and that the spacing of the connectors has a strong influence on the member response. For a typical system, decreasing the connector spacing from 300 mm to 75 mm was found to increase stud capacity and stiffness by up to 12% and 10% respectively when in pure compression and up to 26% and 22% respectively when in pure bending; under combined loading, capacity increases of up to 29% were found.
•Numerical simulation of sheathed studs under combined compression and bending.•Advanced modelling of fasteners, sheathing and boundary conditions at the stud ends.•Validation of developed finite element models against physical tests.•Addition of sheathing found to substantially enhance structural performance.•Decreasing fastener spacing shown to increase capacity and stiffness by up to 29%.
The article compares two modern integration platforms used in production and test environments. These are, a free integrity solution WSO2 data bus and OSB bus, called Oracle Service Bus, which is a ...commercial software. The tests that were carried out on the abovementioned buses and results were discussed. In addition, a comparison of results with conclusions that were drawn after the tests was attached.
The generation and use of GNSS analysis products that allow—particularly for the needs of single-receiver applications—precise point positioning with ambiguity resolution (PPP-AR) are becoming more ...and more popular. A general uncertainty concerns the question on how the necessary phase bias information should be provided to the PPP-AR user. Until now, each AR-enabling clock/bias representation method had its own practice to provide the necessary bias information. We have generalized the observable-specific signal bias (OSB) representation, as introduced in Villiger (J Geod 93:1487–1500, 2019) originally exclusively for pseudorange measurements, to carrier phase measurements. The existing common clock (CC) approach has been extended in a way that OSBs allowing for flexible signal and frequency handling between multiple GNSS become possible. Advantages of the proposed OSB-based PPP-AR approach are: GNSS biases can be provided in a consistent way for phase and code measurements and it is capable of multi-GNSS and suitable for standardization. This new, extended PPP-AR approach has been implemented by the Center for Orbit Determination in Europe (CODE). CODE clock products that adhere to the integer-cycle property have been submitted to the International GNSS Service (IGS) since mid of 2018 for three analysis lines: Rapid, Final, and MGEX (Multi-GNSS Extension). Ambiguity fixing is performed not only for GPS but also for Galileo. The integer-cycle property of between-satellite clock differences is of fundamental importance when comparing satellite clock estimates among various analysis lines, or at day boundaries. Both kinds of comparisons could be exploited at a very high level of consistency. Any retrieved comparison essentially indicated a standard deviation for between-satellite clocks from CODE of the order of 5 ps (1.5 mm in range). Finally, the integer-cycle property that may be recovered between the CODE Final clock and the accompanying bias product of consecutive daily sessions (using clock estimates additionally provided for the second midnight epoch) allows us to deduce GPS satellite clock and phase bias information that is consistent and continuous with respect to carrier phase observation data over two, three, or, in principle, yet more days. Phase-based clock densification from initially estimated integer-cycle-conform clock corrections at intervals of 300 s to 30 s (5 s in case of our Final clock product) is a matter of particular interest. Based on direct product comparisons and GRACE K-band ranging (KBR) data analysis, the quality of accordingly densified clock corrections could be confirmed to be on a level similar to that of “anchor” (300 s) clock corrections.
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