1,721,068 research outputs found

    Cyclic behavior of cross-laminated timber (CLT) wall systems: Experimental tests and analytical prediction models

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    An experimental program was performed at IVALSA Trees and Timber Institute on single and coupled cross-laminated (CLT) wall panels with different anchoring systems and different types of joints between adjacent panels. The mechanical properties of CLT walls were assessed and are critically discussed in the paper. The connector layout and the design of the screwed vertical joints were found to markedly affect the overall behavior of the structural system. The in-plane deformations of CLT panels were almost negligible, whereas concentration of forces and deformations mainly occurred in the connections. Advanced analytical models for nonlinear pushover analysis of CLT wall systems were developed and verified against test results. The models take into account all stiffness and strength components of connectors, as well as the bending and shear deformation of the panels. A parametric study of CLT wall systems with different aspect ratios and wall segmentation was performed, showing that segmentation of CLT walls decreases their stiffness and strength but significantly improves their deformation capacity

    Long-term and collapse tests on a timber-concrete composite beam with glued-in connection

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    The paper reports the results of a comprehensive experimental test performed on a 6m span timber-concrete composite beam with glued rebar connection. The beam had first been subjected to sustained load in unsheltered outdoor conditions for 5 years. Eventually a ramp loading test up to failure was performed. The long-term test showed an increase in deflection mainly during the first two years, while the slip rose during the whole testing period. Thermohygrometric variations of environment caused an important fluctuation of all quantities on both yearly and daily scale. By comparing experimental and analytical results, it is highlighted that composite beams in outdoor conditions should be assigned to the 3rd service class according to the Eurocode 5 (EC5). Analytical predictions based on approximate formulae suggested by such regulation are found to be not conservative for the long-term behaviour and fairly accurate for the collapse behaviour. Since the simplified formulae proposed by the latest versions of the EC5-Parts 1.1 and 2 largely underestimate the actual connection stiffness and strength, it is recommended that realistic values of these properties, such as those obtained through pushout tests, be used when designing timber-concrete composite beams

    "Strength and deformation characteristics of typical X-lam connections"

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    This paper presents some of the results of an extensive experimental programme on typical X-Lam connections, conducted at CNR-IVALSA research institute. The goal of this research is to provide a better understanding of the seismic performance of connections in cross-laminated timber buildings subjected to seismic actions. In-plane monotonic and cyclic shear tests were performed on mechanical screwed connections between adjacent parallel wall-wall and floor-floor X-Lam panels. In addition, monotonic and cyclic tests were carried out on orthogonally connected panels (wall-wall and wall-floor) subjected to shear and withdrawal load. Mechanical properties in terms of strength, stiffness, energy dissipation, ductility ratio and impairment of strength were evaluated. The overstrength factor, which is of great importance in capacity-based design, was also evaluated for the different types of connection tested
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