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The main objective of this work is to characterize the stress–strain relationship of cross-laminated timber (CLT) wall panels when loaded in compression and how different confinement mechanisms provide compression reinforcement for the CLT panels. CLT crushing tests were performed to define the behavior of CLT under compression up to the failure point, defined here as the strain at which the gross stress falls by 20% from the peak value. Testing included monotonic uniform compression experiments of five-ply CLT with specimens that were 0.457 m wide by 1.52 m long. The motion of the specimens perpendicular to loading direction was restrained at midlength to prevent buckling. Twelve specimens were tested, including six bare CLT specimens and six reinforced specimens of CLT—three with self-tapping screws while the other three with self-tapping screws and an additional U-shape steel plate at the bottom of the specimens. Various damage points were observed during the tests, including (1) point at the onset of damage (through visual observation and instrumental observation) (2) point of initiation of strength degradation, (3) point at which buckling occurs, (4) point at which 25.4 mm delamination was observed, and (5) failure point. Three axial compression stress–strain models were adopted, calibrated, and compared. Results indicate that a stress–strain model combining linear and cubic functions for the elastic and softening responses, respectively, captures well the CLT inelastic behavior under compression. [ABSTRACT FROM AUTHOR]

Displacement-based design (DBD) methods were originally developed in the 1990s for concrete structures and later modified for light-frame wood buildings and mass timber buildings. DBD methods use displacement as the design criterion to minimize economic losses, control component damage, and enable rapid return to functionality for increased resilience. This paper introduces a performance-based design check procedure that uses the direct displacement-based design (DDD) method and numerical pushover analysis for the design of cross-laminated timber and light-frame shear (CLT-LiFS) buildings. Prestressing CLT panels with embedded posttensioning high-strength steel cables or external high-strength steel rods enable them to provide robust lateral load resistance and self-centering capacity. LiFS walls offer additional lateral load resistance and energy dissipation through the slip of nail connections. A six-story CLT-LiFS building was used as a design example meeting three performance levels (damage limitation, life safety, 15 and collapse prevention) based on ASCE/SEI 41-17 criteria. Each performance level corresponds to a set of three criteria: interstory drift limits, cable stress limits, and CLT compressive strain limits at the rocking interface. The design was checked using a series of nonlinear time history (NLTH) analyses with a suite of ground motion records. The results from the design check procedure and the statistical distributions of performance criteria from NLTH analysis confirmed that the six-story CLT-LiFS building met performance expectations. Additionally, a collapse fragility curve was developed to provide a comprehensive understanding of the building's behavior. [ABSTRACT FROM AUTHOR]

Mass ply panel (MPP) is a new mass timber product that was recently introduced for structural applications in buildings. Although there have been several studies on characterizing the mechanical properties and structural performance of MPP, there is a lack of understanding regarding in-plane shear properties of the panels. More intensive studies should be done for MPP to provide a comprehensive understanding of its behavior. This paper presents an experimental study to characterize the effective in-plane shear modulus and shear strength of MPP in the major strength direction of the panel. Two experiments, including multiple span-length center-point bending tests and a novel large-scale shear test, were conducted. The test results were presented and compared with previous studies and the manufacturer's product report. The new test proposed for shear strength characterization has the potential to be an industry standard for mass timber panels. [ABSTRACT FROM AUTHOR]

The performance of cross-laminated timber (CLT) panels in building applications have been investigated extensively. However, limited information is available regarding the performance of CLT panels for bridge applications, as well as the torsional performance of CLT panels under asymmetric loading, geometry, and boundary conditions. The objective of this study was to investigate the torsional performance of skewed CLT pedestrian interior bridge deck panels through large-scale structural testing. The panels were designed as a pedestrian bridge crossing over an atrium of The Canyons building in Portland, OR. The test panels were subjected to line and uniformly distributed loads to replicate the reactions from the adjacent panels and design loads directly applied to the panel, respectively. Two different loading configurations based on the 2014 Oregon Structural Specialty Code (OSSC) were applied with up to three different loading intensity levels. An additional loading configuration, which was beyond the scope of the OSSC, was also applied in the second series of tests to determine if panel failure could be induced. The test results demonstrated that the test panels were able to recover their original shape without suffering major damages on the panel. The measured residual deformation after the removal of the applied load was very small. The findings of this study broaden the current state of knowledge of the structural performance of a CLT bridge deck panel under asymmetric loading, and the test results can be used for future design problems. [ABSTRACT FROM AUTHOR]

Mass plywood panel (MPP) is a veneer-based engineered wood product that recently was introduced in the mass-timber construction industry. Preliminary studies show that MPPs can be a preferred construction material for shear walls, floor diaphragms, and roof assemblies. However, no design guide exists regarding the use of MPPs as structural elements. This is compounded by a lack of engineering properties and parameters needed beyond the generic values provided in the product report. To assess the engineering properties and provide a benchmark dataset, a comprehensive experimental testing program characterized the performance of MPPs in flexure, in-plane shear (parallel to major strength direction), compression, and tension. Additionally, the characteristic values of MPPs were derived based on the test results to provide an initial indication of design values of MPPs. The test results presented in this study provide a fundamental basis for the development of a design guide for MPPs. [ABSTRACT FROM AUTHOR]

In nonlinear structural analysis, shear walls within whole-system models are often modeled using a spring model with a single degree of freedom where the lateral stiffness of the shear wall is modeled as a nonlinear spring. The stiffness of the spring is often described by the hysteretic relationship between the lateral restoring force and shear wall lateral deformation. In this study, a new shear element is introduced, which couples the lateral and vertical stiffness of the shear wall. This new shear element is able to better describe the behavior of shear walls in mid-rise and tall buildings. An illustrative example is presented to help explain the application of the new shear element in finite element modeling. In the examples, the new shear element is used to calculate displacement and internal forces for cold-formed steel frames. The results show that without including vertical wall stiffness, the lateral displacement is significantly underestimated. The difference increases with the height of the building and for a ten-story frame the new model demonstrates an increased lateral displacement at roof level of 64.1% when compared with current typical shear element model (lateral stiffness only). [ABSTRACT FROM AUTHOR]