Experimental and FEA Study of Structural Behavior of CLT Shear Walls for Wood Building Applications

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University of Alabama Libraries

Cross Laminated Timber (CLT) is emerging as a sustainable alternative to traditional building construction materials for tall buildings in high seismic regions. However, before they can be incorporated into the building codes, different categories of CLT shear wall systems need to be fully characterized and novel solutions must be implemented to overcome the limitations of existing timber systems. This dissertation addresses analytical modelling of unbonded post-tensioned (PT) CLT rocking wall (CLTRW) system for its use in both rectangular and nonrectangular configurations. A set of laboratory experimental tests and nonlinear finite element analysis (FEA) were compared to investigate and characterize the flexural and lateral behavior of CLTRW system. The flexural performance was studied using a full-scale, 5-layer rectangular CLT panel testing in three-point loading configuration. A three-dimensional (3D) finite element (FE) model with nonlinear geometry and contact properties was developed in ABAQUS using measured material properties. The FE model was validated using the experimental data from the CLT panel bending test. Based on the validated FE model, additional FE models of previously tested post-tensioned CLTRW panels with different wall aspect ratios and tendon configurations were also developed. A close agreement between the measured and FEA models was found in the stiffness behavior, which suggested that the proposed nonlinear FE modelling approach can be employed to predict the performance of other CLTRW systems. This research further analytically investigates shear behavior of high stiffness web-to-flange connections for nonrectangular CLTRW system. The proposed shear connections use spatially arranged self-tapping screws (STS) together with ultra-high-performance concrete (UHPC) shear-keys. 3-D nonlinear FE models for connections with and without UHPC were validated using the available experimental data, which showed that the inclusion of UHPC would significantly improve the stiffness of the connections. The FEM technique for connections was subsequently used to evaluate the lateral load performance of a 36-ft tall, T-shape CLTRW wall with multiple connections. The results from this model were compared to a T-wall without shear-key connections. It was found that the wall with high-stiffness shear-key connections showed better lateral load performance compared to traditional connection wall.

Electronic Thesis or Dissertation
Cross-laminated timber, FEA, Pushover analysis, Shear wall, Timber connections, Wood building