Analysis and design of Cross-Laminated Timber (CLT) walls under gravity loads have been outlined in the Canadian timber design standard with an adequate amount of details. The methods for designing shearwalls to resist lateral loads have not yet been fully developed, with only concepts being adopted, based on generalized capacity-based design concepts and definitions of yielding and non-yielding components. Several studies have focused on developing analytical expressions and design approaches for multi-panel CLT shearwalls, assuming angle brackets only behave in shear to prevent sliding, while ignoring compression zone effects in CLT panels. These assumptions may simplify the analysis, but they are not practical, especially since contemporary angle brackets are available on the market with uplift capacities comparable to those of hold-down connections. This study aimed to investigate the lateral behaviour of multi-panel CLT shearwalls and provided practical and comprehensive analytical expressions and design procedures for this type of structure. The analysis aimed to integrate the effects of all boundary connections, including hold-downs, angle brackets, panel-to-panel connections, and compression zones, into the analysis. On the basis of the developed analytical expressions, a capacity-based design procedure was proposed, which promoted rocking behaviour and optimized energy dissipation in the shearwall system. A novel yield hierarchy among various connections was introduced, and expressions for associated over-strength factors are proposed. For multi-storey applications, an approach which ensures uniform energy dissipation along the structure height and limits soft-storey failures was also presented. Experimental tests were conducted at the connection level to study the performance of conventional connections used in CLT shearwalls and to obtain their associated mechanical properties. Furthermore, the performance of multi-panel CLT shearwalls was investigated by conducting wall-level experimental tests to investigate the kinematic modes and establish levels of resistance and deflection. Numerical models were developed to verify the mathematical accuracy of the proposed analytical and design expressions. Also, to validate the proposed analytical expressions, they were compared against the numerical models, as well as the wall-level experimental tests. The results showed a reasonable match between the different approaches in terms of the general shape of the curves and kinematic behaviour.

The increasing demand for more sustainable construction has led to the development of new structural systems that include wood as building material. Cross laminated timber (CLT) has been identified as a potential system to address this need and to provide alternative options in the range of low- to medium-rise construction. The appeal in using CLT as a shearwall is driven by the combination of the rigid panels and small dimension fasteners, which allows for significant energy dissipation in the structure. However, there is currently no reliable analytical model to accurately predict the behaviour of multi-segment CLT shearwalls. The current study aims to develop an analytical model capable of predicting the elastic and plastic phases associated with the behaviour of multi-panel CLT shearwalls. The model describes the wall behaviour as a function of the connectors’ properties in terms of stiffness, strength and ductility. This dependency means that the only input required in the model is the behavioural parameters of the connections. The proposed model contains six cases with a total of 36 different failure mechanisms. Two final wall behaviours were developed, and it was found that behaviour (i.e. single wall) could be achieved if the yielding in the hold-down occurred prior to yielding in the panel joints. Inversely, the other behaviour (i.e. coupled panels) was achieved if the yielding in the vertical joint occur prior to yielding in the hold-down. The analytical model was validated using a numerical model, and the results of the comparison showed very close match between the two models. The study proposed simplified design provisions with the aim to optimize the walls ductility (CP behaviour) or strength and stiffness (SW behaviour).

An integrated experimental and numerical research program investigating the elastic and inelastic performance as well as the kinematic behaviour of shearwalls with openings is presented in this study. The influence of the geometrical dimensions of the wall configurations and the mechanical properties and configurations of hold-downs on both elastic and inelastic behaviours including the possible kinematic modes of the shearwalls are investigated. The research also proposes the concept of equivalent-frame-model applicable for shearwalls where openings are cut-out from CLT panels. Are also presented, five racking tests performed on full scale CLT walls in order to validate the numerical models as well as the equivalent frame model. From review of the available literature emerges that for CLT shearwalls with openings, studies are not at the same level of abundance in research compared to walls without openings, due to the simple reason that SSW is generally a widespread technique. Thus, the kinematic behaviour and the coupling effect are inexistent and presented here. The investigations of the wall’s behaviour in the elastic and inelastic ranges demonstrate the important effect of the lintel and wall segment slenderness as well as the hold-down stiffness effect on the mechanical behaviour and the global kinematic behaviour as well. It is found that the kinematic modes can change when the walls are stressed beyond their elasticity limit. The failure mode and the global ductility are highly dependent on the hold-down configurations particularly for walls with door openings. The degree of coupling decrease with increased hold-down stiffness and the wall segment width. With regards to the equivalent frame model, a reasonable fit is found between the proposed EFM and a detailed 2D area element model when the global elastic stiffness and tensile load in the hold-down were compared. The model is successfully validated through five full-scale tests on CLT shearwalls with door or window opening as well as two published studies on walls with door openings. The EFM is capable of predicting the behaviour in the wall with reasonable accuracy, especially for walls whose behaviour was dominated by the hold-down behaviour.