Deflection of cross-laminated timber shear walls for platform-type construction

2020 ◽  
Vol 221 ◽  
pp. 111091
Author(s):  
Md Shahnewaz ◽  
Marjan Popovski ◽  
Thomas Tannert
Author(s):  
Md Shahnewaz ◽  
Thomas Tannert ◽  
Marjan Popovski

Cross-laminated timber (CLT) is becoming a viable option for mid-rise buildings in North America. CLT walls are very effective in resisting lateral forces resulting from wind and seismic loads, yet no standard provisions are available to estimate the resistance of CLT shear walls under lateral loading. The present research investigated CLT shear wall’s performance by evaluating the preferred kinematic rocking behaviour. An analytical procedure was proposed to estimate the resistance of CLT shear walls in a platform type construction. Finite element models of CLT shear with various brackets and hold-downs connections were developed. The models were validated against experimental results. Furthermore, a parametric study on CLT shear walls with the variation of type and number of connectors was conducted. The resistance estimated from parametric study and against analytical were compared. The proposed formulas can be useful tool for the design of CLT platform-type buildings, however, require further experimental validation.


Buildings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 100 ◽  
Author(s):  
Md Shahnewaz ◽  
Shahria Alam ◽  
Thomas Tannert

The research presented herein investigated the in-plane performance of cross-laminated timber (CLT) shear walls for platform-type buildings under lateral loading. Finite element models of CLT connections (i.e., brackets, hold-downs and self-tapping screws) were developed in OpenSees and calibrated against experimental tests to represent the connections’ hysteresis behaviour under cyclic tension and shear loading. The results were incorporated into models of CLT single and coupled shear walls. The results in terms of peak displacement, peak load and energy dissipation were in good agreement when compared to full-scale shear wall tests. Subsequently, a parametric study of 56 single and 40 coupled CLT shear walls was conducted with varying numbers and types of connectors (wall-to-floor and wall-to-wall) for evaluating their seismic performance. It was found that the strength, stiffness and energy dissipation of the single and coupled CLT shear walls increased with an increase in the number of connectors. Single shear walls with hold-downs and brackets performed better under seismic loading compared to walls with brackets only. Similarly, coupled shear walls with four hold-downs performed better compared to walls with two hold-downs. Finally, ductility of coupled shear walls was found to be 31% higher compared to that of single shear walls. The findings from this research are useful for engineers to efficiently design CLT shear walls in platform-type construction.


2013 ◽  
Vol 48 ◽  
pp. 980-991 ◽  
Author(s):  
Yin-Lan Shen ◽  
Johannes Schneider ◽  
Solomon Tesfamariam ◽  
Siegfried F. Stiemer ◽  
Zai-Gen Mu

2020 ◽  
Author(s):  
◽  
Hosein Asgari

Cross-laminated Timber (CLT) is increasingly being used in tall buildings. However, there are some challenges when designing high-rise CLT structures, amongst them the need for novel hold-downs (HD), for shear walls. While commonly used HDs behave as a dissipative connection, the current Canadian Standard for Engineering Design in Wood recommends designing HDs as a non-dissipative connection. As hyperelastic material, an elastomer (rubber) is capable to carry high loads without inelastic deformation. This thesis presents experimental studies at material- and component-levels using a hyperelastic rubber HD solution for CLT walls. A total of 53 quasi-static monotonic and cyclic tests were performed. The HDs exhibited high strength and deformation capacity without any residual deformation after unloading. The shape factor and loaded area of rubber layers were found as the main effective factors on the rubber HD’s response, and an empirical load-displacement relation was also developed based on these parameters.


2021 ◽  
Author(s):  
◽  
Abubakar Oyawoye

Cross-laminated timber (CLT) continues to establish a stronger footing in the Canadian construction industry, also as an option for lateral load resisting systems, such as shear walls. Recent modifications to the Canadian Standard for Engineering Design in Wood (CSA O86- 19) allow only rocking kinematics as energy dissipative mechanics for CLT shear walls, whereby hold-down must remain elastic. These provisions necessitate the development of novel hold-down solutions. In this report, the performance of a hyper-elastic high-capacity hold-down was investigated at the component level through tests on: (1) hold-down steel rod, (2) CLT housing, and (3) hold-down assemblies with different sizes of rubber pads. The tests demonstrated that: i) the rubber hold-down can remain elastic under a rocking kinematics provided that the elastic limit of the steel rod is not exceeded; ii) failure of the rod is the subsequent desired ductile mode; iii) the CLT width influences the failure mode; iv) the shape factor influences the achievable deformation of the rubber pad; v) increasing the rubber pad thickness reduces the hold-down stiffness; and vi) increasing the rubber pad width increases the hold-down stiffness. Numerical modelling and optimization suggested that using an intermediate steel laminate between layers of rubber pads could improve its performance. Based on the results of the investigations presented herein, a capacity-design procedure for the hyper-elastic hold-downs was proposed.


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