STF · Timber structures

Interlocking Cross-Laminated Timber Shear Wall Study

Preparing the Blue Frame for the first two-actuator lateral test of a standalone interlocking CLT shear wall.

Graduate researcher: Amirhossein Heidari
Professor / PI: Professor Aryan Rezaei Rad
Research area: Timber structures & lateral force-resisting systems
Application: Mass-timber buildings resisting wind and earthquake loads

01Project objective

This research develops and experimentally evaluates a new interlocking Cross-Laminated Timber (CLT) shear wall system, investigating the wall's kinematics, mechanics, strength, ductility, deformation capacity and energy dissipation to assess its viability as a lateral force-resisting system.

Conventional CLT systems can require numerous shear walls to provide sufficient lateral capacity. Stronger and more ductile wall systems could reduce the number of required walls, optimise material use, and provide greater architectural flexibility in mass-timber buildings.

02Instrumented wall with the DIC camera and data acquisition station

02My contribution

I supported the preparation and modification of the structural testing setup for the upcoming full-scale CLT wall experiments:

Assisted with Blue Frame adjustments and reconfiguration for the new wall-testing application.
Supported structural frame and testing-component assembly.
Assisted with preparation for the two-actuator lateral loading configuration.
Supported CLT specimen assembly and experimental setup activities.
Worked alongside the graduate researcher in preparing the facility for a testing configuration being implemented on the Blue Frame for the first time.

**Clip**Blue Frame reconfigured for two-actuator lateral loading of a standalone CLT wall

03Structural system

The walls are constructed from E1-grade CLT, a standardised structural product recognised under CSA O86. The system relies on the combined behaviour of the CLT wall components and their connections, which directly influence strength, deformation and energy-dissipation capacity. The current full-wall study builds on earlier connection-level experiments.

8 full-wall specimens
4 unique configurations
2 replicate specimens per configuration

04Interlocking connection detail at specimen HD1

04Testing and data collection

The project requires significant modification of the STF Blue Frame, a large-scale testing system historically used for braced-frame and damper research. It is being repurposed into a lateral-loading test system for standalone CLT walls, with two hydraulic actuators working together to transfer controlled lateral loads directly into the specimen. The testing evaluates:

Force-displacement response
Lateral strength and stiffness
Ductility and deformation capacity
Energy dissipation
Sliding, bending and shear behaviour
Connection-level failure mechanisms
Overall proof of concept

05Crushing and localised failure at the interlocking joint

05Results and engineering significance

Unlike simpler structural components, the proposed CLT wall can undergo several interacting behaviours, including sliding, bending, shearing, connection deformation and localised failure. Although this makes the response more complex to characterise, the multiple deformation mechanisms can provide significant opportunities for energy dissipation and improved structural performance.

The project ultimately evaluates whether the interlocking CLT concept can provide greater lateral capacity and deformation performance, potentially allowing more efficient use of mass timber in structural design.

06More from the lab

06Steel connection hardware at the wall base

07Tools and equipment

U of T Blue FrameHydraulic actuatorsLVDTsPotentiometersLoad cellsCLT structural componentsStructural connection hardware

08Engineering exposure

Mass timberCLT shear wallsLateral load resistanceStructural testingHydraulic systemsTimber connectionsForce-displacement behaviourDuctilityEnergy dissipationExperimental setup