An innovative connection system for platform-type mass timber buildings

Abstract

Platform-style construction is a widely recognized and well-established approach among engineers and developers for multi-story mass timber buildings. This construction method offers many advantages, such as rapid assembly, an excellent strength-to-weight ratio, and appealing aesthetic features. In a platform-type construction, each story is constructed by placing the floor panels on top of the load-bearing wall, creating a platform for the level above. Although this method offers numerous advantages, recent research findings have revealed that cross-laminated (CLT) platform buildings with conventional connections, such as wall-to-floor hold-down brackets and shear connectors with nails and screws, are prone to experience a high degree of damage under design-level earthquakes. Consequently, conventional connections in platform-type construction are vulnerable to more damage under aftershocks and do not meet the damage avoidance requirements of seismic design. This paper introduces an innovative floor-to-wall connection for a platform-type low-rise mass timber building that mitigates the limitations of conventional connections. The effectiveness of the proposed connection has been investigated, and the seismic performance of the system, which incorporates the proposed connection, has been outlined in this paper. A numerical model with an innovative inter-story isolation system is developed in ETABS, and the seismic performance of the isolated structure was evaluated using Response Spectrum Analysis (RSA) and Nonlinear Time History Analysis (NLTHA). This study revealed that inter-story isolation systems significantly reduced the seismic demands on the mass timber components, demonstrating the system's ability to dissipate seismic energy. Additionally, the system displayed effective energy dissipation while exhibiting self-centering behaviour.

Keywords

Cross-laminated timber / Low damage / Platform construction / Inter-story isolation / Numerical model

Data availability statement

Some or all data, models, or codes that support the findings of this study are available from the corresponding author upon reasonable request.

Relevance to resilience

This paper presents the performance of a resilient wall-to-floor connection for platform-type mass timber buildings. The proposed connection is to be used as an alternative to the traditional connections that are prone to experience significant damage during an earthquake. The proposed connection can be engineered to the desired strength to accommodate the necessary horizontal displacement while providing the necessary energy dissipation without sustaining any damage in the connection while displaying full self-centering capability that aligns with the goal for the seismic resilient design of structures.

CRediT authorship contribution statement

Rajnil Lal: Writing - review & editing, Writing - original draft, Validation, Software, Methodology, Investigation, Formal analysis, Conceptualization. Ashkan Hashemi: Writing - review & editing, Supervision. Pierre Quenneville: Writing - review & editing, Supervision.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors wish to express their gratitude to WIDE Trust New Zealand for providing the opportunity and funding for this research, as well as QuakeCoRE, a New Zealand Tertiary Education Commission-funded Centre, for partially funding this research. This is QuakeCoRE, publication number 1013.

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