RfP Research Project Stories: Ashkan Hashemi

Resilient Timber Wall Systems

New hot topic: mass timber construction. Layers of wood glued, nailed, or dowelled together create wood products that are strong enough to use in buildings as structural beams, posts, and walls in place of concrete and steel. Excitement over these timber products stems from their potential to be more sustainable and have a lower carbon footprint than other construction materials. The increasing use of mass timber worldwide has accentuated the need for cost-effective low damage design solutions for use in seismically active regions.

Ashkan Hashemi from The University of Auckland is passionate about mass timber construction and low damage design. For his PhD he developed a concept for low damage rocking timber walls. Now, as an early career researcher, he is leading a Te Hiranga Rū QuakeCoRE project entitled, “A low damage wall-to-floor connection for mass timber structures: testing and design.” The project ties in to QuakeCoRE’s Disciplinary Theme 2 (DT2): Whole-of-building seismic performance.

Ashkan, and his PhD student Soheil Khalaji Assadi, are proposing a new concept for resilient timber wall systems that considers wall to floor connections. When buildings shake in earthquakes, separate components move in different ways, so connections are particularly important for minimising damage. The proposed concept uses friction to absorb horizontal seismic energy and slotted holes to allow the floor to move up and down with minimal damage.

The researchers have used numerical modelling to investigate the difference in performance between conventional wall connectors and the proposed solution. Ashkan is confident they have a design that works, and he is looking forward to verifying that with prototype, and then large-scale, testing. Currently they are ordering materials to build a two-storey specimen for testing the wall-to-floor connections later this year. By the end of the project Ashkan hopes to have laid the groundwork for implementing these connections into current design methods.