18-22118 - Cross-Laminated Timber (CLT) Shear Wall 12-Storey Design Mass Timber Building
Definition of the requirement:The National Research Council Canada’s Canadian Construction Materials Centre has been charged with producing a draft document called “Technical Guide for the Design of 12-storey Mass Timber Buildings in Seismic Areas in Canada.” This draft design guide has been prepared and needs to be validated with actual designs and a non-linear analysis of two (2) prototype buildings in seismic areas (i.e., Vancouver and Montreal).The designs are to be peer-reviewed by third-party experts for consideration by Canadian designers of 12-storey tall wood buildings constructed with cross-laminated timber (CLT) panels in a balloon-type structure. The design exercise and expert peer review are then to be submitted for consideration for inclusion in the 2025 National Building Code of Canada as a formal design procedure to determine proprietary ductility and overstrength factors for the seismic design of mass timber buildings.The requirement is to include the following design services:
Determine the lateral force demand of a 12-storey CLT balloon-type shear wall prototype building using the Equivalent Static Force Procedure with preliminary RdRo assumptions for Vancouver and Montreal design uniform hazard spectra. Four wall designs shall account for the effects of the seismic hazard and gravity loads;
Design the yielding element of the CLT shear wall system using energy-dissipative elements for ductility and non-yielding elements for shear load. The non-yielding elements of the CLT shear wall system shall be based on the principle of capacity design;
Perform non-linear time-history analysis to assess structural behaviour and seismic performance. The force and deformation demand and capacity of the non-yielding elements shall be checked to confirm the capacity design principle is satisfied;
Re-run non-linear time-history analysis to examine the applicability of rigid body motion for the CLT panels;
Establish RdRo for the CLT shear wall system;
Re-design the system if the RdRo determined is found to be significantly different from the initial assumption;
Provide the design examples in a detailed report outlining all the steps above;
Comment on the limitations of the examples that may affect the building performance including: seismic hazard, CLT panel aspect ratio, building height, gravity load (balanced and unbalanced), connection backbone curve and hysteresis loops, the design provisions necessary to decouple or account for shear loads in the tension hold-down connections and tension loads in elastic shear connections; and
Prepare presentations for peer review of design examples and participate in review sessions.
