Performance-Based Design of Posttensioned Cross-Laminated Timber and Light-Frame Wood Shear Wall Hybrid System

Abstract

Displacement-based design (DBD) methods were originally developed in the 1990s for concrete structures and later modified for light-frame wood buildings and mass timber buildings. DBD methods use displacement as the design criterion to minimize economic losses, control component damage, and enable rapid return to functionality for increased resilience. This paper introduces a performance-based design check procedure that uses the direct displacement-based design (DDD) method and numerical pushover analysis for the design of cross-laminated timber and light-frame shear (CLT-LiFS) buildings. Prestressing CLT panels with embedded posttensioning high-strength steel cables or external high-strength steel rods enable them to provide robust lateral load resistance and self-centering capacity. LiFS walls offer additional lateral load resistance and energy dissipation through the slip of nail connections. A six-story CLT-LiFS building was used as a design example meeting three performance levels (damage limitation, life safety, and collapse prevention) based on ASCE/SEI 41-17 criteria. Each performance level corresponds to a set of three criteria: interstory drift limits, cable stress limits, and CLT compressive strain limits at the rocking interface. The design was checked using a series of nonlinear time history (NLTH) analyses with a suite of ground motion records. The results from the design check procedure and the statistical distributions of performance criteria from NLTH analysis confirmed that the six-story CLT-LiFS building met performance expectations. Additionally, a collapse fragility curve was developed to provide a comprehensive understanding of the building’s behavior.