Lateral-Load Resistance of Cross-Laminated Timber Shear Walls

Thomas Reynolds,Michael Ramage,Richard Harris,Julie Bregulla,Robert Foster,Wen-Shao Chang

doi:10.1061/(asce)st.1943-541x.0001912

Abstract

Cross-laminated timber shear wall systems are used as a lateral load resisting system in multistory timber buildings. Walls at each level typically bear directly on the floor panels below and are connected by nailed steel brackets. Design guidance for the lateral-load resistance of such systems is not well established and design approaches vary among practitioners. Two cross-laminated two-story timber shear wall systems are tested under vertical and lateral load, along with pullout tests on individual steel connectors. Comprehensive kinematic behavior is obtained from a combination of discrete transducers and continuous field displacements along the base of the walls, obtained by digital image correlation, giving a measure of the length of wall in contact with the floor below. Existing design approaches are evaluated. A new offset-yield criterion based on acceptable permanent deformations is proposed. A lower bound plastic distribution of stresses, reflecting yielding of all connectors in tension and cross-grain crushing of the floor panel, is found to most accurately reflect the observed behavior.

Highlights

Cross-laminated timber (CLT) is a panelised glued-laminated mass timber structural product, comprising sawn timber sections, laid-up in layers, with each layer at right angles to the adjacent layer
A common CLT construction method that can offer considerable advantages for builders is that of platform construction, whereby the CLT floor slab bears directly on the CLT walls below
Serrano and Enquist (2010) measured a mean compression strength, defined by a 1% strain offset, of 5.8 MPa for this orientation, for CLT with density 427 kg m−3 at 10% moisture content, and this compression strength is used to estimate the strength in bearing of the CLT in these tests

Summary

Introduction

Cross-laminated timber (CLT) is a panelised glued-laminated mass timber structural product, comprising sawn timber sections, laid-up in layers, with each layer at right angles to the adjacent layer. CLT floor and wall elements have been used to form the principal vertical and lateral load resisting systems of multi-story buildings around the world. A common CLT construction method that can offer considerable advantages for builders is that of platform construction, whereby the CLT floor slab bears directly on the CLT walls below. Each story forms a stable working platform onto which the story above is built. Forces in the wall elements must pass through the floor plate in the much weaker, less stiff, cross-grain direction

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