Preface
This is the third edition of CSA Standard 086.1, Engineering Design in Wood (Limit States Design). It supersedes the 1989 edition, CAN/CSA-086.1-M89, and its Supplement No. 1-93 (published in 1993). The first edition of the Limit States Design format Standard was published in 1984, followed by a Supplement in 1987.
With the release of this edition, CSA Standard CAN3-086-M84, Engineering Design, in Wood (Working Stress Design) is formally withdrawn. The working stress design version, first published in 1959 with succeeding editions in 1970, 1976, and 1980, will not be updated.
Major changes in this 1994 edition are the addition of Clause 13, Proprietary Structural Wood Products, the modification of Clause 7, Structural Panels, and the extensive changes to portions of Clause 10, Fastenings.
In this edition, Engineering Design in Wood includes provisions for the design of two groups of proprietary structural wood products, prefabricated wood I—joists and Type 3 Design Rated OSB. For these two product groups, manufacturers' proprietary data developed in accordance with referenced standards, certified by an independent agency and modified as specified herein, are now permitted as the basis for design within this Standard. Design provisions for prefabricated wood I-joists were first introduced into the Standard through Supplement No. 1-93.
Clause 7 on Plywood has been changed to Structural Panels with the introduction of specified design values for certified Types 1 and 2 Design Rated (generic) OSB panels. Plywood specified capacities have been expanded to cover thicker layups. Related changes to Clause 8, Composite Building Components, and to Clause 9, Shearwalls and Diaphragms, have' also been made.
Within the Fastenings Clause:
(a ) procedures for calculating lateral strength resistance associated with various failure modes of bolts and lag screws have been modified and moved into the Standard from Appendix A;
(b) a procedure for determining lateral deformations of lag. screws has been added to Appendix A, in lieu of the slip provisions removed from the Clause;
(c) a table giving relative densities of glulam and sawn lumber species groups, used in the design of bolts, lag screws, and drift pin connections, has been re—inserted into the Appendix; and
(d) provisions for the use of glulam rivets (i ) loaded in withdrawal, and (ii) installed in solid sawn wood members 64 mm or greater in thickness, have been added. In the calculation of rivet joint capacities, the designer now must check explicitly both the rivet and wood capacities. Related tables are revised. Provisions also have been clarified for single—sided rivet connections and added for double—sided rivet connections where points overlap.
Other notable changes include the following:
(aa) Machine Stress- Rated (MSR) grades have been revised;
(b) a new mechanical strength grading system, designated as Machine Evaluated Lumber (MEL), has been introduced through the addition of specified strengths and stiffnesses in a new Table 5. 3. 3;
(c) compression perpendicular to grain design procedures have been revised for all structural wood products covered;
(d) provisions for the design of sawn lumber containing notches have been revised; and
(e) three formulae previously used for determining the slenderness factor for glued laminated members have been replaced by a single formula which is consistent with that used for sawn lumber.
This edition is dedicated to the memory of Thomas A. Eldridge, Past Chairman and a committed, vital member of the Committee from the initiation of the first edition, published in 1959, until his death in September 1994.
This Standard was prepared by the CSA Technical Committee on Engineering Design in Wood under the. jurisdiction of the Standards Steering Committee on Structures (Design), and- was formally approved by these Committees.
Scope
1. 1 General
This Standard provides criteria for the structural design and appraisal of structures or structural elements made from wood or wood products including graded lumber, glued-laminated timber, unsanded plywood, design -rated OSB, composite building components, shear walls and diaphragms, piling, pole type construction, structural fastenings prefabricated wood I-joists, and preserved wood foundations employing the limit states design method.
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