CSA S850:23

Preface

This is the second edition of CSA S850, Design and assessment of buildings subjected to blast loads . It replaces the previous edition published in 2012. This Standard is intended for use in the design of new buildings and assessment of existing buildings to resist defined blast threats. While building security, within the context of building protection against blast threats, is beyond the scope of this Standard, it is an essential aspect to evaluating or modifying the design threat and thus must be well understood by the designer. The following are the major changes to this edition: a) load combinations involving accompanying gravity loads have been revised; b) dynamic increase factor tables have been updated, with a new DIF for bond between concrete and reinforcement; c) response limits for wood buildings have been updated; and d) Clause 9.2.9 has been added on precast and prestressed concrete buildings with a new table for response limits for prestressed concrete elements. Although not specifically identified, users should be aware that the authority having jurisdiction might have additional approval requirements, which are outside of the scope of this Standard. See Clause A.1 for additional information on regulatory compliance. CSA Group acknowledges that the development of this Standard was supported by Global Affairs Canada with financial support from National Defence: Defence Research and Development Canada’s Centre for Security Science. This Standard was prepared by the Technical Committee on Blast Resistant Buildings, under the jurisdiction of the Strategic Steering Committee on Construction and Civil Infrastructure, and has been formally approved by the Technical Committee. This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.

Scope

1.1 General

This Standard provides criteria for the analysis and design of new buildings and assessment of existing buildings to resist blast loading. Notes: 1) The main objective of this Standard is to reduce human casualties and damage to assets due to an air blast. 2) It should be recognized that the extent and severity of an explosion and resulting damage cannot be predicted with certainty. 3) The performance of the building and the safety of the occupants are functions of the selected LOP and the DBT. 4) Users should ensure they are familiar with applicable legislation. Where this Standard conflicts with applicable legislation, it is assumed that the legislation applies. For additional information on regulatory compliance, see Clause A.1.

1.2 Materials considered

This Standard provides design criteria for concrete, FRP, masonry, steel, and wood. This does not preclude the use of other materials (see Clause 9.1). Note: FRP design provisions apply to retrofit only.

1.3 Items not addressed

1.3.1 This Standard does not address risk assessment or apply to biological, chemical, cratering, EMP, ground shock, fragmentation loads, induced fire, penetration, perimeter security, radiation, or thermal effects of explosions. Note: Although other effects of explosion such as fragmentation are important considerations, special design requirements have not been provided in this Standard.

1.3.2 This Standard does not define a DBT. A DBT is building and project specific and it should be specified by the building owner and/or the AHJ. 1.4 Terminology In this Standard, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; “should” is used to express a recommendation or that which is advised but not required; and “may” is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.5 Units of measurement

Equations appearing in this Standard are compatible with the following units: a) area: mm2 (square millimetres); b) force: N (newtons); c) length: mm (millimetres); d) mass: kg; e) moment: N•mm (newton millimetres); and f) stress: MPa (megapascals).