BCAB #1647 - Seismic Structural Design for Part 9 Houses, Sentence 9.4.1.1.(1)

May 21, 2008

BCAB #1647

Re: Seismic Structural Design for Part 9 Houses, Sentence 9.4.1.1.(1)

Project Description

The subjects are single storey houses, approximately 170 m2 in area.

Reason for Appeal

Sentence 9.4.1.1.(1) indicates:  Subject to the application limitations defined elsewhere in this Part, structural members and their connections shall

 a) conform to requirements provided elsewhere in this Part,

 b) be designed according to good engineering practice such as that provided in the “Engineering Guide for Wood Frame Construction” published by the Canadian Wood Council, or

 c) be designed according to Part 4 using the loads and deflection and vibration limits specified in

             i) Part 9, or

             ii) Part 4.

Appellant’s Position

The appellant considers the houses to be conventional wood frame construction, and with the exception of pre-engineered component such as roof trusses and beams, complies with Clause 9.4.1.1.(1)(a) “ requirements provided elsewhere in this Part.”  Further, it is the opinion of the appellant that it is the option of the designer/owner to determine which structural design option(s) is to be used.

Building Official's Position

 The Building Official has established a policy in using the criteria of the “Engineering Guide for Wood Frame Construction” published by the Canadian Wood Council, to determine when further seismic design consideration/design must be used. The Building Official considers A-9.4.1.1. and A-9.4.1.1.(3) provides this direction

Appeal Board Decision #1647

It is the determination of the Board that it is the choice of the owner/designer to determine which structural design method described in Sentence 9.4.1.1.(1) to use.

George Humphrey, Chair