B1/AS1: Structural provisions for buildings

B1 STRUCTURE ACCEPTABLE SOLUTION B1/AS1 Buildings and structures 2.3.3 Definitions 2.3.3.1 In NZS 3604 Clause 1.3 Definitions for: a) Good Ground, add “liquefaction, lateral spread” after “subsidence” in subparagraph (c); and b) Bracing rating, remove “when tested in accordance with BRANZ Technical Paper P21” 2.3.4 Bracing design 2.3.4.1 In NZS 3604, make the following modifications in Section 5 Bracing Design: a) modify Figure 5.4 Earthquake zones, so that all the area within the Christchurch City Council boundary is within Zone 2; and b) modify Figure 5.4 Earthquake zones, so that the lowest zone within the Selwyn or Waimakariri District Council boundaries is within Zone 2. Areas within Selwyn District that are designated as Zone 1 in NZS 3604 shall become Zone 2. 2.3.4.2 In NZS 3604, where the bracing rating or bracing capacity of timber framed wall bracing elements must be determined, such as in Clauses 5.4 and 8.3.1, the bracing rating shall be determined in accordance with Subsection 3.5.3 of the Building Product Specifications. 2.3.5 Timber piles 2.3.5.1 Where timber piles are used in accordance with NZS 3604, they shall comply with Subsection 2.1.2 of the Building Product Specifications. 2.3.6 Timber decks 2.3.6.1 Remove Subclause 7.4.1.3 (c) in NZS 3604. 2.3.6.2 Modify Figure 7.10 (b) in NZS 3604 as follows: a) on the plan view replace the text “2/M12 x 250 mm coach screws at 140 crs” with “2/M12 x 240 mm coach screws at 140 crs vertically.”; and b) on the plan view replace “2/M12 at 400 crs” twice with “2 M12 bolts at 140crs vertically to capture end joist laminations and blocking, and boundary joist laminations and blocking, at post centrelines.”; and c) add to Note 3: “All coach screws to have 50 x 50 washers.” 2.3.6.3 Modify Figure 7.10 (c) in NZS 3604 as follows: a) on the plan view, add the text “At each strap location (at joist ends and nogging), 2/M12 x 240 mm long coach screws are required.”; and b) on the plan view, replace the text “2/M12 x 250 mm coach screws at 140 crs vertically” with “ 2/M12 x 200mm coach screws at 140 crs vertically” ; and c) on the section view, replace the text “M12 x 200 mm coach screws at 400 crs vertically” with M12 x 240 mm coach screws at 140 crs vertically”; and d) remove “2/M12 bolts at 400crs” which tie laminations together along edge joists and along boundary joists. 2.3.7 Concrete slab-on-ground floors 2.3.7.1 For foundation and edge details for concrete slab-on-ground floors, make the following modifications in Clause 7.5.2 in NZS 3604: a) replace Clause 7.5.2.3 with: i) “Clause 7.5.2.3 The combined foundation and edge details shall be constructed as shown in Figures 7.13(B), 7.14(B) or (C) (and Figures 7.15(B) and 7.16(B) or (C) for foundations supporting a masonry veneer).”; and MINISTRY OF BUSINESS, INNOVATION AND EMPLOYMENT 28 JULY 2025 Page 8