Section C8 – Unreinforced Masonry Buildings

The Seismic Assessment of Existing Buildings (the Guidelines) provides a technical basis for engineers to carry out seismic assessments of existing buildings within New Zealand.

Part C of the Guidelines describes the Detailed Seismic Assessment (DSA) process used to assess the seismic behaviour of a building. This is a more comprehensive assessment than the Initial Seismic Assessment process described in Part B. The DSA assesses the structural load paths within the building, the capacity of each structural element, the likely inelastic mechanisms, the global building response to earthquake shaking and the impact of secondary structural and critical non-structural building elements.

The DSA process is based on the Part A principles, which are an integral part of the seismic assessment process. Sections C1, C2, C3 and C4 provide an overview of the DSA process, the assessment procedures and analysis techniques, the earthquake demands and geotechnical considerations. Sections C5 to C9 provide recommendations for specific materials and Section C10 provides recommendations for secondary structural and non-structural elements. Each of these build on the common aspects within Sections C1 to C4 and Part A.

Summary and Download

Section C8 (download PDF, 11 MB) gives specific recommendations for buildings generically constructed with unreinforced masonry as well as guidance on establishing capacities for their structural elements and components.

Many existing buildings have elements and components of different construction materials that work together to provide resistance to seismic shaking. The other material sections (C5, C6, C7 & C9) use the same approach to establishing element and component capacities to allow all capacities to be integrated, after making due allowance for deformation compatibility issues.

The recommendations within this section should be used in conjunction with those in Sections C1 to C4 and Part A.

Contact

This web site has a searchable Knowledge Base with answers to questions about the Guidelines. Use article links in the Knowledge Base section to the right to view these.

If you have a question about Section C8, please check the Knowledge Base articles for Part C. If it is not addressed there, please refer to Writing Questions so your question can be efficiently addressed when you send it using the form below. Use the article links in the Knowledge Base section to the right for questions on Part A or Part B.

Amendments incorporated in C8

Section C8 (version 2016_SB) was a revised version of Section 10 of the NZSEE Assessment and Improvement of the Structural Performance of Buildings in Earthquake that was issued in April 2015. Most changes were editorial. The significant technical amendments to Section 10 are listed below:

Section Item Page Amendment
C8.2.14 Heading C8-33 Replaced “Secondary components” with “Secondary structure and critical non-structural items”
C8.8.6.3 Equation C8.36 C8-114 Coefficient 1.3 replaced by Bond pattern factor, αs
C8.8.6.3 Equation C8.38 C8-115 Coefficient “2” deleted from denominator
C8.8.6.3 Equation C8.40 C8-115 Coefficient “2” deleted from numerator
New parenthesis added
C8.9.2 2nd paragraph C8-124 Replace “KA” with “KR
C8.10.3 Heading C8-130 Replaced “Parts and components” with “Secondary and critical non-structural items”
C8.10.5.2 Equation C8.54 C8-132
  • “∆d (mm)” replaced by “∆d(m)”
  • Unit of Wtrib changed to kN
  • Unit of G’d,eff changed to kN/m
C8.10.5.2 Equation C8.55 C8-132 Added to note “0.7 has units of 1/√g”
C8B.2.8 Table C8B.1 Appendix C8-20 Boundary conditions corrected for Boundary Case # 1 and 2.
All sections
  • Replaced “components” with either “elements” or “members/elements”
  • Replaced NZS 1170.5 with NZS 1170.5:2004

Version Control

Download Link Version Size Issued
Initial release (Current) 1 11 MB July 2017
Consultation Draft 2016_C 11 MB 10 October 2016
Sector Briefing Draft 2016_SB 10 MB 30 June 2016
Go to NZSEE Web Site Corrigenda 4 9 April 2015