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BC Update 165: Worked examples of retaining structure seismic design for Canterbury reside

Posted: 24 November 2014

BC Update
Worked examples including concrete cantilever, anchored and crib retaining walls, to accompany technical guidance on the seismic design of retaining structures fro residential sites in Canterbury.

This Building Controls Update is a periodic news bulletin for the building sector.

MBIE have released further worked examples to accompany the technical guidance on the seismic design of retaining structures for residential sites in greater Christchurch.

These worked examples include concrete cantilever, anchored and crib retaining walls. Some minor modifications have also been made to the main guidance document and the worked example already issued (cantilever timber pole wall).

The new guidance on retaining walls will now comprise:

Supplementary guidance on retaining wallsVersion 2
Worked examples:
1. Cantilever timber pole wall Version 3
2. Concrete cantilever wall Version 1
3. Anchored wall Version 1
4. Crib retaining wall Version 1

Please update your retaining walls documents with the above versions.

The modifications made to the supplementary guidance document are annotated and include:

  • Section 2 including the latest GNS reference regarding mass movement areas and the addition of “or” between Points 1 and 2.
  • Changes and additions have been made to text in Sections 7.4, 7.6.1 and 8.2.2.
  • Appendix A – “Application of Mononobe-Okabe equations with high acceleration and/or high back-slope angle” has been added which provides commentary and graphs for the estimation of KAE.

The retaining walls guidance is supplementary to the Guidance document ‘Repairing and rebuilding houses affected by the Canterbury earthquakes’, December 2012.

It is intended for engineers and designers of retaining walls and for building consent officers. It shows how to incorporate the effects of earthquake shaking into the design loadings for residential retaining walls.

Revised supplementary guidance and the associated worked examples for the seismic design of retaining structures for residential sites in greater Christchurch

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: