New Zealand’s current legislation relating to insured structures affected by Natural Disasters falls under the Earthquake Commission Act 1993. The Earthquake Commission (EQC) as the administrators of the general insurers requires that assessments of claimed damage to insured structures be undertaken in order to determine whether the damage has been caused by a natural disaster.
Given the scale of damage throughout the Canterbury region, iStructures has been engaged to inspect the effects of the Canterbury series of seismic events on over 200 residential dwellings to date. iStructures coverage of Canterbury covers all Technical Land categories, flat and hillside properties, along with multi-dwelling structures such as adjoined units.
The general purpose of the inspections was to determine whether observed damage such as cracked foundations and out of level floors were due to the series of seismic events or whether the issues were pre-existing.
Where issues were identified as being related to the seismic events, justification was provided within the Structural Inspection reports to facilitate acceptance by EQC for coverage, along with proposed repair strategies on how to restore the dwellings back to the likely pre-earthquake condition. For example addressing global settlement of dwellings from 0-200mm in TC3 zoned land, differential settlement leading to damage of walls and foundations, investigating retaining wall damage in hillside properties, and voids beneath concrete slabs due to tailing movement.
Design of re-levelling strategies for dwellings may range from Jack and Pack of timber floors in accordance with NZS3604, underpinning and raising of concrete perimeter foundations and slabs in accordance with NZS1170 and NZS4229 loadings based on shallow geotechnical testing of on-site conditions, and working with specialist firms for re-levelling of floor slabs using Low Mobility Grout.
Where repair is not feasible, safe, or within the requirements of the building act, replacement components or structures were designed to meet current building code and AS/NZS standards. For example, replacement of double skin brick walls within 1m of a property boundary with modern fire-rated timber-framed walls and replacement of damaged brick chimneys.
Where requested by the Client, iStructures is able to provide assistance in designing replacement and or retrofit solutions to address non-earthquake related issues. Such as undersized structural beams that feature visible sagging of ceilings or inter-storey floors.
iStructures earthquake related structural inspections and prosed repair strategies comply with section 112 of the Building Act 2004, and fit within the Ministry of Business Innovation and Employment (MBIE) Guidelines to ensure unnecessary delays are avoided in the repair process.
iStructures designs for residential repairs mainly utilise the following New Zealand design standards to suit the specific requirements as identified on site.
NZS 1170 – Structural Design Actions
NZS 3603:1993 – Timber Structures Standard
NZS 3604:2011 – Timber-framed buildings
NZS 4229:2013 – Concrete masonry buildings not requiring specific engineering design
NZS 4210:2001 – Masonry construction: Materials and workmanship
NZS 4230:2004 – Design of reinforced concrete masonry structures
NZS 3109:1997 – Concrete construction
Should you have any queries or design requirements for your home or require assistance through EQC – EQR process, please feel free to contact us anytime.
Phone: 03 349 4040, email: firstname.lastname@example.org