There are many different types of disaster to prepare for.  These include the natural hazards included in the Building Act – erosion, falling debris, subsidence, inundation and slippage. In addition earthquakes, liquefaction, lateral spread and cyclones are less predictable but also lead to major destruction of buildings. 

TheCanterburyearthquakes are the biggest disaster to have affectedNew Zealand. They have culminated in a combination of these hazards affecting the region. Liquifaction and lateral spread have affected the topography, created more low lying areas and raised the beds of rivers.  This has lead to much greater threat of flooding and tidal inundation. Rockfalls and subsidence have affected the Port Hills and there is a huge risk of further subsidence and rockfalls affecting hillside communities.

Three major earthquakes and more than 8000 aftershocks have also affected virtually every building in the City and region resulting in 317,000 claims to EQC. 

Earthquake	Mag.	MMI	Duration
Darfield	7.1	7 - 8	43 sec
Boxing Day	5.1	7 - 8	7   sec
Lyttleton	6.3	9 -10	15 sec
June 13 (1st EQ)	5.7	6	10 sec
June 13 (2nd EQ)	6.3	7- 8	12 sec

(Mag – magnitude. MMI – Modified Mercalli Scale)

This situation has tested all of the building related legislation, standards and guidelines. The death of 182 people has focussed attention on the failure of buildings in the City and this is now the subject of a Royal Commission of Enquiry into the catastrocic failure of buildings in the CBD.  The Commission will investigate the responsibility of all involved in particular buildings particularly the CTV, PGC, Forsyth Barr andGrande ChancellorBuildings.  Focus will be on the Property Owners, Engineers, Councils and their responsibilities under the Health and Safety in Employment Act 1992 and Building Act 2004.

The Building Act 2004 is the primary legislation that governs the control of building work, performance of people in the industry and the performance standards for buildings. What follows as an appendix is an outline of the purpose and responsibilities under the Building Act.  A failure to comply with the Building Act carries with it penalties under that Act but also the wider penalties under the Health and Safety in Employment Act – where a failure leads to death or injury of occupants or employees in a building.  

Issues –

The major building issues affecting owners of buildings inChristchurchat present are:

1.    Risks from occupation of buildings that are damaged, earthquake prone, structurally unsound, subject to hazards i.e. rock falls, not weathertight, damaged heating sources, no sewer systems.

2.    Owners obtaining engineers reports (or not) and seeking to occupy buildings with Red, Yellow, Green placards.

3.    Owners undertaking emergency building works to make buildings structurally safe and weathertight. These are being completed as emergency works but in many cases need a building consent, certificate of acceptance or certificate of public use prior to reoccupation.

4.    Building works and change of use of buildings trigger strengthening requirements of earthquake prone policy and review of accessibility and fire egress. 

5.    Owners of Red zone buildings in CBD – not allowed access to make repairs or occupy.  New CBD plan just announced.

6.    Owners of homes in red and orange residential zone areas where ground conditions don’t allow for rebuilding.

7.    Displaced businesses occupying buildings that are not safe or not necessarily suitable for the use.

These issues raise important considerations immediately and in the context of the response to future disasters.

Building Owner Responsibilities:

The key issues for building owners in considering their responsibilities are:

1. Is the building placarded by Civil Defence or the Council.  Follow the instructions on the placards before allowing access to the building.  Generally Red, Yellow and Green placards on commercial buildings require a Structural Engineer to prepare an engineering report to determine no damage and can be occupied or building requires consentable building work. Residential buildings require review by a Building Professional.

2. Establish that the building structurally sound and building systems are working, in all cases – irrespective of placard status before allowing occupation.  Ensure no external hazards from adjacent buildings, rock falls, subsidence.

3. Emergency building works can be undertaken to stabilise, secure or make safe the building immediately following the disaster.  Ensure work is undertaken safely. A Certificate of Acceptance can be obtained from Council where these works would normally have required a building consent.

4.  Building work to repair minor damage is exempt from requiring building consent.  However any structural, weathertight works or work on building systems requires a building consent.

5. Obtain a code compliance certificate, certificate of acceptance before allowing occupation of the building. Where building works are not fully complete for part of the building a certificate of public use can be obtained to allow occupation of part of the building. Electrical certification will be required to be provided prior to issue of certification.

6. The relocation of a building on a temporary nature can be permitted under the Permitted Activities Order in Council. 

Notes:

A Building Consent, change of use or Certificate of Acceptance will trigger Councils Earthquake Prone Policy and the building owner may be required to strengthen the building. See the practicable guide below.  It will also trigger a section112 review of disabled access and fire egress of the building.

Numbers of Buildings - Building Construction Methods In Christchurch

Figure 1:

• Unreinforced masonry - 1860 to 1940s.  The highest risk construction method.  Floors and roof generally light timber framed.  Cost of strengthening typical building $350-450/m2 to 33% FCL (full code level).
• Riveted steel frame - 1900 to 1950s.  Steel frames generally encased in concrete.  Cost of strengthening typical building $150-300/m2 to 33% FCL (full code level).
• Welded and bolted Steel Moment Frame - 1950s to present.  Not generally EQP.  Cost of strengthening typical building $150-300/m2 to 33% FCL (full code level).
• Concrete or steel frame with infill - 1900 to 1960s.  A higher risk construction method. Columns and beams infilled with brick and masonry which reduces ductility of structure.  Cost of strengthening typical building $250-400/m2 to 33% FCL (full code level).
• Non-ductile Concrete moment Resisting Frames - 1900 to 1975.  Some poor seismic performance due to lack ductility and sheer capacity.  Cost of strengthening typical building $250-400/m2 to 33% FCL (full code level).
• Ductile Concrete Moment Resisting Frames - 1975 to present.  Designed to resist seismic attack.  Cost of strengthening typical building $800-1,200/m2 to 67% (FCL).  Will meet 33% already.
• Single Level Tilt panel - 1950s to present.  Lightweight metal roves with steel portal frames.  Problem early on at connection points with floor.  Cost of strengthening typical building $50-100/m2 to 33% FCL (full code level).
• Multi Storey Tilt panel - 1970s to present.  Designed generally to meet seismic standards. A few issues with connection points in some buildings.  Cost of strengthening typical building $50-100/m2 to 33% FCL (full code level).
• Concrete Sheerwall Structures - 1925 to present.  Will generally not collapse in earthquake and meets 33% generally.  Cost of strengthening typical building $800-1,200/m2 to 67% FCL (full code level).
• Lightly reinforced partially filled concrete Masonry - 1940 to present.  May experience moderate damage in earthquake.  Cost of strengthening typical building $250-400/m2 to 33% FCL (full code level).
• Fully Filled Reinforced Concrete Masonry - 1970 to present.  Will generally not collapse in earthquake and meets 33% generally.  Cost of strengthening typical building $800-1,200/m2 to 67% FCL (full code level).

Practicable Repair of Earthquake Damaged Buildings:

The Christchurch Earthquake Prone Policy requires that buildings with less than 33% of current code capacity are strengthened to 67%.  Under the Building Act, buildings that require repair for damage to structural elements have been required to obtain Building Consents.  This has triggered general requirements for strengthening existing buildings, and may be resulting in buildings being unoccupiable while repairs are carried out.

Also, in Canterbury, since September, the definition of Dangerous Buildings has been extended to include EPBs.  Use therefore of the existing policies and the Building Act as it stands may be resulting in buildings being unoccupied that may otherwise be considered safe enough to use in the interim following simple repairs, while full strengthening schemes are reviewed.

A possible repair and strengthening strategy is proposed below which will enable engineers and owners some flexibility in reoccupying buildings.  The basic concept is to require a minimum standard of safety in accordance with the revised Dangerous Buildings definition, rather than full strengthening, prior to occupation.  This has the effect of decoupling repairs and strengthening, which may also assist in easing delays due to insurance negotiations. 

Figure 0‑1: Recommended Repair and Strenthening Strategy

Notes to Figure:

1,2:         Depending on the nature of the damage, it may be possible to repair and strengthen isolated damaged elements immediately (to 67% minimum) in order to increase the capacity of the building to >33%NBS.  This will allow interim occupation, subject to agreement with the BCA.

3:            Times for strengthening (T1) are to be determined in accordance with the BCA EPB policy.

4:            A building with high levels of damage throughout is unlikely to be able to be partially repaired in order to facilitate interim occupancy.  A period for strengthening, (T2) is to be agreed with the BCA. 

5:            A building with low levels of damage may be repaired in order to allow interim occupancy, with agreement of the BCA.  Timeframe T3 may vary according to whether the building has had structural work performed in order to achieve interim occupancy.

6:            Although strengthening is not required under existing EPB policies, these buildings are still considered earthquake risk buildings, and owners are advised to consider strengthening.

7,8:         Although buildings with capacity >66%NBS are not considered to be earthquake risk buildings, the level of damage may be considered indicative of the overall performance of the building.  This should be considered when determining a long-term strategy for the building.

9:            No action required.

Recommended timeframes will need to be further considered by Council.  At this time in Christchurch, only policies for earthquake prone buildings have been determined, according to building occupancy, as per Table 0‑1: Time limits for strengthening to CCC EPB policy below.  Suggestions are included in the table for revised timeframes.  Note that for the purposes of this table, the building occupancy categories are from the EPB policy, and are slightly different to the building occupancy classifications from NZS1170.

Table 0‑1: Time limits for strengthening to CCC EPB policy

Times (years)	Building Occupancy Category
	A	B	C
T1	15(2)	20(8)	30(16)
T2	(2)	(4)	(8)
T3	(2)	(8)	(16)

 

Note:   Figures in brackets are recommendations only.  Note that Category A buildings include post-disaster facilities which should be strengthened as nearly as is practicable to 100%NBS

Building Occupancy categories are:

Category A:    Buildings with special post-disaster functions as defined in AS/NZS1170.0:2002 – Importance Level 4

Category B:     Buildings that contain people in crowds or contents of high value to the community as defined in AS/NZS1170.0:2002 – Importance Level 3 .

Note that “contents of high value to the community” does not include the fabric of the building itself.

                        Buildings constructed of unreinforced masonry or unreinforced concrete.

Category C: •  Buildings with an importance level less than 3 is as defined in AS/NZS1170.0:2002

In practice, although many buildings may be below 33%NBS, ie are now EPBs, they may also have most damaged focused in relatively few elements.  For example in cases of buildings that have weak shopfronts but the balance of the building may be relatively mildly damaged.  In such cases, full strengthening (to 67% or more) of the damaged area may be sufficient to allow the building as a while to achieve >33% strength.

In the example below, the building would be considered and EPB as the front wall has too little capacity.  Although (insurable) repairs may be required to the other walls, full strengthening may be a significant undertaking, with upgrades required to all parts of the building.  As an alternative, if the front wall is repaired and concurrently strengthened to at least 67%, it raises the overall capacity of the building with minimal other effort.  This allows the owner to commence trading in the interim, while ensuring the building is not dangerous as defined under the Act.

Figure 0‑2: Example of Interim Repair Strategy

The proposed policy is relatively simple to apply and should help to allow business to resume in many buildings which may otherwise be forced to remain empty for a significantly longer time. 

The Canterbury Earthquakes Statistics:

• 8020 quakes since 4 Sept
• 352 quakes since 22 Feb
• 260 quakes since 13 June
• 182 deaths
• 25 magnitude 5+ earthquakes
• 900 CBD buildings to demolish
• 300 suburban commercial buildings to demolish
• 3m increase in distance Rangiora to Kaiapoi after 4 September
• 40cm Port Hills higher
• 370,000 tonnes of liquefaction silt removed
• 5548 Number of vehicles removed from CBD
• 317,000 EQC claims
• 160,000 buildings in Christchurch
• 5100 houses in residential red zone (not repairable)
• 580 houses evacuated on Port Hills
• 22,000 houses with $100,000+ repairs
• 21,000 chimneys demolished
• 5200 Heat Pumps installed
• 1970 Log Burners installed

Appendix: Building Owner Responsibilities – The Legislation.

Health and Safety in Employment Act 1992. All practicable steps

• (1) In this Act, all practicable steps, in relation to achieving any result in any circumstances, means all steps to achieve the result that it is reasonably practicable to take in the circumstances, having regard to—
  • (a) the nature and severity of the harm that may be suffered if the result is not achieved; and
  • (b) the current state of knowledge about the likelihood that harm of that nature and severity will be suffered if the result is not achieved; and
  • (c) the current state of knowledge about harm of that nature; and
  • (d) the current state of knowledge about the means available to achieve the result, and about the likely efficacy of each of those means; and
  • (e) the availability and cost of each of those means.

(2) To avoid doubt, a person required by this Act to take all practicable steps is required to take those steps only in respect of circumstances that the person knows or ought reasonably to know about.

Building Act 2004Purpose

• The purpose of this Act is to provide for the regulation of building work, the establishment of a licensing regime for building practitioners, and the setting of performance standards for buildings, to ensure that—
  • (a) people who use buildings can do so safely and without endangering their health; and
  • (b) buildings have attributes that contribute appropriately to the health, physical independence, and well-being of the people who use them; and
  • (c) people who use a building can escape from the building if it is on fire; and
  • (d) buildings are designed, constructed, and able to be used in ways that promote sustainable development.

Principles to be applied in performing functions or duties, or exercising powers, under this Act

………..

• the need to ensure that any harmful effect on human health resulting from the use of particular building methods or products or of a particular building design, or from building work, is prevented or minimised:
• (c) the importance of ensuring that each building is durable for its intended use:
• …
• (e) the costs of a building (including maintenance) over the whole of its life:
• (f) the importance of standards of building design and construction in achieving compliance with the building code:
• (g) the importance of allowing for continuing innovation in methods of building design and construction:
• (h) the reasonable expectations of a person who is authorised by law to enter a building to undertake rescue operations or firefighting to be protected from injury or illness when doing so:
• (i) the need to provide protection to limit the extent and effects of the spread of fire, particularly with regard to—
  • (i) household units (whether on the same land or on other property); and
  • (ii) other property:
  • (j) the need to provide for the protection of other property from physical damage resulting from the construction, use, and demolition of a building:
  • (k) the need to provide, both to and within buildings to which section 118 applies, facilities that ensure that reasonable and adequate provision is made for persons with disabilities to enter and carry out normal activities and processes in a building:
  • (l) the need to facilitate the preservation of buildings of significant cultural, historical, or heritage value:
  • (m) the need to facilitate the efficient use of energy and energy conservation and the use of renewable sources of energy in buildings:
  • (n) the need to facilitate the efficient and sustainable use in buildings of—
    • (i) materials (including materials that promote or support human health); and
    • (ii) material conservation:
  • (o) the need to facilitate the efficient use of water and water conservation in buildings:
  • (p) the need to facilitate the reduction in the generation of waste during the construction process.

Buildings not to be constructed, altered, demolished, or removed without consent

• (1) A person must not carry out any building work except in accordance with a building consent.

(2) A person commits an offence if the person fails to comply with this section.

(3) A person who commits an offence under this section is liable to a fine not exceeding $100,000 and, in the case of a continuing offence, to a further fine not exceeding $10,000 for every day or part of a day during which the offence has continued.

Building on land subject to natural hazards

• (1) A building consent authority must refuse to grant a building consent for construction of a building, or major alterations to a building, if—
  • (a) the land on which the building work is to be carried out is subject or is likely to be subject to 1 or more natural hazards; or
  • (b) the building work is likely to accelerate, worsen, or result in a natural hazard on that land or any other property.

(2) Subsection (1) does not apply if the building consent authority is satisfied that adequate provision has been or will be made to—

• (a) protect the land, building work, or other property referred to in that subsection from the natural hazard or hazards; or
• (b) restore any damage to that land or other property as a result of the building work.

(3) In this section and sections 72 to 74, natural hazard means any of the following:

• (a) erosion (including coastal erosion, bank erosion, and sheet erosion):
• (b) falling debris (including soil, rock, snow, and ice):
• (c) subsidence:
• (d) inundation (including flooding, overland flow, storm surge, tidal effects, and ponding):
• (e) slippage

Owner must comply with requirement for compliance schedule

• (1) An owner of a building for which a compliance schedule is required under section 100 must obtain the compliance schedule.

(2) A person commits an offence if the person fails to comply with subsection (1).

(3) A person who commits an offence under this section is liable to a fine not exceeding $20,000 and, in the case of a continuing offence, to a further fine not exceeding $2,000 for every day or part of a day during which the offence has continued.

Owner must obtain reports on compliance schedule

• An owner of a building for which a compliance schedule has been issued must—
  • (a) obtain annual written reports relating to the inspection, maintenance, and reporting procedures of the compliance schedule signed by each licensed building practitioner or other person who carried out 1 or more of those procedures; and
  • (b) keep those reports, together with the compliance schedule, for a period of 2 years; and
  • (c) produce those reports for inspection, when required, by—
    • (i) the territorial authority; and
    • (ii) any person or organisation who or that has the right to inspect the building under any Act; and
  • (d) show the location of those reports and the compliance schedule on the building warrant of fitness displayed in accordance with section 108(4).

Annual building warrant of fitness

• (1) An owner of a building for which a compliance schedule has been issued must supply to the territorial authority a building warrant of fitness in accordance with subsection (3).

(2) The purpose of a building warrant of fitness is to ensure that the specified systems stated in the compliance schedule are performing, and will continue to perform, to the performance standards for those systems that are set out in the relevant building consent.

(3) The building warrant of fitness must—

• (a) be supplied on each anniversary of the issue of the compliance schedule; and
• (b) state that the inspection, maintenance, and reporting procedures of the compliance schedule have been fully complied with during the previous 12 months; and
• (c) have attached to it all certificates, in the prescribed form, issued by a licensed building practitioner that, when those certificates are considered together, certify that the inspection, maintenance, and reporting procedures stated in the compliance schedule have been fully complied with during the previous 12 months; and
• (d) have attached to it any recommendation made by a licensed building practitioner that the compliance schedule should be amended to ensure that the specified systems stated in the compliance schedule are performing, and will continue to perform, to the performance standards for those systems; and
• (e) be in the prescribed form; and
• (f) contain the prescribed information.

(4) The owner must publicly display a copy of the building warrant of fitness in a place in the building to which users of the building have ready access.

(5) A person commits an offence if the person—

• (aa) fails to supply to the territorial authority the building warrant of fitness in accordance with subsection (1); or
• (a) fails to display a building warrant of fitness that is required to be displayed under this section; or
• (b) displays a false or misleading building warrant of fitness; or
• (c) displays a building warrant of fitness otherwise than in accordance with this section.

(6) A person who commits an offence under this section is liable to a fine not exceeding $20,000.

(7) In subsection (3)(d), a reference to a licensed building practitioner is a reference to the licensed building practitioner or licensed building practitioners who carried out the inspection, maintenance, and reporting procedures stated in a compliance schedule during the previous 12 months.

Meaning of dangerous building

• (1) A building is dangerousfor the purposes of this Act if,—
  • (a) in the ordinary course of events (excluding the occurrence of an earthquake), the building is likely to cause—
    • (i) injury or death (whether by collapse or otherwise) to any persons in it or to persons on other property; or
    • (ii) damage to other property; or
  • (b) in the event of fire, injury or death to any persons in the building or to persons on other property is likely because of fire hazard or the occupancy of the building.
• (1) A building is earthquake pronefor the purposes of this Act if, having regard to its condition and to the ground on which it is built, and because of its construction, the building—
  • (a) will have its ultimate capacity exceeded in a moderate earthquake (as defined in the regulations); and
  • (b) would be likely to collapse causing—
    • (i) injury or death to persons in the building or to persons on any other property; or
    • (ii)
• A building is insanitaryfor the purposes of this Act if the building—
  • (a) is offensive or likely to be injurious to health because—
    • (i) of how it is situated or constructed; or
    • (ii) it is in a state of disrepair; or
  • (b) has insufficient or defective provisions against moisture penetration so as to cause dampness in the building or in any adjoining building; or
  • (c) does not have a supply of potable water that is adequate for its intended use; or
  • (d) does not have sanitary facilities that are adequate for its intended use.

 Meaning of earthquake-prone building123 Meaning of insanitary buildingProtecting safety of members of public using premises open to public or intended for public use

• (1) A person who owns, occupies, or controls premises to which section 362Aapplies must not use, or permit the use of, any part of the premises that is affected by building work—
  • (a) if—
    • (i) a building consent is required for the work; but
    • (ii) no building consent has been granted for it; or
  • (b) if a building consent has been granted for the work, but—
    • (i) no code compliance certificate has been issued for the work; and
    • (ii) no certificate for public use has been issued under section 363A for the part; or
  • (c) if a building consent has been granted for the work, and a certificate for public use has been issued under section 363Afor the part, but—
    • (i) no code compliance certificate has been issued for the work; and
    • (ii) the certificate for public use has been issued for the part subject to conditions that have not been complied with.

(2) For the purposes of subsection (1), a part of premises may be affected by building work—

• (a) whether or not the work has been completed; and
• (b) whether the work is being or has been done to or in, or involves or involved the building of,—
  • (i) the part itself; or
  • (ii) some other part of the building that the premises comprise or form part of.

(3) A person who fails to comply with subsection (1) commits an offence.

(4) A person who commits an offence under this section is liable to a fine not exceeding $200,000 and, in the case of a continuing offence, to a further fine not exceeding $20,000 for every day or part of a day during which the offence has continued.