Ministry of Education Canterbury Earthquakes

Impact on the Ministry of Education’s School Buildings Ministry of Education

Canterbury Earthquakes

Impact on the Ministry of Education’s School Buildings

Prepared By Opus International Consultants Ltd Toby Tscherry Christchurch Office Structural Engineer 20 Moorhouse Avenue PO Box 1482, Christchurch Mail Centre, Christchurch 8140 New Zealand

Reviewed By Telephone: +64 3 363 5400 Will Parker Facsimile: +64 3 365 7858 Technical Principal – Earthquake Engineering & Building Structures Date: 16 January 2015 Reference: 5-C2102.00 Status: Issue 10 FINAL

© Opus International Consultants Ltd 2015 Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings i

Executive Summary

This report has been written for the Ministry of Education (“the Ministry” or MoE). The purpose of this report is to review performance of school buildings in the Canterbury earthquake sequence. The intent is to assist the Ministry of Education in improving the resilience of their current and future school buildings in Christchurch and throughout New Zealand.

The post-earthquake review sampled 70 school buildings in Canterbury classified into 25 types. The majority of school buildings reviewed are single storey, with the remainder being a maximum of 2 storeys.

Buildings selected range in age from the 1930s through to 1990s. The buildings have been chosen to be representative of school blocks throughout New Zealand, thus the majority of the sample captures buildings from the 1950s through to the 1970s, when ‘standard’ designs were used nationally (or regionally). After this period, one-off designs prepared by local architects seem to dominate the building stock. It was not attempted to capture these newer designs in the sample, because the lessons from these one-off designs have less relevance to the national portfolio.

Conclusions drawn about safety emphasize that there were no fatalities on school sites although some injuries occurred, mostly resulting during egress. The Ministry’s earthquake strengthening programme has been effective; it prevented building collapse, provided a safe environment for teachers and students and limited damage to buildings that would otherwise have been more severely affected. A significant conclusion is that a large proportion of damage was the result of ground deformation. A key recommendation is that the Ministry consider this and other site related risks nationally.

Conclusions on structural performance are:  Lightweight wall and roof timber buildings have performed very well generally and in excess of their calculated capacity.  Seismic retrofit work undertaken has been effective.  A large proportion of building damage was due to ground deformation.  Lightweight buildings with suspended timber floors on shallow footings generally accommodate ground deformation well and can often be quickly and cost effectively re-levelled.  Overhead heavy building services or items unsecured on shelves can be a falling hazard.  Most heavy roofs have been removed and replaced with lightweight material, which has reduced the seismic load and damage.  Where blocks have been joined together and the alignment of the principle axes are no longer maintained such that the footprint is not symmetrical, i.e. joined together to form a T shaped footprint, increased damage was observed.  Heavy veneer cladding increases damage to internal linings.  Overhead heavy veneer can be a falling hazard if not well tied to timber framing, particularly above doors and windows.  The open plan blocks have minimal bracing which increases frame distortion and damage.  Some CEBUS type buildings have external nail plates that have failed during shaking without resulting in collapse. These can be simply retrofitted.  One of the Pre-1930’s Two Storey Block’s has Potential Critical Structural Weaknesses while up to 11 others have structural weaknesses.

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Site Considerations – Recommendations Buildings and Infrastructure  An egress and evacuation plan should be put in place for each school site. The main issues are concerning stuck doors due to differential settlement and potential fall hazards. The assembly point should also be considered.  Overhead falling hazards relating to poorly tied brick veneer, heavy building services or items on shelving should be assessed, and if required secured or removed to a lower height.  Consideration should be given to assessing and, if required, strengthening, or removing the veneer at height to mitigate this risk in a future significant earthquake event. Lowering the veneer will have the added benefit of reducing the seismic load on the buildings’ structure and improving its overall performance.  Consideration should be given to upgrading site infrastructure during significant developments. This would reduce the extent of aged, frequently extended, brittle pipe networks present on many school sites.  Consideration should be given to the assessment of schools’ existing infrastructure networks, for their condition and capacity i.e. compliance and vulnerability. This would indicate a need for the upgrade of any existing infrastructure with newer, more robust systems. This also reduces the risk of major costs associated with repairing older systems, when repairs carried out in the future might trigger the requirement for a Building Consent. Discussion with Councils should also be considered to seek clarity on compliance requirements.  Consideration should be given to contingency measures for lifeline services (water supply & sewer).  Consider options for hardstands that include ‘full design life’ to mitigate known geotechnical risks.

Process – Recommendations and further review  Issue minimum standard brief and guidelines for engineering assessment and design which embodies current ‘best practice’. (We note that the Ministry have subsequently issued guidelines on importance level for retrofit and new design).  Consider adopting damage resistant designs in high seismicity areas. This could also reduce the cost to repair non-structural damage, which is estimated to be approximately 70% of the total repair cost for commercial buildings.  Review processes around construction quality control and construction monitoring by the designer and Territorial Authorities’ (TA’s) to ensure efficiency and confidence that the design intent is achieved during construction.  Consider setting up a review panel, perhaps a continuation of the Engineering Strategy Group (ESG) or similar to USA practice where an independent consultant from an approved panel reviews design and or construction.

Learnings from other commercial and Ministry of Education buildings should be applied to the portfolio, for example:  Stairs; review in accordance with Ministry of Business, Innovation and Employment (MBIE) guidelines.  Precast panels; especially connections and requirements for ductility.  Shear walls; in line with interim design guidelines by Structural Engineering Society New Zealand (SESOC).  Cross bracing; particularly Reid Brace especially connections and requirements for ductility.

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Contents

Executive Summary ...... i

1 Introduction ...... 1

2 Assessment Scope ...... 1 2.1 Limitations ...... 1 2.2 Infrastructure ...... 2 2.3 Peak Ground Acceleration ...... 2 2.4 Geotechnical ...... 7 2.5 Potential Structural Weaknesses ...... 12

3 Selection of Buildings ...... 12 3.1 Considerations for Selection ...... 12 3.2 Selection Criteria ...... 12 3.3 Buildings Selected ...... 12

4 Building Type Structural Review ...... 16 4.1 Rating System ...... 16 4.2 Flowcharts and Reference Material ...... 16

5 Key Findings ...... 20 5.1 Summary of Building Results ...... 20 5.2 Discussion/Analysis of Results ...... 25

6 Conclusions ...... 30 6.1 General Conclusions ...... 30 6.2 Infrastructure Performance/Damage ...... 31 6.3 Block Specific Conclusions ...... 32

7 Recommendations ...... 32 7.1 Site Considerations – Buildings and Infrastructure ...... 32 7.2 Process ...... 33 7.3 Further Review ...... 33

8 Limitations ...... 34 8.1 Other Site Risks ...... 34

Appendix A - School Building Types ...... A1 A1 Two Storey Classroom Block ...... A2 A2 Subfloor Framing ...... A3 A3 Pre 1930s Two Storey Block ...... A4

Appendix B – Block Types by School ...... B1

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Appendix C – Building Type Performance Summary ...... C1

C1 Open Air Veranda block ...... C2 C1.1 Recommendations & Conclusions ...... C2

C2 Dominion block ...... C3 C2.1 Recommendations & Conclusions ...... C3

C3 Canterbury block ...... C4 C3.1 Recommendations & Conclusions ...... C5

C4 12 Classrooms double storey Block ...... C6 C4.1 Recommendations & Conclusions ...... C6

C5 Open Plan Block ...... C7 C5.1 Recommendations & Conclusions ...... C7

C6 CEBUS MK 1 & 2 ...... C8 C6.1 Recommendations & Conclusions ...... C8

C7 CEBUS Modified (1990) ...... C9 C7.1 Recommendations & Conclusions ...... C9

C8 Prefabs - Paul Wilkin Design ...... C10 C8.1 Recommendations & Conclusions ...... C10

C9 Nayland Block ...... C11 C9.1 Recommendations & Conclusions ...... C11

C10 Hall with Sub-basement ...... C12 C10.1 Recommendations & Conclusions ...... C12

C11 Hall without Sub-basement ...... C13 C11.1 Recommendations & Conclusions ...... C13

C12 Portacom ...... C14 C12.1 Recommendations & Conclusions ...... C14

C13 Subfloor Framing ...... C15 C13.1 Recommendations & Conclusions ...... C15

C14 Pre 1930s 2 Storey Block ...... C16 C14.1 Recommendations & Conclusions ...... C17

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C15 1940s Single Storey Weatherboard Block ...... C18 C15.1 Recommendations & Conclusions ...... C18

C16 1950s Double Storey ...... C19 C16.1 Recommendations & Conclusions ...... C19

C17 1960s Nelson Block "Straight" ...... C20 C17.1 Recommendations & Conclusions ...... C20

C18 1960s Nelson Block "H Plan" ...... C21 C18.1 Recommendations & Conclusions ...... C21

C19 Nelson Single Storey ...... C22 C19.1 Recommendations & Conclusions ...... C22

C20 S68 (school 68-72) ...... C23 C20.1 Recommendations & Conclusions ...... C23

C21 Secondary School Hall ...... C24 C21.1 Recommendations & Conclusions ...... C24

Appendix D – Geotechnical Description of School Standard Blocks ...... D1

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1 Introduction

Opus International Consultants (Opus) has been commissioned by the Ministry of Education (“the Ministry”) to review damage to school buildings caused by the recent Canterbury earthquakes. This report was first issued on 10 February 2012 and has been updated to include:

 Refinement to the intensity of shaking zonation to reflect the PGA contours, provided by GNS, now available on the Canterbury Geotechnical Database1.  Review the Critical Structural Weaknesses (CSWs) in context of the current classification of structural weaknesses for light-weight timber buildings.  Improve the data on damage for the various blocks based on information available to the Ministry.  Improve the ground damage classification/zonation to identify the influence that ground movement had on building damage.  Clarify the standard block types using the Catalogue of Standard Buildings produced by the Ministry.  Include data from the standard block assessments.  Update the conclusions and recommendations to reflect the amendments to the report. 2 Assessment Scope

This report assesses the structural performance of a series of school building types located at over 40 school sites in Canterbury. The scope of work is to:

 Provide a detailed and concise report for use by the Ministry on the impact of the recent Christchurch earthquakes (September 2010, February 2011 and June 2011) on the Ministry’s school buildings and infrastructure.  The purpose of this report is to highlight aspects of the buildings and infrastructure that performed well / poorly to allow the Ministry to improve the resilience of their current and future school buildings in Christchurch and throughout New Zealand.

2.1 Limitations

The structural assessments conducted by various structural consulting firms were reviewed along with any information provided by the Ministry and the schools themselves. No additional structural assessments were performed as per the scope of this project.

The reports reviewed consist of Rapid Assessment forms, which involves a walk around and through the building (if safe to do so) looking for visible signs of significant structural damage. This is specified as post-disaster Building Safety Evaluation endorsed by the MBIE (formerly Department of Building and Housing). Following this, Detailed Engineering Evaluation (DEE) reports have also been prepared for the Ministry, these generally involve a detailed visual inspection and calculation of the existing structural capacity of the buildings compared against the current building code. Where available these have been reviewed to verify the findings discussed in this report.

1 canterburygeotechnicaldatabase.projectorbit.com

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The reports used for this review were completed by a range of consulting firms over an extended period of time, and this information has been used without review. Opus takes no responsibility for the reliability of these structural reports, nor the information from these reports that has been used herein.

The standard building types considered for this study are not exhaustive. If none of the standard building types match the school of interest, no conclusions should be taken from any similar building types. The standard building types found in the Canterbury region differ from those found in other regions. Therefore it is important to use the building type description to get an exact match. The standard building type names are indicative only, as the same type of buildings may have different names across the country.

2.2 Infrastructure

This report is focussed on the performance and damage of school buildings, a review of other Ministry infrastructure is outside the scope of this report. From our involvement in infrastructure repairs at a number of school sites Opus have formed and provided some conclusions on the general performance of infrastructure. 2.3 Peak Ground Acceleration

The school buildings have sustained damage in both the 2010 Darfield and 2011 Christchurch earthquakes. The overall damage resulting from the series of earthquakes is considered in this report. No distinction is explicitly made between the different events, which may have resulted in different types of damage. It is not possible to clearly state which events caused specific observed damage. As an example, the 4 September earthquakes might have caused unobserved damage to structural elements which failed during the 22 February earthquake.

The ground accelerations were recorded and are shown on Figure 1 and Figure 2, extracted from the GNS report2. The peak ground acceleration (PGA) in the horizontal direction closely correlates to the extent of damage caused by the earthquakes.

2 Webb T. H., Beaven J., Brackley H., Gerstenberger M., Kaiser A., McSaveney E., Reyners M., Somer-ville P., Van Dissen R., Wallace L., Bannister S., Berryman K., Fry B., Holden C., McVerry G., Pettinga J., Rhoades D., Stirling M., Villamor P., and Zhao J., ‘The Canterbury Earthquake Sequence and Implications for Seismic Design Levels’, GNS Science Report 2011/128, July 2011.

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Figure 1 : Maximum horizontal and vertical PGA’s recorded during the 4 September 2010 earthquake at GeoNet stations

Figure 2 : Maximum horizontal and vertical PGA’s recorded during the 22 February 2011 earthquake at GeoNet stations

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Figure 3 and Figure 4 show banded summary contour maps of the ground shaking experienced in Canterbury as a result of the September 2010 and February 2011 earthquakes overlaid with the school locations, refer to Figure 7 for a full list of Ministry schools. The PGA contours have been obtained from the Canterbury Geotechnical Database.

The four different bands are representative of the design level earthquakes where the ‘Return period’ (R) factor relates to the various expected earthquake intensities for a building with a 50 year design life. The severity rating of each band relates to the annual probability of an earthquake event, as shown in Table 2-1.

Table 2-1: Return Period Factor Range*

R or R Return Period Description u s Return Period Range Factor Range Severe R ≥ 1.8 >1/2500 High R = 1.0 to 1.8 1/500 to 1/2500 Moderate R = 0.75 to 1.0 1/250 to 1/500 Low R = 0.35 to 0.75 1/50 to 1/250 *based on new seismicity (Z=0.3)

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Z=0.3

Figure 3: Combined Peak Ground Acceleration - Christchurch

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Z=0.3

Figure 4: Combined Peak Ground Acceleration - Canterbury

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2.4 Geotechnical

Widespread liquefaction occurred during the 22 February event. Figure 5 and Figure 6 show the foundation technical categories from the MBIE, overlaid with the school locations, refer to Figure 7 for a full list of Ministry schools. These maps provide an indication of the susceptibility to liquefaction in the city and wider Canterbury.

Comments have been included in Table 5-1 to provide an indication of the extent of damage which can be attributed to ground movement, and that which has resulted from ground shaking. Reference can also be made to the maps in Figure 5 and Figure 6 which show the school locations in relation to the extent of shaking and liquefaction.

2.4.1 Category

The geotechnical classification has been developed by the Ministry and will be available for Canterbury schools to differentiate the classification from the MBIE Technical Categories for residential properties (e.g. TC1 – TC3). The report incorporates these classifications where available, alternatively where these are not available, the MBIE technical categories for the neighbouring residential properties have been used.

GH1 Geotech Hill Category 1

Future land damage from subsidence or land slip is unlikely and there is no rock fall hazard. Likely to be able to use standard foundations for buildings of a similar structure and size to those already present on site.

GH2 Geotechnical Hill Category 2

There is risk from land slips, subsidence and / or a rock fall hazard. Specific engineered foundation and rockfall mitigation design will be required.

GC1 Geotechnical Category 1

Future land damage from liquefaction or lateral spreading is unlikely. Likely to be able to use standard foundations for buildings of a similar structure and size to those already present on site.

GC2 Geotechnical Category 2

Minor to moderate land damage from liquefaction or lateral spreading is possible in future significant earthquakes. The use of standard timber piled foundations for simple single storey buildings (up to average house size) with lightweight cladding and roofing and suspended timber floors is likely to be acceptable. The use of enhanced concrete foundations that tie the structure together for single storey buildings (up to average house size) with concrete slab floors is likely to be required. Multi-storey and larger buildings may require a site-specific geotechnical investigation and specific engineered foundation design.

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GC3 Geotechnical Category 3

Moderate to significant land damage from liquefaction or lateral spreading (< 500mm) is possible in future significant earthquakes. Site-specific geotechnical investigation and specific engineered foundation design is likely to be required.

GC4 Geotechnical Category 4

Significant land damage from lateral spreading (>500mm) is possible in future significant earthquakes. Site-specific geotechnical investigation and specific engineered foundation design will be required.

2.4.2 Data Reliability and Confidence

The reliability and confidence of geotechnical information varies depending on the level of information available at the time of writing the respective school reports. This has been assessed and commented on in the geotechnical reports when they have been completed by the respective consultants however it has not been replicated or explicitly stated in this report. Readers are directed to the source reports for further information of data reliability and confidence.

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Figure 5: Technical Categories - Christchurch

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Figure 6: Technical Categories - Canterbury

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Figure 7: Full List of Ministry Schools

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2.5 Potential Structural Weaknesses

A “Critical Structural Weakness” (CSW) refers to a component of a building that could contribute to increased levels of damage or cause premature collapse of a building.

Apart from one pre 1930s 2 storey block, no blocks were found to have CSWs. Some school buildings however, do have structural deficiencies or weaknesses that adversely affect the building’s seismic performance. These weaknesses are not considered to be critical to life safety or collapse. In these cases the term ‘structural weakness’ has been used. 3 Selection of Buildings

3.1 Considerations for Selection

The aim of the block selection process was to provide a representative of the range of school buildings typically found throughout New Zealand. Primary, intermediate, and secondary school building types were considered to account for the differences in building form and scale between school sectors. Although some of the buildings are suitable for more than one school sector, the difference in the building footprint between sectors is significant.

Given the relative size of the greater Wellington region and its location in a high seismicity area, additional effort was made to find block types common in the Wellington region. Notable block types in Wellington include:

 1950s Henderson Blocks: Heretaunga College (none of these have been located for this report).  S68 Blocks (late 60s early 70s): Porirua College, Wainuiomata High.  Nelson Library Blocks: Heretaunga College, Porirua College, Wainuiomata High. 3.2 Selection Criteria

The selection of the school buildings was made based on the following criteria:

 Location in the Christchurch area.  Representative of New Zealand school building types.  Range of earthquake damage from minor to significant. and,  Access to existing structural reports and in some cases, structural drawings. 3.3 Buildings Selected

The following buildings have been selected to represent standard types of buildings. The full description of each building type is presented in Appendix C.

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Table 3.1: Standard Block Locations

Standard Type of Building Location

Primary and Intermediate Schools Shirley Intermediate – 60 Shirley Road, Shirley, Chch Wharenui Primary – 32 Matipo Street, Riccarton, Chch Open Air Veranda Block Wairakei Primary – 250 Wairakei Road, Bryndwr, Chch Bamford Primary – 6 Gould Crescent, Woolston, Chch Hammersley Park Primary – 90 Quinns Road, Shirley, Chch

Dominion Block Banks Avenue Primary – 91 Banks Avenue, Dallington, Chch Addington Primary – 22 Brougham Street, Addington, Chch Thorrington Primary – 22A Colombo Street, Lower Cashmere, Chch Heathcote Valley Primary – 61 Bridle Path Road, Heathcote Valley, Chch Hoon Hay Primary – 91 Sparks Road, Hoon Hay, Chch Freeville Primary – 1 Sandy Avenue, North New Brighton, Chch Canterbury Block Banks Avenue Primary – 91 Banks Avenue, Dallington, Chch Russley Primary – 75 Cutts Road, Avonhead, Chch Sumner Primary – 15 Colenso Street, Sumner, Chch Darfield High – 16 Ross Street, Darfield, Canterbury Central New Brighton Primary – 140 Seaview Road, New Brighton, Chch Manning Intermediate – 50 Hoon Hay Road, Hoon Hay, Chch Twelve Classroom Double Storey Block Branston Intermediate – 35 Amyes Road, Hornby, Chch Shirley Primary – 11 Shirley Road, Shirley, Chch Fendalton Open Air School – 168 Clyde Road, Fendalton, Chch Open Plan Blocks Central New Brighton Primary – 140 Seaview Road, New Brighton, Chch

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Standard Type of Building Location

Heathcote Valley Primary – 61 Bridle Path Road. Heathcote Valley, Chch Queenspark Primary – 222 Queenspark Drive, Parklands, Chch Bromley Primary – 33 Keighleys Road, Bromley Chch Banks Avenue Primary – 91 Banks Avenue, Dallington, Chch Hoon Hay Primary – 91 Sparks Road, Hoon Hay, Chch Shirley Primary – 11 Shirley Road, Shirley, Chch CEBUS MK I & II Van Asch Deaf Education Centre (Block K) – 38 Truro Street, Sumner, Chch Heathcote Valley Primary – 61 Bridle Path Road, Heathcote Valley, Chch St Martins Primary – 24 Albert Terrace, St Martins, Chch

CEBUS 4 Bamford Primary – 6 Gould Crescent, Woolston, Chch Bromley Primary – 33 Keighleys Road, Bromley Chch Fendalton Open Air Primary – 168 Clyde Road, Fendalton, Chch CEBUS Modified (1990) Russley Primary – 75 Cutts Road, Avonhead, Chch Sumner Primary – Colenso Street, Sumner, Chch Paul Wilkin Design Banks Avenue Primary – 91 Banks Avenue, Dallington, Chch Middleton Grange – 50 Acacia Avenue, Riccarton, Chch Nayland Burnside High – 151 Greers Road, Burnside, Chch Kaiapoi Borough Primary – 20 Hilton Street, Kaiapoi Halls with Sub-basement Russley Primary – 75 Cutts Road, Avonhead, Chch under stage Hammersley Park Primary – 90 Quinns Road, Shirley, Chch Avonhead Primary – 55 Avonhead Road, Avonhead, Chch Hall without Sub-basement under stage Linwood North Primary – 221 Woodham Road, Linwood, Chch

Portacom Burnside High – 151 Greers Road, Burnside, Chch

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Standard Type of Building Location

Hoon Hay Primary – 91 Sparks Road, Hoon Hay, Chch St Martins’ Primary – 24 Albert Terrace, St Martins, Chch Subfloor Framing Mt Pleasant Primary – 82 Major Hornbrook Road, Chch

Secondary Schools Hagley Community College – 510 Hagley Avenue, Addington, Chch Pre 1930s 2 Storey Block Avonside Girls’ High – 180 Avonside Drive, Avonside, Chch Christchurch Boys’ High – Straven Road, Riccarton, Chch Papanui High – 30 Langdons Road, Papanui, Chch 1940’s Single Storey Heaton Intermediate – 125 Heaton Street, Merivale, Chch Weatherboard Wairakei Primary – 250 Wairakei Street, Bryndwr, Chch Linwood College – 85 Aldwins Road, Linwood, Chch Cashmere High – 172 Rose Street, Somerfield, Chch 1950s Double Storey Avonside Girls’ High – 180 Avonside Drive, Avonside, Chch

Rangiora High – 125 East Belt, Rangiora Avonside Girls’ High (Gresson Block) – 180 Avonside Drive, Avonside, Chch Nelson Block "Straight Block" Papanui High (Plimsol Block) – 30 Langdons Road, Papanui, Chch Burnside High – 151 Greers Road, Burnside, Chch Linwood College – 85 Aldwins Road, Linwood, Chch Nelson Block "H Plan" Mairehau High – 440 Hills Road, Mairehau, Chch Cashmere High – 172 Rose Street, Somerfield, Chch Lincoln High – 25 Boundary Road, Lincoln

Nelson Single Storey Mairehau High – 440 Hills Road, Mairehau, Chch Shirley Boys’ High – 59 North Parade, Shirley, Chch Kaiapoi High – 101 Ohoka Road, Canterbury

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Standard Type of Building Location

S68 (schools 1968) and MKII Hornby High – 180 Waterloo Road, Hornby, Chch in 1972 Lincoln High – 25 Boundary Road, Lincoln

Secondary school Hall Papanui High – 30 Langdons Road, Papanui, Chch Cashmere High – 172 Rose Street, Somerfield, Chch 4 Building Type Structural Review

For this review, school buildings have been identified by their standard type. A “Building Performance Assessment” has been prepared and undertaken for each building by an Opus Structural Engineer to assess the damage, consider the repair work undertaken and or required, identify the structural weaknesses and rate the building. 4.1 Rating System

A rating system has been implemented to simplify the performance evaluation of the buildings and provide comparison between the different types. The Table 4-1 shows the rating descriptions which have been used by Opus to rate the performance of each building.

Table 4-1: Summary of Performance/Damage Rating System Rating Rating Performance/Damage Description Number Title

1 Very Well It withstood the earthquake without any significant damage.

It withstood the earthquake with minor non-structural 2 Well damage which required minor repairs prior to occupancy. It had extensive non-structural and/or minor structural 3 Fair damage. It needed repairs prior to usage. It had significant structural damage affecting overall 4 Poor structural integrity. The building suffered severe structural damage and required 5 Very Poor urgent strengthening or demolition.

4.2 Flowcharts and Reference Material

All of the information used about the various school buildings and the conclusions drawn after completion of the Building Performance Assessment forms, are contained in the Appendices A - C. This material includes:

 Flowchart of types: The flowchart is presented in Figures 8 - 11. These have been designed to help identify the type of building.  School block ordered by type: All block types are listed along with their locations.

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 School blocks ordered by name: Schools are listed with the types of building that have been reviewed as part of this work.  Each type of building reviewed has its datasheet containing general photos along with specific earthquake damage photos. The summary of each building is listed in short form along with the rating and the earthquake intensity zone.

Figure 8: Single storey relocatable classroom flowchart identification tool

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Figure 9: Single storey permanent classroom flowchart identification tool

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Figure 10: Double storey classroom flowchart identification tool

Figure 11: Non-classroom building flowchart identification tool

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5 Key Findings

5.1 Summary of Building Results

Table 5.1 shows the different building types with their overall rating and comments considering ground shaking and geotechnical category (refer to Figure 3 to 5).

Table 5-1 - Standard block summary

Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

Shirley High TC3 3 Intermediate Shaking damage primarily due to ground deformation. Open Air Wharenui Primary High TC2 2 Connection of sub-floor framing to Veranda Block * building assessed to be 11%NBS. Bamford Primary Severe GC2 2 Once strengthened, building is assessed to be greater than 34%NBS. Wairakei Primary Low TC2 2 Blocks 1, 2 Banks Avenue Primary ground Banks Avenue and 4- GC4 deformation contributed to damage. High 5 Primary (>500mm of Plan irregularity (structural lateral spread) weakness) due to full length windows Dominion Block Hammersley Park on one side of building; may cause Moderate TC3 3 Primary excessive deformation and potential falling hazard from the brick veneer. Addington High GC2 2* The assessed capacity is 70%NBS Primary (NZSEE, Sp = 0.5, Z = 0.3). Thorrington High TC2 4 Primary Heathcote Valley Severe TC2 1 Primary Hoon Hay High GC2 2 Primary Freeville Primary Low GC3 2 The damage to Thorrington Primary Canterbury Blocks 1, 2 and Banks Avenue Primary is mostly Banks Avenue and 4- GC4 Block High 2 due to ground deformation. Primary (>500mm of The assessed capacity is 41%NBS lateral spread) (NZSEE, Sp = 0.5, Z = 0.3). Russley Primary Low TC1 2 N/A Rural and Darfield Primary High 3 Unmapped Sumner Primary Severe TC2 1 Central New Moderate TC3 2 Brighton Primary * These ratings are based on the DEE summary report as no primary source information about the damage is available.

3 Notes from standard reports and assessments by Opus and others. 4 Establishing the Resilience of Timber Framed School Buildings in New Zealand; 2014 NZSEE Conference

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Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

Manning Lower intensity zone samples. Twelve Moderate TC3 2 Intermediate Limited conclusion but wall Classrooms irregularity may be a structural Double Storey Branston weakness. Moderate GC1 3 Intermediate No significant ground deformation.

Shirley Primary High TC3 2

Fendalton Open Moderate TC3 2 Air Primary

Central New Moderate TC3 1 Central timber framed shear walls Open Plan Brighton Primary assessed to be 38%NBS. Blocks No structural weaknesses for the

* superstructure. Bromley Primary Severe GC2 1 No significant ground deformation.

Heathcote Valley Severe GC1/GH1 3 Primary

Queenspark Low TC2 2 Primary

Resistant to damage due to ground deformation. No structural weaknesses for the superstructure. CEBUS 1 Heathcote Valley Superstructure assessed to be Severe GC1/GH1 1* Primary 49%NBS (NZSEE, Sp = 0.5, Z = 0.3). Foundations assessed to be approximately 40%NBS. No significant ground deformation. Blocks 1, 2 Banks Avenue and 4- GC4 Resistant to damage due to ground High 1 Primary (>500mm of deformation. lateral spread) Simple design with a portal frame bracing system. Monitor condition of Hoon Hay High GC2 1* the gangnail plates which provide the Primary connection at the external frame CEBUS 2 (MK I connections. These might start to & II) Heathcote Valley work loose. Severe GC1/GH1 1* Primary No structural weaknesses for the superstructure. Superstructure assessed to be Shirley Primary High TC3 1 49%NBS (NZSEE, Sp = 0.5, Z = 0.3). Foundations assessed to be Van Asch Deaf Severe GC1 2 approximately 40%NBS. Education Centre

* These ratings are based on the DEE summary report as no primary source information about the damage is available.

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Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

Resistant to damage due to ground deformation. Fendalton Open Similar structure to the CEBUS Mk Moderate TC3 1 Air Primary 1&2. Lower intensity zone samples with no damage. CEBUS No structural weaknesses for the Modified (1990) superstructure. Superstructure assessed to be 49%NBS (NZSEE, Sp = 0.5, Russley Primary Low TC1 1 Z = 0.3). Foundations assessed to be approximately 90%NBS. No significant ground deformation. Resistant to damage due to ground CEBUS 3 Woolston Primary Severe GC2 1* deformation. No significant ground deformation. Resistant to damage due to ground St Martin’s High GC2/GH1 2* deformation. Primary No structural weaknesses for the superstructure. CEBUS 4 Superstructure assessed to be Bamford Primary Severe GC2 1* 49%NBS (NZSEE, Sp = 0.5, Z = 0.3). Foundations assessed to be Bromley Primary Severe GC2 2* approximately 40%NBS. No significant ground deformation. Blocks 1, 2 Banks Avenue and 4- GC4 Paul Wilkin High 2 Performed well subjected to ground Design Primary (>500mm of movement. Foundations are easily re- lateral spread) levelled. Sumner Primary Severe TC2 1 Lower intensity zone samples. Nayland Middleton Grange Moderate TC1 1 Limited conclusions can be drawn. Burnside High Low TC1 2 No significant ground deformation. Kaiapoi Borough Moderate GC3 2 Plan and vertical irregularity. This Primary Hall with Sub- may be a structural weakness due to basement Russley Primary Low TC1 2 the tendency of the two sections of building to respond differently. Hammersley Park Moderate TC3 2 No significant ground deformation. Primary Avonhead Roof diaphragm action and wall Low TC1 2 bracing provide additional bracing. Hall without Primary Lightweight cladding materials Sub-basement reduce the seismic demand on the Linwood North High GC2 3 structure. Primary No significant ground deformation. Burnside High Low TC1 1 Portacom Performed well subjected to ground Hoon Hay High GC2 2 movement. Primary * These ratings are based on the DEE summary report as no primary source information about the damage is available.

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Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

St Martin’s High GH1 3 The foundation/structure connection Subfloor Primary details are critical as they could fail Framing N/A Port Hills during large ground deformation or Mt Pleasant Severe & Banks 3 intense shaking Primary Peninsula These buildings built in the 1930s are Hagley likely to have CSW, such as Community High TC2 2 unreinforced brick walls that may College become a falling hazard. Strengthening works in the 1990’s carried out to address most Pre 1930’s 2 Avonside Girls’ High GC2-3. 5 earthquake prone building issues Storey Block High provides an explanation for their relatively good performance. These buildings are heavy and stiff. Christchurch High TC3 2 Extensive damage at Avonside Girls’ Boys’ High High School due to ground movement.

Papanui High Low GC2 2 This lightweight and low building 1940’s Single performs well under seismic loads. Storey Heaton Normal Ground deformation at Heaton Moderate TC3 3 weatherboard Intermediate Normal Intermediate caused significant damage to foundations and superstructure cracking. Wairakei Primary Low TC2 1

GC3 (CPT Linwood College High 3 Heavy concrete structure susceptible >100mm) to ground deformation. This occurred at Linwood College and Avonside N/A Rural and Rangiora High Low 2 Girls’ High School. 1950’s Double Unmapped Insufficient bracing (potential CSW) Storey in the longitudinal direction due to Cashmere High High TC3 3 the clerestory windows between the concrete columns; may result in significant damage to beams and Avonside Girls’ High GC2-3 4 columns. High School Extensive damage at Avonside Girls’ High School due to ground Avonside Girls’ GC2-3. See High 4 deformation. High plot provided. Two storeys of window openings with masonry veneer beneath the 1960’s Nelson ground floor windows cause plan Block “Straight” irregularity (structural weaknesses). Strengthening works in the 1990’s- 2000’s carried out to address most Papanui High Low GC2 1 earthquake prone building issues which explains their relatively good performance. * These ratings are based on the DEE summary report as no primary source information about the damage is available.

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Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

Two storey timber framed building in general “H” formation. Lacks lateral load resisting elements on the end walls. Lateral load resisting system Burnside High Low TC1 2 in both directions relies in part on timber columns cantilevering above braced walls. These can be considered as structural weaknesses. Building assessed to be 36%NBS with concrete stairs or 38%NBS with timber stairs (NZSEE, Sp = 0.5, Z = 0.3). General performance of the Linwood College High GC3 1 building is likely to be better than the figures shown above. Higher capacities may be gained by 1960’s Nelson estimating the impact of factors such Block “H Plan” as load redistribution, secondary structural elements, energy dissipation and conservatism in estimated strength capacities of the Mairehau High Moderate TC2 1 structural elements. These buildings generally performed adequately in Christchurch and are unlikely to collapse during a moderate earthquake. Strengthening works in the 1990’s- 2000’s carried out to address most earthquake prone building issues which explains their relatively good Cashmere High High TC3 3 performance. The majority of damage at Cashmere High School is due to ground deformation.

Lincoln High High TC1 1 1960-70’s Single At Shirley Boys’ High School, most Storey of the damage recorded was due to Weatherboard Mairehau High Moderate TC2 1 ground deformation. The lack of bracing between the windows is a structural weaknesses. Shirley Boys’ High TC3 3 High Lateral load resistance in both directions provided by reinforced block walls and built in reinforced * Kaiapoi High Moderate GC2 2 block piers. Some loads at roof level transferred S68 (School 68- to block walls through light, 72) primarily gravity, steel frames. This

may be considered a structural weakness, but is unlikely to lead to Hornby High Low TC1 1 collapse during a moderate earthquake. The damage at Kaiapoi High School is mostly due to ground deformation.

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Shaking Geotech Building Type School Name Rating Comments 3,4 Intensity Category

* These ratings are based on the DEE summary report as no primary source information about the damage is available.

Lincoln High High TC1 1 Secondary Low and moderate intensity zone School Hall Papanui High Low GC2 1 samples and no damage.

No significant ground deformation. Cashmere High High TC3 1

Aranui Block Woolston Primary Severe GC2 1*S

* These ratings are based on the DEE summary report as no primary source information about the damage is available.

5.2 Discussion/Analysis of Results

Table 5-2 provides a brief overview of building performance by type, relating the level of shaking with the level of performance in broad qualitative terms.

Buildings that have experienced high or severe shaking but have low damage are identified as high performers in the upper left (green shaded) cells. In contrast, those buildings that have significant damage whilst only experiencing low or moderate shaking are identified as poor performers and are shown in the lower right (red shaded) cells.

These results should be read with due consideration for the many factors that affect the behaviour of a structure, including:

 The intensity zone in which the building was located. The “Low” zone buildings should be considered as not seismically tested. When looking at results for the “Moderate” and “Severe” zones, the buildings have been considered to have been tested by seismic activity.  The type of shaking or the ground deformation effect differs from site to site.  Blocks which have been identified as a certain building type and built in a specific era may have been modified more recently. This has generally not been taken into account for this review.

Note that the red text in italics indicates that this block has a geotechnical category of 3-5 (1 being “good” ground, 5 being red zone).

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Table 5-2: Performance Summary

Performance/Damage Rating

1 2 3 4 5 Very Well Well Fair Poor Very Poor

Severe Canterbury (2) Open Plan CEBUS 1 Open Air Veranda Subfloor Framing (unmapped) CEBUS 2 CEBUS 2 Open Plan CEBUS 3 CEBUS 4 Paul Wilkin Aranui

High Open Air Veranda Open Air Veranda CEBUS 2 Canterbury & Canterbury Canterbury (unmapped) CEBUS 2 Paul Wilkin Dominion Canterbury Single Storey WB Open Plan Single Storey WB Dominion 1950s 2 storey Secondary Hall CEBUS 4 1950s 2 storey (2) Pre-1930 2 storey Nelson Straight Secondary Hall Portacom Nelson H Shaking Nelson H Pre-1930 2 Storey Subfloor Framing Intensity Pre-1930 2 Storey Hall without SB

Moderate Open Plan Canterbury CEBUS M Open Plan Single storey WB Nelson H 12 Classrooms 2 storey Dominion Nayland Hall SB (2) 12 Classrooms 2 storey Single Storey WB S68

Low Open Air Veranda CEBUS M Nayland Single Storey WB Canterbury Secondary Hall Hall SB & Hall without SB

Portacom 1950s 2 storey (unmapped) Nelson Straight Nelson H S68 Open Plan Single Storey WB Note that the Italics and red text indicate this block has a geotechnical category of 3-5 (1 being “good” ground, 5 being red zone)

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5.2.1 Earthquake Damage

When liquefaction and ground deformation have been observed, a large proportion of the building damage is likely to be attributable to ground deformation. Consequently, a site geotechnical assessment should be performed in addition to building type assessment to show which blocks are more vulnerable to shaking and ground deformation.

5.2.2 Building Type Modifications

Different types of modifications such as retrofitting and strengthening of buildings may have been undertaken. For example, the MoE directed that heavy roof tiles be removed following a report completed by Connell Wagner Limited5; a lightweight roof improves seismic performance.

5.2.3 Construction Issues

Some construction problems were noted during the overall assessment process. For example, the lack of sufficient connections from the brick veneer to the timber walls which can be a hidden structural weakness. Variable mortar quality also affects the performance of brick veneer.

Investigation findings into the performance of veneer ties has been undertaken by Opus (refer to Opus methodology report for MoE). Investigation into non-structural veneers in Canterbury and around New Zealand continues and information currently available has found that the effectiveness of installed ties is highly variable. An early recommendation from this work is to carry out a veneer tie investigation in areas of high seismicity, where veneer could be a potential fall hazard. If ties are adequate, the veneer performance is likely to be good.

5.2.4 Analysis of Results

Table 5-2 illustrates how the different block types have performed under varying shaking intensities and geotechnical conditions. The following describes performance trends observed.

5.2.4.1 Data Scatter

There are a number of blocks of the same type which have a different rating, for example the Canterbury block for high shaking intensity is rated 2, 3, and 4 (well, fair and poor) at different sites. This sort of scatter is normal in earthquake damage data, and is due to a number of factors including:

 Variation in shaking due to local soil effects;  Different block orientation;  Different block construction details, due to age and architectural finishes; and,  The limitations and simplifications made in the assessment.

5 Connell Wagner Limited, ‘Technical Guidelines for Structural Mitigation Work’, www.minedu.govt.nz, July 2003 – revision 7

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5.2.4.2 Best Performing Blocks

All of the timber framed standard school block designs performed well. The most common blocks in the review; Canterbury, Open Plan, and CEBUS all performed “very well” or “well”, even in high or severe shaking intensity areas.

Generally, the high performers were blocks which had tolerated ground deformation with minimal damage. The reasons for the lightweight and ‘prefab’ type blocks performing well are:

 The re-locatable classrooms are designed to be lightweight so they can be easily lifted;  Lightweight cladding means less seismic mass and therefore lower demand on the structure; and,  The foundations are typically timber piles with timber subfloor frames which can accommodate differential movement without significant structural damage, although linings may be affected.

The high performing blocks with low damage (rating 1 and 2) with high or severe shaking and high geotechnical category were:

 CEBUS 2;  Hall;  Paul Wilkin;  Canterbury Block;  Pre 1930s 2 storey; and,  Nelson H.

With the exception of the pre 1930s 2 storey block and Nelson H block, all of these buildings are single storey comprising a lightweight timber frame. The pre 1930’s 2 storey blocks are essentially unreinforced masonry (URM) structures and would typically be expected to have a poor earthquake response. However, at Christchurch Boys High School, extensive structural strengthening works were completed in the 1990s which significantly reduced damage.

Blocks with low damage (rating 1 and 2) with high or severe shaking intensity and a low geotechnical category (GC1-2 “good” ground) were:

 Canterbury Block;  Paul Wilkin;  Single Storey Weatherboard;  Hall;  CEBUS 2;  Open Air Veranda;  Open Plan; and,  Portacom.

All of these buildings are lightweight timber framed structures, generally having lightweight roof cladding. These buildings have been shown to perform very well in earthquakes due to the high ductility, flexibility and strength of light timber frame construction.

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5.2.4.3 Blocks with Significant Damage

Blocks with significant damage (rating 3 and 4) with high shaking and high geotechnical category (GC3-5) were:

 Open Air Veranda;  Dominion;  Single Storey WB;  1950s 2 storey;  Nelson Straight; and,  Nelson H.

With the exception of the 1950s 2 storey blocks, the high damage rating is due to substantial land deformation rather than structural damage due to shaking. These structures are of lightweight timber framed construction and although the Nelson blocks can have structural weaknesses, these were remediated with structural strengthening in the 1990s.

The 1950s 2 storey blocks are heavy reinforced concrete structures, potentially having insufficient longitudinal bracing due to clerestory windows. Two of these blocks were also subjected to land deformation, further increasing the observed damage.

Blocks with severe damage (rating 5) with high shaking, coupled with both differential settlement and ground deformation were:

 Dominion Block; and,  Pre-1930s 2 storey;

The Dominion Block was located at Banks Avenue Primary. This site has a geotechnical category of GC4, with significant lateral spread expected. Although the building comprises a relatively lightweight timber frame with brick veneer, more damage was observed compared with other blocks of this type due to significant land deformation.

The Pre-1930s 2 storey block which performed poorly was located at Avonside Girls High. This site suffered extensive land deformation. Despite the strengthening in the 1990s, the ground deformation caused significant damage to this heavy brittle building.

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6 Conclusions

Due to the qualitative nature of this review, the conclusions have been separated into three categories;

6.1 General Conclusions

6.1.1 Building Types

 70 school buildings classified into 25 types have been reviewed.  The majority of school buildings reviewed are single storey. The remainder are a maximum of 2 storeys.

6.1.2 Safety/Occupancy

 There were no fatalities on school sites during the Canterbury earthquake sequence.  Some injuries occurred, mostly resulting during egress.  Potential / critical structural weaknesses did not result in collapse of any school buildings but did result in additional damage.  The Ministry’s earthquake strengthening programme has been effective, as it prevented building collapse, provided a safe environment for teachers and students, and limited damage to buildings that would otherwise have been more severely affected.  We understand that prior to the earthquakes, a programme of replacing glass with safety glass in windows and doors along exit routes had been implemented. This appears to have been effective as there has been very few reported instances of broken glass.

6.1.3 Building Performance/Damage

 Lightweight timber framed buildings have performed very well and generally in excess of their calculated capacity.  Seismic retrofit work undertaken has been effective.  A large proportion of building damage was due to ground deformation.  Lightweight buildings with suspended timber floors on shallow footings generally accommodate ground deformation well and can often be quickly and cost effectively re-levelled.  Overhead heavy building services or items unsecured on shelves can be a falling hazard.  Most heavy roofs have been removed and replaced with lightweight material, this has reduced the seismic load and subsequent observed damage.  Where blocks have been joined together and the alignment of the principle axes are no longer maintained such that the footprint is not symmetrical, i.e. joined together to form a T shaped footprint, increased damage was observed.  Heavy veneer cladding increases damage to internal linings.  Overhead heavy veneer can be a falling hazard if not well tied to timber framing, particularly above doors and windows.

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6.1.4 Process

 There is inconsistency around the naming of school buildings.  There is no reliable database of drawing information for the building portfolio.  The post-earthquake inspection regime adopted by MoE has been effective.  Retrofit and assessment of buildings in some cases has not adequately addressed global site issues, such as liquefaction related lateral spread at Jobberns/Gresson Blocks at Avonside Girls High.

6.2 Infrastructure Performance/Damage

6.2.1 Water

 School water supply systems generally performed well, particularly flexible pipework (polyethylene). Older galvanised pipe was more susceptible to damage, mostly in the areas where significant ground movement occurred, mainly due to its inherent rigidity and deterioration over time.  For most urban school sites the critical factor was the non-availability of water from the Council supply.  In the immediate term this was managed by installing large plastic water tanks which were filled by potable water. Ministry of Health guidelines required that these tanks be sterilised, and filled with potable water. Water stored this way needed to be chlorine-dosed regularly to maintain potability. In many sites once water supply from the Council system was restored, tanks were drained and left onsite. This was a contingency measure to manage ongoing risk, requiring only 24 hours stand-down time for sterilisation during the aftershock sequence. The majority have now been removed.

6.2.2 Sewer

 Older pipework systems, particularly earthenware and reinforced concrete were least able to withstand ground movement. This was often compounded by pre-existing deterioration due to age. These systems tended to pull apart easily, allowing groundwater and silt from liquefaction to enter pipelines and clog them. Newer systems constructed with PVC have more material and connective flexibility and were able to withstand a greater amount of ground movement while remaining intact. At some sites with PVC pipework, even when pipe grades have flattened as a result of pipe movement, sewer systems at the school have remained operational, providing a reasonable level of service to the school.  For most urban schools, the critical factor was the damage to the Council sewer systems in the street. This meant that even if pipework within the site had sustained little damage, schools still needed emergency measures. This was managed by portaloos at some sites, while others installed large sewage holding tanks (similar to the ones for water supply), which the school’s wastewater was pumped into. These tanks were emptied frequently. Once Council sewer service was restored to sites, some schools have retained the emptied tanks onsite as a contingency measure to manage future risk.

6.2.3 Stormwater

 The issues with stormwater are similar to those for sewerage, with the exception that temporary measures for stormwater service were not implemented. Instead, schools with damaged

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stormwater systems are experiencing more frequent ponding on site as water is less able to drain away. This presents nuisance (puddles and mud) and slip hazards in winter (freezing).  Repairs to stormwater systems are potentially costly due to a combination of very old systems still in existence, and the need to comply with current building code requirements. In the sites with the most severe damage, replacement of the entire stormwater system is the only compliant option, which can be expensive.

6.2.4 Hardstand

Options for hardstand repairs range from the ‘do minimum’ to ‘full design life’ approach, with the former aimed at repairing superficial defects and restoring immediate levels of service but accompanied by the risk of ongoing repairs. The ‘full design life’ approach involves full remediation of the hardstand surface, specifically designed to mitigate against known risks (such as liquefaction or lateral spread) by inclusion of engineering measures such as geotextiles and geogrids, with the aim of lessening the cost of repair in a future earthquake event.

6.3 Block Specific Conclusions

6.3.1 Block Performance/Damage

 The open plan blocks have minimal bracing which increases frame distortion and damage.  Some CEBUS type buildings have external nail plates that have failed during shaking without resulting in collapse. These can be simply retrofitted.  One of the Pre-1930’s Two Storey Block’s has Potential Critical Structural Weaknesses while up to 11 others have structural weaknesses. 7 Recommendations

Following this structural review, our recommendations for the Ministry have been separated into three categories. 7.1 Site Considerations – Buildings and Infrastructure

The following items can be implemented immediately by the Ministry to reduce the risk during a future emergency:

 An egress and evacuation plan should be put in place for each school site. The main issues are concerning stuck doors due to differential settlement and potential fall hazards. The assembly point should also be considered.  Overhead falling hazards relating to poorly tied brick veneer, heavy building services or items on shelving should be assessed, and if required secured or removed to a lower height.  Consideration should be given to assessing and, if required, strengthening, or removing the veneer at height to mitigate this risk in a future significant earthquake event. Lowering the veneer will have the added benefit of reducing the seismic load on the buildings’ structure and improving its overall performance.  Consideration should be given to upgrading site infrastructure during significant developments. This would reduce the extent of aged, frequently extended, brittle pipe networks present on many school sites.

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 Consideration should be given to the assessment of schools’ existing infrastructure networks, for their condition and capacity i.e. compliance and vulnerability. This would indicate a need for the upgrade of any existing infrastructure with newer, more robust systems. This also reduces the risk of major costs associated with repairing older systems, when repairs carried out in the future might trigger the requirement for a Building Consent. Discussion with Councils should also be considered to seek clarity on compliance requirements.  Consideration should be given to contingency measures for lifeline services (water supply & sewer).  Consider options for hardstands that include ‘full design life’ to mitigate known geotechnical risks. 7.2 Process

In addition to the items in section 7.1, the following items should be implemented by the Ministry to improve the quality and consistency of additional design and remediation works throughout the portfolio.

 Issue minimum standard brief and guidelines for engineering assessment and design which embodies current ‘best practice’. (We note that the Ministry have subsequently issued guidelines on importance level for retrofit and new design).  Consider adopting damage resistant designs in high seismicity areas. This could also reduce the cost to repair non-structural damage, which is estimated to be approximately 70% of the total repair cost for commercial buildings.  Review processes around construction quality control and construction monitoring by the designer and Territorial Authorities’ (TA’s) to ensure efficiency and confidence that the design intent is achieved during construction.  Consider setting up a review panel, perhaps a continuation of the Engineering Strategy Group (ESG) or similar to USA practice where an independent consultant from an approved panel reviews design and or construction. 7.3 Further Review

This report has involved a review of existing Ministry documentation on a selection of typical blocks. However other learnings from commercial and Ministry buildings should also be applied to the portfolio, for example:

 Stairs; review in accordance with Ministry of Business, Innovation and Employment (MBIE) guidelines.  Precast panels; especially connections and requirements for ductility.  Shear walls; in line with interim design guidelines by Structural Engineering Society New Zealand (SESOC).  Cross bracing; particularly Reid Brace especially connections and requirements for ductility.

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8 Limitations

8.1 Other Site Risks

This assessment has only considered the hazards relating to earthquakes, and damage due to the Canterbury earthquakes. There are other risks which should be considered by the MoE on a site wide basis, including flooding, tsunami etc.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings A1

Appendix A - School Building Types

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings A2

Appendix A describes the typical school building types used in New Zealand which are not included in the Catalogue of Standard School Building Types August 2013 and published by the MoE. A brief description is provided to help identify these building types. The type names are not consistent across the country, therefore a description is given along with photos and sketches of the most distinctive details related to these types. A1 Two Storey Classroom Block

This type of two storey building comprises of multiple classrooms with stair wells at the rear of the building. They have large glazed northern walls. This block was usually built with a total of 12 classrooms per block, i.e. six classrooms on each level, however could also have ten classrooms in total. The construction type is similar to the 1950s double storey comprising a reinforced concrete and timber infill framing.

Figure 12 : Typical drawing of a 12 Classrooms Block Double Storey structure

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A2 Subfloor Framing

This type of building was considered due to the foundation details. The purpose of a subfloor braced framing foundation is to account for slope and uneven terrain.

Figure 13 : View of Subfloor Framing CEBUS block

Figure 14 : Typical sketch of a subfloor framing structure (taken from NZS 3604:2011)

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A3 Pre 1930s Two Storey Block

This type of building is generally easily identified by the date of construction. The cladding is often brick, which was popular at the time.

Figure 15 : Pre 1930s Two storey block plan view

Figure 16 : Front facade view of a Pre 1930s Two storey block

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings B1

Appendix B – Block Types by School

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings B0

Schools Block ID Type Intensity zone Shirley Intermediate – 60 Shirley Block 1 Open Air Veranda moderate Road, Shirley, Chch Wharenui Primary – 32 Matipo Street, Block 1 & 2 Open Air Veranda Riccarton, Chch moderate Wairakei Primary – 250 Wairakei Block 1,2 & 3 Open Air Veranda Street, Bryndwr, Chch Learning Centre 1940s Single Storey low Weatherboard Hammersley Park Primary – 90 Hall Hall with Sub-basement Quinns Road, Shirley, Chch under stage moderate Block 1 (Rooms 8-14) Dominion Block Heathcote Valley Primary – Bridle Block 2 (Rooms 1,2,3) Open Plan Blocks Path Road. Heathcote Valley, Chch Junior Block (Canterbury Education Board) Blocks 3, 5, 12 and 13 CEBUS Mk 1 and 2 severe (Classrooms) Block 1 (Room 11&12) Canterbury Block Banks Avenue Primary – 91 Banks Block 2 (Rooms 15-22) Dominion Block Avenue, Dallington, Chch Block 4 (Rooms 4-7) Canterbury Block Block 6&8 (Rooms CEBUS Mk 1 and 2 severe 1,2,13,14) Block 10 & 11 (Rooms 23- Prefabs – Paul Wilkin 27) Design Fendalton Open Air School – 168 Block 2 (Rooms 1-6) Open Plan Blocks Clyde Road, Fendalton, Chch (Canterbury Education Board) moderate Block 12 (Rooms 16-17) CEBUS Modified (1990) Thorrington Primary – 22A Colombo Block 1 Canterbury Block Street, Lower Cashmere, Chch moderate

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Schools Block ID Type Intensity zone Sumner Primary – 15 Colenso Street, Administration/Block 1 Canterbury Block Sumner, Chch (Rooms 11-15) severe Block 19 Paul Wilkin Design Hoon Hay Primary – 91 Sparks Road, Block 8 CEBUS Mk 1 and 2 Hoon Hay, Chch Block 14 & 17 Portacom low Block 1-2 & 3 Canterbury Block Freeville Primary – 1 Sandy Avenue, Learning studio 1 & 2 Canterbury Block North New Brighton, Chch (Rooms 9-12) severe Russley Primary – 75 Cutts Road, Block 1 Canterbury Block Avonhead, Chch Block 12 CEBUS Modified (1990) low Block 4 (Community Hall) Halls with Sub-basement under stage Darfield High – 16 Ross Street, Block 2 (Admins and rooms Canterbury Block Darfield 9-12) severe Heaton Intermediate – 125 Heaton Block 2 & 4 1950s Double Storey Street, Merivale, Chch Block 5 1940s Single Storey moderate Weatherboard Manning Intermediate – 50 Hoon Hay Block 2 Twelve Classroom Double Road, Chch Storey Block low Branston Intermediate – 35 Amyes Block 2 Twelve Classroom Double Road, Hornby, Chch Storey Block low Shirley Primary – 11 Shirley Road. Block 2 Open Plan Blocks Shirley, Chch (Canterbury Education Board) moderate Block 10 CEBUS Mk 1 Block 8 (Rooms 9-12) Canterbury Block severe

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Schools Block ID Type Intensity zone Central New Brighton Primary – 140 Library Open Plan Blocks Seaview Road, New Brighton, Chch (Canterbury Education Board) Queenspark Primary – 222 3 of them Open Plan Blocks Queenspark Drive, Parklands, Chch (Canterbury Education moderate Board) Middleton Grange – 50 Acacia Block B Nayland Avenue, Riccarton, Chch low

Van Asch Deaf Education Centre – 38 Block K (Rooms 14-20) CEBUS Mk 1 and 2 Truro Street, Sumner, Chch severe

Avonside Girls’ High – 180 Avonside Block A - 1927 Brick Pre 1930s 2 Storey Drive, Chch Jobberns Block C 1950s Double Storey Gresson Block B 1960s Nelson Block severe straight block

Kaiapoi Borough Primary – 20 Hilton Hall Halls with Sub-basement Street, Kaiapoi under stage severe Linwood North – 221 Woodham Road, Hall Hall without Sub- Linwood, Chch basement under stage severe Burnside High – 151 Greers Road, No block number Portacom Burnside, Chch Block G (Block D Nayland low extension) Block B (Block E) 1960s Nelson "H Block" Hagley Community College – 510 Main Block Pre 1930s 2 Storey Block Hagley Avenue, Chch moderate

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings B3

Schools Block ID Type Intensity zone Christchurch Boys’ High – Straven Block A (incl. library/audit Pre 1930s 2 Storey Block Road, Riccarton, Chch and classrooms wings) moderate Papanui High – 30 Langdons Road, Block I (Block A) 1940s Single Storey Papanui, Chch Weatherboard Block F (Plimsol) & Block 1960s Nelson Straight G or L (Library) Block moderate Block B (Hall) Secondary School Hall

Linwood College – 85 Aldwins Road, Library B1, Classroom 1950s Double Storey Linwood, Chch B1,B2, C1 & C2 moderate Block F 1960s Nelson "H Block" Cashmere High – 172 Rose Street, Performing art Centre Secondary School Hall Somerfield, Chch Block S 1960s Nelson "H Block" moderate Block A & B 1950s Double Storey Rangiora High – 125 East Belt, Block C,D,E 1950s Double Storey Rangiora low Mairehau High – 440 Hills Road, Tennant Block 1960s Nelson "H Block" Mairehau, Chch Block F Nelson Single Storey moderate Cartwright block 1960/70s Single storey weatherboard Lincoln High – 25 Boundary Road, Block D (LHS block C) 1960/70s Single storey Lincoln weatherboard Block D Nelson Single Storey low Hall Secondary School Hall

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings B4

Schools Block ID Type Intensity zone Shirley Boys High – 59 North Parade, Block F 1960/70s Single storey Shirley, Chch weatherboard moderate Block E Nelson Single Storey Kaiapoi High – 101 Ohoka Road, First stage S68 (Schools 1968) and Kaiapoi MKII in 1972 severe Second stage S68 (Schools 1968) and MKII in 1972 Hornby High – 180 Waterloo Road, Block D,E,F S68 (Schools 1968) and Hornby, Chch MKII in 1972 low

Avonhead Primary – 55 Avonhead Block 2 - Hall Hall without Sub- Road, Avonhead, Chch basement under stage low

St Martins Primary – 24 Albert Room 26-27 CEBUS with Subfloor Terrace, St Martins, Chch Framing moderate Mt Pleasant Primary – 82 Major Room 9 CEBUS with Subfloor Hornbrook Road, Mt Pleasant, Chch Framing severe Bamford Primary – 6 Gould Crescent, Block 2 Dominion Block Woolston, Chch severe Addington Primary – 22 Brougham Block 1 & 5 Dominion Block Street, Addington, Chch moderate Bromley Primary – 33 Keighleys Block 2 library Dominion Block Road, Bromley, Chch severe

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C1

Appendix C – Building Type Performance Summary

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C2

C1 Open Air Veranda block

Typical photos Observed Damage Damage Description Cracking in weatherboard; sign of frame movement.

Shirley Intermediate Shirley Intermediate Cracking of foundation

Wairakei School Wairakei School

Building #1 Shirley Intermediate Liquefaction Zone Blue Intensity level High Rating 3

Building #2 Wharenui School Liquefaction Zone Yellow Intensity level High Rating 2

Building #3 Wairakei School Liquefaction Zone Yellow Intensity level Low Rating 2

C1.1 Recommendations & Conclusions

The rating of 3 for Shirley Intermediate is predominantly due to ground deformation. The connection of the sub-floor framing to the building was assessed to be 11%NBS. Once this is addressed the building is assessed to be greater than 34%NBS.

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C2 Dominion block

Typical photos Observed Damage Damage Description Rocking of Brick

Banks Avenue Banks Avenue

Banks Avenue

Building #1 Banks Avenue Liquefaction Zone Red Intensity level High Rating 5

Building #2 Hammersley Park Liquefaction Zone Blue Intensity level Moderate Rating 3

C2.1 Recommendations & Conclusions

The brick veneer on the Dominion Block at Banks Avenue School had to be removed. Liquefaction caused differential settlement at various locations. The Dominion Block has a plan irregularity (structural weakness) due to the full length windows on one side of building. This weakness results in excessive deformation which causes the brick veneer to become a falling hazard.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C4

C3 Canterbury block

Typical photos Observed Damage Damage Description Minor cracking in block veneer

Sumner School Thorrington School Moderate damage to the summerhill stone veneer walls. Mostly occurs in the concrete masonry.

Hoon Hay School Russley School Building #1 Thorrington School Building #5 Banks Avenue Liquefaction Zone Yellow Liquefaction Zone Red Intensity level High Intensity level High Rating 4 Rating 2 Building #2 Heathcote Valley School Building #6 Russley School Liquefaction Zone Yellow Liquefaction Zone Grey Intensity level Severe Intensity level Low Rating 1 Rating 2 Building #3 Hoon Hay School Building #7 Darfield Liquefaction Zone Yellow Liquefaction Zone N/A Intensity level High Intensity level High Rating 2 Rating 3 Building #4 Freeville School Building #8 Sumner Liquefaction Zone Red Liquefaction Zone Yellow Intensity level Low Intensity level Severe Rating 2 Rating 1 Building #9 Central New Brighton Liquefaction Zone Yellow Intensity level Moderate Rating 2

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C3.1 Recommendations & Conclusions

The Hoon Hay School buildings (Block 1,2 & 3) were retrofited in 1989 (built in 1960) and the Thorrington School Block 1 was built in 1957 and retrofitted in 1962. The damage to the Thorrington block is mostly due to ground deformation.

The Canterbury Block has plan irregularity which is defined as a structural weakness. The type of damage noted was consistent and the brick veneer became a falling hazard. These blocks have generally performed better than the assessed capacity of 20-30%NBS, depending on the number of adjoined blocks.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C6

C4 12 Classrooms double storey Block

Typical photos Observed Damage Damage Description Slabs not level in various areas of the classroom block

Manning Intermediate

Manning Intermediate

Building #1 Manning Intermediate Liquefaction Zone Yellow Intensity level Moderate Rating 2

Building #2 Branston Intermediate School Liquefaction Zone Grey Intensity level Low Rating 3

C4.1 Recommendations & Conclusions

The samples for this building type are in low and moderate intensity zones, and so limited conclusions can be drawn as to this building type's seismic performance. Irregular wall layout may be a structural weakness. This could explain the rating of 2 in a low intensity zone. Further data for other buildings of this block type in a zone of higher ground shaking would assist in assessing the performance of this block.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C7

C5 Open Plan Block

Typical photos Observed Damage Damage Description Moderate structural damage to the wall and significant frame distortion.

Heathcote Valley School Lateral translation of slab at joint with adjoining part of building.

Heathcote Valley School Movement to wall and ceiling linings at sheet edge.

Queenspark School

Fendalton Open Air School Building #1 Shirley Primary School Building #4 Heathcote Valley Liquefaction Zone Blue Liquefaction Zone Yellow Intensity level High Intensity level Severe Rating 2 Rating 3

Building #2 Fendalton Open air School Building #5 Queenspark School Liquefaction Zone Blue Liquefaction Zone Yellow Intensity level Moderate Intensity level Low Rating 2 Rating 2

Building #3 Central New Brighton Liquefaction Zone Yellow Intensity level Moderate Rating 1

C5.1 Recommendations & Conclusions

This block has large open spaces with minimal internal bracing walls. The roof does not act as a diaphragm and so is not effective at distributing roof loads evenly throughout the structure to the bracing walls. This results in increased frame distortion which has caused some windows to break. The large open space, minimal bracing, ineffective roof diaphragm resulting in increased deformation is considered to be a structural weakness.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C8

C6 CEBUS MK 1 & 2

Typical photos Observed Damage Damage Description Pavement cracking outside and minor evidence of frame distortion part of building.

Hoon Hay School

Banks Avenue

Hoon Hay School

Building #1 Banks Avenue Building #3 Shirley Primary School Liquefaction Zone Red Liquefaction Zone Blue Intensity level High Intensity level High Rating 1 Rating 1

Building #2 Hoon Hay School Building #4 Van Asch School Liquefaction Zone Yellow Liquefaction Zone Yellow Intensity level High Intensity level Severe Rating 2 Rating 2

C6.1 Recommendations & Conclusions

CEBUS of building has a simple design with a portal frame bracing system. This type of building performed well and no critical structural weakness has been identified. Attention should be paid to the condition of the gangnail plates which provide the connection at the external frame connections. These have been seen to become loose over time and become ineffective during repeated cycles of earthquake shaking.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C9

C7 CEBUS Modified (1990)

Typical photos Observed Damage Damage Description Some ceiling panels damaged

Russley School

Fendalton Open Air School

Building #1 Fendalton Open air School Liquefaction Zone Blue Intensity level Moderate Rating 1

Building #2 Russley School Liquefaction Zone Grey Intensity level Low Rating 1

C7.1 Recommendations & Conclusions

The samples for this building type are both in the lower intensity zones, limited conclusions can be drawn as to the seismic performance of this building type. Further data for buildings in a zone of higher intensity of ground shaking would be beneficial to their overall assessment. Both the superstructure and foundations were assessed to be approximately 90%NBS.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C10

C8 Prefabs - Paul Wilkin Design

Typical photos Observed Damage Damage Description No photos taken Some foundation settlement

Sumner School

Typical timber truss system

Building #1 Banks Avenue Liquefaction Zone Red Intensity level High Rating 2

Building #2 Sumner School Liquefaction Zone Yellow Intensity level Severe Rating 1

C8.1 Recommendations & Conclusions

This type of building performed well, even when subjected to ground movement. The foundations were easily re-levelled. Where necessary, the building can be lifted to enable new foundations to be constructed.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C11

C9 Nayland Block

Typical photos Observed Damage Damage Description No photos taken Some minor cracking

Middleton Grange School

Discover School Halswell (not part of this assessment)

Building #1 Middleton Grange School Liquefaction Zone Grey Intensity level Moderate Rating 1

Building #2 Burnside High School Liquefaction Zone Grey Intensity level Low Rating 2

C9.1 Recommendations & Conclusions

The samples for this building type are in the low and moderate intensity zones and so limited conclusions can be drawn as to the seismic performance of this building type. The nearest ground shaking information generally showed no to minor ground damage and so further data from a zone of higher intensity ground shaking would be beneficial in the assessment of this block.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C12

C10 Hall with Sub-basement

Typical photos Observed Damage Damage Description xvxcxcxxczxc The hall has sustained some minor damage, such as hariline cracking to a soffit cladding panel and

minor movement of Hammersley Park School internal GIB linings.

Russley School

Hammersley Park School

Building #1 Kaiapoi Borough School Liquefaction Zone Yellow Intensity level Moderate Rating 2

Building #2 Russley Primary School Liquefaction Zone Grey Intensity level Low Rating 2

Building #3 Hammersley Park School Liquefaction Zone Blue Intensity level Moderate Rating 2

C10.1 Recommendations & Conclusions

This type of hall with a sub-basement under the stage has plan and vertical irregularity. This is a structural weakness due to the tendency of the two sections of building to respond to the earthquake shaking differently.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C13

C11 Hall without Sub-basement

Typical photos Observed Damage Damage Description Moderate crack in foundation on the eastern side. Foundation has dropped.

Linwood North School

Linwood North School Windows broken.

Linwood North School

Building #1 Avonhead School Liquefaction Zone Grey Intensity level Low Rating 2

Building #2 Linwood North school Liquefaction Zone Blue Intensity level High Rating 3

C11.1 Recommendations & Conclusions

This type of hall does not have any particular structural weaknesses. Primary school halls tend to be smaller, and so roof diaphragm action and wall bracing will provide additional bracing. Lightweight cladding materials reduce the seismic demand on the structure.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C14

C12 Portacom

Typical photos Observed Damage Damage Description Minor frame distortion and evidence of floor subsidence.

Hoon Hay School Hoon Hay School

Hoon Hay School

Building #1 Burnside High School Liquefaction Zone Grey Intensity level Low Rating 1

Building #2 Hoon Hay School Liquefaction Zone Yellow Intensity level High Rating 2

C12.1 Recommendations & Conclusions

This type of building performed well when subjected to ground movement, and the foundations were easily relevelled.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C15

C13 Subfloor Framing

Typical photos Observed Damage Damage Description Out of plumb piles under the Room 27 building. The lateral displacement is observed to be over 50mm.

Mt Pleasant School

St Martins School One bearer has cracks over the top of the pile.

St Martins School

St Martins School

Building #1 St Martins School Liquefaction Zone Blue Intensity level High Rating 3

Building #2 Mt Pleasant School Liquefaction Zone N/A Intensity level Severe Rating 3

C13.1 Recommendations & Conclusions

This type of foundation performed well but has been highlighted to demonstrate the importance of subfloor framing and its correct installation. The connection details between the foundation and the structure are critical. If large ground deformations or intense shaking occur, the connections could fail, resulting in movement between the structure and the foundation. Both buildings had a combination of ground deformation and shaking.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C16

C14 Pre 1930s 2 Storey Block

Typical photos Observed Damage Damage Description Major vertical cracks right through the building (around the perimeter wall).

Christchurch Boys High School One masonry lintel beam has large shear cracks between Rm 37 and adjacent hallway

Avonside Girls High School Out of plane failure at apex - N elevation (masonry veneer).

Avonside Girls High School Minor cracking to internal plaster at wall/ceiling joints.

Avonside Girls High School Building #1 Hagley community College Liquefaction Zone Yellow Intensity level High Rating 2 Building #2 Avonside Girl's High School Liquefaction Zone Orange Intensity level High Rating 4 Building #3 Christchurch Boys' High School Liquefaction Zone Blue Intensity level High Rating 2

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C17

C14.1 Recommendations & Conclusions

The Pre-1930s Two Storey Block at Avonside Girl's High School was retrofitted by adding reinforced concrete walls and steel beams attached to the brick facades. Extensive damage to the brick facade was due to ground deformation. The damage to this block at Christchurch Boys High School was mostly due to differential settlement which made doors unable to be opened properly. In the case of the Hagley Park Comunity Centre, the main structural weakness is the difference in construction between the two sections of the building. In general, these buildings built in the 1930s are likely to have critical structural weaknesses such as unreinforced brick walls that present a falling hazard. Strengthening works carried out in the 1990s were aimed at addressing the earthquake prone building issues which explains their relatively good performance.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C18

C15 1940s Single Storey Weatherboard Block

Typical photos Observed Damage Damage Description Moderate structural damage. Cracking to ceiling, corniche and concrete beams.

Heaton Normal Intermediate School

Heaton Normal Intermediate School West corner of building appears to have some settlement under one pile.

Wharenui school

Heaton Normal Intermediate School

Building #1 Papanui High school Liquefaction Zone Grey Intensity level Low Rating 2

Building #2 Heaton Normal intermediate School Liquefaction Zone Blue Intensity level Moderate Rating 3

Building #3 Wairakei School Liquefaction Zone Yellow Intensity level Low Rating 1

C15.1 Recommendations & Conclusions

This type of one storey building performs well under seismic loads. It is a lightweight and low building. However at Heaton Normal Intermediate, ground deformation caused significant damage to the foundation causing cracking throughout the structure.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C19

C16 1950s Double Storey

Typical photos Observed Damage Damage Description Severe damage to the columns in corridor. Shear craking just below the beam junction.

Linwood College

Linwood College Seismic joint opened up and cover plate damaged with 100mm gap between adjacent block.

Avonside Girl’s High School

Linwood College Building #1 Linwood College Building #2 Rangiora High School Liquefaction Zone Blue Liquefaction Zone N/A Intensity level High Intensity level Low Rating 3 Rating 2

Building #3 Cashmere Building #4 Avonside Girls’ High School Liquefaction Zone Yellow Liquefaction Zone Orange Intensity level High Intensity level High Rating 3 Rating 4

C16.1 Recommendations & Conclusions

There is insufficient bracing in the longitudinal direction due to the clerestory windows between the concrete columns. This is a structural weakness which results in significant damage to beams and columns.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C20

C17 1960s Nelson Block "Straight"

Typical photos Observed Damage Damage Description Separation around frames and windows.

Avonside Girl’s High School

Avonside Girl’s High School Severe liquefaction caused differential settlement of 50mm approx. and lateral spreading. The perimeter walls settled.

Avonside Girl’s High School Avonside Girl’s High School

Building #1 Avonside Girl's High School Liquefaction Zone Orange Intensity level High Rating 4

Building #2 Papanui High school Liquefaction Zone Grey Intensity level Low Rating 1

C17.1 Recommendations & Conclusions

One side of the building consists of two storeys of window openings with masonry veneer beneath the ground floor windows. This plan irregularity could be a structural weakness. In addition, two structural weaknesses found at the Avonside Girl's High School are a lack of complete diaphragm and connections to structure at 1st floor level, and a lack of restraint to the concrete staircase in longitudinal direction. It should be noted that the Avonside school building has had retrofitting to improve the performance of the brick walls. The strengthening works carried out in the 1990s and 2000s aimed to address most earthquake prone building issues which explains their relatively good performance.

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C18 1960s Nelson Block "H Plan"

Typical photos Observed Damage Damage Description The school is no longer level due to differential settlement.

Cashmere High School

Linwood College

Building #1 Burnside High School Building #3 Mairehau High Liquefaction Zone Grey Liquefaction Zone Yellow Intensity level Low Intensity level Moderate Rating 2 Rating 1

Building #2 Linwood College Building #4 Cashmere High Liquefaction Zone Blue Liquefaction Zone Yellow Intensity level High Intensity level High Rating 1 Rating 3

C18.1 Recommendations & Conclusions

The Cashmere High school rating of 3 is mostly due to ground deformation. Burnside High school which had not undergone much shaking but still had cracking caused by differential settlement. Otherwise, this type of structure seems to have withstood shaking quite well. The combination of one and two storeys and different construction materials can result in structural weaknesses. The strengthening works carried out in the 1990s and 2000s aimed to address most structural weaknesses which explains their relatively good performance.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C22

C19 Nelson Single Storey

Typical photos Observed Damage Damage Description Cracking and spliting between two parts of building

Shirley Boys High School Shirley Boys High School

Shirley Boys High School

Building #1 Lincoln High School Liquefaction Zone N/A Intensity level High Rating 1

Building #2 Mairehau High school Liquefaction Zone Yellow Intensity level Moderate Rating 1

Building #3 Shirley Boys High School Liquefaction Zone Blue Intensity level High Rating 3

C19.1 Recommendations & Conclusions

This lightweight building has generally performed well. Most of the damage recorded was due to ground deformation. A structural weakness may be the lack of bracing between the windows.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C23

C20 S68 (school 68-72)

Typical photos Observed Damage Damage Description Minor cracks observed in door lintel adjacent internal courtyard on two-storey side of courtyard. Masonry block loose on left hand side of doorway on East courtyard elevation.

Kaiapoi High School Kaiapoi High School Minor cracks observed in door lintel adjacent internal courtyard on two-storey side of courtyard. Masonry block loose on left hand side of doorway on East courtyard elevation.

Kaiapoi High School

Kaiapoi High School

Building #1 Kaiapoi High School Liquefaction Zone Yellow Intensity level Moderate Rating 3

Building #2 Hornby High School Liquefaction Zone Grey Intensity level Low Rating 1

C20.1 Recommendations & Conclusions

This one storey building has a structural weakness due to the unreinforced blockwork walls. The damage that occurred to the Kaiapoi school building is mostly due to ground deformation.

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Canterbury Earthquakes – Impact on the Ministry of Education’s School Buildings C24

C21 Secondary School Hall

Typical photos Observed Damage Damage Description

No damage found

Cashmere High School

Building #1 Lincoln High School Liquefaction Zone N/A Intensity level High Rating 1

Building #2 Papanui High school Liquefaction Zone Grey Intensity level Low Rating 1

Building #3 Cashmere High School Liquefaction Zone Yellow Intensity level High Rating 1

C21.1 Recommendations & Conclusions

The samples for this building type are in the low and moderate intensity zone, limited conclusions can therefore be drawn as to this building type's seismic performance. Further data for other buildings of this type in a zone of higher intensity would be beneficial.

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Appendix D – Geotechnical Description of School Standard Blocks

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Table of Results – Geotechnical Description

Table D.1 presents the observed ground damage made available by the Canterbury Geotechnical Database. The information presented in this database in the form of a Google Earth map is almost entirely associated with residential properties. Therefore, the information presented is essentially a summary of the behaviour of the residential sites surrounding the school properties.

Where no damage was observed, no entry was made in the table. In most cases where the lateral spread at the specified school site or that of the surrounding areas has been identified, ground cracking was also seen.

The information shown in Table D.1 below regarding the Ministry of Education Geotechnical Classification was obtained from the Ministry of Education whilst some information was provided from the assessments carried out by Opus Geotechnical.

Table D.1 - Schools and their respective standard blocks

School Block Type Ground Damage Observed Rating

Addington Primary Dominion - *

Hall without Sub- Avonhead Primary - 2 basement

Pre 1930’s 2 Storey September 4

Lateral Spread: None to major observed

Ejected liquefiable material: Often 1950’s Double Storey observed 4 Avonside Girls February

Lateral spread: Moderate to major

1960’s Nelson Ejected liquefiable material: Often “Straight” observed 4

CEBUS 5 February 3

Lateral Spread: Moderate to major

Bamford Primary Open Air Verandah Ejected liquefiable material: Often * observed

Ground cracking: Minor CEBUS 5 *

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September 1 Dominion Ground cracking: Minor

Lateral spread: Severe (across the Canterbury river)

Ejected liquefiable material: Often observed (across the river) * Banks Avenue Primary CEBUS 2 February

Ejected liquefiable material: Often Prefabs observed *

Ground cracking: Minor

Paul Wilkin Design

February

No site information. Site is west of the CBD. Closest site information generally shows no obvious ground Twelve Classroom damage with only small scattered Branston Intermediate 3 Double Storey areas of :

Lateral spread: Moderate to major

Ejected liquefiable material: Often observed

February CEBUS 5 Bromley Primary * Ejected liquefiable material: Minor to Open Plan moderate

Nayland 2 Portacom Burnside High No liquefaction or lateral spread. 1 1960’s Nelson “H 2 Plan”

1950’s Double Storey 3 1960’s Nelson “H February 3 Cashmere High Plan” Ejected liquefiable material: Minor to 1 Secondary School Hall moderate to the north 2 Canterbury

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Central New Brighton Primary Open Plan - 1

Christchurch Boys’ High Pre 1930’s 2 Storey - 2

February Christchurch South Intermediate Portacom - Ejected liquefiable material: Large quantities

September

No site information. Nearby area experienced: 2

Open Plan Ground cracking: Minor Fendalton Open Air Primary CEBUS Modified February

Lateral spread: Moderate to major 1

Ejected liquefiable material: Often observed

February Freeville Primary Canterbury 2 Ejected liquefiable material: Large quantity

February Hagley Community College Pre 1930’s 2 Storey 2 Ejected liquefiable material: Minor to moderate

February 3 Dominion Lateral spread: Moderate to major Hammersley Park Primary Hall with Sub- basement Ejected liquefiable material: Often 2 observed

Canterbury 1 Open Plan 3 Heathcote Valley Primary CEBUS 2 - * CEBUS 1 * Paul Wilkin Design

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Unit Classroom

February 3 1940’s Single Storey Weatherboard Lateral spread: Moderate to major Heaton Normal Intermediate 1950’s Double Storey Ejected liquefiable material: Minor to 3 large

September 2 Canterbury Ground cracking: Minor 2 CEBUS 2 Ejected liquefiable material: Minor to Hoon Hay Primary moderate Portacom 2 February CEBUS (various) 2 Ejected liquefiable material: Minor to moderate

No site information. Site to the west of CBD. Closest site information Hornby High S68 (School 68-72) 1 shows generally no to minor ground damage.

September

No site information. Closest sites 2 experienced: Hall with Sub-

basement Kaiapoi Borough Primary  Ground cracking: None to minor CEBUS (various)  Lateral spread: Moderate to major *  Ejected liquefiable material: Large quantities

Kaiapoi High S68 (School 68-72) - 3

CEBUS (various) Kaiapoi North Primary - * Canterbury

1 No site information. Site to the south- west of CBD. Closest site information Lincoln High GC1 shows no to minor ground damage observed. 1

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3 1950’s Double Storey February Linwood College 1960’s Nelson “H Ejected liquefiable material: Minor to Plan” moderate 1

February Hall without Sub- Linwood North Primary 3 basement Ejected liquefiable material: Large quantities

Open Air Verandah Lyttelton Main GC2 * Dominion

February 1 Mairehau High 1960’s Nelson “H Plan” Ejected liquefiable material: Minor to 1 moderate

September

Ground cracking: Minor

Ejected liquefiable material: Minor to Twelve Classroom Manning Intermediate moderate 2 Double Storey February

Ejected liquefiable material: Minor to moderate

No site information. Site is to west of Middleton Grange Nayland CBD. Closest site information shows 1 no to minor ground damage.

Mt Pleasant Primary Subfloor Framing - 3

1940’s Single Storey September Weatherboard 2 No site information but surrounding 1930’s Nelson suburbs generally experienced: * “Straight” Papanui High Ground cracking: Minor 1 Secondary School Hall Ejected liquefiable material: Minor to * 1950’s Single Storey moderate * CEBUS (various) February

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Nelson Library Ejected liquefiable material: None observed

September

Ground cracking: None observed

Ejected liquefiable material: None observed Queenspark Primary Open Plan 2 February

Ground cracking: Minor

Ejected liquefiable material: Minor to moderate

Rangiora High 1950’s Double Storey - 2

Canterbury 2 CEBUS Modified No site information. Site is north-west Russley Primary (1990) of CBD with no to minor ground 1 damage. Hall with Sub- 2 basement

September

Surrounding sites experienced no observed damage. Shirley Intermediate Open Air Verandah 3 February

Ejected liquefiable material: Minor to moderate

September 2 Surrounding sites experienced no Open Plan observed damage. Shirley Primary CEBUS 2 February

Ejected liquefiable material: Large 1 quantities

September 1960-70’s Single Shirley Boys’ High 3 Storey Weatherboard Surrounding sites experienced no observed damage.

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February

Lateral spread: Moderate to major

Ejected liquefiable material: Often observed

Subfloor Framing 3

Open Air Verandah * St Martin’s Primary - CEBUS 1 *

CEBUS 4 *

Canterbury 1

Paul Wilkin Design 1 Sumner Primary - CEBUS (various) *

Canterbury (modified) *

February

Lateral spread: Moderate to major Thorrington Primary Canterbury Block 4 Ground cracking: Minor

Ejected liquefiable material: Large quantities

CEBUS 2 2 Van Asch Deaf Education Centre - CEBUS (various) *

September

No site information but adjacent areas 2 Open Air Verandah experienced: Wairakei Primary 1940’s Single Storey Ground cracking: Minor Weatherboard 1 Ejected liquefiable material: Minor to moderate

Site lies to near-west of CBD which Wharenui Primary Open Air Verandah generally experienced no to minor 2 ground damage.

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February Aranui Block Woolston Primary * Ejected liquefiable material: Minor to CEBUS 3 moderate

* These ratings are based on the DEE summary report as no primary source information is available.

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