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1 Aurecon New Zealand Limited Level 2, Iwikau Building 93 Cambridge Terrace Christchurch 8013 New Zealand T F E W christchurch@aurecongroup.com aurecongroup.com 15 May 2017 GW Haslwell Ltd 145 Papanui Road PO Box Christchurch 8146 Issued via to: Dean Gregory dean@gwlimited.nz Geotechnical Subdivision Completion Report Kirkwood the Conclusion This geotechnical completion report, and supporting Statement of Professional Opinion, is submitted in accordance with Clause 21 Subdivision Consent Application RMA/2016/3606. Introduction GW Halswell Limited is in the process of developing the Kirkwood The Conclusion residential subdivision at located at 150 Dunbars Road, Haslwell, in Christchurch. This development comprises 28 residential lots and associated roads and access ways. During the geotechnical investigation of the site parts of development were identified as being susceptible to a varying degree to the effects of seismically induced liquefaction. The liquefaction risk was assessed as being variable across the site. As such an engineered fill capping layer has been created across Lots 12, 13 and 25 to 25 in order to increase the seismic resilience of these lots. See attached plan for the extent and cross-section of the capping layer constructed at Kirkwood The Conclusion. The conditions of Aurecon s engagement are as per our original agreement relating to initial geotechnical investigation carried in September 2015, and are set out in our letter of engagement dated 14 August Geotechnical Investigation and Liquefaction Hazard Assessment Aurecon undertook a geotechnical site investigation across the site in September 2015 to support the subdivision application. This investigation is described in the Aurecon Report 150 Dunbars Road, Haswell, Geotechnical Subdivision Report, Revision 1 dated 22 September A liquefaction hazard assessment was carried out as part of the site assessments using the method prescribed in the Ministry of Business, Innovation, and Employment guidelines for residential development in Canterbury (MBIE Guidelines) following the Canterbury earthquake sequence. Based upon this assessment: Lots 1 to 11 and 14 to 24 The calculated liquefaction induced ground deformations were within the limits of a Technical Category 2 (TC2) classification. Lots 12, 13 and 25 to 28 Lots 12, 13 and 25 to 28 in their natural form were identified as being non-compliant with the full requirements of a TC2 classification based on an indexed liquefaction induced Project File Kirkwood the Conclusion 224 Sign Off Report - Rev1.docx 15 May 2017 Revision 1 Page 1

2 reconsolidation settlement criteria and thickness of non-liquefiable crust. This non-tc2 compliance is due to the southern end of the site having an increased thickness of potentially liquefiable silty-sandy soils in combination with perched groundwater table. The combination of the increase in theoretical reconsolidation settlement due to increased thickness of siltysandy soils and the thinner non-liquefiable crust due to elevated groundwater level resulted in non-compliance with the requirements of TC2. Liquefaction Risk Mitigation Due to the identified liquefaction risk, liquefaction hazard mitigation has been undertaken across the site as part of the development: Lots 1 to 11 and 14 to 24 No additional liquefaction risk mitigation is required for these lots other than an enhanced TC2 type of foundation system as per the requirements of the MBIE Guidelines. Lots 12, 13 and 25 to 28 In order to ensure a TC2 classification across the entire site and provide additional seismic resilience to the development shallow ground improvement works have been undertaken in Lots 12, 13 and 25 to 28. The ground improvement works have been based upon the concept of 2m re-compacted engineered fill capping layer option presented in Section 15 of the MBIE Guidelines. With this ground improvement implemented a TC2 foundation system can be used at these sites. Due to depth to groundwater at the site, the engineered fill layer has been reduced to a thickness of 1.7m. To compensate for the reduction in thickness the bottom 300mm of the fill layer has been formed with geogrid reinforced crushed concrete. This composite reinforced 1.7m thick layer is considered to have the same engineering properties of 2m of re-compacted site won fill. This engineer fill layer is capped with 0.3m of topsoil. Plans showing the location and a cross-section of this capping layer are appended to this report. This geogrid reinforced gravel capping layer has been constructed under the supervision of the project Civil Engineer s, Optimum Projects Limited, as part of the bulk earthworks process carried out as part of the subdivision development. Aurecon has visited the capping layer construction at critical stages. Technical Category Classification We have assessed the liquefaction hazard at the site using the method recently prescribed by MBIE guidelines, observed site performance during the major seismic events in the Canterbury earthquake sequence. Based upon our geotechnical site investigations, the liquefaction hazard assessments and the implementation of an engineered fill capping layer (in Lots 12, 13 and 25 to 28) we believe: Lots 1 to 28 fulfil the requirements of TC2 Classification, Lots 50 and 61 are roading and access right-of-way areas; therefore no Technical Category Classification is applicable for these lots. Foundation Recommendations A TC2 Classification effectively means that the MBIE believe that Minor to moderate land damage from liquefaction is possible in future significant earthquakes. With Lots 1 to 28 enhanced TC2 foundation are required as outlined in Section 5 of the MBIE Guidelines. In accordance with the Guidelines standard shallow lot specific shallow geotechnical investigations will be required during the Project File Kirkwood the Conclusion 224 Sign Off Report - Rev1.docx 15 May 2017 Revision 1 Page 2

detailed house design to assess the lot specific ground conditions and bearing capacity values. This assessment should be undertaken by the foundation designer.

3 detailed house design to assess the lot specific ground conditions and bearing capacity values. This assessment should be undertaken by the foundation designer. Limitations We have prepared this report in accordance with the brief as provided. The contents of the report are for the sole use of the Client and no responsibility or liability will be accepted to any third party. Data or opinions contained within the report may not be used in other contexts or for any other purposes without our prior review and agreement. The recommendations in this report are based on data collected at specific locations and by using suitable investigation techniques. Only a finite amount of information has been collected to meet the specific financial and technical requirements of the Client s brief and this report does not purport to completely describe all the site characteristics and properties. The nature and continuity of the ground between test locations has been inferred using experience and judgement and it must be appreciated that actual conditions could vary from the assumed model. Subsurface conditions relevant to construction works should be assessed by contractors who can make their own interpretation of the factual data provided. They should perform any additional tests as necessary for their own purposes. Subsurface conditions, such as groundwater levels, can change over time. This should be borne in mind, particularly if the report is used after a protracted delay. This report is not to be reproduced either wholly or in part without our prior written permission. This conclusions in this report draws on investigations, analysis and conclusions from various investigations stages and numerous reports. For specific details please refer to the above mentioned references or contact the writers. If you have any queries regarding the content of this letter, please do not hesitate to contact the undersigned. Yours faithfully Dr Jan Kupec Technical Director Ground Engineering Enc: Site Layout Plan and Capping Layer Detail Statement of Professional Opinion Project File Kirkwood the Conclusion 224 Sign Off Report - Rev1.docx 15 May 2017 Revision 1 Page 3

$It shall not be reproduced without the written consent of optimum projects ltd and is confidential in terms of the building act. S 26.37 Z:\JOB FILES\2630 - KIRKWOOD - THE CONCLUSION\DRAWINGS\2630-C.$ DWG 12/05/17 15:13 A1 ORIGINAL 16 S 26.53 S 26.49 61 6.70 15 14 11 S 26.36 Lo DP 33 S 26.70 13 Lot 1 DP 439427 S 26.40 Lot 2 DP 439427 25 12 Lot 3 Area of TC3 remediation 7 Lot 4 DP 439427 28 S 26.

DWG 12/05/17 15:13 A1 ORIGINAL 16 S 26.53 S 26.49 61 6.70 15 14 11 S 26.36 Lo DP 33 S 26.70 13 Lot 1 DP 439427 S 26.40 Lot 2 DP 439427 25 12 Lot 3 Area of TC3 remediation 7 Lot 4 DP 439427 28 S 26.

4 This drawing is subject to copyright and remains the property of optimum projects ltd at all times. It shall not be reproduced without the written consent of optimum projects ltd and is confidential in terms of the building act. S Z:\JOB FILES\ KIRKWOOD - THE CONCLUSION\DRAWINGS\2630-C.DWG 12/05/17 15:13 A1 ORIGINAL 16 S S S Lo DP 33 S Lot 1 DP S Lot 2 DP Lot 3 Area of TC3 remediation 7 Lot 4 DP S S Lot 2 boundary 300mm topsoil existing surface 27 Lot 1 S S m site won fill compacted to NZS S existing ground 0.3m pitrun / crushed concrete tensar TX-160 geogrid to be installed in strict accordance with the manufacturers specification on bidim A19 geofabric S Lot 74 typical remediation of TC3 land a1, a3 Note: 1. granular and cohesive soils are to be compacted to a minimum of 95% MDD, in addition to the requirements of NZS During excavation, silt is to be separated from the sandy material and placed at the surface of the 2m ground improvement, with the sandy material placed at the base on the geogrid. 3. Refer to geotechnical site notice for further installation requirements. 4. services installed above geogrid. Engineer to be notified prior to construction if services are to be installed through or lower than geogrid. TC3 remediation location a1, a3 4 as built kb optimum projects ltd project P O Box revised for approval kb christchurch site 2 for approval kb kb kb as shown gw halswell ltd kirkwood - the conclusion TC3 remediation area C1.2 ph: for approval 4 kb solutions issue description by appd. date drawn designed approved scales client project title drawing title drawing no issue

5 Statement of Professional Opinion on the Suitability of Land for Subdivision (Appendix I to the Infrastructure Design Standard) Issued by: Aurecon New Zealand Limited (Geotechnical engineering firm or suitably qualified engineer) To: GW Halswell Limited (Owner/Developer) To be supplied to: Christchurch City Council (Territorial authority) In respect of: Residential Subdivision (Description of proposed infrastructure/land development) At: Lot 43, DP , 1 Stallion Avenue, Halswell, Christchurch (Address) I (Geotechnical engineer) Dr Jan Kupec on behalf of (Geotechnical engineering firm) Aurecon New Zealand Limited hereby confirm: 1. I am a suitably qualified and experienced geotechnical engineer and was retained by the owner/developer as the geotechnical engineer on the above proposed development. 2. My/the geotechnical assessment report, dated 7 October 2016 and 224 Certificate geotechnical completion report 15 May 2017 has been carried out in accordance with the Department of Building and Housing Guidelines for geotechnical investigation and assessment of subdivisions and includes: (i) Details of and the results of my/the site investigations. (ii) A liquefaction assessment. (iii) An assessment of rockfall and slippage, including hazards resulting from seismic activity. (iv) An assessment of the slope stability and ground bearing capacity confirming the location and appropriateness of building sites. (v) Recommendations proposing measures to avoid, remedy or mitigate any potential hazards on the land subject to the application, in accordance with the provisions of Section 106 of the Resource Management Act In my professional opinion, I consider that Council is justified in granting consent incorporating the following conditions: The recommendations presented in the following reports are implemented: - '1 Stallion Ave, Halswell, Geotechcnail Subdivision report', Revision 2, Job No , dated 7 October 'Geotechncail Subdivision Completions Report - Kirkwood the Conclusion' Job No , dated 15 May This professional opinion is furnished to the territorial authority and the owner/developer for their purposes alone, on the express condition that it will not be relied upon by any other person and does not remove the necessity for the normal inspection of foundation conditions at the time of erection of any building. Updated: of 2 P-055

5. This certificate shall be read in conjunction with my/the geotechnical report referred to in Clause 2 above, and shall not be copied or reproduced except in conjunction with the full geotechnical

6 5. This certificate shall be read in conjunction with my/the geotechnical report referred to in Clause 2 above, and shall not be copied or reproduced except in conjunction with the full geotechnical completion report. 6. The geotechnical engineering firm issuing this statement holds a current policy of professional indemnity insurance of no less than $ 250,000 (Minimum amount of insurance shall be commensurate with the current amounts recommended by IPENZ, ACENZ, TNZ, INGENIUM.)... (Signature of Engineer) Date: 15 May 2017 Qualifications and experience: PhD, MSc, canding, MIPENZ, CPEng, IntPE Updated: of 2 P-055

STRUCTURAL CALCULATIONS & DETAILS

S y n g e C o n s u l t i n g Ltd. S t r u c t u r a l E n g i n e e r i n g STRUCTURAL CALCULATIONS & DETAILS Pole Retaining Wall at 61 Exploration Way Whitby Lot 100 DP 478324 Prepared for: Keys Construction