C5 24 Mt Eden Road (House of Knives) SSCNVMP

C5

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24 Mt Eden Road (House of Knives) SSCNVMP

C5.1 Introduction

This Site Specific Construction Noise and Vibration Management Plan (SSCNVMP) is for the commercial building located at 24 Mt Eden Road. A SSCNVMP is required because construction is predicted to exceed the noise and vibration standards in CRL designation condition 31 and 33.

This SSCNVMP has been prepared in accordance with CRL designation condition 37 and 38 and is Appendix C5 of the Mt Eden Main Works Construction Noise and Vibration Delivery Work Plan (CNV DWP). It is a supplementary document that builds on the CNV DWP, and therefore directly references relevant sections of the CNV DWP to avoid repetition. The objective of this SSCNVMP is to detail the best practicable option(s) (BPO) to avoid, remedy or mitigate the identified adverse effects from noise exceedances at 24 Mt Eden Road. This SSCNMP has been prepared for the Link Alliance and forms part of the Construction Environmental Management Plan (CEMP) for the Mt Eden Station Main Works. It builds on the SSCNMP previously prepared and implemented for the Mt Eden Enabling Works.

C5.2 Engagement

Mt Eden Enabling Works (for information)

Link Alliance representatives Sonya Leahy, Thibaut L'Hopital, Aidan Kirkby-McLeod, Duncan Whyte and Craig Fitzgerald (Marshall Day Acoustics) met with John Fryer on 11 September 2019. The matters discussed included:

An overview of the project General programme, demolition, piling and rock breaking/blasting activities

Overview of the CNV DWP and this SSCNMP, communications triggers and protocol The site is used for commercial purposes, with the House of Knives cookware shop fronting Mt Eden Road. Shop opening hours are generally 9.30am –5pm, Monday to Saturday. Mr Fryer voiced concerns about vibration associated with previous C6 piling works. From Mr Fryer’s description, the source of the vibration was from vibrated pile casings installed on the adjacent site and from vertically dropping an auger from height onto the ground. Mr Fryer was advised that vibro piling was not part of the current piling methodology for the new Mt Eden Road bridge and that dropping an auger bit was most likely avoidable with good practice. Figure B.4 in Appendix B of the Mt Eden Enabling Works CNV DWP shows that the south and west façades are predicted to be exposed to noise levels between 75 –80 dB L Aeq during the closest bored piling activities, exceeding the 75 dB L Aeq noise limit. Activity specific mitigation and management measures are included in Section 9 of the CNV DWP and not repeated here (e.g. Section 9.8 piling). The buildings at 24 Mt Eden Road are primarily single story with either weatherboard or brick façades, operable glazing and a steel pitched roof. The estimated sound level difference across the façade with the windows and doors closed is 25 decibels. The predicted construction noise effects from Table 12-1 in Section 12.1 are predicted to be typically acceptable, but with the potential for some disturbance during installation of the closest bridge piling and demolition works. Physical receiver mitigation, such as temporary relocation of affected receivers, alternative ventilation and façade sound insulation

Mt Eden Main Works CNV DWP –Appendix C SSCNVMPs

improvements, have been considered, but are not required as part of the BPO for the C3 enabling works. During further consultation on 10 October 2019, a pre construction building condition survey in accordance with CRL designation condition 46 will be undertaken to provide confidence that any vibration damage is identified for remediation. Mr Fryer agreed that prior communication of timeframes for works with the potential to exceed the relevant noise limits was an acceptable means of managing effects. No further activity specific consultation is necessary over and above regular communication (refer Section 10).

Mt Eden Main Works

Link Alliance representatives Helen Jansen and Craig Fitzgerald (Marshall Day Acoustics) met with building representative John Fryer and his son on 24 July 2020. The matters discussed included:

Summary of works and engagement to date (e.g. Mt Eden Enabling Works) A brief overview of the next project phases (Mr Fryer is well informed and in regular contact with the comms team)

General programme, adjacent piling platform compaction, excavation, piling, and potential rock removal works

General review of CNV DWP and this SSCNVMP, communications triggers and monitoring

Attended noise and vibration monitoring of adjacent compaction works on 14 July. The primary effect related to reradiated noise from crockery in the shop at vibration levels above ~0.7mm/s. The effect was prominent during ramp up and ramp down of the vibro unit in the roller. The outcomes included review of vibro rolling management measures and ensuring ramp up/down of roller is undertaken away from House of Knives. Mr Fryer provided updates on two matters:

Shop opening hours are 9.30am –5pm Monday to Friday and 9.30am –2pm on Saturday

It was clarified that previous concerns about vibration from C6 works related to banging an auger bit on the ground to dislodge spoil. In response, it was noted that vibration from the described activity is avoidable and not acceptable as part of the main works contract. CNV DWP Section 7 identifies the potential scale of noise and/or vibration exceedances using the modelling outputs in insert hyperlink to the GIS maps here. The relevant stages are summarised below. Activity specific mitigation and management measures are included in Section 9 of the CNV DWP, and referenced in brackets, rather than repeated.

Noise

Retaining walls (refer piling in Section 9.8)

Excavation (refer concrete and rock breaking in Section 9.7) The existing perimeter hoardings on the south boundary provide effective screening for site works, aided by the lower site ground level. It was noted that utilities works were currently being undertaken in the footpath outside House of Knives without perimeter noise mats. However, Mr Fryer preferred no noise mats to ensure better street viability for the shop frontage.

Page 24 Mt Eden Main Works CNV DWP –Appendix C SSCNVMPs

The predicted construction airborne noise effects from Table 12.1 in Section 12.1 are predicted to result in typically acceptable noise effects. The primary residual effect relates to reradiated noise, induced by vibration (discussed below). Further physical receiver mitigation, such as temporary relocation of affected receivers, alternative ventilation and façade sound insulation improvements, have been considered, but are not required as part of the BPO for the Mt Eden Station Main Works.

We discussed the potential to locate a noise monitor on the façade of House of Knives for relevant periods of works. Mr Fryer is happy to accommodate this, but equally happy if it is located on another site, such as the Horse and Trap.

Vibration

Excavation and piling (refer breaking, piling and compaction in Sections 9.7, 9.8 and 9.10) The above activities are predicted to have the potential to exceed the commercial cosmetic building damage thresholds. Cosmetic building damage effects are deemed ‘minor damage’ in the DIN Standard (Section 5.2), such as cracking in paint or plasterwork, and can generally be easily repaired. A pre construction building condition survey has been undertaken in accordance with CRL designation condition 46 will ensure any damage is identified for remediation.

Monitoring from nearby compaction activities resulted in management outcomes (refer previous page). We discussed the potential to locate a long-term vibration monitor within the shop, near the south façade during relevant periods of construction (e.g. adjacent piling works). The monitor would provide real-time feedback to LA and act as a proxy for the wider community, then be moved elsewhere thereafter. Mr Fryer is happy to accommodate this. A location within the shop was identified and subsequent conversations will follow when the monitor is available for installation. In the meantime, targeted vibration monitoring will continue, starting with attended monitoring for the commencement of nearby piling in early August. Mr Fryer agreed that prior communication of timeframes for works with the potential to exceed the relevant noise and vibration limits was an acceptable means of managing effects. No further activity specific consultation is necessary over and above regular communication (Section 10).

C5.3 Review Process

If Mr Fryer requests consultation in the future, this SSCNVMP will be updated in accordance with CRL designation condition 37.5 and 38.5, with consideration given to the following:

The extent to which noise may exceed the designation noise standards

The timing and duration of any exceedance

The type of activity causing any exceedance

A summary of the communication and consultation with the receiver

The methods and measures to mitigate noise effects

A statement of why they reflect best practicable option Communications records are contained in the communication and consultation plan (CCP). This SSCNVMP will be updated to summarise engagement and any agreed site-specific measures.

Page 25 Mt Eden Main Works CNV DWP –Appendix C SSCNVMPs