Statement of evidence of Stephen Lee (wharf design and construction methods)

Transcription

1 Before Hearing Commissioners at Christchurch under: the Resource Management Act 1991 in the matter of: applications CRC175507, CRC176030, CRC175508, CRC175509, CRC to reclaim land and construct a wharf in Te Awaparahi Bay, Lyttelton Harbour and in the matter of: Lyttelton Port Company Limited Applicant Statement of evidence of Stephen Lee (wharf design and construction methods) Dated: 1 September 2017 REFERENCE: JM Appleyard (jo.appleyard@chapmantripp.com) JR Cross (jessie.cross@chapmantripp.com)

2 1 EVIDENCE OF STEPHEN LEE INTRODUCTION 1 My name is Stephen Lee. 2 I hold a Bachelor of Engineering, Civil (1 st Class Hons) from the University of Canterbury. 3 I am a Technical Director of Civil Structural Engineering at Beca. 4 I have over 18 years practical experience in the design of civil structures including wharves, bridges, tunnels, retaining walls and other such structures in New Zealand, Australia, Fiji, America Samoa, Solomon Islands, Indonesia and in the United Kingdom. A selection of my wharf design experience follows: (a) (b) (c) (d) (e) (f) (g) (h) 350m long Fergusson North Container wharf, Ports of Auckland; 100m extensions to Bledisloe B2 and B3 wharves and 50m extension to Fergusson FZ wharf, Bledisloe and Fergusson Container Terminals, Ports of Auckland; 800m long wharf, Roy Hill Iron Ore project in West Australia; 200m long North Mole Cargo wharf extension, PrimePort Timaru; 260m No.2 Wharf, PrimePort Timaru; 140m Service Wharf at Pago Pago in American Samoa; 600m long container and bulk cargo wharf at Marsden Point; 360m long wharf at Bua Bay Fiji. 5 In addition to my ports design experience, I have led civil structural designs on some of New Zealand s most significant engineering projects such as Transmission Gully PPP, the Victoria Park Tunnel, the New Lynn Rail Trench and the Manukau Harbour Crossing. 6 I contributed to the sections of the Beca report on wharf design and construction which was included in Lyttelton Port Company Limited s (LPC) application for resource consents to reclaim land and construct a wharf at Te Awaparahi Bay in Lyttelton Harbour

3 2 (Applications). Together, the Applications are to undertake works known as the Te Awaparahi Bay Reclamation Project (Project). 7 The report is called Te Awaparahi Bay Reclamation Project: Design Information for the Resource Consent Application and it was Appendix 1 to the Applications (Report). SCOPE OF EVIDENCE 8 This evidence is divided into three parts. Part 1 consists of a summary of my Report, Part 2 is a response to issues raised by submitters on the Applications, and Part 3 is a response to issues raised in the section 42A report. 9 My Report covered: 9.1 Wharf Concept Design Overview (section 4.1 of Report); 9.2 Wharf Design Basis and Structure Performance (section 4.2 of Report); and 9.3 Description of the Wharf Key Elements (section 4.3 of Report); and 9.4 Wharf Construction Sequence (section 5.1 of Report); and 9.5 Wharf Construction Methods (section 5.2 of Report). 10 I respond to the following issues raised by submitters: 10.1 Submitter: Louis Sanson, Director-General of Conservation, requesting that a new condition be applied requiring use of vibro-driving/drilling technology to be used where practicable instead of, or in part replacement for, direct pile driving to reduce the adverse effects of noise. 11 I also respond to the following issues raised in the section 42A report: 11.1 Paragraph 210, regarding the estimated duration of pile installation activity and associated effects on Hector s dolphins. 12 In preparing this evidence I have reviewed: 12.1 Te Awaparahi Bay Reclamation Project: Design Information for the Resource Consent Application prepared by Beca, Appendix 1 to the Applications; and

4 Submission by Louis Sanson, Director-General of Conservation Section 42A Report. 13 Although this is not an Environment Court hearing, I note that in preparing my evidence I have reviewed the code of conduct for expert witnesses contained in part 7 of the Environment Court Practice Note I have complied with it in preparing my evidence. I confirm that the issues addressed in this statement of evidence are within my area of expertise. I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed. PART 1: SUMMARY OF REPORT Overview of Wharf Concept Design 14 Section 4.1 of my Report provides an overview of the wharf concept design process. A process of option identification, development and assessment was carried out in order to arrive at a preferred design for the wharf. This included consideration of the functional performance, cost, design and construction programme, risks and other such selection criteria for a range of wharf forms. Options evaluated included the following: 14.1 Traditional piled supported wharf deck integrated with a revetment; 14.2 Traditional piled supported wharf deck, separated from the revetment/reclamation, and accessed via bridges; 14.3 Quay wall (retaining wall) comprising a piled wall, tied back with anchors to a parallel anchor wall located some distance behind within the reclamation; 14.4 Gravity wall structures, such as counterfort retaining walls and caisson type structures. 15 Ultimately it was found that the significant soil/structure interaction effects associated with the settlement and lateral movement of the reclaimed land over time governed the wharf structure design. This discounted the use of retaining wall type structures, as these needed to be in place prior to undertaking the reclamation work. Accordingly, the structure would be subjected to the full magnitude of the ground movement/settlement effects from the start. 16 The selected design for the wharf is a traditional pile supported wharf deck integrated with a below-wharf rock armoured revetment

5 4 (refer to wharf general arrangement drawing s appended to my report, drawing numbers A08110, A0811 and A08112). This structure type was found to most efficiently address the issues and risks associated with reclamation movements, as the wharf could be constructed independently and after the reclamation was in place, allowing sufficient reclamation consolidation to take place without impacting the wharf structure. 17 The Stage 1 wharf is approximately 350m long and 34m wide, Stage 2 wharf to the east is to be approximately 290m long and to the west is approximately 60m long, giving a total wharf length of 700m. Key elements of wharf design 18 Section 4.3 of my Report sets out the key elements of the wharf design. The wharf piles comprise driven steel tubes, in-filled with reinforced concrete over the upper extents to increase pile capacity, flexural stiffness, and to form the connection with the wharf deck. 19 Piles are spaced on approximately a 7-10m square grid. Piles could be in the order of 1.0m 2.0m in diameter. Pile founding level is approximately 100 m below Chart Datum. 20 Stage 1 consists of an approximately 350m x 34m wide reinforced concrete deck. A retaining wall, integral with the wharf, is provided along the inner edge of the wharf to transition between the reclamation level and the revetment slope m gauge quay crane rails and a power cable slot in the seaward edge run the length of the Stage 1 and Stage 2 wharf. 22 Concrete support panels located on the seaward wharf edge provide support to rubber fenders against which the ships will berth. 23 Other wharf furniture including bollards, and ship to shore services will all be accommodated on the wharf. 24 The end of the existing Cashin Quay breakwater will be removed during either the Stage 1 or Stage 2 construction works to accommodate the new wharf and reclamation layout. This will facilitate construction of the Stage 2 western wharf extension. The existing breakwater comprises a rock bund and will be removed using long-reach diggers working from on the bund and also from badges. Removed materials will be transferred back in to the reclamation.

6 5 25 The timing for construction of the Stage 2 wharf extensions is approximately 15 years after completion of the Stage 2 bund - allowing for settlement of the bund and construction time. Location of wharf 26 The proposed wharf is located parallel to and within the southern edge of the reclamation and within the Area A as shown on Planning Map 10.10, as shown on the drawings appended to my report and indicated in the figure attached as Appendix 1 to my evidence. The wharf does not extend beyond the 34 hectares shown as Area A on Planning Map of the Regional Coastal Environment Plan (RCEP) as amended by the Lyttelton Port Recovery Plan (LPRP). Statutory requirements Rule The Council has reserved control over a number of matters in Rule 10.2 of the RCEP that are relevant to the wharf design and construction, as set out below. Control is reserved over the following matters: b) The design, construction and maintenance of the Wharf Structure, including its stability and integrity in terms of expected weather and seastate conditions, and materials used in its construction; and c) If the Wharf Structure is used for the conveyance of any bulk hazardous substances from a vessel to land, the methods to avoid any potential spillages and measures to contain spillages, including the installation of infrastructure to facilitate the rapid deployment of booms around a vessel; and f) The extent to which the Wharf Structure is a barrier to water or sediment movement in Lyttelton Harbour; and g) The collection and treatment of stormwater captured from the Wharf Structure Rule 10.2 b). The wharf design and construction basis is set out under paragraph 29 below. The wharf structure, moorings and all their elements are designed to comply with the stability, strength (integrity) and durability requirements of the New Zealand Building Act 2004, with reference to the New Zealand Building Code (Acceptable Solutions). A 100 year design life is adopted.

7 Rule 10.2 c). The wharf is not proposed to be used for direct conveyance of hazardous substances so matter of control (c) is not relevant Rule 10.2 f). The wharf structure is not a barrier to water or sediment movement within Lyttelton Harbour. It is an open structure comprising a pile supported deck slab, which allows water to move freely around piles under the deck slab Rule 10.2 g). Storm water runoff from the wharf deck will be collected in drains located behind the wharf and treated via a proprietary storm water treatment device, such as Vortex Stormwater 360 device, before being discharged into the harbour. This solution is already successfully implemented at the recently completed Cashin Quay 2 wharf rebuild The treatment device will be designed and operated to remove total suspended solids and hydrocarbons from the storm water runoff in accordance with Christchurch City Council s Waterways, Wetlands and Drainage Guide The device details will be determined during detailed design, but will include a filtration system and compartments to treat stormwater and contain solids/contaminates. The armoured shoreline will protect against localised scour from any storm water discharge. Methodology and sequence of wharf construction 28 Section 5.0 of my Report provides a typical methodology and sequence for construction of the wharf that represents best practice to mitigate effects on the environment, including managing propagation of sediment plumes. More specific details on the environmental controls are also provided in the Construction Environmental Management Plan (CEMP). The actual construction methodology and sequence will be determined by the selected contractor(s) for the wharf/ revetment/reclamation construction packages, in accordance with the CEMP. In comparison to the reclamation works, the wharf construction creates little seabed disturbance and potential for sediment plumes. A summary of the wharf construction process (which represents best practice) is provided below. Reshaping of bund 28.1 Prior to commencement of the wharf construction, the temporary rock armour installed during the construction of the southern bund will be either left in place or removed and recycled for re-use. Any reshaping of the southern bund will

8 7 be completed by land-based excavators. This may involve localised filling and/or trimming, depending on settlement that may have occurred. Pile driving methods 28.2 Steel pile casings will be driven by land based plant from west to east using driven piles and temporary staging as works progress. Piles will be driven open ended to design depth which is estimated to be to RL-100m CD. The piles will be pitched and initially driven with a vibro hammer or similar, and extended by welding before final driving with a large hydraulic hammer or similar. In some instances, due to the length of the pile and the encountered ground conditions, it may prove necessary to bottom drive the pile using an internal drop hammer Seabed disturbance and the creation of sediment is expected to be minimal during pile installation After driving, the piles will be filled with aggregate, rebar cages and concrete. The risk of spilling concrete into the sea will be mitigated by the use of concrete pumps in preference to concrete skips/buckets wherever practicable. Revetment armouring rock placement 28.5 As the piling moves forward installation of the revetment armouring rock will follow. The rock will be installed using a combination of land based and barge-mounted long-reach diggers. Armour rock is carefully placed, rather than dumped from the barge, which minimises disturbance of the revetment slope and reduces potential for sediment plumes. Concrete deck construction methods 28.6 The next stage will be construction of the deck slab and edge beams using formwork installed within the pile lines. The precast retaining walls at the rear edge of the deck will also be constructed as part of this phase of work The risk of spilling concrete into the sea will be mitigated by the use of concrete pumps to deposit directly on to the deck formwork. The concrete formwork surface will provide a fully sealed area to contain deposited concrete, thus preventing potential for any discharge into the sea.

9 8 Furniture and fittings installation method 28.8 As sections of the deck slab become available, wharf furniture and fittings will be installed, including: (a) (b) (c) (d) (e) (f) (g) Crane rails; Mooring bollards; Pre-cast fender support panels, followed by the fenders; Stormwater drainage; Water supply; Power and communications; and Navigation aids Once the wharf structure is complete, the fill along the north edge of the wharf will be re-graded to match the elevation of the wharf deck. Any temporary asphalt or hardfill surfacing will be removed, trenching and backfilling for service connections undertaken, additional basecourse placed and compacted, and new asphalt placed at a suitable grade for the port s heavy equipment. Construction equipment fuelling All powered equipment will require refuelling, which will be carried out by a tanker truck at the worksite. In accordance with the environmental requirements set out in the CEMP, spill containment and clean-up materials will be kept on site as a contingency. Equipment working over the sea will use biodegradable hydraulic oil to mitigate the effect of a spill. Design Basis and Structure Performance 29 Section 4.2 of my report outlines the wharf design standards, design loads and performance criteria, as summarised below Design Standards: The wharf structure, moorings and all their elements are designed to comply with the stability, strength (integrity) and durability requirements of the New Zealand Building Act 2004, with reference to the New Zealand Building Code (Acceptable Solutions). A 100 year design life is adopted.

10 Vessel Berthing and Mooring: Berthing and mooring forces are based on AS 4997: 2005 and/or BS : 1984 and/or BS :2000 and/or PIANC Guidelines for the design of Fender Systems: 2002, as applicable. A maximum vessel size of 340m long with displacement weight tonnage of 143,000t has been considered in the design Wave and current loads: Wave and current loadings are determined based on a site specific wave study and in accordance with AS 4997: Seismic Design: Seismic design of the wharf has been carried out in accordance with ASCE/COPRI Seismic Design of Piers and Wharves. The wharf structure is to be designed for three levels of earthquake as follows: (a) (b) (c) Operating Level Earthquake (OLE): 50% probability of exceedance in 50 years (return period of 72 years). Contingency Level Earthquake (CLE): 10% probability of exceedance in 50 years (return period of 475 years). Design Level Earthquake (DE): 1.5 x CLE. Under the CLE and DE level earthquakes, the structure is designed to respond in a ductile manner experiencing limited inelastic deformations in the piles. This is considered to be controlled damage in accordance with ASCE Under the OLE earthquake the structure remains elastic with minimal residual deformation Reclamation Loads: The settlement and lateral movement over time of the reclaimed land dominates the options and performance of the wharf structures. The revetment slope laterally displaces significantly during the filling, dredging, surcharging and consolidation process. To minimise the amount of movement the wharf piles will be subjected to, the piles must be installed after sufficient consolidation has taken place Operational Live loads: The wharf has been designed to support multiple quay container cranes, various operational plant such as container straddle carriers, forklifts, trucks and mobile cranes, and a 55kPa uniformly distributed load to represent stacked containers and other bulk cargo.

11 10 PART 2: RESPONSE TO ISSUES RAISED BY SUBMITTERS Department of Conservation 30 Louis Sanson, Director-General of Conservation has requested that a new condition be applied requiring use of vibro-driving/drilling technology to be used where practicable instead of, or in part replacement for, direct pile driving to reduce the adverse effects of noise. 31 The use of drilled (bored) piles is not practicable at this site. Piles are to be installed through over 100m depth of soft sediments/soils in order to reach the founding rock level required to support the wharf loads. The soft sediments/soils would not stand unsupported during pile drilling (excavation) and would require the installation of permanent steel pile liners down to founding rock level. These long steel liners would need to be installed using the same methods as driven piles, so no benefit/difference is provided. 32 Vibro-driving techniques are typically used to install piles through materials that provide low to moderate driving resistance and where required pile load capacities are also relatively low. This is because the vibro method does not provide enough driving energy to the pile to advance it through harder materials or to penetrate sufficiently into founding rock in order to generate the required load resistance. In this instance, the piles are long and the wharf loads are significant. Vibro-driving will be suitable as an initial driving method, but as the installed pile length increases and once founding rock level is encountered, a large hydraulic hammer or similar drop hammer will be required in order to generate sufficient driving energy in order to advance the pile to the required depths and to the required penetration into the rock. 33 I support the submitter s request for a new condition that requires the use of vibro-driving/drilling technology to be used where practicable instead of, or in part replacement for, direct pile driving to reduce the adverse effects of noise. However, I note that vibrodriving will only be feasible during the initial stages of pile installation and direct pile driving methods will also be required. Therefore I consider that proposed condition 8(c)(v) of CRC & CRC176030, which requires LPC to consider minimisation of underwater noise levels when selecting piling plant/techniques, is satisfactory for reducing piling effects of noise.

12 11 PART 3: RESPONSE TO SECTION 42A REPORT 34 Paragraph 210 of the Section 42A report states the following: Given the estimated 350 piles will be placed over several years with an area of effect potentially out to 20 kilometres, any effects on Hector s dolphins are likely to be significant and extended. 35 It is noted that the duration for wharf pile installation for each of the two stages is estimated as 12 months, with the two stages occurring several years apart. CONCLUSION 36 The proposed design and construction solution for the wharf meets the applicable matters for control as outlined under the RCEP. 37 I support the submitter s proposed new condition that requires the use of vibro-driving/drilling technology to be used where practicable instead of, or in part replacement for, direct pile driving to reduce the adverse effects of noise. However, I note that vibrodriving will only be feasible during the initial stages of pile installation and direct pile driving methods will also be required. 38 The duration for wharf pile installation for each of the two stages is estimated at 12 months, with the two stages occurring several years apart. Dated: 1 September 2017 Stephen Lee

13 1 Appendix 1 Figure 1: Te Awaparahi Bay General Layout