town pier refurbishment method statement

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Bantry Inner Harbour Development: Phase 1

Bantry Inner Harbour Development Phase 1 Port of Cork Tender Submission 15 October 2015 BAM Method Statements

Introduction

Prior to any works commencing on site, Site Specific Method Statements will be prepared for all the major elements of the work. These method statements will outline precisely how Bam will approach and carry out the works associated with the Bantry Inner Harbour Development – Phase 1 Contract. These method statements will be submitted to the Employers Representative for approval, work will not commence prior to the relevant method statements being approved.

The method statements will be prepared by the Project Manager Collins Connolly and the Site Agent Seamus O’Sullivan, however the various other members of the site management team will be asked to contribute to the relevant sections of the method statements as required. The method statements will be prepared in line with the Works Requirements, Specifications, Guidance Documents and Consultations meetings with various other stakeholders.

While the more specific in-depth method statements will be prepared once we get to site, below are the overall method statements which will outline our general approach and methodology to the Bantry Inner Harbour Development – Phase 1 Contract.

Introduction

This method statement incorporates Bam overall approach for the Town Pier Refurbishment Works, option 3-variant. Prior to any works commencing on site more comprehensive and detailed, task specific method statements will be prepared by Bam for each element of the works.

Scope of Works

The works will consist of the following:

Proposed Plant

Variant Option Overview

Excavation Works

Quay Wall Construction

Rock Anchoring (N/A for option 3)

Ancillary items such as bollards, ladders etc.

Works Proposals – Option 3

Part 1 Site Specific Method Statements – MS04-3 Town Pier Refurbishment Works

Town Pier Refurbishment Works

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Location of the Works

Figure 1: Site Location Map

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Figure 2 - Town Pier Refurbishment works

Figure 3: Looking west from the N71 towards the existing town pier

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Proposed Plant

Details are listed below of plant and equipment to be utilized in the construction of the town pier refurbishment, including access and egress support to be used in the works.

The details provided are specific to the project. All plant relating to the construction of the Town Pier Widening are listed.

Most of the equipment is BAM owned or will otherwise be hired/ subcontracted.

Item Activity/ Roles Quantity [nos.]

G130 Rammer 8.5t rock hammer

Dredge rock 1

250HP separator power pack To run rock hammer 1

135 cfm compressor To run underwater rock hammer 2

65t long reach excavator with GPS system & 4t breaker

Dredging of rock and slipway from shore

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Longreach excavator with grab Offloading material transfer barge and depositing material in stabilisation cells

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Longreach excavator with loading bucket

Long trucks with stabilised material/ retrieving dredged rock from shore

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Testing Equipment Testing of materials 1

Vibration and noise monitoring equipment

Monitoring the works 1

Welding Plant Temporary works for storage cells on flat top barge

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Oxygen/ Acetylene set Pile cutting and preparation 1

Safety boat Works over water 1

Crawler crane 100 tons Piling Handling/Storage area 1

Lighting Tower Site Lighting 1

Pickup Site attendances 1

Bog mats Protect pavement from damage

Heras Fence Secure the handling and storage area.

Generator Providing power 1

Survey equipment Survey 1

Tipper Truck/ Volvo A25 Moving of material on site 1

Handrailing Fall protection at water edge

Further equipment is also available from our subcontractors and sister companies in the BAM group.

All mechanical plant will be in good working order and subject to a regular maintenance regime. Only suitably qualified and experienced personnel will be allowed to operate plant and equipment.

All Vehicles will be fitted with reversing beacons and a flashing light and will be directed by a banksman. All plant certification will be checked by the BAM Civil Safety Officer prior to commencing works on site. A register of all plant and equipment checks will be kept on site for the duration of the project.

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Quay Wall Construction: Method Overview: The Quay wall extension will be constructed using land based plant form the existing pier. Access passed the works will be maintained at all times during the works.

Bam are proposing two solutions for the Town Pier widening, a “Shallow Rock Head solution” and a “Deeper Rock Head solution”. See Sketch below which defines the location of each.

Figure 5: Schematic showing extent of each solution

Figure 4: Bam Marine Plant

Figure 6: Extent of each solution

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Shallow Rock Head Solution

BH4 indicates that rock head is at -5.91m AOD and BH3 indicates that rock head is at -6.2m AOD. In this area Bam is proposing to construct a mass concrete base to -1.2m AOD bearing onto Rock, with a precast wall to underside of the new deck slab. The new cast in-situ reinforced concrete deck will be stitched to the existing deck using B25 dowels at 300mm ctrs as per Byrne Looby drawing B1372.1002

Figure 7: Shallow Rock Head Proposed Solution-Extract from Byrne Looby drawing B1372.1002

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Deep Rock Head Solution

BH3 to BH 1 where Rock head is indicated to be at -15.8m AOD. In this area Bam is proposing to construct a Sheet Piled wall driven to a nominal embedment into the rock head. The Sheet pile is then supported at the top by a suitably sized GEWI bar ties to the sheet piled wall on the opposite side of the pier. The void between the existing wall and the new sheet piled wall is to be filled with gravels won from the dredging operations. Reference Byrne Looby Drawing B1372.1003. (Temporary tie & wailer will also be deployed in the temporary state to service the sheet pile)

Note: In addition to the above prior to backfill operations grout will be pumped into the silts and gravels to stabilise the material as identified in BH01, Bam may verify the BH by carrying out additional site investigations if required for the design.

Figure 8: Deep Rock Head Proposed Solution-Extract from Byrne Looby drawing B1372.1003

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Excavation: (including sheet piling & Mass Concrete) Shallow Rock Head – Pier Widening The Pier wall widening in this location will be constructed using a temporary sheet piled wall driven to a rock at 4.5m offset from the existing pier wall. The sheet piled wall will be constructed prior to any dredging against the face of the existing pier wall. This will allow dredging works between the temporary wall and existing wall outside the November to March window, as the dredging work will be contained.

Stage 1: Piling Works. The Temporary sheet piled wall in the shallow rock area will be constructed using a suitably sized sheet pile. The piles will be driven to rock head by a 100 ton crane set up on the pier. The temporary sheet piled wall will be driven at an off-set from the front of the new pier wall suitable to allow for a to be placed to form the underwater concrete.

Pile Delivery & Transportation

The sheet piles will be procured and ordered at the commencement of the project, it is anticipated that delivery of these piles will take circa 12 weeks. These piles will vary in length between 10 and 20m and it is expected that these piles will be delivered to site by articulated lorry. The piles will be delivered to the town pier where the existing crainage will be employed to unload the piles. The piles will then be transported to designated storage areas along the length of the pier. The exact location of these storage areas will be finalized and agreed on site in the event of our tender being successful.

Piling Frame

The sheet piles will be installed using a piling frame, see figure 8 & 9 above with up to 20 sheets installed per frame set-up. The sheets will be installed in pairs. Bam will drive the piles with the vibro hammer as well as the hydraulic impact hammer whilst the pile remains secured in the frame. The frame will be firstly held in position on temporary piles, or using cantilevered ballast where room allows off the existing pier. The frame may also have to be positioned cantilevered off the pier where a toe in is not available due to rock head levels. The piling frame will be positioned to an exact position by the Bam Site Engineer. A spud pile and one pile from the previous setup will be employed to hold the frame in position. Adjustable crossheads on the spud piles will allow the alignment of the guide beam to be exact.

Figure 9: Sheet piled wall under construction

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The piling frame will be designed by a competent design and a full set of design drawings and calculations will be produced for the piling frame. The frame will also contain an access platform which will enable the checking of the piles during the piling operation.

Driving the Piles

Two types of hammers (or similar) will be used to install the piles:

BSP CG 300 PTC 130 Installation of Sheet Piles

To lift the sheet piles vertical, quick release shackles connected via wire ropes to the Auxiliary hook of the crane will be used. The sheet pile, driven in pairs, will be lowered approximately 1m into the clutches of the adjacent pile. The Sheet pile will stand vertical, supported by the piling frame and the Auxiliary hoist of the crane. Whilst still connected to the Auxiliary hook, the Vibro hammer connected to the Main hook of the crane is maneuvered on to the sheet pile. Once the Vibro Hammer is attached the quick release shackles are removed and the sheet piles are driven.

Note: in the Deep rock solution the following will apply. The Piles will be fabricated with an over-length of 500mm which will act as a safety measure to ensure the required Toe levels are reached. The extra 500mm is expected to be driven into the Toe to keep the pile within tolerance. The Piles subjected to the PDA testing will be fabricated with an over length of 1m to allow for the test. These piles will need to be cut to level.

Figure 10: Marine Sheet piling works previously carried out by Bam

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Figure 11: Plan view of quick release shackles and vibro hammer connection the sheet piles

Stage 2 Temporary works supports will be installed to support the sheet piled wall. Then the silt/gravels between the existing pier wall and the temporary pier wall will be excavated on a hit and miss basis, to the underside of future dredge level -6.3m AOD

Figure 12: Excavation between new and temporary quay walls

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Stage 3

Mass concrete is then placed in 3 layers from -6.3m AOD to -1.2m AOD. As per the sketch below.

Dredging & Mass concrete infill (for shallow rock area only)

On completion of the sheet piled wall, dredging works between the old and temporary walls will commence. This will be outside the dredging window of November to March, however the dredging operations will be contained within the piled wall and therefore any silt plumes will be contained.

The excavation depths will vary depending on the present bed level and the future dredge depth, in principal materials will be excavated to a minimum of -6.3m AOD.

The sea bed between the temporary and old wall will be reduced to -2.0m AOD, this is to facilitate the installation of a temporary prop at the low tide level. Once the prop is in place the excavation will be taken down to -6.2m AOD on a hit and miss basis, in 5m lengths. Care will be taken to ensure the batters of the miss area are made safe to allow divers to enter the excavation. Once a hit is excavated a steel shutter will be placed along the alignment of the new pier wall by a dive team and strutted from the sheet piles wall. Mass concrete will be tremmied into the excavation and brought up a minimum of 1.7 m in depth, this will insure the base of the existing sheet piled pier wall is propped. On completion of the concrete prop in the base of the excavation, the temporary prop at the -2.0m AOD level can be removed and the excavation completed along the full length of the pier.

Mass concrete will then be tremmied between the 5m hits into the excavation and brought up in layers so as not to overload the temporary sheet piled wall. The rate of rise is maximum 2m vertically per day, to a level of -1.2m AOD. Note that started bars will be cast into the top pour in order to stitch the precast unit to the mass concrete.

Excavation will be completed using a long reach excavator, and completed with a clamp shell working form the same crawler crane that installed. Where rock is encountered it will be broken with a 4 ton breaker on the long reach excavator, the breaker will be fed by a 130 cfm compressor.

Figure 13: Mass concrete & demolition

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Note: All excavated material from the pier wall will be transported to the Quay reclamation area and treated there as part of the land reclamation works.

Quay Wall Construction Stage 4 Install Precast concrete L-wall with in-situ concrete stitch, and construct in-situ concrete deck. Including all ancillary items such as bollards and ladders.

Figure 14: New sheet piled pier wall temporarily supported on a previous Bam project

Figure 15: Precast L-wall & Deck slab

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The precast wall panels will be cast off site and transported to site on articulated lorry and stored on the reclamation area. The units will be lifted into place using the crawler crane from the sheet piling installation. Recessed will be preformed in the precast units for ladder access points. The units will be lifted into position and temporarily supported by the sheet piled wall.

The precast wall will then be stitched onto the mass concrete with a series of steel dowels and an in-situ concrete toe stitch to the backfilled side of the wall.

Once the Precast wall has been completed and the in-situ base concrete has reached a required strength the area on top of the base will be filled with treated dredge materials up to the underside of the new deck slab. As per figure 16 above.

Excavation: (including sheet piling & dredge infill) Deep Rock Head – Pier Widening The Pier wall widening in this location will be constructed using a new sheet piled wall driven to a nominal embedment into rock at the required offset from the existing pier wall. The sheet piled wall will be constructed prior to any dredging against the face of the existing pier wall. The piling operation will be very similar to the works outlined above in the shallow rock head area, with the difference being that the piles will be permanent and driven to a greater depth.

Figure 16: Detail of deep rock section

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As the piles are driven to the required depth they will be tested as per the specification and temporarily supported back to the existing pier prior to the treated dredge material being placed between the new and old pier walls. The material will be placed in layers and the piles consistently monitored for movement by the Bam Site Engineer.

The top of the dredge infill will be trimmed to grade and blinded to the underside of the capping beam as shown on Byrne Looby drawing B1372.1003. Sections of the deck will then be demolished to allow the installation of the proposed horizontal ties through the exiting pier deck.

The reinforcing cage for the capping beam will have been prefabbed and lifted into position on the blinding prior to the anchors being placed. The concrete will then be placed in the capping beam to the underside of the new deck level.

The precast wall facing panels will be cast off site and transported to site on articulated lorry and stored on the reclamation area. The units will be lifted into place using the crawler crane from the sheet piling installation. Recessed will be preformed in the precast units for ladder access points. The units will be lifted into position and temporarily supported by the sheet piled wall.

Ancillary items such as bollards, ladders etc. The new concrete deck and ancillary items will be constructed as per dwg 16341-1202. Temporary fencing will be erected to separate the works from the rest of the pier and members of the public.

On completion of the sheet piled wall and mass concrete, demolition works as detailed on drawing 16341-1050 & 16341-90100 will commence.

Firstly the toilet block will be demolished, toilets sinks and all fitting will be removed to storage for reuse. The gateway and gangway for the ferry will be removed and later reinstated on the new deck edge. The crane surround wall will be demolished with the metal railing removed and stored for reuse on the new crane location, as will the handrails to the existing steps.

To facilitate the tie in for the new section of deck slab and the removal of the existing deck furniture a 0.5m wide strip of the existing quay edge will be demolished. A clean line will be cut using a road saw to a depth of 100mm into the slab, the section of deck slab will then be broken out using a hydraulic 1.5ton breaker on a 14ton excavator. All deck furniture will be removed to storage for possible reuse.

The works will progress south to north in direction. Access will be maintained at all times to all vessels and users of the existing pier.

Brackets and gangways will be fitted to the existing pier wall for access and egress along the perimeter of the pier. See Photo below.

Figure 17: Precast facing panel installation in Baltimore Pier

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Reinforcement cage for the new deck slab will be fixed with starter bars connecting to the starter bars from the precast wall. 50mm cover will be provided to all reinforcement. The base slab will be shuttered and poured as detailed on Byrne Looby drawing B1372.1002 & B1372.1003.

The new deck slab will be formed by the erection of shuttering to achieve the required concrete finish as outlined on the drawings.

Reinforcing cage will be fixed as per the contract drawings

25mm dia x 800mm long steel dowel bars at 300mm c/c will be resin fixed into the existing deck slab for the shallow rock head area.

Steel Nosing will be fixed to the shutter for the outer capping beam to the levels shown on the drawings. The formwork will be spaced from the deck reinforcement and propped from the gangway behind.

The deck slab will be poured in sections with construction joints agreed on site with Engineer.

Ladder recesses will be formed whilst shuttering the deck.

The C32/40 concrete with polypropylene fibre reinforcement will be ramped down to the existing deck level over the required distances.

The concrete deck will be brush finished and cured for 7 days.

All concrete will be tested for workability on arrival on site and sample cubes will be taken to determine the characteristic 28 day strength.

Joints in the new deck slab will be filled with a two part polysulphide sealant as detailed in the Specification.

Figure 18: Bantry Fishing pier deck slab constructed by Bam

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Safety

• Risk assessments have been carried out and are included in the Health and Safety Plan. The Health and Safety Plan is included in section 3 of the submission.

• All work will be carried out in accordance with the Health and Safety Plan for the site.

• The site operates an induction procedure for personnel prior to commencing work on site.

• P.P.E. will be worn by everyone involved on this project at all times to include a minimum of high visibility vest, hard hat, safety glasses and safety boots.

• All plant will be in good working order and equipped with yellow flashing beacons

Programme of Works

Refer to construction program as included in section 2

Quality an Environmental management

The project Quality Plan will be implemented after being approved by the ER and the inspection and test plan will be adhered to rigidly. A copy of the Quality Management Plan will be kept on site. Seamus O’Sullivan will be the person with responsibility for quality control. Site audits will be carried out to ensure compliance with the Quality Plan. Periodic company audits will be carried out to ensure QA standards are being maintained on the project.

All works will be undertaken in accordance with the Site Specific Environmental Management Plan and the Waste Management Plan. These plans have been included in section 5. The main environmental impacts and considerations associated with the works are as follows:

• Waste Management: Waste management will be as specified in the site WMP

• Water Pollution: No contaminated water to be discharged into the harbour.

• Noise: All plant and machinery used on site will be serviced regularly to avoid excessive noise. Noise levels on site are not expected to exceed the legal but where necessary, mandatory warnings signs shall be erected informing all when ear protection is required to be worn.

• Protection of Watercourse: The water course shall be protected from pollution, by ensuring that generators, pumps etc are placed in drip trays. Spill kits shall be located adjacent to the watercourse and clearly identified. Spill kits shall also be placed in all machines. Details of procedure for dealing with oil spillages and procedure for protecting water courses are contained in BAM Environmental Management Plan

• Hazardous Substances: All hazardous substance will be stored in the hazardous store and all generators will be placed on a drip tray at all times.

• Washing of concrete trucks to take place at a designated concrete wash out area.

Figure 19: Screen Shot of Town Pier refurb from Main Programme

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Appendix – Byrne Looby Drawings