Downtown seawall repair project updates Downtown seawall repair project updates
2018
19 April 2018
Auckland Transport has completed repairs to erosion (scours) found on sections of the Quay Street seawall. This includes a major scour at the base of the Downtown ferry terminal building near Pier 1A and a smaller scour adjacent to Pier 2A. Control of the work sites have been handed back to Fullers and normal ferry service operations have resumed.
16 April
Auckland Transport is pleased to announce the repair to the scour on the seawall underneath the Downtown ferry terminal building has been successfully completed.
Last week the 15-metre “elco-rock” sandbag was installed at the base of the seawall and filled with around 110 tons of sand, successfully completing the repair.
The hoardings have been removed and the public once again have a clear view of the ferry basin.
The barges have now relocated between piers 2A and 3A, where work on the minor scour repair to the seawall has commenced adjacent to pier 2A. This is will allow the Bayswater and Birkenhead ferries to return to pier 1A. We are planning resumption of services for the weekend from Thursday 19 April. We will advise once the dates are formally confirmed.
There will be ongoing regular inspection of the wall including monitoring the fixings for corrosion, however the installation of custom made anodes over the next fortnight will provide a 20-year corrosion life span.
This week:
There will be some minor tidy up activity by divers at the ferry terminal building site this week but the teams focus is on commencing work on the smaller scour site to west of the ferry terminal building adjacent to pier two.
Although hoardings have been erected at the new site, there is no change to ferry services on piers 2 and 3. The AT Hop machines at pier 3 remain in the same location and are accessible to customers.
When normal services resume ferry departure points will be as follows:
- Pier 1 A: Ferries depart here for: Birkenhead, Bayswater.
- Pier 1 B: Ferries depart here for: Devonport and Stanley Bay.
- Pier 1 C: Ferries depart here for: Half Moon Bay.
- Pier 2B: Ferries depart here for: Waiheke.
- Pier 2C: Ferries depart here for: Waiheke.
- Pier 3 & 4 no changes expected.
Until that time ferry departure points will remain as listed below:
- Pier 1B - Devonport and Stanley Bay (no change), Bayswater departs 1840 and 2010 from 1B.
- Pier 1C - Bayswater, Birkenhead and Half Moon Bay.
- Pier 2B & 2C - Waiheke (no change).
- Pier 2B - Half Moon Bay services departing at 4.15pm, 5.15pm and 5.45pm (all other Half Moon Bay services will remain at pier 1C).
- Pier 3 & 4 no changes expected.
20 March
Success at the base of the seawall
Progress at the base of the seawall below the Ferry Terminal building has been excellent over the past few weeks.
All of the protective stainless steel plates have been successfully fitted and secured, and the grout installation has been completed without a hitch.
The grout (underwater concrete mix) has been used to fill in the scour holes behind the protective plates and to secure the plates to the wall and seabed.
There have been several inspections by the dive engineer over the past fortnight, deeming the work excellent quality, paving the way for the final phase of the project.
Final phases:
The final step is the installation of a specially constructed, 13-metre elco-rock "sandbag".
Once installed along the base for the seawall, the super durable, long life "sandbag" will be filled will a mixture of sand and seawater slurry using a purpose designed pump. When filling is complete and the sand has consolidated, the bag will provide stability and protection against further erosion.
We expect the sand bag will be fully secured in place week ending Friday 30 March. Once confirmed, preparations for removal of the site hoardings and re-opening of pier 1a can commence. Auckland Transport will advise all impacted stakeholders as details are confirmed.
Up next
Once the Ferry Terminal repair is complete, the dive team will move to the site of the smaller scour site west of the Ferry Terminal building adjacent to pier two.
Dive teams have already been working on cleaning the face of the seawall in preparation for application of a similar design to repair the scour. Works are due for completion at end April 2018.
20 January
After a relatively short holiday break, the seawall dive team has been back on the job since Wednesday 3 January 2018.
The dive roster has expanded to two four man teams. Each operates five days on with planned overlaps between the two teams. This approach ensures the sea wall is being worked on seven days a week. Monday, Thursday and Friday are overlap days where both teams operate.
The increased working capacity has meant progress on the face of the sea wall has considerably sped up. Row’s A and B of the steel protection plates (13 in each row) have now been installed, meaning over half the plates are now in place.
Two rows of the protective stainless steel plates have now been installed on the face of the ferry terminal seawall
Preparation for installation of row C plates is well advanced and measurements taken from the face of the seawall have been fed back to the designer for plate design and fabrication.
Once all plates have been successfully installed and anchored in place, work will begin to pump grout (concrete) into the scour located behind the protection plates. Based on current progress the grouting programme looks set to begin mid-February.
Once the Ferry Terminal repair is complete, the dive team will shift operations to the two minor scours identified earlier in updates from 2017. One is slightly to the west of the main work site and the other between piers two and three. The scours are not considered to represent any danger to the public.
We anticipate all repairs are likely to be complete early April 2018. Regular monitoring and inspections of the seawall and ferry terminal building has been ongoing. These continue to show both structures are stable and that there has been no further scouring at the repair site.
2017
21 December
Read the media release: Seawall repairs the first of their kind in NZ.
20 December
Completion date extended
Timing for completion of works on the seawall repair has been extended to late first quarter 2018.
Originally scheduled for completion pre-Christmas 2017, the complexity of the underwater works and the rough, non-uniform surface of the seawall has meant cleaning and levelling the face is taking longer than expected.
The 2 additional smaller scour holes detected in other parts of the wall will be repaired immediately after completion of works on the main scour. It makes sense to complete these at this time as the necessary equipment and expertise is already in place.
This is the first time works of this nature have been undertaken in New Zealand. They require a highly specialised skill set from the divers and engineering team. We have brought in specialised equipment from overseas and custom made other tools specifically for the job.
The contractor is also looking to employ a second dive team to speed up the process, but this is a few weeks away due to their availability and the specialist training required to do the work.
In spite of the additional work, AT remains confident there is no risk of further damage to the seawall. Regular underwater inspections of the site have revealed no further scouring of the wall.
The real-time monitoring tools installed since the scour was discovered have confirmed the seawall is stable and that there is no danger to the public.
Although Christmas is rapidly approaching it is anticipated that with the current measures in place, relocating some ferry services will ensure customers can enjoy their holiday plans with minimal impact.
11 December
Week 9 update
Week 9 of works has been a solid 7 days of testing. Several of the key elements of the repair design have been put through their paces to optimise performance.
This week there was further trial drilling and anchoring carried out with one anchor bolt tested to 36 Kilo Newtons (3.5 tons) of pull out force.
Also there was successful trial fit ups of four stainless steel panels (above the low tide level). These panels are now fixed in place, although the anchors have still to be tested to make sure they will be permanently fixed. The four plates have aligned and joined seamlessly which is a good sign for the more complex work to be carried out under water.
Grout testing has been delayed until a new precision mixer can be procured to ensure proper and thorough mixing prior to underwater delivery (custom purpose hose).
In the mean-time, divers have also continued to literally chip away at the face of the seawall, levelling the surface for eventual plate installation.
The contractor is looking to employ a second crew of divers to accelerate the process and the first diver has arrived on site and is receiving training. Others will follow as they come available from other jobs.
This week
- Divers will continue cleaning the face of the seawall.
- On-going trialling of anchor fixing components and optimisation of tools to be used in
the repair. - Routine monitoring of movement on the seawall and Ferry Terminal building.
- On-going grouting tests underwater.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
4 December
Week 8 update
Week 8 of works has seen the surface cleaning and “barnacle busting” of the seawall face continue while preparations for other elements of the repair design are also put in place.
The dive team has undertaken trial drilling and anchor fixing tests to optimise the tools and components to be used on the final repair. The benefits of these trials is that potential issues can be ironed out before moving into the final repair phase.
Last week’s dive engineers’ inspection has confirmed the quality of the cleaning and cutting of the wall as well as satisfaction with the wall strength and quality of the core concrete.
Image: Chemical adhesive anchors used in trail on the sea wall.
Image: Concrete plug extracted by core drill displaying good density with minimal air voids.
The contractor is now looking to employ a second dive crew to speed up works on site. We are currently confirming divers are availability as they may need to give notice on current contracts. They’ve also ordered a second core drill machine from Italy so the two teams can work concurrently.
One of the regular inspections last week revealed a small scour several metres west of the main work site. The scour is small, measuring approximately 3 metres by 0.5 m at an approximate depth of 0.3 metres.
The erosion is not considered substantial nor a risk to safety, it will be repaired using a similar design fix, once the priority repairs in the main work site have been completed.
This week
- Divers will continue cleaning the face of the seawall.
- On-going trialling of grouting mix.
- Routine monitoring of movement on the seawall and Ferry Terminal building.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
27 November
Week 7 update
Week 7 has seen continuation of wall cleaning and barnacle busting required to ensure the stainless steel plates fit true to the wall. The divers are making solid progress with approximately 50 % of the wall now levelled and cleaned. Once the entire wall is cleaned there will be a final assessment for fit before the plates are fitted. There may be further minor levelling required at that point to ensure a flush fit.
The dive engineer was in the water late last week to inspect the wall for regularity (level surface) and cleaning including assessing the work done to this point. This is a critical part of the systematic cross checking to ensure optimum safety and construction standards.
Also this week a second set of steel beams was installed. While the first set of beams will lift the stainless steel plates into place, this second set will carry the diver’s umbilical. It is critical to physically separate the plates from the umbilical to prevent potential severing or crushing of the diver’s air and communication source. Carriages will be fitted to the beams to allow the plates to be moved laterally as the divers move around below the surface.
One of the key tools when the divers are working under water is a recently arrived vaccum tool, which has been custom made to clear the silt and debris in the erosion cavitites.
Development of emergency protocols ahead of the repair work starting are also well advanced. These are a critical part of preparation as an active work site on the piers means changes may be required to evacuation procedures and assembly points in case of fire or an on-site emergency for example.
We are currently finalising these procedures and once complete, will be engaging with all affected stakeholders to outline any changes in procedure on the wharf.
This week
- Divers will continue cleaning the face of the seawall.
- On-going trialling of grouting mix.
- Routine monitoring of movement on the seawall and Ferry Terminal building.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
20 November
Week 6 update
Week 6 of the seawall repairs has seen the arduous task of barnacle busting and levelling cleaning the sea wall continue.
The face of the wall below sea level is extremely uneven and the physically demanding work has been steady but slow grind for the four man diving team. They have now completed two of the five bays using a cutting machine, handheld levels and hammers.
In an effort to speed progress is currently looking at bringing in a second dive team to work on the wall.
Image: Divers using the cutting machine to level the face of the seawall in readiness for securing the steel plated which will protect the wall from future scouring.
As works continue, there is a growing understanding of how the wash and waves from ferry sailings (for example the Devonport Ferry has 45 sailings per day) and other craft (there are 84 Cruise Ships visiting this summer) impact the work of the divers underwater, making a challenging environment even more difficult.
Given the time the seawall surfacing is taking and the impact of the boar wash, Auckland Transport is currently reviewing the timing of the construction works programme which is currently scheduled for completion in January 2018. Once the assessment is complete, Auckland Transport will advise of any change in the expected completion date.
Divers also under took their second emergency drill this week, simulating an underwater rescue of an entangled diver. Entanglement of umbilical cables is a real risk with underwater works, especially in low visibility. At worst, the divers air supply can be cut off and he is unable to get free without cutting the umbilical. The divers carries an emergency reserve tank on their back for this purpose.
Image: Diver enters the water with umbilical cables clearly visible. The drills are essential for the dangerous underwater work these divers undertake under water.
The movement sensors and measurement tools have now been in place for four weeks. Over this time bench mark data has been collected and analysed. Although data streams constantly in real time, there is a weekly survey of the Seawall and Ferry Terminal building as part of the formal monitoring process. These regular readings have confirmed that the sea wall is stable and safe with minimal movement. There has been some minor movement of the Ferry Terminal Building, but this is attributed to normal movement associated with temperature changes over the course of each day.
This week
- Divers will continue cleaning the face of the seawall.
- On-going trialling of grouting mix.
- Routine monitoring of movement on the seawall and Ferry Terminal building.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
13 November
Week 5 update
Week 5 of the seawall repair has seen the focus firmly shift to preparing the face of the seawall for the eventual installation of the steel plates which will prevent future erosion.
The public have been able to catch glimpse of the divers in action through the Perspex windows installed on the hoardings overlooking the construction site in front of the Ferry Terminal building.
Image: The viewing windows overlooking the work site just below the Ferry Terminal Building.
The underwater wall cleaning and barnacle removal, which also includes levelling the face of the wall, is an arduous but essential process. Divers are currently levelling the wall using a cutting machine and hand tools. This will ensure the steel plates fit tight to the wall when installed. The old wall has a number of bulges and an uneven face which needs to be removed by hand underwater. This can be very dangerous for the divers as the air hose can be cut or the concrete saw can snag and jump back potentially causing serious injury. Careful preparation and a methodical approach are critical to safe working.
Image: Concrete debris removed from the seawall by divers.
Testing has continued on the grouting mix to find the optimum mix. This involves assessing the flow, strength, flexibility and final finish of the grout in an underwater environment. A number of different mixes have been trialled this week as the contractors get closer to the ideal make up for the conditions in the ferry basin.
Image: One of the trial grout mixes set for assessment after underwater application.
Installation of the steel support beam scaffolding hanger carriages has almost been completed, with just one more beam to be secured this week. These will be used to lower the steel plates into the water and hold them in place as they are fixed to the seawall.
Work is progressing steadily towards commencement of the actual repair. This will begin once the face of the wall is prepared. When the priority works are complete, the contractors will shift to a site between piers two and three to repair a smaller scour uncovered recently during on-going wall inspections. The additional erosion is significantly smaller than the main wall scouring and present no risk to public safety. We anticipate this section will be repaired in early 2018 once the current repair is completed.
The week ahead
- An independent dive company will undertake an audit to verify safety of marine and underwater operations prior to work commencing on the repairs.
- Daily monitoring of sensors continues to track and benchmark minor movements of the wall. External stability surveys have also been undertaken, confirming the stability of the wall within the limits of theodolite precision of about 3mm.
- Divers will continue cleaning the face of the seawall
- On-going trialling of grouting mix
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
30 October
Week 3 update
Week 3 of the seawall repair programme has continued without issue as preparatory works on the Seawall draw to a close.
The section of wall to be repaired has been cleaned above the tidal line by workers standing on pontoons. The wall must be clear of barnacles, other crustaceans and sea build up to attach the steel plates which are an integral part of the repair work.
The dive team completed their preparation work including running a successful trial diver rescue drill. As the work is physically demanding and dangerous, each diver must execute their tasks and drills with absolute precision to ensure safety is maximised at all times.
Image: Trial rescue of a diver from a 6 m depth on the 27 October. The rescue drills are critical to ensuring the dive team is well prepared with all the essential safety protocols in place.
As part of the safety requirements a new set of stairs has been fitted to help divers exit from the water. There are also plans to install an air hoist which is capable of lifting an unconscious diver out of the water. These extra precautions are critical as a diver in full kit weighs in well in excess of 100 kilograms.
Image: A new set of stairs has been installed to assist divers exiting the water.
The week ahead
Support beams will be fitted under the walkway this week. Securing these beams is difficult as they are floated into position on a pontoon rather than by crane (using the crane is not possible under the walkway). The beams will carry the chain hoist which will allow divers to lower the stainless steel plates into position for securing to the seawall.
The various sensors and measurement tools are now in full operation, recording movements of the seawall and Ferry Terminal building. The monitoring system needs to run for several days to establish benchmark data on patterns of normal movements caused by tide, solar radiation, and vibration.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
24 October
Week 2 update
Week 2 of the seawall repair programme has been a busy one, with extensive preparation work undertaken while equipment has been installed on site in readiness for initial construction work beginning.
Three barges are now moored in position in the ferry basin and have been loaded with the specialised equipment required to support the repair works as they progress.
The protective timber hoarding around the site is now in place with perspex windows installed to allow the public to observe construction.
Image: Diving support crew working from one of three barges moored in the ferry basin.
Image: Diver ready to go into water. This helmet costs $12,000 and is very high tech with speakers and voice communications. Air is pumped from the surface, allowing continuous diving operations.
The four divers who will be working on the repairs have also established themselves on site. They have conducted initial surveys along the section of wall to be repaired and tested their specialist dive equipment in ferry basin conditions.
Image: Chartered Dive Engineer undertaking measurements and sampling. The water is murky with limited visibility making for a challenging working environment.
The necessary monitoring tools and equipment have also been installed. These allow ongoing measurement of the key data metrics to take place. The availability of this data enables precise operation moving forward and provides the technical information required to refine the detailed repair design. One key facet being carefully monitored is the impact ferry movements have on the sea current. A still and calm ferry basin is required for the divers to work in safety.
The week ahead
This week, actual work on site will commence with cleaning of the wall and installation of support beam scaffolding.
The beams will allow the contractor to lower steel plates into the water and hold them in place while they are anchor bolted to the face of the wall. The steel plates are a key part of the repair design and are being installed to prevent further erosion occurring once the repairs are complete.
Ferry service changes
The closure of Pier 1A has shifted departure of Bayswater and Birkenhead to Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The changes have continued to operate smoothly with minimal impact on services.
16 October
Week 1 update
The first week of work on the seawall has progressed smoothly with the contractor, STF Limited, securing the site and starting preparatory operations.
These have included closing Pier 1A to establish the site and driving 5 timber piles into the seafloor. These piles will support a silt screen which will protect divers when they are working in the water on the seawall.
Timber hoardings to protect the public are being erected around the site. This will be finished early next week.
Image: Timber hoardings around the site with windows cut in.
Barges, a crane barge, and tug vessels have also taken up camp on site in readiness for construction work beginning next week.
Image: Crane barge setting up on site at Queens wharf
Measurement tools to monitor and measure the seawall, sea bed, and Ferry Terminal building have been set in place. This allows on-going strength testing of the seabed foundation and seawall. It also sets benchmarks which allows detection of any structural movement during construction.
The week ahead
This week, STF will begin removal of barnacles on the sea wall in readiness for the first dive operations. The dive team will be on site, commencing preparatory work and undertaking surveying.
Ferry service changes
The closure of Pier 1A on Monday saw Bayswater and Birkenhead services shifted to depart from Pier 1C, and some evening Half Moon Bay services leaving from Pier 2B.
The first week of service changes has progressed well with minimal impact on services and no customer complaints received.