Auckland Transport under fire for following ‘do minimum’ advice given by engineering experts

Auckland Transport under fire

Auckland Transport followed “do minimum” advice to save $300,000 – that decision may have cost ratepayers $3.85 million.

The council organisation received the recommendation in a report from an engineering company regarding cracks found in a North Shore carpark.

Two years later, those cracks became landslides.

On October 9 and November 28, 2017 two massive landslides swallowed the back end of Birkenhead’s Rawene car park, threatening nearby buildings and destroying infrastructure.

A Geotechnical Assessment Report was completed by engineering company GHD group in 2015, to assess the cracks and stability of the car park and surrounding area.

NOTE: Click here to See original article for A snip from the October 2015 GHD report, which recommends Auckland Transport monitor the to-be Birkenhead slip site, labelled as the “do minimum” option.

Auckland Transport were given three options: A “do minimum” option of monitoring the area, a reinforced soil structure, and a retaining wall.

The report recommended monitoring and maintenance because of the relatively high cost, which Auckland Transport followed.

“The ‘Do minimum’ option is considered most feasible and appropriate at this stage,” the report dated October 2015 said.

Even though it was the highest risk of future failure, the immediate cost at $20,000 was substantially less than $500,000 each for the other two options.

But on February 27 this year, Auckland Council found itself forced to approve an amount of $3.85 million for the Rawene Slip.

Of that, $2 million will cover the emergency works already completed, and $1.85 million for the design and permanent stabilisation works and the construction will be in addition to this.

A joint statement from Auckland Council and Auckland Transport defend the actions taken by staff.

“The remedial option recommended in 2015 by GHD was monitoring, which would not have prevented the slip occurring,” a spokesperson said.

“The options described may have provided some extra stability to the slope but given the scale of the Birkenhead slip it is quite possible that they would not have prevented it occurring.

“It was considered unlikely that the GHD proposed monitoring gave any enhanced level of warning, over and above visual monitoring, to realistically allow time to install physical mitigation measures other than fencing the area off to ensure the safety of the public.

Kaipātiki Local Board deputy chairwoman Danielle Grant said the information from the report was not shared with the local board.

“The report was several years ago. The stress that this [slip] has caused our Birkenhead community, it is extremely concerning that AT hadn’t shared that information earlier,” she said.

“They didn’t act on it. It wasn’t really until the significant cracks were appearing, that it was brought to the attention of the local board.”

Current geotech lead Ross Roberts said that Auckland Transport did broadly follow the recommendations of the 2015 report and to say otherwise is inaccurate.

“It [the report] didn’t recommend building a retaining wall. The recommended option was monitor the site,” Roberts said.

Article by Laine Moger
Published 03 March 2018 > North Shore Times -stuff.co.nz

Birkenhead slip: early warning system advice rejected by AT

Birkenhead slip

Auckland Transport rejected advice by engineers to install an “early warning system” to monitor unstable land long before two massive slips in Birkenhead that could cost $24 million to put right.

The revelation has shocked local residents, businesses and Northcote MP Jonathan Coleman, who said AT had the information about unstable land at Rawene Rd carpark, did not act on it and have let down the community.

Auckland Council’s chief operating officer, Dean Kimpton, has defended the actions of AT staff, saying although they did not follow engineers’ recommendations, they carried out regular visual inspections of the carpark and acted when large cracks appeared.

The warning bells were sounded in 2015, two years before the first slip swept away 25 carpark spaces in October last year, followed by a second, larger landslide in November that sent a drilling machine tumbling into the Rawene Reserve and workers scattering.

Papers obtained by the Weekend Herald under the Official Information Act show a geotechnical assessment by GHD engineers in 2015 found signs of pavement cracking and kerb stones separating.

Boreholes revealed poorly compacted fill to build up the car park was capable of moving under its own mass, particularly if saturated.

GHD recommended two options to fix the unstable land at the carpark for $500,000 or $550,000, and a “do minimum” option of geotechnical monitoring. The latest council estimates put the cost of fixing the slips between $14m and $24m.

GHD said the option of monitoring the site monthly was the most feasible and appropriate and would act as a “early warning system” to respond to any undue movement efficiently and cost-effectively.

In a statement from AT chief engineer Andrew Scoggins attached to the OIA response, he said the car park was monitored for cracks on a “nominal monthly basis … however the site visits were not documented, which is normal process for an area that is not showing change”.

The monitoring did not include ground monitoring pins and sealing existing cracks as recommended by GHD because it was considered unlikely to give any enhanced level of warning over and above visual monitoring, said a joint statement from AT and council.

It was not until two years later on September 14, 2017, when large cracks appeared in the car park, that AT brought back a geotechnical specialist to check the ground and its stability.

“Auckland Transport needs to explain why they didn’t act on this independent advice … something major has happened which could have been averted,” said Coleman.

Birkenhead Brewing Company co-founder Brad Boult said “somewhere along the line their systems have failed dramatically”. Highbury optometrist Tony Chadwick said: “You do have to wonder why in a body funded by the people for the people there is so much closed door secrecy going on.”

Claire Balfour, the body corporate chairwoman at the nearby Mokoia Ridge Apartments, said the latest revelations showed a bureaucratic aversion to do anything. Another resident, Graham Tucker, said AT had put his family and others at risk by not acting on the GHD report.

“I’m shocked they didn’t do anything. It’s starting to make me very angry,” Tucker said.

Kaipatiki Local Board chairwoman Danielle Grant said the slips had impacted on the community and caused huge distress, both financially and emotionally. The GHD report should have been shared with the Local Board to have the opportunity to consider the options, she said.

No one from AT would be interviewed about the GHD report, on the basis Auckland Council is now managing the issue, overseen by Kimpton.

Kimpton said AT staff decided not to do geotechnical testing on the carpark but to visually monitor the site, which was successful because when they noticed additional movement they got engineers back and protected public safety.

He said there is cracking and movement at hundreds of sites across Auckland, saying AT made the right call based on experience and the evidence at hand.

“They have no interest in losing an asset down a hill and when they did spot the cracks they got Opus (engineers) in to have a look,” he said.

Kimpton said even if an inclinometer – a geotechnical instrument for monitoring movement below ground – had been set up at the carpark as recommended by GHS, it would not have bought enough time to do anything because the slip happened quickly.

The AT-council statement said the options to fix the unstable land may have provided some extra stability to the slip but given the scale of the slip it is quite possible they would not have prevented it occurring.

It said most of Auckland has soils that swell in winter and shrink in summer. Building controls take this into account and council created a small team of geotechnical specialists last year to respond to issues and recommend solutions where public land may be affected, including coastal erosion.

Asked by the Weekend Herald several times how much it would cost to fix the slips, Kimpton said he had “no idea” or “nothing that can be relied upon” beyond a minimum of $1.8m for temporary repairs so far.

A report to this week’s finance and performance committee said urgent repair works have cost $2m, design and other work is expected to cost $1.85m and preliminary costs for a permanent fix are between $10m and $20m.

It is also costing $80,000 a month to pump stormwater and wastewater out of the landslide, which continues to move slowly and remains a significant risk, the report said.

The GHD costs of $500,000 and $550,000 for a permanent fix did not include detailed design, site supervision, land purchases, GST and a recommended contingency of 30 per cent.

Meanwhile, a $9m stormwater project to strengthen unstable land at Chelsea Heritage Estate below the slip means the project cannot be built as planned for safety reasons and “may have to be cancelled or subject to significant cost and programme overruns”, said the report.

Timeline

2010:

Serious stability issues given as a reason for not granting consent to lease Rawene Reserve below the carpark.

October 2015: Routine inspection of carpark prompts Auckland Transport to hire GHD for a geotechnical investigation of subsoil conditions relating to potential slope instability.

Late 2015-September 2017: Casual monitoring of the carpark, which is not documented for an area “not showing change”.

September 14, 2017: Geotechnical specialist hired by AT when large cracks appear.

September 19, 2017: Carpark closed off.

October 9, 2017: First slip swallows about 50m of carpark.

November 28: Second slip sends a drilling machine and more debris tumbling into Rawene Reserve.

December 18: Herald reveals Auckland Transport and Auckland Council officers knew from February 2017 that a leaking stormwater pipe was causing cracks to the carpark but it was not fixed before the first slip. Council says it is unlikely stormwater pipes played a significant role.

Article by Bernard Orsman

Published 03 March 2018 > The New Zealand Herald – nzherald.co.nz

Auckland car park landslide holding: Community discusses its future

Auckland car park landslide holding: Community discusses its future

Despite recent torrential rain, the Auckland landslide that swallowed a Birkenhead car park has stabilised and plans for the future of the area are being considered.

Auckland Council’s geotech lead Ross Roberts said there had been very small scale movement since the sheet piles were put in, over the New Year period.

So far, the slip was behaving as the council wanted it to, Roberts said.

The community was now being asked what they wanted the land to be used for in the future. But this did not mean that the council was opposed to turning it back into a car park.

“Lots of things could be done,” Roberts said. “If we can use it to improve things, then we should.”

Submissions for community input closed February 20 and Auckland Council was collating the feedback, Rawene Landslide Project communications lead Amanda Blakey said.

A number of things were happening with the site, including resource consents, iwi consultation, as well as the ongoing consultation with Birkenhead community.

But, a definitive directive regarding the future use of the site is still “some way off yet”, Blakey said.

Chairman of the business association Pete Taylor said that, in the wake of the car park slip, Birkenhead had created a lot of other parking in the village.

Taylor said the stabilisation news was good for land and business owners’ peace of mind and if businesses got the parking back, that would be a bonus.

“But, if it’s something else, then that’s okay too. They are making headway – and it’s working.”

Meanwhile, the Earthquake Commission (EQC) announced in media release it was putting funding towards new technology to monitor how the land was moving on 10 slopes in different parts of Auckland. Birkenhead was one of these sites.

EQC general manager resilience Dr Hugh Cowan said research on landslides was very important for New Zealand.

“Most years, EQC gets more claims for landslide damage than any other natural hazard,” Cowan said.

The new technology would provide valuable data for Auckland Council on the specific research sites, and would help develop a cost-effective way for any council to map the stability of slopes.”

Article by Laine Moger
Published 28 February 2018 > North Shore Times – stuff.co.nz

Council drills piles while sun shines at site of giant car-park slip

Council drills piles while sun shines

Stabilising work on a massive urban landslide has begun in earnest this week, three months after a slip took out much of an Auckland car park.

A footpath collapsed into the landslide in last week’s wild New Year’s storm, worsening damage from two earlier slips in October and November.

Now Auckland Council has taken over management of the site from Auckland Transport and started drilling sheet piles to stabilise the landslide, which is creeping ever closer to buildings in the North Shore shopping centre.

Geotech lead Ross Roberts said Auckland Transport initially took control because it could mobilise quickly for the emergency response, but now the site was in the “recovery” stage.

Roberts said he expected more slips, so the sheet piles were being put in to protect the properties in the area.

The sheet piles were long blocks that were moved into position by a crane, and then drilled into the rock beneath the earth. They were acting as a retaining wall.

There were spaces between the piles, so as not to risk creating an underground dam.

Birkenhead’s Mokoia Rd shops were currently at a low-risk status, Roberts said.

“Once the sheets are in, the ground will be the same as for a new build. It is safe to be there [Mokoia Rd] and we are monitoring the situation.”

There has not yet been an attempt to retrieve the Hiway Stabilizers machine, the remotely operated drilling apparatus that was swallowed by the second slip in November.

Focus is still stabilising the top of the slip, Roberts said.

Roberts said the emergency works had interfered with how much engagement had been with the community, and as the next “strategic phase” was initiated, there would be more engagement.

Auckland Council had carried out a comprehensive review of the Birkenhead landslide, and regular updates were available on Our Auckland.

To subscribe to receive these updates by email or to ask questions about the Rawene project contact: rawene@aucklandcouncil.govt.nz.

Article by Laine Moger
Published 13 January 2018 > Auckland – stuff.co.nz

Footpath collapses into monster urban slip

Footpath collapses into monster urban slip

A gigantic landslide in a shopping centre car park on Auckland’s North Shore has worsened in the current storm, with a footpath collapsing into the slip.

Auckland Council engineers and consultants are confident the buildings behind the car park are safe, but are currently monitoring the site 24/7.

The slip hit the Birkenhead car park in October, following reports from local businesses of cracks in the car park since August.

A second slip hit six weeks later, in November, worsening the landslide and taking away a contractor’s stabilisation equipment.

At 4.30pm on Thursday afternoon, the section of footpath collapsed into the landslide, following a series of slips beneath the path had undermined it in past weeks, Ross Roberts, Auckland Council’s geotechnical and geological practice lead said.

“We [council engineers] have inspected the area and confirmed that no new cracks are forming behind it, and there are no indications of further regression at the moment.

“We have undertaken topographical surveys of the site yesterday morning [January 4] (before the collapse) and again yesterday evening from 8pm after the movement to confirm that ground closer to the buildings has not moved.

“These surveys, along with our other monitoring, have confirmed that large-scale movement is not taking place. We will continue with this monitoring today.

“We do not consider there to be any increase in risk to the buildings as a result of this movement.”

Article by Jodi Yeats
Published 05 January 2018 > Auckland Now – stuff.co.nz

More slips likely in Birkenhead, but buildings should be safe

More slips likely in Birkenhead, but buildings should be safe

More slippage is expected in the Auckland suburb of Birkenhead, while the land settles down after a second massive landslide, but residents to not need to worry, geotech expert says.

Birkenhead’s second landslide, which swallowed a piece of stabilising machinery, tore a lot closer to the back of the Mokoia Rd shops on November 28.

This followed a first slip, which took out half the carpark on Rawene Rd in early October.

Auckland Council officers answered questions from concerned residents and business owners at a meeting organised by the Kaipātiki Local Board on December 7.

Auckland Council’s geotech lead Ross Roberts said he was “expecting more subsidence”.

However, Roberts said there was no danger to the buildings in the area because the slip so far has been only legacy landfill.

“The fill is moving away but the natural ground is staying where it is,” he said.

“The Mokoia Ridge apartments are on natural ground, built on the ridge before the fill was in place. For that reason we are not worried about the buildings.”

Recently, there have also been concerns about a second crack that has appeared in the Mokoia Rd car park across the road from the original slips.

Roberts said there was no reason to be concerned about this new crack.

The crack is consistent with damage from vehicle loading and is not related to the fill, he said.

“It is inconsistent geologically with the slip. There is no danger.”

Currently, geotechnical testing was ongoing around the site, to identify the cause and the remedy for the incident.

The first priority was making sure stormwater didn’t get into the slip. The second was trying to stabilise the area.

In the long-term, Roberts said a full fix will be some variant of building a wall into the ground.

Resident Ruth Jackson asked for reassurance the natural soil hadn’t been eroded.

Roberts said it was very, very unlikely.

“In general, fill is erodible, the clay is not erodible but we are doing investigations.”

Brian Cox said he was more than frustrated that Auckland Council was not being open to the public.

“The mere fact that you have a machine in the gully, you have no idea what’s going on,” Cox said.

Article by Laine Moger
Published 08 December 2017 > The North Shore Times – stuff.co.nz

Birkenhead’s second slip adds to town centre parking disaster

A second slip has torn another chunk from the slope of a car park in Auckland’s Birkenhead seeing the landslide creep closer towards businesses.

What began as a small crack in Rawene Rd car park in August, has steadily worsened. In October, the back half of the car park slipped down a gorge on October 8.

Now, a second landslide has appeared directly next to the initial slip, on the western side, and the edge of it is a lot closer to the back of Birkenhead’s Mokoia Rd shops.

However, in spite of the growing hole in the middle of the Birkenhead village, local morale remains high and there even a few “slip” puns flying around the town, said Birkenhead Town Centre Association chairman Pete Taylor.

The new slip is visibly steeper in appearance compared to the initial slip in October but not as deep.

Of course there are worries about the slip, but the main concern for the businesses is the parking situation, Taylor said.

“Although the slip is increasing, we’ve actually managed to mitigate the car parks,” he said.

“We have come up with some really cool solutions. We want our customers safe and enjoying the village.”

Brett Norris, a worker in nearby Rawene Chambers, said it is disappointing the slip has happened, but due to the instability that was “always likely”.

“It’s going to cause more issues going forwards. The business association has done a good job of trying to free up car parks and Auckland Transport is helping,” Norris said.

“This extra problem is not one we expected or anticipated. I think it caught everyone by surprise.”

Auckland Transport Mark Hannan said for public safety all pedestrian and vehicle access to the Rawene car park access road is now prohibited.

The kerb that joins the Rawene car park access road to the pavement is split apart like a broken zipper.

An engineering team and technical specialist was working on the problem and reviewing the stabilisation work which was being done.

“Options to progress the stabilisation work are being investigated and we expect this work to be paused for at least one week.”

Article by Laine Moger
Published November 30 2017 North Shore Times – stuff.co.nz

It has happened again: Second slip in Auckland’s Birkenhead car park

It has happened again: Second slip in Auckland's Birkenhead car park

A second landslide has torn away another chunk of a car park in Auckland’s Birkenhead, and is creeping towards businesses.

What began as a crack in the public car park in August, has steadily worsened. The back half of Rawene Rd car park slipped down a gorge on October 8.

Now, a second landslide has appeared directly next to the initial slip, on the western side, and the edge of it is a lot closer to the back of Birkenhead’s Mokoia Rd shops.

The kerb that joins the Rawene car park access road to the pavement is split apart like a broken zipper. The slip is visibly a lot steeper in appearance compared to the initial slip in October but not as deep.

Auckland Transport’s Mark Hannan first announced there had been another slip via media release on November 28 at 5pm.

This morning, Hannan said there was no overnight movement of the site following the second slip.

At least 10 engineers were on site on Wednesday morning.

“Building inspectors have assessed surrounding properties and there continues to be no indication of a risk to those properties,” Hannan said.

“Specialists are continuing to monitor the site and stabilisation work has been paused while the impact of the second slip is being investigated.

“In the interest of public safety, pedestrian and vehicle access to private car parks via the slip road is now prohibited.”

Hannan said a piece of equipment, which is described as similar to a platform, fell about three metres. Hannan confirmed no-one had been injured.

Kaipātiki Local Board chairwoman Danielle Grant was at the slip this morning.

Grant said the board was waiting for geotechnical reporting and a stabilisation plan to gain a better understanding of the next steps.

“The main thing businesses are after, at the moment, is clear and ongoing communication.”

‘ACCIDENT WAITING TO HAPPEN’

Claire Balfour, chairwoman of the nearby Mokoia Apartments body corporate, said residents were concerned about the significant drop in the car park when it first appeared almost three weeks before the slip happened.

She said the asphalt had originally been poured onto unstable land without a retaining wall and was “an accident waiting to happen”.

Auckland Transport has defended its management of the gaping hole that has appeared where the car park used to be.

AT’s chief infrastructure officer Greg Edmonds said the car park had washed away into the gorge below it following “pretty significant rains” over the past 12 months.

Edmonds said AT had been monitoring the site for 12 months and it took appropriate action when the crack appeared, closing part of the car park and fencing it off for public safety.

Article by Laine Moger
Published November 29 2017 stuff.co.nz

Local Board Gives $15k To Boost Businesses Hit By Giant Slip

Local Board Gives $15k To Boost Businesses Hit By Giant Slip

After a giant slip hit a parking lot, Auckland’s Birkenhead is getting $15,000 to encourage shoppers back into the town centre ahead of Christmas.

The Kaipātiki Local Board agreed to give $15,000 to the Birkenhead Town Centre Association at a board meeting on November 15.

Construction work had reduced parking spaces before the slip hit, and association chairman Pete Taylor said the money would fund a marketing plan to say: “Birkenhead still has free parking”.

Media attention seems to be giving the wrong impression about Birkenhead’s parking situation given recent events, Taylor said.

“It is certainly not the case that there is no parking left in Birkenhead,” he said.

In the past six months, the Birkenhead town centre has dealt with Rawene Car Park space shortages caused by Auckland Transport renting out public car parks to the neighbouring private developers, as well as the Rawene car park slip.

Most recently, Auckland Council confirmed a $3-million construction plan to upgrade town centre would be going ahead on schedule, despite pleas from business owners asking for a deferral.

The Birkenhead Town Centre Association wants to promote the fact city shoppers can jump on the ferry to Birkenhead, and enjoy the experience of free parking while shopping.

“There are also lots of activities in Birkenhead leading up to Christmas, so the timing of the promotion is good,” Taylor said.

“It will make a difference to lift the public awareness about what is available. The $15,000 will help us tell that story better.”

The local board’s $15,000 funds were reallocated from a budget originally for earmarked for a Birkenhead development programme.

Kaipātiki Local Board chairwoman Danielle Grant said the money was available because a few other projects have been delayed.

“It felt like there was a big need, and they had a good marketing plan,” Grant said.

The board decided to supplement that marketing plan and encourage people in the area to shop locally, she said.

In the meantime, Auckland Transport is working alongside the local board and Auckland Council to identify ways to improve parking and connections in Birkenhead.

Article by Laine Moger
Published 28 November 2017 > Business Day – stuff.co.nz

Auckland Council started $9m project to stabilise land six weeks before landslide

Auckland Council started $9m project to stabilise land six weeks before landslide

The huge Rawene car park slip could create a dam endangering the iconic Chelsea heritage park below it, council engineers say.

At a local board meeting on Wednesday, Auckland Council’s geotech lead Ross Roberts said they were monitoring the situation “carefully” as there was a risk of the landslide causing a dam.

“The real problem we are considering is that there will be a load of silt coming down,” he said.

Member Lindsay Waugh asked: “On a worst-case scenario could it take out the bank above the lower lake/cooling pond?”

Roberts said he had visited the Chelsea Estate Heritage Park below the slip and the worst-case scenario was “highly unlikely” as any flooding from a dam establishing and breaching would result in over-land flow rather than underground erosion.

“It would spread out and be a bit of a mess on the surface,” Roberts said.

“I might hold you to that one,” Waugh said.

Six weeks before the landslide swallowed the back end of the Auckland City car park, Auckland Council began an “essential” $9-million project to strengthen unstable land below that leads to the Chelsea Heritage Estate.

Auckland Council said, in an email dated August 15, that the Chelsea Heritage Estate stormwater project was to renew the aging and damaged stormwater pipes to reduce the risk of collapse and blockage.

In a prescient email, project spokeswoman Liz Kirschberg said: “Surface runoff from the Huka Road and Rawene Road stormwater drain flows over the former landfill and may cause slope instability during large rain events.”

Construction began at the end of August 2017 and was planned to end December 2018.

Local board chairwoman Danielle Grant said in August, the stormwater improvements to Chelsea Estate Heritage Park should see the land stabilised, the water quality improved and an overall improvement to the main walking tracks in the construction area.

The stormwater project is on-going but engineers are now “monitoring the situation” at the slip-site above.

Article by Laine Moger
Published 20 October 2017 > The North Shore Times – stuff.co.nz