Ferrymead Bridge Replacement
Tuesday 29 January 2013
Ferrymead Bridge Replacement
A public information drop-in session on the replacement of the Ferrymead Bridge is being held on Tuesday 29 January from 4 pm to 7 pm at the Mt Pleasant Yacht Club.
Members of the public will have the opportunity to talk with experts on the construction project and find out how the project will affect them.
Workers have constructed two temporary bridges which will maintain the connection between Sumner and the City. Vital services – traffic, water, sewage, power and telecommunications now run under the new temporary bridges and will be maintained throughout the demolition and construction process.
Christchurch City Council City and Environment General Manager Jane Parfitt emphasised the strategic significance of the bridge.
“It is a crucial structure connecting the city to the coastal suburbs in the south east. Its construction is closely connected to the long-term prosperity of the city. This is a strategic transportation corridor and shows that the rebuild is extending beyond the Central City to the suburbs.”
The next stage of the construction project involves the demolition of the old Ferrymead Bridge using a type of crane called a “nibbler”. Demolition is expected to take about three months.
Piling work will then begin which involves driving 10 piles with a diameter ranging from 1.1 metres to 2.4 metres 25 metres into the river bed. Piling work is expected to take 15 months.
Mrs Parfitt says, “This is a huge construction project. We are building the Ferrymead Bridge to the very highest engineering standards to ensure that the lifeline between the city and Sumner, Redcliffs, and Mt Pleasant suburbs is maintained.
“When you drive piles into the ground there’s going to be noise and vibrations. Work on the Ferrymead Bridge has been scheduled for a long time. The earthquakes have delayed this project and made us reconsider the seismic dangers in the area. Consequently, we are getting a much more robust engineering solution but it will take time.”
The $34.87 million project has received substantial funding from the NZ Transport Agency (NZTA) which is providing $22.12 million.
NZTA Southern Regional Director Jim Harland says the NZTA has always recognised the significance of the bridge, having committed before the earthquakes to provide more than half the cost of upgrading the bridge.
“Following the February 2011 earthquake and the need to rebuild the damaged bridge, the NZTA increased its funding to more than $22 million.
"The NZTA's investment in this project will ensure residents have a new bridge that is 100 per cent of the new building code and will provide an improved certainty of continued access if there is another significant event."
He says the new bridge will also help support better passenger transport links to the eastern hill suburbs, with the additional bridge capacity enabling the implementation of Bus Priority on the Sumner route and improvements to both cyclist and pedestrian safety in the area.
"This is part of the NZTA's One Network approach to ensuring there is a transport network that enables ease of movement between places by safe, efficient and resilient links, and offers travel choice for residents."
Updates will be posted at www.ccc.govt.nz/ferrymead
Ferrymead Bridge replacement and approach works 2013 – 2015: Frequently Asked Questions
Click for big version.
is the Ferrymead Bridge project
Ferrymead Bridge is a lifeline providing a vital transport connection to the eastern suburbs and the port of Lyttelton for overweight and over-dimension loads. It also carries vital water, sewer, power, phone and other services. This project will make sure that the connection remains usable in the event of a future significant earthquake and will provide additional capacity that will subsequently enable a Bus Priority lane on the Sumner route. The project improves safety for pedestrians and cyclists through the area.
Ferrymead Bridge carries
about 30,000 vehicles per day and serves 11,000 people,
4,450 households, or about 3.5 per cent of Christchurch
residents, and carries water, pumped sewage mains, telecom,
and power services.
What is the New Zealand transport Agency’s role in this?
New Zealand Transport Agency (NZTA) has provided $22.12m towards the cost of the project. The NZTA is playing a critical role in the recovery of Christchurch through its funding, as part of the Government's partnership with the City Council, the repair of the roading infrastructure damaged by the earthquakes.
This is part of the NZTA's One Network approach to ensuring there is a transport network that enables ease of movement between places by safe, efficient and resilient links, and offers travel choice for residents.
Who has been awarded the tender for carrying out the project?
HEB Construction Limited brings extensive experience to the project and have worked with the Council and Opus International Consultants to develop a new bridge design. They have also undertaken work on temporary infrastructure, diverting wastewater, power and water supply on to the temporary bridges and the approach roads.
What is the cost breakdown of the project?
The total cost of the project is $34.87M of which the New Zealand Transport Agency (NZTA) has provided $22.12 M. The following table gives a simple breakdown.
|Ferrymead Project Cost Breakdown|
|Cost to date |
(Including original design, consent, partial construction, Earthquake Recovery works, detailed geotechnical investigations, new design, traffic and services diversions to rebuilt temporary bridges)
|Construction including demolition of the old bridge and new approach roads and new service connections||$21.39M|
|Provisional sums including insurance costs, construction monitoring and contingency.||$3.93M|
What challenges are there for the bridge foundations?
The ground conditions at Ferrymead are particularly challenging which has added significantly to the cost.
Design standards for structures and buildings have increased, resulting in the need to strengthen the foundations of the new bridge to meet these new post-earthquake standards.
At Ferrymead the underlying rock slopes from Mt Pleasant towards the city. This means that the loadings from liquefaction on each abutment are uneven, making the design for the bridge and the piles complicated.
The following stylised drawing shows the bridge and underlying ground conditions.
Click for big version.
What have geotechnical investigations revealed?
Extensive and detailed geotechnical investigations were undertaken in the locations of the new piles for the new bridge so that an accurate understanding of the underlying rock could be known. This has shown that the underlying rock is extremely variable with some layers being very weak, resulting in the piles for the new bridge having to be founded about eight metres into the underlying rock to enable adequate support to be gained for the structure.
How long will it take to build the new bridge?
After the temporary
bridges are connected the old bridge will be demolished.
This is expected to take about three months. Piles will then
be driven into the riverbed to a maximum depth of 20 metres.
The piles will go through sand and mud and then be driven a
further five to eight metres into bedrock so that the bridge
meets new safety requirements. This is a difficult and
complicated job. It will take about 15
Construction of the rest of the bridge will then take about another year. The whole infrastructure upgrade will take about two-and-a-half to three years.
What disruption will the work cause?
The temporary bridges provide one-lane traffic in both directions, so traffic disruption will be minimal. Motorists are requested to follow road signs.
There will be no disruption in telecommunications, water, sewage transfer. These services have already been secured to the temporary bridge’s and will remain in place until construction of the new bridge is complete.
Demolition and piling work is noisy and can cause vibrations. Work will be carried out from 7 am to 6 pm on weekdays, 7 am to 12 noon on Saturdays with shorter hours during winter. This work will cause disruption and is necessary to maintain the lifeline to the city.
How strong will the vibrations be?
The vibrations will be noticeable for people in buildings close to the construction work. In terms of magnitude and intensity it cannot be compared to the earthquakes which had epicentres in the region.
How are we protecting the environment?
The estuary and river environment are important to us. As part of the demolition process slabs of rock are placed under the bridge and will catch concrete and other particles as the bridge is taken down. This is then collected and taken to Kate Valley Landfill. The current state of the estuary will not be affected by the work.
Did you know?
The bridge will be supported by 10 piles. Each pile is about the height of a seven storey building – 25 metres (the height of eight red buses stacked on top of each other). Each pile weighs about 50 tonnes. The smallest are 1.1 metres in diameter and the large ones are 2.4 metres.
The bridge will have about 300 tonnes of reinforcing steel.
There are 26 Super Tee Beams which make up the final stage of construction. Each one weighs 45 tonnes.
The machines used to demolish the old Ferrymead Bridge weigh 12 tonnes and are called “nibblers”.
The temporary bridges can carry loads of 150 tonnes – a car weighs less than a tonne, a truck weighs 5-10 tonnes.
How can I keep up to date
Visit www.ccc.govt.nz/ferrymead for updates.