As lead consultant, GHD was responsible for the design and delivery management, together with the construction supervision (as per NZS3910) of the overall project. GHD’s commission was led by the Infrastructure Delivery team which is predominantly chartered engineers, all with project management backgrounds, providing the right balance of engineering judgement, construction contract acumen and project management principles.
The key challenge of this project was to deliver 1km of new cycleway, requiring major infrastructure design (such as Canada St Bridge), from concept to completion in just over a year. This together with the complexities of utilising a disused existing off-ramp to fit the new infrastructure would typically take over 2 years to delivery.
To meet this accelerated timeframe, some examples of the project management principles applied by the team were as follows:
- Programme management: By selecting a route on a disused (steep) embankment, in NZTA designation, the team significantly reduced consenting and consultation programme risk, but increased engineering complexity. This decision demonstrates how risks out of the team’s control were identified, such as consenting, and exchanged for engineering complexity that could be managed by the team.
- Standardisation: With upwards of 600 posts (supporting the 3m screens), with most requiring a unique connection due to irregularity of the existing infrastructure, the team managed to value engineer 18 standard post connections. In total this optimisation approach, as opposed to a case by case approach, resulted in a total saving of around $700k as well as whole life cost saving for future maintenance.
- Change Management: The team maintained clarity and control during a major scope change mid-construction, with the introduction of artworks including 290 LED lighting features amongst others. The team incorporated this major scope increase, including all required design and redesign of the existing scope, within the existing timeframe.
The design delivered by GHD’s Infrastructure Delivery team was to the highest quality, whilst also cost effective. The team demonstrated their project management capabilities by delivering this unique project in half the time regularly acceptable, with a design that was twice as ambitious.
The GHD electrical engineering team provided customised solutions for the project including an electrical distribution system, lighting for the cycleway and bridge, LED feature lighting, power supply to an integrated CCTV network infrastructure, as well as electrical protection and earthing.
The vast majority of these designs were bespoke due to the challenges presented by the existing off-ramp, its location and the necessity to run the majority of cabling above ground or across structures. The project also brought with it other unique criteria, such as producing a functional maintainable design that integrated seamlessly into the high standard of architectural features. However, the biggest challenge to the team was presented mid-construction, with the introduction of the LED column concept to the off-ramp. Up until this point, in an already accelerated delivery, the only lighting design required was street lighting placed on either side of the off-ramp. To adapt to this new brief, the team had to rapidly redesign the street lighting and CCTV infrastructure to move to the eastern side of the off-ramp, together with designing 290 bespoke LED feature lights to fit into the existing design.
For lighting on the off-ramp, including that for the LED feature lighting, the electrical cabling pathways had only 400mm of available space for laying cabling. In particular for the LED feature lighting, the design needed to provide protection between the power cabling and data cabling to minimise electrical interference. This electrical system had to also withstand the in-rush current to operate 290 LED lights along the cycleway, should they all be illuminated at once. To maintain the architectural design features, every detail on the project was carefully designed down to components such as bespoke junction boxes and trunking.
On the Canada Street Bridge, the LED lights were integrated into the handrails, with LED drivers and cabling (in 50mm ducts) running within the confined steel kerbs. Paramount to all designs, the team ensured that future maintenance could be easily carried out and minimised the risk of vandalism.
The solutions delivered by GHD team were all cost effective while still aesthetically pleasing. Furthermore, lighting on the cycleway has been a standout feature and is an impressive sight on an evening cycle or walk. This is all the more impressive knowing the pressurised timeframes the team successfully delivered under.
As lead designer, the GHD transportation team faced a number of challenges on this project from the outset:
- Deliver a cycleway from concept to opening in just over 1 year
- Scheme assessment and design of a new 1km cycleway requiring major infrastructure design
- Utilising a disused existing off-ramp to fit new infrastructure
- Obtain approval required within this accelerated timeframe
- Keep the off-ramp available for use as an emergency detour for cars and light vehicles
- Geometric challenges – design for cars versus cyclists and pedestrians.
The initial challenge faced by the team was to update the scheme assessment report and select the optimum route which best met geometric challenges, safety concerns, structural viability, CPTED recommendations (Crime Prevention Through Environmental Design), consentability and security concerns.
The previous report commission by another party identified a bridge connection to South Street as the preferred option; however this had key safety and geometry issues. GHD provided further options in a revised report. Analyses of these against the criteria and delivery milestone, led the team choose a route on NZTA designation. This significantly reduced consenting and consultation programme risk, but increased the engineering complexity. This holistic approach challenged the norm of the previous scheme assessment and considered ways to repurposing otherwise redundant NZTA land, whilst also successfully addressing the critical criteria. This significantly reduced the consenting and consultation programme risk, but increased the engineering complexity (due to its location and topography), this however could be managed by engineering expertise and maintained delivery within the accelerated programme.
Another design consideration was to maintain emergency access from SH1 for cars and light vehicles. To accommodate this, a sliding gate was designed within the 3m screen capable of providing vehicle access to the off-ramp behind the existing emergency barriers. Egress (and access) points at Union Street were also designed.
An access point specifically for larger maintenance vehicles was also required. This was accommodated by designing a removable fence at SH1 off-ramp’s intersection with Union Street. All access and egress points were designed to be safely and manually operated by the AMA and designed in discussion with AMA using vehicle tracking paths.
A key component designed by the GHD Structural team is the 3m high screens that line the off-ramp and support the Plexiglas panels and interactive LED lighting units. The team was challenged with providing a solution that could arrive on site prefabricated and treated, ready to be bolted into the irregular existing off-ramp and guardrail; this required a standardised screen/post design. This posed a number of difficulties, the post connections were governed by the existing guardrail which varied in height up to 130mm, as well as each post being spaced unevenly, ranging from 1.1m to 2.2m. The posts also needed to connect to the existing deck, avoiding any existing structural steel.
With upwards of 600 posts, almost each unique in connection, the team managed to design 18 standard post connections with multiple base connection options on each to avoid reinforcement in the deck. Furthermore, the clamping plate design (to hold the Plexiglas) was also selected to facilitate width tolerance, reducing options to 14 standard widths.
In total, this optimisation approach as opposed to case by case resulted in a saving in the region of $700k.
Key components delivered by our team were the landscape design and screen concept, which now lines the Nelson St Off-ramp animated by LED columns and Maori art panels.
For the landscaping design, the initial brief was for a simple regenerative landscape, maintaining continuity with the existing landscape of Upper Queen Street. As the project brief developed, together with the bridge doubling in length during the later stages of design, so too did the need to create a relationship between the architectural form of the bridge structure and the landscape buffer separating the motorway from the area south of Karangahape Road.
The key driver for the landscape design was then to create an interactive transition for the end user as the meandering bridge elevates them from Canada Street. Users would be bought on a journey from the low level pedestrian planting, progressing into a dense tree canopy creating a “gateway” effect over the bustling state highway, before landing on the colourful off-ramp. This was achieved using strategically placed native trees whilst encouraging strong visual connections to the surround area forming a big part of the experience as well as enhancing passive surveillance for safety.
A key challenge for the team was to be reactive and capable of adapting the initial design to meet changes to the brief without incurring any additional cost or delays to the construction contract.
In a restricted, otherwise disused space, the landscape design has successfully repurposed the space and in time will provide not only cyclists and pedestrians with a visually interesting and interactive urban environment, but a dynamic landscape that will develop further as vegetation begins to establish, improving the socio-ecological conditions of the area as well as adding to the distinctive character of Auckland’s CBD transport infrastructure.
The Planning team began work immediately after GHD was awarded the design of the project. With a tight timeframe of only 5 months to design and consent the project, the team worked to prevent any potential time delays that could occur.
Working closely with the team at Novare and the engineering teams at GHD, we provided input to the preliminary design and highlighted areas of importance from a regulatory perspective. As soon as a detailed bridge design was developed from the Preliminary Design Plans the team started working on the Resource Consent and Outline Plan of Works applications. Historic contamination concerns were quickly identified that had to be investigated to ensure the project could be built without affecting the health of people or the environment. Scheduled trees and general design issues were also noted early and teams engaged to consider the implications of these. To overcome these challenges, the team provided a high level of detailed information for the applications, along with their understanding of designation and consenting requirements and the regulatory authority’s expectations this helped GHD’s team prepare applications that resulted in approval within the statutory timeframes. Strong relationships with the engineering teams meant they were also able to effectively input into the design of a product that would ultimately be acceptable to regulatory authorities and the Client’s requirements.
GHD’s Stormwater team provided surface water assessment and design services to provide an integrated drainage solution for the client.
There were a number of challenges involved with this project. An overland flowpath which ran down Canada Street and crossed the alignment of the proposed cycleway embankment was identified early on. To counteract this, GHD suggested the proposed bridge was extended to Canada Street to prevent interference with the overland flowpath, which would eliminate a potential flooding risk.
Special drainage design was required to keep with the high standard of architectural features of the bridge. Four bespoke grated drains were designed to collect stormwater upstream of the bridge expansion joints and to pass water through holes in the sealed bridge deck; from here the water will trickle down hanging chains onto bespoke splash pads.
Another challenge was the conveyance of stormwater across the expansion joint of the existing Old Nelson Street off-ramp. A fixed/sliding joint using a steel channel was designed to sit flush with the abutment, to span across the expansion joint and allow for stormwater to pass over the bridge expansion joint.