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The highway is being built by an Alliance that includes Waka Kotahi NZ Transport Agency, HEB Construction, Fulton Hogan, Aurecon, WSP, Rangitāne o Manawatū, Rangitāne o Tamaki nui-a-Rua, Ngāti Kahungunu ki Tāmaki nui-a-Rua, Te Runanga o Raukawa (Ngāti Raukawa ki te Tonga and Nga Kaitiaki ō Ngāti Kauwhata). The Alliance was formed in 2019 with construction beginning in early 2021.
Project construction has been reliant on significant craneage managed and engineered by the Alliance team, including cranes supplied by Smith Crane and Construction.
The project construction cost will be NZ $700 million and has provided work for up to 350 people at any one time, with over 2,500 staff and contractors inducted to the site since the project commenced in 2021.
The project involves the construction of six bridge structures along the highway, with two of the bridges spanning over 300 metres long – the Parahaki bridge over the Manawatu River and the Eco Viaduct over an ecologically significant wetland area.
For craneage, like any major construction project, the team is required to complete thousands of general site lifts, along with many larger and/or more complex lifts to deliver the project.
The site conditions restricted the size, and somewhat the capacity, of the cranes the team could use. The Parahaki bridge, predominantly constructed from staging limited the crane size to a 280t class crawler machine, due to staging width and span lengths. The Eco Viaduct bridge was consented to and allowed to be constructed from a causeway of limited size (footprint, width and elevation) due to construction in a critical ecological part of the site – this again limited the crane size to a 280t crawler crane footprint to access to all areas for general serving and major lifts.
Both major bridges only allowed construction access from one the western side of each bridge, meaning the height of structure compared to the position and elevation of the crane needed to be considered from an early stage through the planning and build of each structure.
Throughout the project to date the team has mobilised nine different lattice boom crawler cranes, two tower cranes on static bases, two telescopic crawler cranes along with five mobile/rough terrain cranes to undertake all works from site set up, piling works to major beam and component installation and removal works across all the six bridge structures.
When it came to crane choice and selection, daily crane needs and configuration options were considered, along with engineered solutions to undertake the major lifts the project required, with consideration of the restrictions the team had to overcome.
Smith Crane and Construction was able to supply efficient crane solutions to the project which included three LR1280 Crawler cranes, with all configuration options available to the project team. The use of two remote control Liebherr static based tower cranes was a smart, cost effective solution the team used on the Parahaki bridge to service day to day works on the bridge where appropriate.
The success of the crane solutions and engineering on the project was largely due to the configuration options the team had available to them, from the use of superlift, luffing and fixed fly configurations along with many boom length changes.
The project’s engineering team was challenged to design or adapt the design of the temporary staging structures, lifting locations on the components, crane pads and causeway designs to take the different loadings that the crane configurations produced across the project.
To date the team has completed over 60 lifts requiring the Superlift on the LR1280 machines, with 30 of these from the temporary staging bridge over the Manawatu River. At the Eco Viaduct bridge 14 of the 21 beam pairs, being 70t and 100t weathering steel beams, required Superlift from the causeway.
Six of the Superlift operations have been with tandem lift operations and numerous complex lifts including superlift operations required pick and carry cranes for completion across the project. Many lifts required full crane capacity and were deemed engineered lifts prior to being undertaken.
Initial challenges and the risks involved – Parahaki Bridge
The Parahaki bridge is situated at the base of a wind farm and also crosses the Manawatu River at the western entrance to the Manawatu Gorge. The site posed many challenges, from wind to river level limitations and flooding.
Parahaki Bridge was predominantly constructed from a temporary staging bridge over the Manawatu River. Height and reach requirements from limited access posed a challenge to the construction works. Limited space to operate and work with construction plant and cranes was also a challenge. The staging was initially designed to suit a 250-280t class sized crane.
The Staging Capacity for heavy lift operations requiring superlift from the staging was a challenge that pushed the staging capacity and required further analysis, which led to staging modification early in the project for the team to be able to make efficient program gains due to crane capacity and configuration gains.
On early review cranes were required to be centred over headstocks due to the capacity limitations within the staging spans when using Superlift. This was not a solution the team was able to work with. The decision was made to strengthen the staging to handle the loads required, however the same width needed to be maintained.
Three areas of staging, ranging from 15m to 20m in length adjacent to Piers one, two and three, were strengthened to handle a 50t load at 40m radius with a suspended rear ballast load of 120t at 13m. The team also allowed for pick and carry operations with suspended superlift in these areas on the LR1280 machine.
Images: HEB Construction.
Some of the initial challenges and the risks involved – The Eco Viaduct
The Eco Viaduct is a 7-span steel girder bridge built over a large wetland that is significant to the local ecosystem. A 250m long causeway was constructed to allow construction works within a limited and controlled area. This was generally 12m wide along the mainline with three 9.5m wide fingers and a small laydown area under where spans 4 and 5 were to be placed. The restrictions on the causeway included limited ground pressure and offset from the edge for plant operation.
The ground pressure significantly reduced within one metre of the causeway edge, meaning no loading was allowable within 500mm of this causeway edge. This was overcome by choosing cranes that had a small footprint, configuration options for all phases of construction including false work, beam install, deck precast panel placement and finishing works.
People
The TAAT Project employed and engaged skilled crane and rigging personnel and contractors to undertake key roles within the project planning team and on the ground as required for certain complex crane and lift operations. The construction team was able to integrate these people to ensure an understanding of the constructions team’s requirements, ability and limitations within complex lift operations.
Being a multi disciplined major infrastructure project, the integration of skilled ‘crane specialists’ into the day- to-day construction operations and the upskilling of some of the construction team to aid in the complex crane works has been a major success of the project and has led to an efficient crane and construction outcome.
Why the project crane solutions have been a success
The team recognised the need for integrated crane and heavy lift operations within the day-to-day construction due to the complexity and interrelation of the works, coupled with the engineering to make it all work.
The TAAT team was able to choose a crane supplier in Smith Crane and Construction that was committed to making sure the project had the required cranes and crane attachments whenever needed, along with a team that was committed to the project.
Access to crane works called for many engineered and creative lift solutions, from lifting frames to lowering systems and everything in between, all done considering the constraints with staging, causeway and crane pad designs to allow the team to manage difficult lifts and loads.
The project undertook numerous rigging designs required to handle the bespoke loads, the team delivered many studies on complex lift designs and technical assessments. Most importantly, the team successfully performed these lifts on site on a regular basis and without incident.
The planning and design of lifts considered the safety of the team and plant itself. Full risk assessments in this planning phase ensured potential risk exposure was identified and managed.
A key philosophy for the project was “It was better to undertake a larger complex lift than to have a prolonged exposure to working at heights for a greater number of people to achieve the same outcome.” Cranes were critical in achieving this and this approach was the most program-efficient and cost effective, making it the best for the project both as a target and for the outcome achieved.
As we approach completion of the project we can begin to reflect on what has been achieved on some of the most challenging structures built in New Zealand. While the outcome is clearly visible in what has been constructed, the journey to get there is something we are extremely proud of and is only visible as we review what has been done. The complexity from the beginning to end has been a constant to address with all challenges successfully met with great people and great plant. Craneage was critical to enable us to be successful on all fronts.