PROJECTS

Britomart Tunnel – Load Transfer

Auckland, New Zealand

Situation

Meccanico played a crucial role in widening the Britomart tunnel for an upgraded Metro Line below Auckland City. Tasked with engineering the project, we designed temporary structural steel to support the demolition and devised the methodology for technically jacking the existing 400mm thick tunnel wall, which bore the load of a fifteen-storey building.

Simultaneously, we constructed a new wall in advance and closely monitored data on wall and tunnel soffit displacement every fifteen minutes during the construction phase. After completing the new wall, we strategically installed double acting 250-tonne locking jacks into the existing wall’s slots, using a synchronized system for systematic jacking based on target loads. Upon achieving our target loads, the jacks were mechanically locked, allowing us to cut the existing wall with the structure fully supported on the jacks. Subsequently, we activated a controlled lowering cycle, closely monitoring loads to ensure a slow and correct transfer onto the bearings and the new wall.

Challenge

The challenges for this project were managing the sequence of technical tasks involved in the jacking process and the significant weight of the load being transferred from the old tunnel wall to the new tunnel wall. This had to be done incrementally by controlling the load in a negative cycle. During this phase of calculations we carefully lowered the jacks into decompression.

Solution

Meccanico designed the engineered, temporary works plan as well as the engineered methodology. This included calculations of what specific equipment could be used to achieve the best outcome for the lift and lowering process. We purchased twenty, 250 tonne, locking jacks from our partner, Holmatro and flew back to Amsterdam for further training. This was to ensure the project would be executed accurately and efficiently for Martinus Rail , NZTA and Kiwi Rail.

TESTIMONIALS

Working with the world’s best

I have been involved with Rod and Meccanico for three large bridge lifts on two of New Zealands significant infrastructure roading projects in the last few years. I was the structures lead for the design team and was involved in the construction monitoring during the construction phase of the projects.

Jacking each bridge was a complex operation and required well controlled load and displacements in each of the jacks as we simultaneously lifted (up to 13 beams) concrete bridge beams that were rigidly connected together by a concrete deck.

Our company is also involved in the maintenance for many of New Zealand’s existing bridges and I would have no hesitation in using Meccanico when we need to jack an existing bridge to replace the existing bridge bearings in the future.

Ted Polley

Technical Director Structural Engineering

Martinus engaged Meccanico for the demolition of an existing wall inside Britomart Tunnel in Auckland CBD. Scope of works consisted of jacking to transfer load from the existing wall to a newly constructed wall, continuous monitoring of deflections, and design of all associated temporary works. Meccanico engaged Quoin to develop the temporary works design in collaboration with Martinus, Aurecon and City Rail Link Ltd. and developed the jacking methodology in accordance with the permanent works design requirements. The jacking works were completed successfully as critical path works during a rail shutdown with a very happy client as a result.

Throughout the works, it has been great to work with Meccanico as a trusted partner to deliver a robust solution, work to the program, and produce solutions where required. Impressed with the ability and flexibility of the team to get the job done. It was a pleasure to work with Rod & team!

Martinus Rail

We engaged Rod and his team to lift and an industrial warehouse roof back in March 2022 in New Lynn.

Rod visited our site and provided a safe methodology and successfully raised the full roof structure to the heights we required meeting our agreed timelines and budget.

I would have no hesitation recommending Rod and his team and will definitely chose to use them again for any future works we have.

Mark Niccolls

QDC Works Ltd

Due to unexpected settlement, the bridge had warped and required intervention to remove the warping stresses. We engaged Meccanico for this challenging operation, which involved synchronous operation of each jack and precise control of jack loads to prevent structural damage.

Under the leadership of Rod, his team worked with efficiency and competence, demonstrating excellent collaboration skills when dealing with higher than expected loads. Throughout the project, Rod kept variations to a minimum and provided a reasonable price for his services.

Overall, we were impressed with Meccanico’s expertise and professionalism in handling this complex project, and we would not hesitate to recommend them to others in need of similar services.

Dylan