temporary works

Temporary works are required on almost every single infrastructure project. They are “those parts of the works that allow or enable the construction of, protect, support or provide access to the permanent works and what might not remain in place at the completion of the works”. The bits that enable construction, but don’t stay afterwards.

We know how to plan, manage, and execute temporary works.

Our approach of simple, safe, lean, adaptable, reusable guides us to optimised solutions earlier.

Close collaboration with constructors to better understand their preferred construction methodology and plant is often key to achieving the best outcomes. By understanding the required functionality of the permanent design we assess how best to integrate any temporary works to minimise carbon and lower cost.

This was demonstrated by us most recently where we undertook the design of a secant piled shaft for an underground pump station. Not content with limiting our analyses to the simple provision of earth pressures for the structural engineer to adopt, we undertook a state-of-the-art 3-D finite element model of the entire structure, including internal dividing walls to assess all of the major structural design load cases required by the Principal’s requirements. This ensured seamless soil and structural integration in the design and led to a significant optimisation of the required structural reinforcement.

The Andy O’Sullivan team developed the design for the temporary works as part of the Barber Grove ECI. This included several aspects of geotechnical design from retaining structures to specialist considerations associated with MTBM works.  The AOS team provided practical and progressive solutions in a demanding geotechnical environment and as a result, the well-considered designs bought real value to the project.

Daniel Crichton – Senior Principal Engineer, McConnell Dowell Constructors Ltd

we have successfully delivered temporary works solutions on the following projects

  • St Marys Bay to Masefield Beach Water Quality Improvement, Auckland – Design of temporary shafts and technical support to main contractor McConnell Dowell Constructors Ltd.
  •  Lawson’s Creek Branch Sewer, Auckland – Economic design for seven temporary launch and retrieval shafts up to 12m deep using a combination of drilled shafts (up to 3.6m diameter), sheet piles and conventional pile and timber lagging. Elements used in temporary works were up to 90% recoverable.
  • Glendowie Branch Sewer Upgrade, Auckland – Innovative design of 8no MTBM launch and retrieval shafts up to 18m deep using combination of deep soil mixing, jet grouting and unreinforced secant piles. Scope included design of ground retention for 20m diameter and 18m deep main pump station.
  • Māngere Bridge, Auckland – Design of seven temporary cofferdams required for construction of new bridge foundations 9m under Mean Highwater in Manukau Harbour in challenging and variable ground conditions. Close attention to soil and structure response and construction methodology resulted in a reduction in overall footprint and minimisation of internal propping requirements.
  • KiwiRail Bridge 100 – North Auckland Line – Design of temporary MSE wall and culvert diversion required for Rail Bridge Replacement under the tight block of line constraints.
  • Peacocks Bridge, Hamilton – Technical guidance on Piling Operation at cliff edge in sensitive ignimbrite material.
  • Ngaio Gorge, Wellington – Technical guidance and analysis for the construction of a piled retaining wall across multiple active slip sites.
  • Kennedy Point Marina, Auckland – Pile Drivability Assessment.
  • Te Atatū Transpower Pile, Auckland – Pile Drivability Assessment.
  • 2-12 Aitken Street, Wellington – Temporary Works design for complex basement excavation in Wellington Central.
  • Auckland City Rail Link – Delivery of over 120 separate temporary works packages for Aotea, Karangahape and Mt Eden station sites, as well as the North Auckland Line (Western Line), works. Our involvement includes providing geotechnical engineering services on various aspects of the project including temporary support of excavations, temporary and permanent retaining wall design, working platform design, ground settlement prediction and design of anchored retaining walls in a congested urban environment.
  • Auckland Central Interceptor – Geotechnical peer reviewers on 12.4km long tunnel sewer through Auckland. Alignment up to 110m deep with maximum shaft depth up to 86m. Input into value engineering and detailed design of additional complex confluence and auxiliary structures through a wide variety of ground conditions.

key personnel

Temporary Works Glendowie Andy OSullivan
Temporary Works 2 Andy OSullivan

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