Services: Structural Engineering

Te Papa Tongarewa – The National Museum of Aotearoa New Zealand

Te Papa Tongarewa is the National Museum of Aotearoa New Zealand, located on the Te Whanganui-a-Tara (Wellington) waterfront—an iconic museum entertaining millions of visitors from all over the world. Te Papa hosts many stunning artifacts of Aotearoa New Zealand’s cultural heritage, providing a direct link to the country’s recent and distant past. Working in partnership with Arup, Holmes’ engineering experts successfully delivered a landmark structure with a design life of 150 years, in a highly seismic environment.

From a technical perspective, the project was exceptionally challenging. The museum is designed for very heavy floor loads with an extremely large grid to maintain future flexibility for exhibitions and storage of collections. The building foundation platform required ground improvement, with heavy weights dropped across the entire site over several months to compact the softer materials. Te Papa itself is base isolated, resting on lead rubber bearings and teflon sliders that cushion the building, its occupants and contents from earthquake. In fact, the museum actually features an exhibit about earthquakes and how the structure protects against them!

If you haven’t already been to Te Papa, we recommend you schedule it in as soon as possible. While many of the exhibits will take your breath away, don’t forget to enjoy the structure itself—an intelligent engineering design that demonstrates the very best in structural thinking.

Christchurch Town Hall

Acclaimed world-wide for both its architecture and acoustics, the Christchurch Town Hall holds a special spot in Cantabrian hearts. Its position at the centre of the new Performing Arts precinct reinforces its status as a premier gathering place for both performances and events.

As a result of the devasting 2010 and 2011 earthquakes, and due to the land damage beneath, the Town Hall required the strengthening of foundations and damage repair to the original design. For Holmes, this NZ $167M+ conservation project was both technically complex and interesting. With significant portions being upgraded, repaired and restored, and additional areas undergoing a complete rebuild—this project offered the full spectrum of structural and geotechnical challenges. Holmes collaborated with the geotechnical engineers to design a new foundation raft atop ground improvement that tied the existing building elements together and provided additional resilience to the complex. Through high end analysis we’ve minimised the strengthening work required for the superstructure to achieve 100%NBS—an achievement we’re incredibly proud of!

In addition to the excellent engineering we achieved, we aimed to help preserve the original character and style of the building with its white marble, dark timber, rich red fabrics and vibrant artworks–because it was important to our client. Maintaining the original identity of the building provides a tangible link to ‘prequake Christchurch’, and Holmes was delighted to be involved with the preservation of such an iconic building.

In 2021, the project won the highly coveted and exclusive ‘Supreme Award’, at the 2021 Structural Awards by The Institution of Structural Engineers. It also won its nominated category ‘Structural Heritage’ too.

Waipapa | Christchurch Hospital

The new Acute Services Building at the Christchurch Hospital is a vital piece of infrastructure for the city, and a project demanding some clever engineering in a tight programme. Holmes was brought in for structural and civil engineering on the strength of our extensive healthcare expertise and our ability to deliver a robust, resilient design appropriate for Christchurch’s extremely challenging seismic environment.

We applied the principles of Low Damage Design to underpin the continuity of this Importance Level 4 structure which is base isolated—providing the necessary post-disaster resilience for the region and local community. Particular care was taken to ensure the appropriate seismic detailing was consistently applied to the building services, fit-out and contents, to mitigate damage during earthquakes.

The redevelopment is being undertaken within the context of a busy working hospital campus—putting extra emphasis on designs that are easy to construct, creating minimum disruption. The steel moment frame structure was designed to be prefabricated in sections and bolted together on site. The requirement for site welding and work on site has been minimised, meaning the onsite programme is far more efficient. The steelwork has also been designed such that elements can be easily transported by road or ship. This has given the contractor flexibility in the location of fabrication, allowing the structural cost to be minimised—an important saving in a big ticket, high profile project.

We’re delighted to have had the opportunity to make such a strong contribution to a building so critical to Christchurch’s future.

Te Pae Christchurch Convention Centre

The Te Pae Christchurch Convention Centre is an ambitious project, creating a large mixed-use precinct in the heart of the city. The development has a large and varied stakeholder group, including Te Rūnanga o Ngāi Tahu, Christchurch City Council and the private sector—as well as the communities the centre will serve. Capable of hosting up to 2,000 delegates for a variety of national and international events, the state-of-the-art centre includes a 1,400-delegate auditorium, a 3,600m² exhibition hall and 1,600m² of meeting rooms. This is a project of significant local and national importance, delivering a vital events hub that will attract domestic, national and international visitors and events.

Holmes was brought in to handle the structural design for the convention centre, working in partnership with an overseas architect with very little experience in our market. Our designs to date have focused on delivering a robust, resilient structure that supports the Centre’s commercial ambitions—a facility that creates the right atmosphere and flow for visitors, as well as demonstrating the flexibility convention centres demand. With large wide open spaces a key deliverable, our engineers have applied their deep knowledge of long-span structures to optimise the space and functionality of the centre.

In the challenging geotechnical conditions and seismic environment, our experience was invaluable in designing a structure that will stand the test of time and form an important part of the city’s cultural and commercial landscape.

 

Checkout this very cool construction sequence video from CPB Contractors!

Isaac Theatre Royal

The Isaac Theatre Royal is one of Christchurch’s most iconic heritage buildings, and the Grade-A heritage listed theatre was badly damaged in the 2010 and 2011 Canterbury earthquakes. The project included the rebuild of a large portion of the structure while retaining the historic unreinforced masonry façade, ornate plaster ceiling dome and the entrance feature marble staircase.

Two major constraints on the project were the fixed $40M budget and the opening date for the first show. The theatre needed to be open for the 2014-2015 summer show season to keep key staff on. This required the design and construction to occur in two-thirds of the time of a conventional project. Holmes were the structural and fire engineers for the rebuild, and it became the first major entertainment venue to reopen for business in the CBD following the 2010 and 2011 earthquakes.

Fire Engineering

Holmes was brought into the project during construction to review the existing Fire Engineering Strategy provided by another consultant. Through performance based design we were able to present a robust solution on schedule and on budget.

The new Fire Engineering Strategy was produced within three months of engagement. The fire engineering design process also included:

  • Collaboration with the University of Canterbury to develop a new egress modelling tool for Holmes Fire use, which could undertake the buildings comprehensive egress assessment of merging crowd spaces;
  • Development of a fire strategy which considered an alternative compliance with the New Zealand Building Code in order to maintain the original architectural vision of a building designed over 100 years ago;
  • A hands-on approach to proactively integrate the Fire Strategy with the operational needs of the Theatre.
  • Consideration to Safety in Design, which included the physical practicality of installation and maintenance of the proposed fire strategy; and
  • Implementation of a complex fire and security interface which included multiple tests and training of theatre staff.

The design team had a vision of reviving the building to its original design including several key heritage features such as the auditorium dome and plaster detailing, marble stairs, and Edwardian façade. The dome and plaster detailing, in particular, relied heavily on our assessment.

Using smoke modelling tools, we were able to eliminate the need for the existing motorised smoke curtains covering the full width of the theatre adjacent to the dome. This also allowed the client to remove all of the access gantries and maintenance of the system.

Throughout the project, we were able to work collaboratively with the client to provide a unique, performance-based solution tailored specifically to the needs of the heritage building.

Structural Engineering

The tight construction period was achieved through the use of information sharing with the contractor and other consultants in the form of 3D Revit models, a close working relationship with the contractor, and looking outside the box in terms of materials (such as shotcrete) and construction sequencing.

The Theatre’s fixed budget consisted of insurance money and various grants and fundraising commitments. A key part of managing the budget was cost certainty during the design phases. The use of 3D drawings allowed the quantity surveyors to more easily identify pinch points and difficult areas, especially with regard to conflicts with heritage fabric. This helped to identify, manage and reduce these high risk cost areas throughout the project.

Nearly all the unique heritage features of this building were saved and carefully restored by skilled craftsmen—leaving the theatre in a better condition than it was pre-earthquake.

Auckland War Memorial Museum

Tāmaki Paenga Hira/Auckland War Memorial Museum is one of New Zealand’s iconic heritage buildings. It is a treasured part of Auckland’s cultural heritage, ‘telling the story of New Zealand’ to a huge number of local, national and international visitors. It’s a site of enormous cultural significance, occupying a commanding position on Auckland’s skyline.

When the structure of the museum needed to be seismically strengthened and modernised, Holmes technical design experts were the logical choice. Our design of this multi-award winning project integrated dramatic architectural and engineering features into a world class facility, bringing a national heritage building into the 21st century.

Structural Strengthening and Fire Design

The museum redevelopment was delivered in two major stages over 12 years. The first stage comprised a well-crafted refurbishment of the existing Historic Places Category I building and exhibition design for all of the gallery spaces. Significant earthquake strengthening and securing works were also undertaken, carefully integrated with existing heritage spaces to preserve the elements that make the building so distinctive and compelling.

The second stage, the Grand Atrium Project, delivered an ambitious, four storey, seven hundred tonne suspended building within the existing courtyard.  An adjacent two-level underground visitor car park was also developed, and overall floor space was increased by 60%. Two storage and curatorial basements were added beneath the stunning ground floor atrium. By utilising a wide variety of performance-based fire engineering design methods, specifically tailored to the constraints imposed by the building’s configuration and uses, Holmes optimised the performance of the egress routes within the addition, minimised the amount of applied fire proofing needed for the structural steelwork and verified the extensive use of architectural timber lining.

Finally, teaching and performance spaces situated within the suspended ‘bowl’ are crowned by the spectacular events centre, under the feature wave dome roof.

Holmes’ engineering services enabled the architect’s original vision for the project to be realised with a minimum of compromise and in a manner that significantly exceeded the client’s expectations.

Commercial Bay | Te Toki i te Rangi

Commercial Bay is the largest mixed-use development ever undertaken in Tāmaki Makaurau (Auckland) CBD. The project combines two existing office towers with a new three level high-end retail complex and a new 39 level commercial tower—all above three levels of basement car parking and two train tunnels, with associated major complexities and structural transfers. Holmes was the Lead Structural Engineer on this important project, as well as providing fire and infrastructure engineering.

Structural Engineering 

The architecture of the flagship 39 level Commercial Bay tower in downtown Tāmaki Makaurau celebrates and showcases the structural form of the building. Working closely with the architect and the wider project team, Holmes designed visually striking columns and diagonal braces, which are clad to express and accentuate the structure. The structural system of the tower consists of a diagrid structure, featuring composite concrete filled hollow section steel tube columns and braces and long span beams.

In a large complex project with many stakeholders and challenges, the Commercial Bay tower is an example of a well-coordinated structure, underpinned by great BIM execution and a willingness for project partners to work through challenges collaboratively. This result was achieved through excellent continuous ongoing collaboration and communication between project stakeholders—particularly the architect and the structural engineers. Weekly exchanges of Revit files via a shared FTP site ensured well-coordinated Revit models and delivered a clear accurate picture of progress.

The penetrations through the floor slab were modelled in the structural slab, and penetrations for building services were incorporated into the structural steelwork floor beams. Across the project, regular meetings, ongoing communication and open, positive discussions ensured alignment and synergy through the design process.

With a premier site overlooking the harbour, Commercial Bay is already an iconic landmark on the Tāmaki Makaurau foreshore and skyline.

Fire Engineering

Holmes provided fire engineering advice for the entire development, including master-planning to allow for future subdivision of the entire block into four discrete separate properties. The fire engineering allows for separate phased evacuation and independent commissioning and ownership of fire protection systems serving the retail centre and the office tower. Holmes was also engaged to provided advice to almost all of the retail and office tenants, to integrate their specific tenancy fitout design with the overall base building fire engineering strategy.

Holmes was also engaged to provide specialist structural fire engineering services to rationalise the passive fire protection requirements of the entire tower. Advanced finite element modelling was undertaken to analyse the response of the whole floor and megaframe in fire. The analysis demonstrated the robustness of the whole structural frame in resisting a full burnout fire. The resulting analysis showed the composite columns and secondary beams did not require passive protection and a reduced FRL could be applied for the primary beams. The analysis was peer reviewed by Professor Jose Torero who is a renowned international expert in structural fire engineering.

This resulted in major savings on site with regard to project timeframes, labour and material costs, and the improved aesthetic and air quality within the space. The costs savings in fire proofing alone was estimated to be approximately NZ $4M.

City Rail Link Tunnels

The City Rail Link (CRL) runs beneath the Commercial Bay site on the Auckland CBD waterfront. Holmes, as part of a Fletcher Construction Design and Build Team, were responsible for the structural engineering design and documentation of the portion through the Commercial Bay site for the owner Precinct Properties and key stakeholder Auckland Transport. This separate CRL tunnel portion ties into the two adjacent enabling C1 contracts, C1 (Britomart Station) and C2 (Albert St).

The two box tunnels are on a curved alignment and merge into a twin tunnel box within the site. Separation of the tunnels from the surrounding development and the transfer of loads from the multi-storey office tower above were among the considerable challenges involved. The CRL box tunnels are constructed within the Commercial Bay basement area, with the structure of the development forming an enclosure over the top of them. Tension piles resist hydrostatic pressures on the base of the tunnels. The cast insitu tunnel base, walls and roof were formed using moveable formwork. The tunnels were designed for IL3 loads, with a 100-year design life.