Services: Structural Fire Engineering

Atlassian

Over 39 storeys high, Atlassian’s proposed Australian headquarters, to be funded and developed by one of Australia’s leaders in property Dexus, will soar above the new innovation and technology precinct, Tech Central, located above Central Station as Sydney’s tallest hybrid-timber commercial tower, and the tallest of its kind in the world. The complex design will not only push physical limits but will also set a new benchmark in sustainable design and future-proofing. Atlassian and Dexus have been working with the NSW Government, undertaking a thorough planning process and international design competition to determine the amazing design for the Atlassian building, and various commercial and technical agreements to enable development on the YHA site. The hybrid-timber design will predominantly house commercial offices, with retail and accommodation facilities that are adaptable for the changing needs and expectations of Sydney’s tech community.

Holmes is proud to be contributing to the fire engineering and structural fire engineering design of this signature building. Our experienced engineers have been working closely with the design team and approval authorities to inform the building’s design and fire safety strategy, with careful consideration of the development’s connection with surrounding existing and future developments. Advanced thermal and structural fire analysis will be utilised to support and verify the design of the primary exoskeleton and the mass timber habitats. Our team is looking forward to continuing to work on this project for the next few years and contributing to an iconic development that is sure to be considered a significant milestone in Sydney’s built history.

Santa Sophia Catholic College

The multi-storey Santa Sophia Catholic College campus will provide the next generation of students with contemporary learnings and recreational spaces. The innovative design features a six-storey building comprising five interlinked blocks, all connected via extensive, open-corridor play areas with classroom spaces, a creative hub for art and applied sciences, a research hub for science and fitness, a large theatre/hall as part of a performance hub, a professional hub comprising administration and staff space and a community hub comprising a knowledge centre.

The intrinsic theme of this design is connectivity – between students, different areas of the school and the natural environment. The design team recognised the importance of including atria and open corridor play areas for the different year groups.

Holmes’ early involvement in the project allowed the design team to consult on fire safety requirements that could be potentially restrictive to the architectural vision if addressed at a later stage. The proposed architectural design resulted in significant non-compliances to the BCA Deemed-to-Satisfy Provisions. However, Holmes developed fire engineering solutions that utilise the intrinsic architectural features as part of the fire strategy, supported by advanced numerical tools such as computational fluid dynamics and dynamic occupant evacuation.

Each level of the five blocks will be connected via concrete floor slabs resulting in the entire building being considered one large fire compartment. Ventilated circulation spaces have been introduced between the buildings to offset the effects of a fire in the oversized fire compartment. The school’s design also includes numerous stairways connecting the different levels which have all been utilised in our fire safety assessment, offering multiple alternative exits routes for students and staff to reach a place of safety on the ground.

The structural fire engineering analysis focused on the protection of the steel structure in the Performance Hall. Holmes undertook a series of assessments to rationalise the level of fire proofing that was necessary. Additionally, due to the various fire proofing methods implemented in the building, Holmes provided strategies to address the junctions where the different fire protection systems overlap.

Open in late 2021, Santa Sophia Catholic College will be central to the Box Hill communities continued and thriving growth.

The Ainsworth Building

This groundbreaking multi-level timber facility will provide the university with contemporary teaching spaces, lecture theatres and team based learning areas for future medicine and health science students. The unique design features a prefabricated Glulam and Cross Laminated Timber (CLT) structure. The building, interconnected with an internal stairway across four storeys also has a custom fire separation strategy, protecting the top storey from a potential ground level fire.

Holmes worked with the client to create flexibility in the design for potential change in building function in the future. The Structural Fire Engineering team undertook a detailed analysis to provide versatility in the floor plate layout in the event of a catastrophic fire event, considering varying options in the space and how it may be used in the future. Numerous egress and fire services design issues were allowed for and considered in the design of the building, ensuring aesthetic appeal and functionality could be maintained whist providing the highest levels of fire safety. Multiple primary egress routes, avenues of attack for fire brigade, and increased provision of wet fire services were key elements to providing a high level of safety throughout the building.

Other design aspects include a striking timber colonnade entry, incorporating both steel and timber elements, unprotected timber within internal areas, bespoke structural connections, all of which were a key focus of the fire engineering strategy to enable the execution of this innovative design.

Monterey, Kangaroo Point

Situated at Kangaroo Point, Monterey will be a 12 storey mass timber hybrid, aimed at the luxury end of the residential sector. The building features a pool, gym and a rooftop recreation space offering panoramic views of Brisbane River and the city skyline.

Monterey aims to become the benchmark for sustainability in Brisbane utilising glulam mass timber construction for the majority of the building superstructure. The building core is constructed of reinforced concrete for both lateral stability and to facilitate parts of the fire safety strategy.

Our Structural Fire Engineers prepared a bespoke fire engineering design that incorporated a progressive passive protection strategy that allowed for a reduced level of protection throughout the residential apartments and exposed timber surfaces in corridors and balcony soffits. The fire safety strategy also incorporated the utilisation of steel columns in the penthouse apartment and open pergola style roof.

Our team have been providing construction review services and ongoing technical support to the wider team as the building takes shape in preparation for its grand opening at the end of 2020. Our engineers’ experience with approval authorities was key in facilitating the communication process between all project parties and approval authorities, such that compliance issues with this bespoke structural system were successfully navigated without project delay.

44 Martin Place

The historic MLC building is a prominent sandstone icon of Martin Place. The heritage listed commercial development, located in central Sydney CBD was originally built in the 1930s, and has previously undergone redevelopment in the 1980s.

The building has recently undergone redevelopment to incorporate a large feature atrium through the centre of the building and add two new storeys above, using Cross Laminated Timber (CLT). The building required a bespoke fire engineering strategy that had to consider the heritage nature of the building and the specific requirements by the building owner to have an open atrium and highly interconnected working space.

Holmes previous experience with atrium design and our established relationship with local Fire Brigades allowed our team to provide the client and design team with specialist fire safety advice that shaped the atrium design to satisfy the safety requirements whilst also staying sympathetic to all other stakeholder objectives. The resulting design ticked all the boxes in terms of architecturally beautify, architecturally functional, flexible to accommodate tenant fitouts and robust enough to deliver occupant safety in a fire scenario. Specifically our design adopted horizontal fire curtains at the base of the atrium void thereby separating out the Ground Level portions and providing flexibility for the use of this Ground Level space to include a café, displays and decorations.

Structural Fire Engineering was also utilised to rationalise and optimise the level of protection to be applied to the mass timber structure while ensuring that structural stability and occupant life safety is maintained. Advanced finite element modelling is being used to establish a holistic and cost effective re-mediation strategy to the dilapidated existing steel concrete composite structure, which does not comply with the most recent fire standards.

Jubilee Place

As part of the transformation of the Fortitude Valley in Brisbane, this composite steel building will project outwardly with a externally braced load-bearing diagrid structure resembling a large steel web. The development has a strong focus on the people and their experience in the building. This project has prioritised environmental conscious design by setting the bar high in terms of sustainability targets, achieving a six-star Green Star, five-star NABERS and Gold WELL Building Standard.

The structural fire engineering of the building is a key aspect to the design, as the unique and complex nature of the building dictates a first principles approach to be followed when designing for fire safety. The structural fire engineering team developed a holistic fire safety design that removed unnecessary and redundant passive protection, quantified actual building behaviour under fire and building loads, and provided a defensible and robust pathway for building approval.

Additional fire engineering solutions where also developed throughout the building to enhance occupant safety and usability, to mitigate the risk of fire spread between properties, and to specifically design a bespoke passive fire protection strategy for the building.

Jubilee Place as a result, will not only be an architectural statement but also become a precedent for good fire safety design utilising advanced Structural Fire Safety principles to encourage more unique and innovative designs.

Little National Hotel

Currently under construction, Little National Hotel promises to offer local and international travellers a luxurious escape in the heart of Sydney CBD. Utilizing the existing Wynyard Walk structure above Wynyard Station, the hotel boasts 230 contemporary rooms enveloped by a striking curved façade and vertical garden. Guests have access to a modern gym, library and exclusive rooftop lounge and bar with city views.

The hotel structure comprises a steel-framed structure with a composite steel-concrete floor system. Holmes’ team of structural fire engineers, in collaboration with the structural engineers’ team from TTW, developed a unique optimised fire protection strategy for the steel structure. Holmes was able to demonstrate via an advanced thermal and structural fire analysis, utilising non-linear finite element software, that the structural frame with an optimised fire protection strategy can maintain structural stability throughout the entirety of a credible fire scenario. This resulted in major cost savings for the client, as the solution allowed for reduced passive protection of steel members, reducing material and labour costs.

In addition to the structural fire assessment, a number of Performance Solutions were required to support the design intent of the building. These included, for example, reduced fire resistance levels to particular areas, external separation of fire compartments, service penetrations through fire rated elements, travel distances to exits, egress width, stair discharge, protection of fire hydrant booster etc. Holmes also analysed any potential impact the fire strategy of the new hotel may have on the existing Wynyard Walk building and helped enable the two buildings having some combined fire services.

One particular challenge faced in this project was the proposed design option of having an external stair instead of an enclosed fire-isolated stair serving levels above 25m in height. This is not permitted in the BCA Deemed-to-Satisfy compliant provisions due to the risk that people would suffer vertigo and the risk that weather conditions, particularly wind, may become more severe above this height. Holmes helped enable this design by performing a detailed analysis of the wind effects on the external stair to show that the wind velocity wouldn’t impact occupant evacuation conditions.

New Performing Arts Venue | QPAC

Nestled in the heart of Brisbane with a design inspired by Brisbane River and Brisbane’s heritage fabric, the New Performing Arts Venue (NPAV) is set to offer a new landmark on the banks of the Brisbane River. Featuring a sinuous, folding glass facade with an impressive timber cladding lining the internal walls, this performing arts centre is pushing the envelope for cultural building designs in Brisbane. NPAV will provide the current Queensland Performing Arts Centre with an additional 1500 seats and studio spaces to support the growing needs of the Brisbane community and tourism industry.

To deliver the Fire Engineering strategy, Holmes is currently undertaking computational fluid dynamics (CFD) modelling and egress modelling that are proving critical to execution of the spatial planning and overall architecture of the building. The project is still under the final design phase so additional changes could still be presented.

Holmes is also providing specialist structural fire engineering services to rationalise and optimise the level of protection to the steel elements within the building. This fire protection strategy is supported through a performance based structural fire engineering solution, to demonstrate that the proposed steel design can satisfy the Performance Requirements of the Building Code of Australia. The development of a robust fire safety strategy for the building will be paramount in the successful delivery of a flexible design ensuring the achievement of the architectural vision for the building whilst still prioritising fire safety.

Australis Nathan Building

These historic buildings, built in 1903 and 1904 were originally warehouse and storefronts for importers and merchants, fast forward over 110 years and these have been transformed to bring these heritage buildings back to life. Australis House and the Nathan Building was an ambitious refurbishment combining the two buildings to function as a single structure and repurposed them to include high end retail, hospitality and office spaces. These buildings had strong character with a combination of cast iron columns, heavy timber columns and beams, timber floors with herringbone bracing and impressive brickwork.  

Our brief on this project was to avoid providing ceilings beneath these floors and encasing these columns in order to celebrate these features. Our performance-based design solution involved a combination of sprinkler installation, assessment of inherent timber strength and application of clear intumescent coatings to achieve sufficient fire separations within the building and achieve Building Code compliance.

Skyhaus, 420 Macquarie Steet

Located in Liverpool, one of the key satellite suburbs of Sydney, 420 Macquarie Street is currently the tallest residential development in the area. The residential complex comprises two 32 storeys towers plus a sister tower at six storeys. The buildings include retail spaces on the lower levels and swimming pool located on a shared roof space. The complex will usher in a new generation of high-end living into Liverpool, and inject more life into the already vibrant community.

A very high degree of fire engineering and structural fire engineering principles were applied to the building. One of the unique input Holmes  brought to the project was the reduced flat slabs that were demonstrated to achieve the required fire resistance levels throughout the building. This performance solution resulted in considerate savings to the project including approximately 1600m3 of concrete and 4000 tonnes of concrete. This not only improved the constructability of the project, but significant benefits were realised such as improved cost-efficiency and simpler construction techniques, while also improving the occupational performance of the complex over the lifetime of the structure.

Despite the significant benefits this provided in reduction to construction resourcing costs and timeframes, notable flow-on benefits of the thinned slabs was the design flexibility for the project. Standardised façade systems were catered for without increasing the overall inter-storey height of the building, and slab set-downs in wet areas were also not required, resulting in further cost savings to the project. Subsequently, the considerable benefits to this project has led to this structural fire engineering analysis to be conducted on a multitude of reinforced concrete projects, with dozens completed to date.

40 King Street

40 King Street is an existing 100-year old eight storey office building in central Sydney. Due to a proposed major refurbishment, the building had to comply with the requirements of the current Building Code of Australia. The existing concrete slabs within the building could not comply with the current concrete code requirements due to insufficient concrete cover to the reinforcing bars. To upgrade the existing slabs to comply with the current code requirements would involve the addition of passive fire protection to the slab soffit; this would not only have been costly but time consuming and would damage the existing heritage fabric of the building.

Holmes carried out advanced analyses to determine the inherent fire resistance of the existing slab. The analysis demonstrated that the existing slab had enough inherent fire resistance to withstand a realistic fully developed fire, thereby negating the requirement to apply additional passive fire protection or to thicken the slab to meet the prescriptive requirements of the Code and Standards. This provided significant cost savings to the project and minimised disruption to the fabric of the existing building.

Christchurch Justice and Emergency Services Precinct

As the first ‘anchor project’ delivered in the rebuild of the Christchurch CBD after the 2010 and 2011 earthquakes, the Christchurch Justice and Emergency Services Precinct will always be remembered as a project of national significance. It is the first multi-agency government co-location project in New Zealand’s history. The forward-thinking design brings together all of the region’s critical services, including the Ministry of Justice, New Zealand Police, Department of Corrections, New Zealand Fire Service, St John New Zealand, and the Ministry of Civil Defence and Emergency Management, to name a few—and accommodates an estimated 2,000 workers daily.

Holmes provided the fire and structural engineering for this innovative new precinct.

Fire Engineering

Holmes carried out not only the general fire engineering services for the team but also advanced structural fire analyses for the project, specifically the Justice Building. The fire engineering team who delivered the project remained together for the entire five year design and construction period. This continuity of service typifies Holmes’ approach to major projects and allowed the Client (Ministry of Justice) to achieve a fantastic result with continuity of the design and consultancy team.

From a structural perspective, the building has stringent requirements of structural robustness for seismic and fire resistance, due to the Emergency Operations Centre located in the Emergency Services Building – this is the centre for emergency response and coordination in the event of a natural disaster. The design of an Emergency Communications Centre (effectively a nationwide 111/000/911 call centre) was also required to have continuous occupation and operation in the event of a fire within any other part of the building.

A series of advanced analyses using non-linear finite element analysis was carried out by Holmes to test the robustness and stability of the structure in fire conditions. The analysis consisted of 3D modelling of the structural frame under exposure of a realistic fire, looking at its effect on each structural component. Unique and specialist 3D modelling inputs allowed the structural design to be safely optimised, whilst avoiding over-design. The resulting analysis demonstrated that the concrete filled steel hollow section columns and the secondary steel beams did not require additional passive fire protection. This provided significant cost savings for the project through the reduction of passive fire protection to the beams and columns.

This structure needed to not only resist fire but also be immediately operational post-emergency events. As a specialist design and project for Holmes, the technical detail of the fire safety of its smoke control system throughout the five level atrium, through to its specialist structural fire analysis is an exemplary example of how consultancy can be co-ordinated and managed to offer the most advanced fire safety response to serve an advanced function in not only its building design, but its users.

Structural Engineering

The precinct consists of four, four storey towers supported on a common base isolated podium structure. The base isolated podium we designed aims to mitigate structural and non-structural damage following a major earthquake and ensure continued functionality of the facility. This was an extremely challenging design brief that we were delighted to take on—an important and positive project in Christchurch’s rebuild.

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.

ASB Waterfront Theatre

Located in Auckland’s popular Wynyard Quarter, ASB Waterfront Theatre is the first theatre in the Southern Hemisphere to be targeting a 5 Green Star rating for efficiency and sustainability. Offering a 650 seat theatre, it features a glass walled air bridge linking the theatre to the ASB Bank. The public artworks within the theatre have become a major attraction of the building’s design with one of the works featuring 10,000 LED lights, creating an image visible through the theatre’s glass wall.

The building was redesigned in 2012 after an initial preliminary design phase was put on hold. The new design was one of the first buildings in New Zealand to adopt the new C/VM2 Verification method for quantified performance based design. This new design approach was significant, as it allowed Holmes to develop a solution that did not require smoke detection nor a dedicated smoke extract system. This is of huge benefit to a performing arts theatre as it eliminates the risk of false activation of smoke detectors and smoke control systems as theatre effects use haze, dry ice, and artificial smoke. This solution also avoids the need to have an ‘isolate’ facility on the smoke detection and fire alarm system eliminating the need for the stage manager to monitor haze effects and other theatre-created environments which typically play havoc with smoke detection systems. Designing a fire compliant solution without a dedicated smoke extract system, activated with hatches and doors, avoided the inevitable potential compromise into what otherwise needs to be an acoustically sealed auditorium.

Key parts of the steel structure were assessed for adequate fire resistance without the need for passive fire protection, saving on construction cost.

V by Crown

V by Crown is a new 30 storey residential development in the heart of Parramatta, incorporating 519 apartments, with a mix of short-term and long-term accommodation. Designed by Allen Jack Cottier with interiors by Koichi Takada Architects, the building also includes an archaeological display and interpretation centre, international business centre, retail areas, rooftop bar, swimming pool, gymnasium, theatrette and six-storey basement carpark.

Holmes provided extensive fire engineering for the project, doubling the allowable occupant load within the Level 26 roof top bar. Computer simulation of fire, smoke and evacuation was utilised to demonstrate that the increased occupant number coupled with the installed fire safety systems resulted in safe egress time. Additionally, Holmes justified the design of an alternative smoke detection system within the Class 3 portion to reduce the likelihood of false alarms; omission of passive fire protection to multiple steel beams; reduced fire resistance levels in the retail areas; justification of extended travel distances and oversized corridors to avoid the need for additional smoke doors and egress stairs; unprotected openings between separate fire compartments; the use of glazing within fire walls; discharge of fire–isolated exits; fire hydrant and fire hose reel coverage; deletion of sprinklers from portions of the building; and deletion of zone smoke control to the retail and assembly portions of the building.