2013/04/04

BONDI TO BRONTE COAST WALK EXTENSION - ASPECT STUDIOS

Després d'un temps vivint a Sydney, uns dels projectes que em va fascinar va ser el recorregut que unia les platges de Bondi i Bronte amb un camí que anava amb paral·lel a la línia de costa. Una intervenció molt respectuosa amb l'entorn i que dóna resposta a una sèrie de mancances que els habitants reclamaven.


Bondi to Bronte coast twilight | Florian Groehn


El projecte és d'Aspect Studios, un despatx ubicat a Sydney i amb sucursals a altres punts de la geografia australiana i xinesa. Sacha Coles, director del despatx de Sydney, s'ha ofert a respondre'm unes preguntes i ha cedir-me el material que hi ha publicat al post. Si teniu l'oportunitat de viatjar a Sydney, no us perdeu aquest magnífic projecte, val la pena!


The Bondi to Bronte coast walk is a part of the nationally significant 9km coastal walk from Sydney’s South Head to Maroubra. The project resolves complex geotechnical, structural and heritage conditions to retain the significant cliff top heath community and the remarkable hanging swamps along the exposed sandstone platforms. A set of lookouts strung together by a light thread of walkway along the cliff tops of Sydney’s east captures the sublime of the headlands, the sandstone outcrops and the vastness at the continent’s edge. 

Sensitivity to site is embodied in the simple materials and understated lightness of the walkway’s design as it shifts and slides along the movement path to reveal the story of the cliff top landscape. Each of the five lookout points takes on its own distinctive form as the walkway cranks and fractures in response to the crystalline geology of the site and angular structure of Hawkesbury sandstone. Over remnant vegetation, the walkway’s timber switches to a gridded fiberglass mesh to allow light and water to penetrate. Materials are selected for design quality, durability and sustainability. A limited use of balustrades balances risk with experience. 

Site conditions were complex, and rigorous geotechnical planning was required to work with the rock outcrops and dyke intrusions of the site. In many areas piling was required to breech unstable fill slopes, and environmental sensitivities meant construction access was limited to a four metre corridor. The project originally arose from the need to preserve the historic Waverley Cemetrey, one of Sydney’s most culturally sensitive and spectacular cemeteries, from ongoing damage by the walk’s annual 700,000 visitors.


1. What ASPECT Studios is? 

AS: ASPECT Studios is a group of design studios united through a philosophy that delivers innovative landscape architecture, urban design and digital technologies. 

Since its beginning, ASPECT Studios has grown to over 65 people throughout our Australian and China studios. We have established a reputation for design-led solutions and are recognised as a company with the capability to deliver world leading design excellence through creative and sustainable projects.


2. What expectations did the client and the communities have? 

AS: The brief required the boardwalk to remove the conflicts of people moving through the heritage cemetery and create a cliff top walkway to celebrate the spectacular Sydney sandstone landscape and connect the missing link in the 9km coastal walk. The community wanted to create a unique coastal walkway that was sensitive to the character of the cliff top environment and facilitated improved biodiversity through a staged process of regenerating the indigenous flora.

Retaining access to the coastal walk whilst unlocking the pressure on the cemetery made it possible to remediate the culturally significant heritage structures many of which have become dilapidated due the high numbers of people previously moving through the cemetery. Significant environmental heritage has also been protected by avoiding rock outcrops, and designing to be complimentary to topography. The project has created opportunities for further bush regeneration to occur adjacent the walk way. It has also created places of prospect as a sequence of lookout spaces, which create a richness in the journey. 

Accessibility of the walk has been improved significantly. While all access for the entire length of the walk was strived for and tested it was agreed that it was not possible without substantial aesthetic detriment. The centre of the walk has been designed to be accessible, and provides access to three of the lookouts.


rock slope drawing | Aspect Studios


prespective | Aspect Studios


coastal walk | Aspect Studios


coastal walk | Aspect Studios




3. How did you approach this project in this fragile natural landscape? 


Bondi to Bronte context plan | Aspect Studios

AS: Sensitivity to social, cultural, historical, physical and natural context was addressed in a number of ways; 

> A 3-stage consultation process was undertaken with the community which addressed site planning, materials selection and design options. Additional stakeholder consultation was undertaken with specialist groups including local bush regeneration groups. Direct involvement by the Local Aboriginal Land Council included walk throughs and notification of issues of indigenous significance.

> In response to the potential aesthetic and environmental impacts of the walkway, the timber structure was designed to weather into the surrounding landscape. The Waverley Cemetery has high cultural and heritage significance, and the siting of the walkway below the datum of the eastern perimeter wall of the cemetery assists in restoring the powerful relationship of the cemetery to the Pacific Ocean.

> Biodiversity has been protected and in time will be improved through the decisions to site the walkway away from protected endemic vegetation and to provide permeable decking in proximity to significant vegetation.

> Bush regeneration is a large component of the project and was being undertaken before and during construction, with the bulk of replanting occurring after construction as a long term project. Areas of weed vegetation were retained to provide defacto habitat for small birds and invertebrates with gradual replacement of these weed shelter species. The design height of boardwalk also allows for bush regeneration and maintenance underneath.


Bondi to Bronte section | Aspect Studios

Bondi to Bronte landscape plan | Aspect Studios



4. How did you decide the structure, construction and materials? 

AS: The site planning was rigorous and determined by ecological (avoiding remnant vegetation), geotechnical (rock outcrops, unstable fill slopes, dyke intrusions) and public safety (avoiding potential for cemetery wall collapse. 

The alignment of the walk was designed to avoid any conflict with remnant indigenous vegetation and areas of weed vegetation were retained to provide defacto habitat for small birds and invertebrates. Areas of rock and rubble were also retained as much as possible to protect habitat. Aside from the major benefits of carefully siting the walk, the construction process involved restricted site access for machinery, which resulted in a limit on machinery size, control of stockpile and site shed locations and protection of exposed soil.


All materials selected are robust, long lasting and are selected to minimise ongoing maintenance by the Council. A combination of materials was used for the decking to achieve aesthetic, ecological and durability goals. Fibreglass mesh was used over areas of important remnant vegetation to allow some light penetration, rain permeability and for its construction ease and durability. It was decided that due to the extreme coastal exposure that fibreglass would be the only material to withstand corrosion and meet the design quality and aesthetic objectives. The stainless steel balustrades were electro polished to reduce 'tea staining' corrosion. The quality checks for this process were undertaken by a specialist corrosion engineer. Recycled timber was used in all furniture, and Class 2 hardwood - certified as being from sustainable harvesting operations was used for all the timber decking and sub frame. 

The walk was also designed to avoid changes to pre-existing surface flows. Subsurface seepage supports the protected coastal vegetation and a new retaining wall was required to be built to replace a dilapidated and collapsed boundary wall. Drainage in this wall was designed to let this seepage remain unaltered and prevent any harm to the vegetation. 


Bondi to Bronte lookout | Florian Groehn


Bondi to Bronte boardwalk | Florian Groehn

Bondi to Bronte boardwalk + stairs | Florian Groehn



Bondi to Bronte native wildlife | Florian Groehn


Bondi to Bronte lookout | Florian Groehn


5. What are the main strengths of this project? 

AS: > The Great Public Asset; 
A 515m long publicly accessible walkway perched, folded and stretched over the sublime Sydney landscape adjacent the culturally and heritage significant Waverley Cemetery.

> The Construction; 
Although the brief was relatively straight forward, the site conditions were complex and had a large influence on the design principles, developed concept and method of construction. The structure covers a variety of topographical and geological conditions, In many instances piling was required to broach deep areas of municipal fill waste to reach the bedrock. Site access constraints for machinery resulted in a limit on machinery size, and the construction access corridor was only 4 metres wide. This constraint was maintained throughout the construction process to protect the existing landscape.

> The Consultation Process;
The consultation was comprehensive with a three step process of open meetings, leaflet drops and notification and invitations for comments were backed up by site tours with stakeholders throughout the construction process. Direct involvement by the La Perouse Local Aboriginal Land Council included walk throughs and notification of potential areas of aboriginal archaeology.

> The Complexity of Issues; 
There was a broad spectrum of disciplines contributing professional input into the design process. These included geotechnical, ecological, aboriginal archaeology, heritage, structural engineering, and cost planning. The input from these disciplines was drawn heavily into guiding the design process and project outcomes.

> The Materials;
The choice of materials for the project was carefully considered and tested during the design development process. Various decking materials (including galvanised steel mesh) were placed on site for a period of time to measure the impact of corrosion. The final combination of electropolished stainless steel, fibreglass mesh and sustainably harvested class 2 hardwood was selected to achieve the high quality finish, robustness and sympathy with the surrounding landscape that the project required.


Construction | Aspect Studios

Project Name 
Bondi to Bronte Coast Walk Extension 

Client/Owner 
Waverley Council 

Landscape Architects Firm
ASPECT Studios 

Project Location 
Calga Reserve & Waverley Cemetery, Sydney, NSW, Australia 

Size (sq m) 
515 metres 

Completion Date 
2010 

Photography 
Florian Groehn 

Awards 
2010 Australian Timber Design Awards – Outdoor Timber/Central Region Highly Commended 
2010 Institute of Public Works Engineering Excellence Award 

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