d'Leedon, Singapore, comprises 7 residential towers, 12 semi-detached villas and integrated landscaping with recreation facilities. A unique petal-shaped layout allows for windows on three sides of the apartments to give the highest quality of living for all residents with cross-air flows to the living rooms and bedrooms – as well as natural ventilation in all kitchens and bathrooms; varied balcony geometries and the integrated landscaping all contribute to create a unique project defined by its site conditions and context. The orientation and placement of the buildings is optimized in response to environmental considerations of managing intense sunlight and to maximize views across Singapore. The towers are subdivided into ‘petals’ according to the number of residential units per floor enabling a very large diversity
of apartments. The generative floor plan of the petal changes shape along the height of the tower in relation to the different configuration and type of residential units. The changing composition of unit type enables the towers to respond to a series of parameters dictated by site conditions, internal organization and structural optimization. d’Leedon’s design turns the challenges of the site to the advantage for residents, embrace the concept of differentiation and individuality, where single apartments have been customized and specifically designed according to their location and position within the site, as well as the requirements of the residents. Context d’Leedon is located in the centre of Singapore’s District 10, close to amenities of commercial and civic centres such as Dempsey Hill, Holland Village a
nd Orchard Road as well as popular schools such as Nanyang Primary. With a covered walkway to Farrer Road MRT Station, the development is well connected to public transport links to Singapore’s CBD and Botanic Gardens and Bukit Timah Nature Reserve. The site presented a number of constraints with to the presence of 2 MRT underground tunnels, the main waterline supply to Singapore from Malaysia and strict setback regulations towards the existing residential buildings at the western edge of the site. The d’Leedon site has been arranged according to existing alignments, the primary axis of Farrer Road and surrounding residential buildings that have all informed a series of lines within the d’Leedon site that connect the development directly with its surrounding neighbourhood. These lines flow through the site and are organized in bands which define the location of each tower for optimum orientation, the lines also establish different features and zones within the landscape. The ground level is visualized as a very green layer, which takes advantage of the extraordinary flora of Singapore and its climate. The site levels are re-organized into a series of terraced plateaus to maximise the areas dedicated to communal amenities. Connectivity and navigation within the site and towards the surrounding city become driving elements for overall site organisation. Car circulation is minimised by routing the part of the main driveway into the basement level, creating a pedestrian-friendly landscape throughout the whole development. Environmental considerations and the location along the equator determined the orientation of the towers along the East-West axis in order to minimize solar gain. Sustainable features are introduced to allow generation and re-use of energy on site and minimize its consumption. The development was awarded Gold+ for its design approach. Tower structure - The seven towers are extremely slender in one direction with a height to footprint ratio of over 13/1, which is counterbalanced by the insertion of shear walls within the petal perpendicular to the tower direction. The structural system is a pure reflection of the tower geometry, a reinforced concrete structure with a vertical central core and each petal being defined by curved columns at its corners and post-tensioned slab to retain it towards the core. The vertical elements incline outwards to allow for the growing floor plates, with difference of over 7 meters between the base and the top of the column. An innovative concrete shuttering systems has been developed to allow building columns at varying angles. The balconies and the bay windows have been pre-cast on site and craned to position to be bonded to the tower structure as the tower was climbing. Double curved concrete façade panels were built by prefabricating GRC panels off site, and used as permanent moulds giving a very high level of exterior finish to a complex geometry, those were critical to allow the growth of the central elements of 6 petals towers. The concrete has been simply finished with protective coating and rendered with white paint, leaving the floor structural joints marked. Development of new facade systems development was necessary to realize the inclined operable façade panels. Most precedents of complex geometry in tower facades have full size curtain walling and either fixed windows or very small openings. In a residential development where ventilation and comfort of the residents was a key consideration all windows needed to be opened fully. Extensive testing has been carried out to ensure ease of opening and waterproofing for windows inclined up to 15 degrees from the vertical plane, going up to 25 degrees for the villas. Particular attention was given to two of the 6 petals blocks where the bay window surface itself is twisted. This has been resolved geometrically by staggering blocks of windows to guarantee the same level of functionality of the other units, while generating and interesting façade feature with the central petals projecting out of the building mass at the top of the tower. The glass was selected to have the best performance with the strong sun radiation and the colour of the mullions to match to keep a simple monolithic appearance. Zaha Hadid, founder of Zaha Hadid Architects (ZHA), was awarded the Pritzker Architecture Prize in 2004. Each of her pioneering projects builds on over thirty years of exploration and research in the interrelated fields of urbanism, architecture and design. Hadid completed her first building, the Vitra Fire Station, Germany in 1993. She is currently a professor at the University of Applied Arts in Vienna. Working with office partner, Patrik Schumacher, Hadid’s work integrates natural topography and human-made systems, leading to innovation with new technologies. The MAXXI Museum in Rome demonstrates ZHA’s quest for complex, fluid space. Previous seminal buildings such as the London Aquatics Centre have also been hailed as architecture that transforms our ideas of the future with new spatial concepts and visionary forms. In 2010 and 2011, ZHA’s designs were awarded the Stirling Prize by the RIBA. In 2012, Hadid was made a Dame Commander of the Order of the British Empire by Queen Elizabeth II.