To help regenerate an area of Milan dislocated from the centre by the railway (a disused land), the Porta Nuova development forges new connections with the city. It is a mixed-use scheme with distinctive and contemporary-style public spaces inspired by the city’s role as a world- class centre for fashion. The concept is that through elements such as lighting and planting, the spaces can change with the seasons.

Designed to complement the bold architecture of Cesar Pelli, establish a new high-quality destination and weave this scheme into the surrounding urban fabric, the quality and style of the public realm is seen as crucial to the success of the project.

As lead designer for the Porta Nuova public realm design, AECOM Building+Place work includes the main public space, the Gae Aulenti Piazza Circolare, walkways and connections to the neighboring park. Strategic guidelines for the public space were established by Gehl Architects.

Situated in Italy’s fashion capitol of Milan, Piazza Gae Aulenti forms the heart of the Porta Nuova development, which stitches together existing urban fabric and includes offices, residential neighborhoods and retail. The piazza exemplifies flexibility of use, sustainable design, and the application of advanced technology. On one level it is a beautifully crafted space and popular destination; on another level it is a highly functional piece of urban infrastructure. Its wide, shallow reflecting pool has become a place to play and cool down during hot summer months. Oval holes in the surface allow water, air and light to reach the underground spaces below, acting as a natural ventilation system. Undulating sculptural seating (reminiscent of fashion models’ sensual curves) encircles the pool, drawing people to rest, work, or socialize within view of surrounding cafés and retail. The result is a reinvention of Italy’s traditional plaza in a thoughtfully crafted contemporary space credited by Italian national newspapers as “the piazza of the future.”

A Contemporary Traditional Space

In a bold move, the Porta Nuova or ‘New Gate’ development bridges across rail lines and main roads adjacent to the city’s primary train station to reconnect the Isola district to the north with Milan’s bustling center. Piazza Gae Aulenti lies at the fulcrum of this new gateway, creating a destination for new and old communities to meet. The 95m (310ft) diameter space is distinctly contemporary in style, highlighted by being named in commemoration of one of Italy’s renowned architects, Gae Aulenti. One of the key challenges the piazza answers is creating a welcoming human scale within a large space surrounded by high-rise towers while simultaneously being founded on the Italian tradition for open piazzas with few vertical elements, to form an authentic public space in the best tradition of Milanese culture. The tension between the vision for the piazza and the potentially overbearing character of the surrounding architecture was compounded by a desire to naturally ventilate the parking levels below, which dictated huge openings in the plaza surface.

The solution has been to learn from the best of traditional piazza design and apply these lessons to this contemporary place. Two key moves have been employed: first to activate the edges of the plaza, and second to animate the center. This second aspect was inspired by images of Venice’s Piazza San Marco flooded at night, the glistening reflections of the surrounding buildings animating the water-covered plaza surface. In a similar manner, the center of Piazza Gae Aulenti is flooded, creating a dramatic 60m (196ft) water skin. The height of the surrounding skyscrapers is now brought down to ground level through their reflections, which continuously change the surface patterning of the plaza through daily shifts in light and color. The water skin also creates a place of play, both for children to run across and adults to bathe their feet during Milan’s hot summer months.

Pathways following key desire lines cut across the space, dividing it into four quadrants. Three surround the oval ventilation holes, with the fourth facing toward the rest of the development’s public realm area. This quadrant can be easily drained of water, transforming into a grand space for large events, from classical concerts to art festivals.  For the majority of the time, however, it forms the most interactive piece of the water feature, either as a water skin, or a dry fountain with jets and color-changing LED lights adding to the entertainment within the space.

Complementing the water skin are the sculpted linear benches that wrap around the space, following the arc of the buildings. They form a highly activated curved pedestrian walkway, the seating on one side and the buildings’ active frontages on the other. In the best of Milanese tradition, this includes fashion retail and cafés with outdoor seating.  Shade canopies cover the café seating, forming an armature for wisteria to climb, the flower being a local favourite. The linear bench seating reflects the city’s reputation as the home of refined furniture design. Both an elegant piece of abstract sculpture and a pragmatically generated element, its form is an extrusion of a series of seating elements, from a seat with a back to a double bench facing the water. This creates a series of sinuous elements, their forms inspired by the sensual curves of fashion models on Milan’s famous runways, a theme in keeping with the surrounding fashion retail. The result is a socialising element, encouraging people to stay and linger within the space, to interact, to relax by the soothing water skin, or use the public space as urban workplace with laptop in hand.    

In this way the piazza accommodates public participation at every scale—children splashing and playing in the water, crowds enjoying a performance, or individuals taking a solitary rest in the curves of the seating—and presents a changing face to welcome its variety of uses.

A Place of Sustainable Infrastructure

In keeping with the piazza as a symbol of contemporary Milan, it is both a refined public space and highly functional piece of urban infrastructure. One of the key sustainability objectives for the development as a whole was to maximise the use of natural ventilation within the many levels of car parking beneath the piazza. If consolidated into one area, the holes in the plaza surface would have resulted in a 25 m (80 ft) opening in the center of the space. Through careful coordination among the design team, the final scheme, with three separate oval holes, was developed and made an intriguing feature of the plaza. These wells of illumination and ventilation connect the piazza with the underground levels upon which it stands, benefitting the area below with a sustainable source of natural light and fresh air while minimising the use of artificial systems.

From the lowest parking level, visitors are welcomed by dramatic views up through the holes to the towering spire of the Unicredit office building, the tallest high-rise in Italy. At plaza level the holes become a point of intrigue. Through the careful placement of the pathways crossing the space, the sight lines only permit people to see the retail spaces directly below the plaza and not the parking. The water surrounding them appears to cascade out of sight down into these openings. For those who venture onto the water skin, sculpted deterrent paving keeps the adventurous away from the guardrail-protected edge.

The sustainability strategy also extends to paving selection. Locally sourced granite is used throughout the project, quarried from the Alps, which are clearly visible from the site. Within the water feature, irregular flagstones are used, contrasted with rectilinear pavers encircling the space, and radiating outward to interconnect with the surrounding context.

Digital Craftsmanship

The piazza’s sculptural seating showcases the potential for digital fabrication in the public realm, proving the positives of the technology and advantages over traditional approaches. During the design process, 3D models were used to make physical CNC models at 1:20-m scale out of high-density foam, enabling the client to examine and assess the design and make confident decisions based on the physical model’s high degree of accuracy. Once the design had been agreed upon, the fully detailed design information and associated 3D models were optimized for construction. This process included rationalizing the number of different pre-cast units being proposed, with the final design using just six types. The pre-cast moulds were then fabricated using CNC with the same 3D files. The result is a best-in-class example of the important role that CNC can play in creating complex pre-cast concrete, delivering an elegant yet cost-effective solution of the client.

Despite the predominantly corporate nature of the neighboring buildings—in particular the towering Unicredit office that marks the plaza by the tallest spire in the Milanese skyline—the gracious Piazza Gae Aulenti has become a firm favorite with many types of visitors, both locals and tourists. The wide expanse of water reflecting the perimeter buildings and the Milanese sky, combined with  the gently curving seating and respect for Italian placemaking tradition create an example of multi-use public space at its most flexible, sustainable, and technologically advanced in design.


James Haig Streeter

Claudio Zappia