EXPO Milano 2015 (concorso)

ILLUSTRATIVE REPORT
(LANDSCAPE INTEGRATION AND ENVIRONMENTAL MITIGATION PROPOSALS FOR INTERSECTIONS (ROUNDABOUTS AND SIGNIFICANT SECTIONS OF THE ROUTE))

PREMISE

Designing infrastructure involves considering its environmental and landscape integration, particularly at critical junctions, as a fundamental component on par with structural, functional, and traffic concerns. “Critical junctions” refer to challenges arising whenever the route intersects with other transverse infrastructures or undergoes drastic changes, such as road lowering relative to the surroundings or underground tunneling. In these cases, the primary focus on functional issues in raw route design often leaves residual spaces that are challenging to manage from a landscape integration perspective. The approach taken in this specific case started from this consideration, aiming to simplify these spaces by eliminating as many residual areas as possible.

The second consideration guiding the proposals relates specifically to roundabouts, the commonly adopted solution for at-grade intersections. Roundabouts manage traffic nodes independently from the converging roads, redistributing traffic flow without stopping it. The current standard is the roundabout with ring priority, meaning that the roundabout’s ring has priority over converging roads. Correct roundabout design, considering the landscape integration of the space occupied by the traffic node—sometimes of considerable size—requires specific evaluations.

THEORETICAL DESIGN GUIDELINES

IMPROVEMENT OF ENVIRONMENTAL INTEGRATION AND AESTHETIC VALUE

The need to intervene in multiple areas with similar challenges provided an opportunity to introduce uniformity across interventions, creating a cohesive design language. For roundabouts, specifically, both the internal and surrounding spaces were considered.

1. Characteristics of the Internal Space of the Roundabout:
   Due to the ring’s priority over converging roads, pedestrian crossings are not planned, making the roundabout inaccessible. The space remains unused and cannot be directly experienced. It serves a purely aesthetic function and, in some cases, also an image or representation function depending on location and size.

2. Characteristics of the Surrounding Space of the Roundabout:
   Entering a roundabout breaks the linear progression, promoting a landscape perception of the surroundings. Therefore, the scenic potential of the space around the roundabout is considerable. A dynamic visual perception is created for the driver, as if the entire panorama is revealed while turning. It was proposed to include the areas surrounding the roundabout within the surface design project, within expropriation limits, to ensure harmonious integration into the context.

Based on these premises, it was deemed that an artistic intervention sensitive to the specific qualities of the site (environmental art) and respectful of different visual perception needs could successfully address these spaces, meeting the needs highlighted by the previous considerations.

Since the space cannot be accessed or directly experienced, introducing complex plant compositions is not recommended; rather, a measured use of vegetation is preferred as a complement to the “built” intervention.

THE ROUNDABOUTS

The design of each roundabout adheres to the following general constraints:

• Maintaining visibility from the left for those entering the ring lanes, avoiding sudden visual impacts that may destabilize drivers.
• Enhancing landscape, aesthetic, and environmental integration.
• Optimizing maintenance activities and material durability.

Within these constraints, the design approach applies to each roundabout.

The image of the central island should appear “fixed and solid” yet not monotonous; it should be familiar yet not predictable, evocative, perceivable, and reassuring from afar, while intriguing up close.

The surrounding area should facilitate integration of the new spatial configuration into the context, serving as a transitional element between the interior and exterior. It will therefore feature elements, even simple ones, that visually connect with the central island.

TUNNEL ENTRANCES

The lowering of the road at tunnel entrances presents one of the “critical junctions” in terms of integration into the context, as mentioned in the premise. Often, functional solutions leave residual spaces that are challenging to incorporate into a coherent urban landscape. In this specific case, the approach taken started from this consideration, aiming to simplify these spaces by eliminating residual areas where possible.

For both roundabouts and tunnel entrances, concrete screens adapted to the different circumstances are used as defining elements, providing a cohesive yet non-repetitive design language across interventions.

RETAINING WALLS

Certain significant sections of retaining walls along the route will be treated with the same finishing material as the screens used in the roundabouts and tunnel entrances.

MERLATA ROUNDABOUT

At this intersection, the route lowers by approximately 7 meters in the center to ensure unobstructed linear flow, while a surface-level roundabout integrates the cross streets. The inner space of the roundabout opens upwards with two semi-circular concrete walls coated in a layer of colored tixotropic cement, featuring a stylized landscape design.

BARZAGHI ROUNDABOUT

Inside the roundabout, a slight terrain slope resolves the height difference between a white sand basin, a concrete pavement with Vicenza stone aggregate, and a grassy area. One side of the basin rises as a backdrop painted with a landscape theme, with a tree placed at the highest point of the mound. The traffic medians and the traversable ring are partially paved with white river stones and partially with concrete and Vicenza stone aggregate.

SEMPIONE ROUNDABOUTS

At the tunnel entrance, the traffic solution involves a dual roundabout system. Here, the entire system is defined by curved, inclined screens painted with designs that visually connect the surrounding areas to the roadways through gentle terrain slopes, opening up the visual perception from bottom to top and vice versa. The two roundabouts, partially paved and partially grassy, are also defined by an inclined screen that rises approximately at the center, appearing as a continuation of the slightly sloping paved section. An ideal line connecting the two roundabouts could be marked as a simple line on the pavement, repeated in the pattern separating the paving from the grass.

Project: Arch. M. Tisi
Graphic and Virtual Renderings: Arch. A. Cicconi