Montevideo

Waterfront redevelopment: Neglected docklands all around the world are being transformed into lively districts offering a wide range of commercial and public facilities.

This is a trend which began in Baltimore and Boston, USA, in the late 1950's. Today, waterside living, working, shopping and leisure are highly desirable. The Montevideo apartment building on the Wilhelmina pier in Rotterdam demonstrates the value and possibilities of steel structures in modern waterfront redevelopment.

The Wilhelmina pier played an important role in the development of the Rotterdam harbour. It was from here that the first ocean-going steamers of the Holland-America Line departed for New York shortly after the First World War.

The site is in the heart of Rotterdam and is therefore an attractive location in which to live and work. In the brief the client - ING Real Estate - required 192 luxury apartments, 6000 m² gross area of office space, 1900 m² gross area of commercial space, a health club and 270 parking spaces.

The Montevideo apartment building is the first of a number of high rise apartment buildings which will appear in the Rijnhaven in the coming years.

Apartments
The modern city dweller has high expectations of his home. For this reason ING Real Estate chose to offer a wide variety of apartment types, characterised as "Sky", "Loft", "City" and "Water". Each of these types has its own unique distinguishing features. The City-apartments are in the middle section of the tower, have a floor area of 122 m² and have their own specific layout. The Loft- and Water-apartments have a floor area of 127 m² and are located at the base of the tower on the east side.

The Sky-apartments at the top of the tower are designed according to the ING Optimal Living concept and provide an undivided open space with a floor area of 230 m² and ceiling height of 3.2 m. The inhabitant is able to choose from a number of alternative layouts or may independently engage a consultant, such as an interior designer.

Hybrid structure
The required freedom in choice of layout in the Sky-apartments on the upper floors played an important role in determining the choice of structural system. Structural engineering ABT designed an optimal hybrid structure: the lower section is constructed predominantly in steel-concrete, the middle section in concrete and the upper section in steel. In the Sky-apartments there are no concrete walls and only the occasional slender steel column.

The information below explains the basic structural organisation of the tower.
(First you will see the level, followed by the structural system.)

foundation - concrete tension and cohesion piles, founded at -26 m NAP
-2, -1       - concrete walls and composite columns
0, 1, 2      - concrete core and concrete-filled steel structure
3 to 27     - concrete walls and floors
28 to 43    - tubular steel perimeter structure, no concrete core

Steel structure
From levels 28 to 43 the structure consists entirely of steel. The architect, Francine Houben, of Delft-based architects Mecanoo, chose to expose the steel structure on the interior, making it possible to adopt a simple braced structural system. The floor construction consists of steel H-sections and prefabricated concrete slabs. These slabs rest upon the lower flanges of the H-sections.

These flanges are visible on the underside of the finished floor. The top of the floor is finished with a floating screed in which an underfloor heating system is incorporated. The total thickness of the floor is 300 mm. Due to the floating screed the soundproofing of the separating floors is 10 dB higher than the regulations in the Netherlands currently require. All internal spaces are separated by means of standard metal stud partitions. The partition walls stand directly on the floating screed and are also connected at the top directly to the underside of the structural floor. Insertion of a ceiling is optional.

The integration of architecture and engineering led to the adoption of the braced steel structure. The diagonal bracing members are placed as far as possible to the inside of the façade construction in order to avoid exposing the structure to the external climate.

Fire protection
The Dutch building regulations require that the structure of apartment buildings higher than 70 m must be fire resistant for up to 120 minutes. The installation of a sprinkler system reduces this requirement to 90 minutes. In order to meet this requirement a distinction is made between parts of the steel structure which are entirely or partly exposed, and parts which are protected by internal walls. In this last case the internal walls prevent the structure from being directly exposed to fire.

The visible sections of the steel structure - in particular the columns and diagonals - are partly filled with concrete and also treated with an intumescing coating. The thickness of this coating varies depending on the loading and profile characteristics of the individual steel members. The coating will expand in the event of fire but is applied smoothly enough to be regarded as the finished interior surface. This enables the inhabitants of the Sky-apartments - if they so wish - to incorporate the steel structure as an aesthetic element of the interior.

Project information
Location: Otto Reuchlinweg (Wilhelminapier)
Steel structure: Iemants Steel structures, Arendonk (B)
Gross floor area: 57.530 m²
Building height: 152 m