SAWA: 90% WOOD AND BALCONIES IN SLENDER UHPC

CLT construction in Rotterdam in The Netherlands

CLT CONSTRUCTION WITH UHPC BALCONIES

The SAWA building is an innovative project fully dedicated to sustainability, energy neutrality, circularity, biodiversity, and inclusivity. With a modular main structure in cross-laminated timber (CLT) and slender balconies in Ultra High Performance Concrete (UHPC), the innovative building combines the warmth and beauty of wood with the strength and durability of UHPC.

A NEW LANDMARK IN SUSTAINABLE ARCHITECTURE

The SAWA building, located in Lloydkwartier in Rotterdam, is a new landmark in sustainable architecture. With 90% of its structure made of CLT, the 50-meter-high building is an excellent example of how innovative building materials can be used to create beautiful, innovative, and environmentally friendly buildings.

The use of CLT in construction has become popular due to its strength, sustainability, and versatility. The material consists of sawn and glued timber planks, with each layer oriented perpendicular to the previous one. By assembling the wood layers in perpendicular directions, the panel achieves structural rigidity in both directions. This way, the material gains great tensile and compressive strength, making it an ideal choice for both large and smaller construction projects.

The building's commitment to sustainability and CO2 reduction has led to the modular main structure made of CLT, which is visible in many parts of the building. This material choice not only aligns with sustainability goals but is also known for being lightweight. However, the light weight presented a challenge when it came to anchoring the balconies to the structure using traditional concrete. As a result, the design of the balconies required a solution that could meet the weight limitations while being compatible with the CLT structure and the sustainable focus.

©Mei architects and planners

A NEED FOR UHPC BALCONIES

The structure and ambitions of the SAWA building resulted in the selection of UHPC balconies from Hi-Con, an innovative material that offers a lightweight, strong, and durable alternative to traditional concrete. Compared to traditional concrete, UHPC saves up to 50-60% in weight, making it an ideal material to use in combination with CLT. The decision to use UHPC balconies for the SAWA building was a game-changer, marking the first large-scale project where UHPC balconies were combined with a CLT structure.

Hi-Con will produce a total of 238 balconies and a spectacular walkway connecting the two parts of the SAWA building, all made of UHPC. Despite the use of concrete for the balconies, the overall use of steel and concrete in the building is minimized, aligning with the building's sustainability ambitions.

AWARD-WINNING COLLABORATION

The design team behind the SAWA building, consisting of Mei Architects and Planners, Pieters Bouwtechniek, and Era Contour, worked closely with Hi-Con to design the balconies. The main challenge was to find a way to limit the weight of the balcony slabs while still being supported by the wood-based brackets. The use of UHPC for the balconies not only solved this challenge but also created an eye-catching aesthetic. The UHPC material was designed to resemble wood with a texture and natural color that complemented the warmth and natural appearance of the CLT structure.

The building, now also called "the healthiest building in the Netherlands," has already won several architecture awards even before construction started in the first quarter of 2022.

We will soon share more details with you about the impressive CO2 reduction potential that can be achieved through the use of Hi-Con's UHPC balconies in combination with CLT structures.