Regenerative High-Rise

Bethel Teferra, Senior Consultant at Ramboll, illustrates how a modular, sustainable high-rise tower that evolves with a city's needs could be a future reality and include engineered timber as key component.

Modular houses may have been around for a while, but modular high-rise with flexibility in function is a relatively new concept. Imagine a high-rise building made up of modular units that can be slotted in-and-out, with spaces for living, working and playing – a building whose functions evolve according to a city's needs, built with sturdy and sustainable materials and a building that's adaptable, practical and eco-friendly.  

Created by Haptic Architects and engineering firm Ramboll, the 'Regenerative High-Rise' blends exactly this flexibility and functionality and aims to redefine conventional uses and lifespans of high-rise buildings in cities worldwide. Constructed from a hybrid timber mix, the high-rise shows how tall buildings can be both versatile and green at a time when climate change is a pressing concern and requires a drastic rethink of the built environment.  

So how does this modular structure work? What are the various uses for this type of building – and perhaps most importantly, how can it be made more accessible?

The high-rise structure aims to find the optimum between two key constraints: flexibility in function and sustainability credentials via the use of timber and other similar offsite production structural elements. To equally satisfy the two constraints is a true balancing act as the requirement for large spacious layouts imposes the need for higher capacity structural elements, whereas sustainability is driven by minimalism. Consequently, the highly loaded tower columns supporting large spans with critical load-path are proposed in recycled steel, sand timber-composite and modular options for frames defined within three-storey 'villages'.

The core-wall (framing the lift shaft) gives the high-rise structural lateral stability, using the Lateral Force Resisting System (LFRS) via a precast and steel-brace solution that provides sufficient lateral-stiffness against building sway, enabling the building to resist environmental loads arising from wind and seismic activity. Being an offsite manufactured solution, the precast central-core provide sufficient stiffness and sustainable solution, given its durability and low-carbon footprint.

Overall, the vertical elements including LFRS consist of a 20-40-40 timber-steel-precast ratio. 

The floor divide has a 'hard floor/soft floor' concept. The hard floors at every third level work as a diaphragm mechanism to transfer lateral load to LFRS in the overall structural system. These transfer-floors are proposed to have the flexibility to support the construction of up to three-storey 'villages' which consist of 'soft-floors' and other modular plug-and-play frames. Hence, for the diaphragm horizontal elements, cross laminated timber (CLT) floor construction with recycled steel beams is proposed. The steel beams are used to reinforce the CLT overall, to compose a robust floor-system that resists the above modular three-storey floor occupancy loading as well as assist to meet its serviceability limits. The horizontal elements have a timber-steel proportion of 80-20. This timber-composite mix benefits the high-rise with not only its low carbon footprint, but also imbues it with a warm aesthetic.

The flexibility of the 'hard floor/soft floor' concept is a highlight of the 'Regenerative High-Rise'. The innovative structural and MEP design aims to serve multi-purpose occupancy including hotel, residential, office, retail and entertainment, but the high-rise's flexibility in design means it could also extend beyond these functionalities too, if needed. For example, such buildings could be used to cater to unexpected demands for flexible space as we've seen during the recent COVID-19 crisis, which at its peak brought about a sudden large need for extra hospital rooms, medical treatment centres, testing facilities and quarantine spaces. In such cases, buildings with flexible functionality would be best suited to meet great societal needs, whilst also having a positive impact on the need for sustainable and economical building solutions.

The project utilises offsite construction and is inspired by Scandinavian prefabricated housing. While prefab homes have existed for some time, modular towers are a new and innovative concept, and the global construction market may be slow to adopt new technologies compared to fast-moving industries like information technology, automation, financial markets.

Construction markets vary from region to region, depending on factors such as economy, resources and natural environment. Contractors, engineers and architects' familiarity in the design and delivery of offsite construction solutions, as well as familiarity of skilled labour can be key aspects to widespread adoption of offsite methods. While professional institutions endeavour in continual education of engineers and architects and stimulate wider discussion on latest innovations, another idea to drive offsite to wider market can be that companies specialising in these technologies could actively seek opportunities to enter emerging market economies. Likewise, innovative and adoptable holistic-building design solutions that are aspiring such as advanced modular construction solutions contribute to the advancement of the field – like the regenerative high-rise.

www.uk.ramboll.com

www.hapticarchitects.com