Urban landscapes are constantly evolving, with existing buildings often requiring new functions, sustainable upgrades, and modern aesthetics. In the IAAC’s course on structural optimization, our studio project, “Parasite,” embodies this transformative approach by exploring the potential of hybrid construction methods and adaptive reuse. Our goal was to breathe new life into existing reinforced concrete structures through the strategic addition of lightweight, timber-based parasitic growths that integrate seamlessly with the original architecture.
Concept and Material Strategy
The concept of “Parasite” revolves around creating new functional spaces that “grow” around existing buildings like natural extensions. Timber was chosen as the primary material for these additions for three key reasons:
- Material Differentiation and Functionality: The visual and structural contrast between concrete and timber allows for a clear distinction of functions within the hybrid structure.
- Sustainability: Timber is a renewable resource with a lower environmental impact compared to concrete, aligning with our objective to create more sustainable urban structures.
- Weight Reduction: Timber’s lightness reduces the load on existing structures, minimizing the impact on the original reinforced concrete framework.
The design was inspired by case studies of adaptive reuse and hybrid construction, where industrial structures were transformed into functional and visually compelling spaces. Our approach aimed to integrate new architectural elements while preserving the original character of the buildings.
Structural Approach and Optimization
To ensure that the parasitic timber structures would not compromise the integrity of the existing buildings, we established separate structural models for the two systems using Karamba, a parametric structural analysis tool. This separation allowed us to assign distinct live loads based on the different functional uses of the original and parasitic structures. Key elements of the structural approach included:
- Use of CLT and Glulam: Extensive research was conducted into the properties of cross-laminated timber (CLT) and glulam (glue-laminated timber) to understand their structural behavior under bending stress, moment forces, and shear forces. This informed our design of CLT panels and glulam beams, walls, and slabs, ensuring optimal stability and efficiency.
- Load Distribution and Joint Analysis: Special attention was given to the topology of joints connecting CLT and glulam elements, ensuring smooth load transfer across foundational elements, walls, and slabs. This approach optimized load-bearing efficiency and improved the structural performance of the overall system.
- ULS Testing: Ultimate Limit State (ULS) testing was conducted according to Eurocode standards. We focused on displacement, stress, stability, and overall performance. CLT wall inserts were also tested in both the old and new structures to improve displacement and utilization, with a gradient-based material distribution system applied to optimize efficiency from bottom to top.
Key Design Features
Several innovative design features were introduced to maximize structural efficiency and maintain the stability of the parasitic system. These features include:
- Stabilizing Core: A core was established at the highest point of the structure, serving as the primary stabilizing element. This strategic positioning ensured optimal load distribution across the structure.
- Gradient CLT System: A gradient system for CLT panels was applied, with higher material density at the bottom of the structure to handle greater loads. Thicknesses were gradually reduced toward the top, achieving both material efficiency and visual elegance.
- Structural Façade: The façade was designed as a structural CLT element, contributing to overall stability and reducing the need for internal support. This not only enhanced the visual aesthetic but also played a critical role in the load-bearing system.
Environmental Impact Assessment
Sustainability was at the core of the Parasite project’s mission. Our design process included an in-depth assessment of the project’s CO2 footprint, focusing on the volume of material used. This analysis revealed key insights into the comparative environmental impact of timber and concrete:
- CO2 Footprint Analysis: Our analysis highlighted the stark difference in carbon emissions between concrete and timber. Timber’s significantly lower CO2 footprint underscored the environmental benefits of using this material for parasitic growth.
- Old vs. New Structure Comparison: We compared the CO2 footprint of the existing structure with that of the new timber extension. The findings showcased the clear advantages of reusing existing concrete and incorporating timber-based construction, significantly reducing the project’s overall environmental impact.
Reflections and Future Perspectives
The Parasite project demonstrates the power of structural optimization in transforming existing urban spaces into more sustainable, functional, and visually appealing environments. By rethinking material usage, load distribution, and architectural strategy, we created a harmonious blend of old and new that speaks to the future of adaptive reuse and sustainable construction.
The development of this project was guided by extensive literature and technical data, providing crucial insights into materials, construction methods, and structural behavior. Moving forward, these principles of structural optimization and environmental stewardship can inform similar projects worldwide, pushing the boundaries of what’s possible in urban renewal and hybrid construction.
References
- https://3xn.com/project/quay-quarter-tower-2
- https://www.cobe.dk/projects/the-silo
- https://app.2050-materials.com/product/details_designer/klh-massivholz-gmbh-klh-cross-laminated-timber-clt-3/
- https://app.2050-materials.com/product/details_designer/vaagen-timbers-glued-laminated-timber-glulam/
- https://app.2050-materials.com/product/details_designer/unicon-a-s-standardbeton-c25-30-lava-concrete-in-passive-environmental-exposure-class/
