Stackable Structural Cells for Hardscape Support and Root Space
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Solution Overview
Problem
Trees planted near hardscapes, such as roads and sidewalks, face difficulty in root growth due to soil compaction from the weight of these structures, leading to stunted growth or failure.
Innovation Solution
A stackable structural cell system with a quadrifoil-shaped support member design that allows for unimpeded root growth by maintaining 90% of its volume as free space, preventing interlocking when stacked, and featuring a detachable deck to prevent soil compaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional solid hardscape structures are used to support pathways, then structural strength is improved, but soil compaction increases and tree root growth is impeded
Solution Approach 1:
The hardscape support structure is segmented into multiple cellular units with void spaces. Each cell provides structural support while the void spaces within and between cells prevent soil compaction and allow tree root growth. The cells are arranged in a pattern that distributes load while maintaining open spaces for root penetration.
Solution Approach 2:
The hardscape structure uses a porous cellular design with approximately 90% void volume. This porous structure allows soil to remain uncompacted and accessible to tree roots while still providing sufficient structural strength to support pathways and roads. The void spaces enable root penetration without compromising load-bearing capacity.
2Area of stationary object
If hardscapes are placed close to trees, then urban space utilization is improved, but tree survival rate decreases due to soil compaction
Solution Approach 1:
The cellular structure segments the hardscape into discrete units with void spaces between them. This segmentation allows the hardscape to be placed close to trees for efficient urban space utilization while the void spaces prevent soil compaction, ensuring tree survival and health.
Solution Approach 2:
The cellular hardscape structure acts as an intermediary between the tree root zone and the load-bearing pathway. It transfers structural loads away from the soil while maintaining open spaces that allow root growth, thus mediating between the conflicting requirements of space utilization and tree survival.
3Strength
If support members are added to increase structural capacity, then load-bearing ability is improved, but available volume for root growth decreases
Solution Approach 1:
The support structure is divided into multiple thin-walled cellular units rather than using solid support members. This segmentation provides sufficient load-bearing ability through the collective strength of multiple cells while maintaining high void volume (approximately 90%) for root growth within and between cells.
Solution Approach 2:
The cellular structure uses thin-walled cells that provide structural support with minimal material volume. These thin films and shells form the cell walls that bear load while occupying minimal space, thereby maximizing the void volume available for tree root growth.
4Stability of the object's composition
If stacked cell structures are designed to interlock, then vertical stability is improved, but lateral mobility and root growth space are reduced
Solution Approach 1:
The cell structures feature asymmetric geometry with curved surfaces that provide vertical stacking stability through nested configuration, while the asymmetric shape prevents lateral interlocking. This allows cells to stack stably in the vertical direction while maintaining lateral mobility and open spaces for root growth.
Solution Approach 2:
The cell structures are designed to interlock primarily in the vertical dimension through nested stacking, while deliberately avoiding lateral interlocking. This dimensional differentiation provides vertical stability for load support while preserving lateral openness for root growth and soil access.
Data Source
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AI summary
Structural cells that are placed beneath hardscape. The cells are strong enough to structurally support the hardscape, effectively bearing its weight along with the weight of any load it carries. Furthermore, even though the cells are strong enough to offer structural support of a hardscape, the cells are also designed to be relatively lightweight, stackable, and open, allowing approximately 90% of their volume, or more, to be free volume that can contain uncompacted soil, tree roots, and the like. The cells achieve these attributes through a design that includes a flexible bottom frame, and support members. These support members have a cross-sectional shape that allows for axial rigidity while also preventing any interlocking between support members when cells are stacked. In one embodiment, this cross-sectional shape is a generally quadrifoil shape.