Stratavault
Stratavault
Stratavault supports healthy tree growth while managing stormwater in urban environments.
Structural Soil Cell System for Urban Trees and Stormwater
Nexterra's Stratavault is a patented structural soil cell system from Citygreen Systems, representing the sixth generation of innovation in soil cell technology. Designed to balance strength, sustainability, and efficiency, it creates an expansive underground environment where tree roots can flourish beneath hardscapes while also managing stormwater on site. This dual-purpose system empowers cities to grow healthier, larger trees without compromising infrastructure, making it a cornerstone for resilient and sustainable urban landscapes.
The modular soil cell framework forms a stable underground structure that supports traffic loads while preserving uncompacted soil volume for healthy root growth. Each component interlocks securely and ships nested for efficient transport, reducing both labor and freight costs. With more than ninety percent open soil space and load capacities reaching sixty five point two psi, Stratavault enables stronger pavements, healthier trees, and a greener urban footprint.
Engineered for Urban Environments
Urban areas demand infrastructure that supports both the built and natural environments. Stratavault meets that challenge by providing structural stability underground while promoting robust growth above.
Key design features include:
- Expands soil volume so roots can grow deeper and stronger beneath paved areas.
- Carries heavy surface loads in roads, sidewalks, plazas, and other high traffic zones.
- Modular, snap together design speeds installation and adapts to a wide variety of site layouts.
This structure combines engineering precision with environmental value, giving cities a reliable foundation for green infrastructure that endures.
Growing Trees Under Pavement Without Compromise
Healthy trees and durable pavements can coexist when roots have the right environment. The Stratavault matrix provides space, air, and nutrients underground while keeping hardscape surfaces stable above. Its open design lets roots expand freely beneath plazas, walkways, and streets without disrupting pavement or utilities.
Modules connect quickly in the field, locking together to create a continuous support framework. This ease of assembly saves installation time and keeps urban construction moving efficiently while promoting long term ecological health.
System Operation and Structure
The Stratavault system forms a strong underground framework that carries surface loads and preserves the integrity of the soil environment. Each module works as part of a larger network that protects uncompacted soil volumes, enabling roots to expand naturally.
Operation and assembly process:
- Modules are placed beneath the hardscape and filled with uncompacted soil to support root growth.
- Large openings in the matrix allow roots to extend naturally and access air, water, and nutrients.
- The structural design supports surface loads without steel reinforcements using 30 and 45 series strength ratings.
- Vertical and lateral connectors lock each module into a stable, interdependent structure.
This configuration maintains both soil health and pavement performance for decades of service life.
Why It Matters for Urban Canopy and Site Design
Cities depend on solutions that blend ecology, efficiency, and endurance. Stratavault offers the strength to handle traffic loads and the openness to support thriving tree roots, making it a smart choice for planners, engineers, and landscape architects.
Key benefits include:
- Provides more than ninety percent uncompacted soil volume for unrestricted root growth.
- Delivers load bearing strength of 43.5 psi in the 30 series and 65.2 psi in the 45 series without steel reinforcement.
- Installs quickly with snap together modules that require no ground spikes or fasteners.
- Manufactured entirely from recycled polymer materials that support sustainability goals and LEED credits.
- Incorporates apertures sized for utilities, aeration systems, and conduits within the soil cell matrix.
- Ships in a nested configuration to reduce transport volume and lower shipping costs.
Together, these qualities support long term canopy growth, resilient pavements, and sustainable site performance.
Specifications and Design Options
Each Stratavault module is engineered for durability and adaptability across changing site conditions. The structural matrix has been verified through finite element analysis and full scale load testing to ensure safety, flexibility, and strength under real world pressures.
Specifications include:
- Supports pavement and traffic loads up to sixty five point two psi in the 45 series.
- Maintains over ninety percent open soil volume to encourage natural root expansion.
- Constructed with reinforced copolymers free of steel to prevent corrosion.
- Features patented vertical and lateral connectors that preserve structural integrity under load.
By merging engineering reliability with biological performance, Stratavault provides a tested framework that promotes healthier trees and stronger infrastructure.
Design Integration
Flexibility in design allows Stratavault to fit into nearly any urban or green infrastructure project. It is ideal for both new construction and renovation work where underground soil conditions are limited. The structural framework supports paved areas while protecting large volumes of soil beneath.
Applications include:
- Streetscapes, walkways, plazas, and sidewalks that combine tree health with pedestrian or light vehicle use.
- Parking areas and low volume roads requiring structural soil beneath pavement.
- Redevelopment and infill projects with limited soil volume or restricted surface space.
- Green building projects seeking LEED credits for heat island reduction, stormwater management, or recycled materials.
- Utility corridors where conduits must share subsurface space with healthy root systems.
This adaptability makes Stratavault an essential tool for sustainable city planning and resilient site design.
Upstream and Downstream Integration
Effective green infrastructure depends on how each system connects within the broader stormwater network. Stratavault integrates easily with both upstream and downstream components, ensuring that root health and water management work together below the surface.
Typical integration elements include:
- Upstream filtration: through sediment traps or bioretention features that keep soil cells clean and functioning.
- Flow management devices: that control infiltration rates and direct water through the soil matrix as designed.
- Downstream conveyance: linking to subsurface drains, infiltration galleries, or reuse systems for irrigation and groundwater recharge.
- Overflow structures: that safely channel excess water during major rainfall events.
With proper integration, Stratavault strengthens overall site hydrology while maintaining soil vitality and structural performance.
Performance Highlights
Validated through both laboratory and field applications, Stratavault demonstrates measurable improvements in soil quality, pavement longevity, and canopy development. Its recycled polymer structure resists corrosion, withstands freeze thaw cycles, and maintains stability under load.
Performance features include:
- Over ninety percent of the soil matrix volume remains uncompacted for sustained root health.
- Ultimate load capacity tested at sixty five point two psi in 45 series modules.
- Material composition resists degradation and eliminates rust concerns common to metal systems.
- Snap together connectors ensure structural integrity under seasonal movement and soil shifts.
The result is a reliable soil cell system that preserves tree health, reduces maintenance, and enhances the value of urban landscapes for decades.
Additional Resources
Design guidelines, planting guides, technical specifications, and installation support are available from Nexterra to assist with layout planning, soil mix recommendations, and module selection.
Support Material
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