Truss foundations for single-axis trackers
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Solution Overview
Problem
Single-axis solar trackers require foundations that can effectively withstand both weight and lateral loads from wind, with existing plumb-driven monopile foundations being inefficient due to their poor resistance to moments, necessitating larger beams and deeper embedment depths. Additionally, variations in top-of-pile loads across different tracker components, such as drive motor assemblies and damper systems, are not adequately accommodated by current systems.
Innovation Solution
The EARTH TRUSS system uses a pair of angled legs forming a truss with the ground, joined by a truss cap to form a unitary structure that translates lateral loads into axial forces, allowing for reduced steel usage and shallower embedment depths. This system includes various truss foundations capable of handling additional forces at drive motor and damper assemblies using standard components and installation equipment, ensuring compatibility across different tracker configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plumb-driven monopile foundations are used, then the foundation can support the weight of the array, but larger sized beams and deeper embedment depths are required due to poor resistance to moments from lateral wind loads
Solution Approach 1:
The foundation is segmented into two separate structural members (first and second structural members) positioned at different locations, each optimized to resist specific load components. This segmentation allows each member to be smaller and shallower while collectively providing superior lateral load resistance compared to a single deep monopile.
Solution Approach 2:
The solution transitions from a single vertical monopile (one-dimensional resistance) to a two-member system with both vertical and lateral orientation components. The members can be inclined or positioned to provide resistance in multiple spatial dimensions, effectively converting vertical load paths into combined vertical and lateral resistance mechanisms.
2Strength
If plumb-driven monopile foundations are used, then the foundation can support the weight of the array, but larger sized beams are required due to poor resistance to moments from lateral wind loads
Solution Approach 1:
Dividing the foundation into two separate structural members allows each member to be optimized for specific load paths, reducing the total steel quantity required compared to a single oversized monopile that must resist all loads independently.
Solution Approach 2:
By introducing lateral positioning and potential inclination of structural members, the system gains additional spatial dimensions for load resistance. This dimensional change allows more efficient steel utilization by aligning member orientations with principal stress trajectories.
3Adaptability or versatility
If H-piles are used, then variance in top-of-pile loads at drive motor and damper locations is accommodated, but heavier gauge beams and deeper embedment depths are required
Solution Approach 1:
The foundation system applies local quality by positioning structural members at specific locations optimized for their function, with members that can have different orientations, lengths, or cross-sections tailored to local load conditions at drive motor and damper locations rather than using uniform heavy gauge throughout.
Solution Approach 2:
The two-member foundation system provides multi-functionality by simultaneously supporting vertical weights, resisting lateral wind loads, and accommodating moment variations at different locations. The system serves multiple functions with standardized component types, reducing the need for specialized heavy gauge beams for each load condition.
Data Source
AI summary
Truss foundations for supporting single-axis trackers. A motor truss may be constructed from a pair of adjacent trusses that are braced and interconnected to resist axial loads and bending moments experienced at the drive motor or center structure. Dampers may be added to one or more trusses to protect the tracker from unintended rotation by resisting these forces with the truss legs.