Optimized truss foundations, adapters for optimized truss foundations, and related systems and methods
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Solution Overview
Problem
Conventional single-axis solar tracker foundations, primarily using monopiles, are inefficient in managing lateral loads from wind, leading to oversized foundations and increased material usage, while alternative A-frame foundations face issues with force distribution and potential bending moments.
Innovation Solution
The implementation of A-frame or truss foundations with moderately sloped legs and an adapter system that aligns the torque tube's axis of rotation with the work point, translating lateral loads into axial forces and minimizing material usage by reducing the need for deep embedment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If monopile foundations are used for single-axis solar trackers, then the foundations can resist lateral loads, but the foundations become oversized and require excessive material usage
Solution Approach 1:
The monopile foundation is segmented into two functional parts: an upper H-shaped section that resists lateral loads through its flanges and web, and a lower embedded section that provides anchoring. This segmentation allows each part to be optimized for its specific function, reducing overall material usage compared to a solid monopile of equivalent strength.
Solution Approach 2:
The foundation uses local quality by providing enhanced lateral resistance only where needed (at the above-ground H-section) rather than uniformly throughout the entire foundation. The H-shaped cross-section concentrates material in the flanges and web where lateral load resistance is required, while the embedded portion uses less material since it primarily provides anchoring.
2Quantity of substance
If A-frame foundations are used to reduce material usage, then steel quantity decreases, but bending moments may develop in the truss legs
Solution Approach 1:
The H-shaped adapter serves as an intermediary element that connects the torque tube to the A-frame truss legs. It is positioned and dimensioned to align the torque tube's axis of rotation with the work point of the A-frame, ensuring that lateral loads are applied at the optimal location to minimize bending moments in the truss legs while maintaining structural efficiency.
Solution Approach 2:
The foundation optimizes the geometric parameters of the A-frame, specifically the slope angle of the legs and the height of the adapter, to minimize bending moments. By carefully selecting these parameters, the design achieves a balance between material reduction and stress minimization, ensuring that lateral loads are efficiently transferred to the ground with minimal bending in the truss legs.
3Ease of manufacture
If the torque tube axis is misaligned with the A-frame work point, then installation is simpler, but lateral loads create bending moments instead of axial forces
Solution Approach 1:
The H-shaped adapter acts as a mediator that provides alignment features (such as guide rails or positioning holes) to facilitate precise alignment of the torque tube axis with the A-frame work point during installation. This intermediary element makes the alignment process straightforward while ensuring that lateral loads are correctly directed to minimize bending moments.
Data Source
AI summary
A universal adapter for enabling truss foundations to support conventional single-axis trackers. In some cases, the adapter has a main body with an upper portion that presents a standard I-beam interface with pre-drilled holes to interface to a specific single-axis tracker. A pair of connecting portions point down and away from the main body and enable upper leg sections to connect the adapter to a pair of driven screw anchors located below it. The connecting portions may orient the truss so that the rotational axis of the single-axis tracker is aligned with the work point of the truss foundation made from the adapter, upper legs, and driven screw anchors. This will enable to the truss to interface with many different trackers much like conventional plumb-driven H-pile foundations.