Bidirectional Foundation Testing System with External Jack
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Solution Overview
Problem
Current load testing methods for foundations, such as Top-Down Static Load Test and Bi-Directional Static Load Test, face limitations including high costs, risk of damage to embedded jack assemblies, and insufficient displacement capabilities, making them inadequate for modern foundation types with increased diameter and length.
Innovation Solution
A Top Loaded Bidirectional Test system that applies loads to foundations using stacked steel plates without embedded jacks, allowing for bidirectional loading and unlimited displacement, eliminating the need for beam-based reactions or sacrificial jacks, and enabling compressive force testing without tensile strain reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an embedded jack assembly is used for bi-directional loading, then foundation capacity can be tested with half the jack load compared to top-down testing, but the jack assembly becomes sacrificial and unrecoverable which significantly impacts test cost
Solution Approach 1:
The patent makes the jack assembly reusable by positioning it externally on the foundation top rather than embedding it within the foundation. The jack can be removed and reused for subsequent tests, eliminating the sacrificial nature of embedded jacks and significantly reducing test costs while maintaining the ability to apply bidirectional loads.
Solution Approach 2:
The patent separates the jack assembly from the foundation structure by placing it externally on the foundation top. This segmentation allows the jack to be reused independently while still achieving the bidirectional loading effect on the foundation, resolving the contradiction between testing capacity and cost.
2Reliability
If hydraulic lines and jack assembly are embedded within the foundation, then internal loading can be achieved, but any slight damage to the lines or jack assembly during construction could significantly impact the load test
Solution Approach 1:
The patent extracts the jack assembly from the embedded position within the foundation and relocates it to the foundation top. This eliminates the vulnerability of embedded hydraulic lines and jack assemblies to construction damage, while still achieving the desired bidirectional loading effect through external positioning.
3Device complexity
If a conventional top-down static load test is used, then the testing method is simple with beam-based reaction system, but the structural capacity of the reaction system limits the use of the test for higher loads
Solution Approach 1:
The patent inverts the conventional top-down approach by using bidirectional loading where the jack applies forces in both upward and downward directions on the foundation. This inversion eliminates the need for a complex beam-based reaction system while enabling testing of much higher loads, as the reaction forces are generated internally by the jack itself.
4Length of moving object
If foundations have large displacement requirements at the base, then the installed jack may not have enough stroke to reach the required resistance
Solution Approach 1:
The patent enables dynamic adjustment of the jack position and configuration to accommodate large displacement requirements. By positioning the jack externally on the foundation top rather than embedding it, the system can accommodate greater strokes and displacements without the geometric constraints of embedded installation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a cost-effective, safe, and efficient method for measuring both base and shaft resistance of foundations with enhanced displacement capabilities, suitable for foundations with limited tensile strength and large displacement requirements, and allows for reusable testing components.
Implementation Method 1
an expandable jack or loading source (5) located at a foundation top extent (20)... wherein the expandable jack or loading source (5) pushes upward reacting against at least one top loading plate (2)
Implementation Method 2
one or more shaft mobilizer bars (1) joined between the at least one top loading plate (2) and the shaft bearing plate (8)
Implementation Method 3
one or more base mobilizer bars (6) joined between the bottom loading plate (4) and the base bearing plate (9)
Implementation Method 4
Strain measurements using strain gages on the shaft mobilizer bar(s) and/or the base mobilizer bar(s) provide a check of internal bar forces and jack loads
Data Source
AI summary
A testing system for load test measuring a shaft resistance and a base resistance having first and second operating units with the first operating unit having a bottom loading plate, a base bearing plate and base mobilizer bars operably joined thereto; the second operating unit having a top loading plate, a shaft bearing plate and shaft mobilizer bars operably joining them together wherein the first and second operating units can move relative to one another; the system having a loading sources producing a test load between the top and bottom loading plates to move them apart wherein the shaft bearing plate that is positioned below a foundation element produces an upward compressive force test load on the foundation element to test shaft resistance and the base bearing plate that is positioned between the shaft bearing plate and the bottom surface of the foundation opening produces a downward compressive force test load on the bottom surface to test base resistance.