Methods and apparatus for foundation monitoring
A system for monitoring a foundation includes a sensor cartridge assembly. The sensor cartridge assembly includes a sensor disposed in a sensor tube and a sensor head attached to an end of the sensor tube. Wiring coupled to the sensor and routed in the sensor tube to the sensor head conveys power and/or telemetry between the sensor and a controller. The sensor tube is configured to be inserted into a raceway attached to a foundation. The raceway may be within the foundation and/or located at a perimeter of the foundation. A method for monitoring a foundation includes deriving an elevation of the foundation at the location of the sensor based on pressure measurements made by the sensor within the sensor tube.
1. A foundation monitoring system comprising:
a sensor cartridge assembly comprising:
first and second sensors disposed in a sensor tube; and
a sensor head attached to an end of the sensor tube;
a raceway configured for attachment to a foundation, wherein the sensor tube is configured to be inserted into the raceway; and
a data transmitter configured to receive data from the first and second sensors, and convey the data to a controller;
wherein the controller is configured to acquire simultaneously a first set of temperature and pressure data from the first sensor and a second set of temperature and pressure data from the second sensor.
2. The foundation monitoring system of claim 1 , further comprising:
a third sensor disposed in the sensor head;
wherein the third sensor is configured to measure temperature and pressure.
3. The foundation monitoring system of claim 2 , wherein the sensor cartridge assembly is configured for installation below ground level.
4. The foundation monitoring system of claim 3 , wherein the first, second, and third sensors are immersed in a dielectric fluid.
5. A method of monitoring a foundation, comprising:
acquiring temperature and pressure data from first and second sensors installed within a sensor tube attached to the foundation, wherein:
the temperature and pressure data includes a first set of temperature and pressure data from the first sensor and a second set of temperature and pressure data from the second sensor; and
the first and second sets of temperature and pressure data are acquired simultaneously; and
deriving, from the temperature and pressure data, a first elevation of the first sensor and a second elevation of the second sensor with respect to a predetermined datum.
6. The method of claim 5 , wherein:
the temperature and pressure data includes a third set of temperature and pressure data from the first sensor and a fourth set of temperature and pressure data from the second sensor;
the third set of temperature and pressure data from the first sensor is acquired after the first set of temperature and pressure data; and
the fourth set of temperature and pressure data from the second sensor is acquired after the second set of temperature and pressure data.
7. The method of claim 6 , wherein the third and fourth sets of temperature and pressure data are acquired simultaneously.
8. The method of claim 5 , further comprising determining the temperature and pressure data from the first and second sensors to be stabilized by:
using the first set of temperature and pressure data to calculate a first set of raw elevation values of the first sensor with respect to the predetermined datum;
determining a first standard deviation of the first set of raw elevation values;
using the second set of temperature and pressure data to calculate a second set of raw elevation values of the second sensor with respect to the predetermined datum;
determining a second standard deviation of the second set of raw elevation values; and
determining each of the first and second standard deviations is less than or equal to a predetermined threshold.
9. The method of claim 8 , wherein the predetermined threshold is 0.5 inches.
10. A method of monitoring a foundation, comprising:
acquiring temperature and pressure data from first and second sensors installed within a sensor tube attached to the foundation, wherein the temperature and pressure data includes a first set of temperature and pressure data from the first sensor and a second set of temperature and pressure data from the second sensor;
determining the first and second sets of temperature and pressure data to be stabilized by:
using the first set of temperature and pressure data to calculate a first set of raw elevation values of the first sensor with respect to a predetermined datum;
determining a first standard deviation of the first set of raw elevation values;
using the second set of temperature and pressure data to calculate a second set of raw elevation values of the second sensor with respect to the predetermined datum;
determining a second standard deviation of the second set of raw elevation values; and
determining each of the first and second standard deviations is less than or equal to a predetermined threshold; and
deriving, from the first and second sets of temperature and pressure data, a first elevation of the first sensor and a second elevation of the second sensor with respect to the predetermined datum.
11. The method of claim 10 , wherein the predetermined threshold is 0.5 inches.
12. The method of claim 10 , wherein:
the temperature and pressure data includes a third set of temperature and pressure data from the first sensor and a fourth set of temperature and pressure data from the second sensor;
the third set of temperature and pressure data from the first sensor is acquired after the first set of temperature and pressure data; and
the fourth set of temperature and pressure data from the second sensor is acquired after the second set of temperature and pressure data.
13. The method of claim 12 , wherein the third and fourth sets of temperature and pressure data are acquired simultaneously.