How Inclinometers Can Be Used To Monitor Bridges

By Author: Thelma Micco
Total Articles: 7
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Hazards of potentially dangerous bridges made headlines in August 2007 after Minneapolis’ I-35W bridge collapsed, killing 13 people and injuring more than 100 other people. It’s not the first time a bridge has collapsed or suffered damage that put the safety of commuters and bridge workers at risk. In fact, around the world more than 50 bridges have failed since the mid-1800s. Fortunately, tools like inclinometers exist to help ensure these and other failures do not reoccur. Inclinometers measure slope angles and inclinations; they can be used to monitor bridges, thereby reducing the numbers of bridges that fail or collapse.

Ways Inclinometers Monitor Bridge Safety

Some bridges, like Pennsylvania’s Kinzua Bridge, fail due to storms or severe weather conditions. In the case of the Kinzua Bridge, damage to the bridge was caused by a tornado. Other bridges fail due to factors like wear and tear or poor construction. By using inclinometers, construction crews can measure the accuracy and dependability of their work, as they build bridges. For example, they can use inclinometers ...
... to create artificial horizons, to level platforms and to measure slopes. Furthermore, other functions inclinometers have make it possible to measure the safety of roadways.

According to the October 2008 “Use of Inclinometers for Geotechnical Instrumentation on Transportation Projects” Transportation Research Circular, inclinometers can be installed underground to monitor the settlement of a base foundation. The Circular reports that, “Vertical inclinometers are instruments for measuring relative horizontal displacements affecting the shape of a guide casing embedded in the ground or structure.” Furthermore, “Inclinometer probes usually measure displacement in two perpendicular planes; therefore, displacement magnitudes and directions (vectors) can be calculated.”

The inclinometer probe has been around since 1969. This commonly used probe is designed with servo-accelerometers. In addition to probes and vertical inclinometers, the Circular reports that transportation crews working on bridges can also install horizontal inclinometers to “measure differential settlement along a cross section of an embankment width.”

Benefits of Using Inclinometers to Monitor Bridges

A typical inclinometer is designed with a cable, probe and monitor reader. Benefits of using inclinometers include the ability to detect sudden shifts in bridges, roadways and other structures and the ability to monitor and pick-up slow developing shifts in bridges and other structures. For example, inclinometers can monitor shifts in structures near bridges, shifts that could have a ripple effect and cause properly built bridges to suffer damage or give way.

Employees working in a variety of different industries use inclinometers to perform their jobs and ensure projects they work on are safe for public usage. Some leading industries that use the devices are transportation, aviation, government, civil engineering and military.

There are also different types of inclinometers and accessories to accompany the devices. For example, there are mechanical, backlit and electronic inclinometers. Additionally, types of accessories that can be purchased and used with inclinometers are circular bubble levels, sensors and LCD displays. Electronic sensors are based on gravity; the sensors are designed without moving parts which can increase their reliability and dependability. Overall, as the numbers of transportation and construction crews using inclinometers increases, the numbers of bridge failures may decrease. It’s a safety step well worth taking.

Thelma Micco is a free lance writer interested in inclinometers for construction, as well as companies like Rieker Inc. that specialize in acelerometers, clinometer, and other sensors. For more information about Rieker Inc, visit their website at www.riekerinc.com