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Runways Start Out as being Smooth, but they Often Don't Stay That Way.
Runways are built and accepted by passing stringent smoothness testing. However, as a pavement ages, subtle changes occur that can transform that smoothness into runway roughness. APR's technology and experience can help you track these changes and help you preserve your pavement's life.
The secret to tracking profile shape change is to measure the pavement's "true" profile. To achieve this, the profile data must be measured by a device that uses an external reference or an inclinometer profile measurement device. APR has used both profiling technologies for many years. The key to success is to establish a profile baseline of the runway after construction and then re-measure the same lines of survey every three to five years. This proactive approach allows for early intervention, preventing profile issues from causing poor aircraft performance and potential complaints from pilots and passengers.
Subsurface Conditions that can Cause Profile Shape Change
- Construction requiring a lot of fill material that can result in settlement.
- Construction on highly compressive subgrade materials can result in differential settlement.
- Construction on soil types that absorb moisture creating sporadic swelling.
- Underground structures such as tunneling can cause differential settlement.
Here are Some Examples of Profiles Changing Over Time
This pavement required a lot of fill material during construction that compressed over time. APR was able to capture that settlement occur by updating the profile three times over eight years. APR's surveys showed that this pavement settled a total of 4.5 inches (11.4cm) over eight years. Because it the settlement has a long wavelength, this did not create a ride quality problem for operating aircraft.
Here, APR established a baseline profile prior to the runway opening. The profile on the top of the chart shows this baseline. The profile was surveyed again seven years later and the dip at 4,800 feet was noticeably deeper. APR then surveyed the runway again four years later showing additional settlement. This settlement was caused by poor compaction over a conduit tunnel running underneath the runway. This pavement settled 2.5 inches (6.4cm) over a length of approximately 100 feet (30.5m). APR's aircraft simulation found that this dip would cause unacceptable aircraft response in some conditions.
Establishing a baseline profile is an important factor for maintaining smooth an acceptable airfield pavements. It provides a clear reference point for identifying changes over time, enabling effective evaluations of surface conditions. Active profile monitoring builds on this foundation, offering real-time insights that help detect emerging issues early. Together, these practices ensure timely maintenance, reduce repair costs, and enhance safety and ride quality for aircraft operations. By prioritizing baseline profiling and continuous monitoring, stakeholders can uphold the high standards required for efficient and reliable airfield performance.
How Can APR Help You Today?
From roughness investigation of existing airfield pavements to new airfield pavement acceptance testing, APR has the technology and experience for your needs.