Field Evaluation of Lightweight Noise Barriers and Development of Noise Barrier Inspection and Asset Management Program

About the report

Noise barriers along high-volume roads reduce traffic noise using either normal-weight materials, such as concrete or brick, or lightweight materials, such as metal, composites, fiberglass, or acrylic. Although the Virginia Department of Transportation’s (VDOT) current concrete noise barriers have proven durable, some lightweight metal noise barriers have failed prematurely because of corrosion, prompting the need to better understand the field performance of lightweight alternatives. This project aimed to improve the life-cycle management of VDOT’s noise barrier inventory through field evaluations of lightweight barriers, development of an inspection and asset management framework, and unmanned aerial system (UAS) trial inspections.

The literature review revealed that a few state departments of transportation have noise barrier inspection or asset management programs, typically including condition ratings, deterioration models, budgets, and performance targets. A review of noise barrier databases revealed inconsistencies in field names and wall identification numbers, highlighting the need for a single authoritative dataset. Condition data indicated that most concrete and brick noise barriers were in acceptable condition, whereas more lightweight noise barriers required attention.

Field evaluations of 25 lightweight noise barriers of different material and design types found that perforated metal panels oriented horizontally performed the worst, with estimated service lives of only 10 to 15 years. Other lightweight types generally performed well, with estimated service lives of 50 years or more. Anchor bolts were vulnerable to corrosion, especially when exposed to salt spray.

Based on these findings, a proposed inspection program includes overall condition and element-level ratings of five element types and their associated defect types. Proposed inspection intervals range from 24 to 72 months based on mounting type, ability to fall onto traffic or pedestrians, and overall condition rating. The proposed asset management plan incorporates deterioration models, treatment types, and estimated costs. A Markov chain analysis over a 20-year period showed that an $11 million asset management program could maintain VDOT’s noise barrier inventory below a 10% poor-condition performance target, yielding a 23% return on investment and saving $2.5 million annually.

UAS trial inspections of three noise barriers demonstrated that high-resolution photogrammetry and LiDAR can effectively assess the condition and detect misalignments of noise barriers from both sides. LiDAR was effective even for noise barriers with highly vegetated areas. UASs also showed potential for inspecting other VDOT assets.

Recommendations from the project include VDOT prohibiting the use of perforated metal panels oriented horizontally, establishing a single authoritative noise barrier database, implementing a noise barrier inspection and asset management program, pursuing future research on asset inspections using UASs, and working across divisions on geospatial workflows and data governance.

Supplemental materials can be found at https://library.vdot.virginia.gov/vtrc/supplements

_{Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.}

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