Complying with Vic roads regulations and standards for highway acoustic barriers

Highway acoustic barriers, commonly known as noise walls, play a crucial role in mitigating traffic noise pollution, thereby enhancing the quality of life for communities near major roads. For companies involved in the design and construction of these barriers, compliance with VicRoads regulations and standards is essential. VicRoads provides detailed guidelines to ensure noise walls are effective, durable, and safe. This article outlines the key aspects of these regulations and standards, offering a comprehensive guide for project managers and construction professionals involved in the development of highway acoustic barriers.

Establishing local sound regulations

Noise is measured in decibels (dB), with adjustments made to reflect how the human ear perceives sound, resulting in A-weighted decibels (dB(A)). Professional acoustic consultants follow best practice methodologies and regulatory requirements to measure traffic noise, considering factors such as –

• Traffic volume
• Traffic speed
• Number of trucks
• Road gradient
• Surrounding terrain
• Type of ground or pavement
• Distance from the road
• And existing noise barriers or buildings

During the road planning phase, traffic noise levels are assessed, especially in noise-sensitive areas like residential neighbourhoods, hospitals, schools, and libraries. According to the VicRoads Traffic Noise Reduction Policy 2005, specific noise limits are set for new or upgraded roads. If these limits are exceeded, noise reduction measures, such as the installation of noise walls, are required.

Noise Regulations for Acoustic Barriers

Noise barriers must meet stringent longevity and performance standards. Key design life requirements include:

• Anchorages on bridges, culverts, and major retaining walls must last 100 years.
• Anchorages for other applications and structural components must last 50 years.
• Panels, panel fixings, and fasteners must last 30 years.

Noise walls must comply with AS 5100 standards and additional criteria for wind loading, earthquake resistance, thermal expansion, and handling. In addition, they must adhere to the protection requirements specified in Road Design Note (RDN) 06-13 and Austroads Guide to Road Design (AGRD) Part 6 (2022).

Design and Material Requirements

Noise walls adjacent to or over railways, roads, or pedestrian paths must:

• Comply with the working width allowances of AGRD Part 6.
• Be designed to prevent fragmentation or shattering upon impact.
• Resist damage from debris, stones, and bird strikes.
• Avoid components that could snag or penetrate impacting vehicles.

The materials used in noise walls must withstand impact damage and be easily replaceable. Timber is generally not recommended due to its durability and maintenance needs, though it can be incorporated into panel designs. The design must also account for temperature and moisture effects, ensuring structural support systems effectively seal against noise and accommodate movements from loads.

Foundation Requirements

Foundation design must adhere to AS 5100.3 and BTN 023 standards. Foundations should not impede natural drainage paths, and if affected, alternative drainage solutions must be designed. Noise wall foundations must be checked for both serviceability and ultimate limit states, limiting deflections according to specified tolerances.

For noise walls on earth mounds or batters, there must be a clear, horizontal surface on both sides for at least 1.0 metres in metropolitan regions and 1.5 metres in rural regions. This provides access for construction and maintenance, ensures foundation stability, and prevents undermining. Spread or strip foundations in earth mounds must be at least 1.5 metres from the edge of filled batters.

A concrete maintenance strip, designed to protect panel edges from water ingress, must meet the following criteria:

• Made from 20 MPa strength concrete or geopolymer binder-based concrete.
• Extend at least 200 mm in width on both sides of the noise wall with a thickness of 75 mm.
• Placed on 75 mm of compacted Class 4 crushed rock.
• Have a minimum 5% crossfall, preferably away from the noise wall.
• Be at least 50 mm above natural ground level.
• Include provisions for expansion and contraction at intervals not exceeding 10 metres.

For noise walls on disturbed material, piled foundations designed for specific site conditions are required. Long-term settlement and lateral movement due to embankment consolidation must be considered, especially near embankment edges.

Regulations for Transparent/Translucent Plastic Panels

To avoid overshadowing private properties, noise walls must include a transparent upper section, complying with ResCode standards A13, B20, A14, and B21. The surface finishing of these panels should:

• Have a translucent, opaque, or etched surface for privacy.
• Include a neutral tint or colour to reduce visible dirt.
• Feature an etched surface where public access cannot be restricted, minimising visible scratches.
• Use intense colours or internal horizontal filaments to mitigate bird strikes, especially near bird habitats.

These panels must resist scratching, UV weathering, and discolouration. Transparent/translucent noise walls near roads should be angled outwards by at least 7 degrees to reduce headlight reflection and facilitate natural cleaning.

Compliance experts 

Adhering to VicRoads regulations and standards is not only a legal requirement, but ensures that highway acoustic barriers are constructed safely and are as effective as they are durable. Understanding these comprehensive guidelines helps project managers, engineers and construction professionals ensure that noise walls mitigate traffic noise, while meeting all necessary structural, safety, and aesthetic requirements. For the best outcome, seek the assistance of an expert noise wall team. Wallmark’s noise walls combine aesthetic appeal with functional resilience and are meticulously designed to meet stringent standards and compliance regulations for noise reduction, structural integrity, and environmental considerations. Contact Wallmark – the highway acoustic barrier specialists.