Terra Firma, and Composites Australia partnered with Advanced Composite Structures Australia (ACS Australia) to develop the D240 Trench Cover. This partnership on composites design and analysis was supported by the Victoria Government Advanced Manufacturing Voucher program and provided a voice for composites materials in the Australian Standard AS3996 Access Covers & Grates Requirements. This collaborative effort led to composite access covers being taken up by major utility providers and the introduction of composite access covers into the everyday civil infrastructure of our built environment.

The D240 Trench Cover product (see images) is a light-weight pultruded composite panel construction, which is rated to handle loads of 240 kN (~24 tons), suitable for trucks and other heavy vehicles. ACS Australia supported the design and successful verification of the product using Finite Element Analysis (FEA) simulation. While subsequent physical testing confirmed the trench covers passed AS3996 static strength and deflection testing for Class D criteria. Additional impact, durability, UV resistance, high temperature and sustained load testing was carried out to ensure the product was fit-for-purpose and could meet required performance standards. The pultruded composite design balances the requirement to be easily handled by maintenance personnel whilst still performing well within the limits of the standards.

Composite materials are becoming increasingly popular in civil infrastructure projects due to the material property performance, such as strength, light-weighting and corrosion resistance. This makes them suitable for use in civil infrastructure projects, and in particular composite access covers, pit lids, and manholes designed to provide access to underground utilities, sewer and drainage systems. They are typically made of durable materials, such as glass fibre reinforced polymers (GFRP), in this case the trench cover was designed for a pultruded construction to handle larger working loads and meet the required length and width of the trench. Finite Element Analysis of the composite access cover design is shows (see images) the maximum strain at ultimate load performing well and within required limits.

Composites Australia article in Issue 61 March 2023 (pp.8-9):

To learn more about the project or to get in touch with the ACS Australia team, please don’t hesitate to contact us!

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