GRP Staircase: Knowsley Waste Terminal Access

Requirement

The project involved installing a 13m long and 5m high GRP staircase on a sloped railway embankment in Knowsley, Merseyside. This staircase was designed to provide safe access between the embankment and a cess walkway, equipped with a self-closing safety gate.

The main challenges were:

• Ensuring the structure remained level despite sloped and irregular terrain.

• Overcoming potential ground conditions that could prevent the Anchor Screw piles from reaching the required design depth of 3.60m.

• Meeting a 100-year design life requirement for the anchoring system.

Testing

Torque monitoring was carried out during the installation of the Anchor Screw piles to ensure the project requirements were met. This approach verified compliance with the design criteria and confirmed the piles’ performance.

This testing verified that:

• The ultimate geotechnical capacity of 37.9kN was achieved for the piless

• The piles met resistance criteria as specified in the geotechnical design calculations.

No pre-installation testing was explicitly mentioned, but the torque monitoring provided on-site validation of performance.

Solution

The following solutions were implemented to address the identified challenges:

Anchoring System:

• 16 Anchor Screw piles were selected and installed, each with two helix plates (200/250mm).

• Adjustable interface plates were incorporated to allow for 7° lateral adjustment, ensuring the staircase remained level despite uneven terrain.

• The piles were made of galvanised steel, meeting the 100-year design life requirement.

Installation Methodology:

• The Anchor Screw piles were installed using portable handheld equipment, which allowed for quick and efficient placement without requiring railway isolations.

Result

The project achieved its objectives, delivering a secure and stable GRP staircase on the sloped embankment. The use of adjustable interface plates ensured the staircase remained level, even on challenging terrain, providing a reliable solution for safe access to the cess walkway.

Portable handheld equipment allowed for a quick and efficient installation process, avoiding the need for railway isolations and minimising disruption. This streamlined approach ensured the project was completed on time and with minimal complexity.

The anchoring system met and exceeded performance expectations, offering stability, load capacity, and durability. With a 100-year design life, the system provides long-term reliability, showcasing the practical and effective solutions provided by Anchor Systems for complex geotechnical projects.