Llanharan

Overview

The Trenos Level Crossing near Llanharan was once of the most dangerous crossings in the country and had a recent recorded death.

An FRP design for the full bridge structure crossing had been developed but it had been determined that this solution was not ultimately suitable for the sequencing needed and that it wasn’t suitbale to resist the equestrian loading. DYSE were brought on board to quickly develop an equivalent design for steel ramps and stairs, with the main span to remain as the already fabricated FRP structure. At the stage DYSE were brought on the substructure had already been put in the ground.

Challenges

As the project was behind programme by the time DYSE started, DYSE had very little time to develop a new solution ready for the Christmas blockade. DYSE used their in house skill sand experience to deliver a lead consultant to make sure the project was achieved in time, co-ordinating with WSP who designed the FRP main span.

Fitting a design to a grid of already installed screw piles presented a unique challenge. DYSE needed to accurately set out each column to surveyed information and to allow for high adjustability in the design.

The bridge was to be a bridleway. As such high parapets were adopted with solid infill on the rail side to prevent horses being startled by trains. Rubber matting was used on all ramps to provide a comfortable surface for horses to walk on without making too much noise.

Added value

DYSE developed a highly buildable and durable solution that could be installed rapidly over the railway with minimal disruption in a Christmas 2025 blockade. The bridge was landed without any significant issues leading to a highly successful possession.

DYSE were praised for their use of BIM on the project. DYSE provided visuals and 3D construction sequence animations to aid understanding of installation in a tight blockade. Network Rail also had a requirement that the project us their specialist common data environment ProjectWise. DYSE used their knowledge of this system to fully satisfy this.

Both bridges were checked in house with independent CAT II check teams.