The Issues faced
A detailed inspection and survey resulted in a greater understanding of the different failure mechanisms that had been accelerated by the severe stresses transmitted by passing traffic leading to the failure of the ironwork and breakdown of the installation materials.
The supporting structure and chamber were in poor condition, it was also evident that the bedding materials used had failed.
Closer inspection determined a lack of support under the ironwork in critical functional areas. Evidence of the incorrect type and amount of material needed to ensure a durable installation.