During the design & delivery stages of our project, we identified and implemented the following value engineering and efficiency ideas:
• Following the installation of the main portal frame structure, 11,000 Tonnes of structural backfill was required. By carrying out the series of tests and comparing the results, confirmation by the permanent works designer allowed layers of 500mm to be placed and compacted using 8 passes of a 13T. This saved approx. 4-5 hours in the overall programme and had cost savings due to removing the requirement for testing.
• To minimise the risk of an OLE strike due to height restrictions, it was agreed dozers would be used to push the material rather than risking excavators slewing and potentially damaging the OLE infrastructure.
• A Feasability Report was conducted and from there is was agreed upon that the OLE wires should be raised on the existing structure; and the assembly of the new OLE portal structure off-track. Once the new underbridge was in place the off-track crane was able to land the new OLE portal structure in its entirety. This reduced OLE on-track construction works during the blockade.