After trimming the three beams, in March 2019 one of the trimmed beams was selected for the concrete pouring trial. A steel mould 10 m long was attached to the lower half of this beam. The combined beam and mould were lowered inside the steel lined shaft. A reinforcement cage incorporating T-headed bars for the tension connection, was installed inside the mould.
After 10 days curing, the trimmed beam and attached cast in situ block, with a total weight of about 70 tons, was removed from the shaft, and the mould stripped off. The block was then sawn into three 2.5m long sections, to assess the quality of the cold joint between the beam and the cast in situ panel and in particular the quality of the concrete inside the tracks for visual inspection.
Mould (left) and cage installation (right)
Cast in situ element after extraction and slicing