Careys Civil Engineering was appointed by Siemens to carry out the concrete works package for the new 842 megawatt Combined Cycle Gas Turbine (CCGT) power plant at Marchwood, near Southampton. Our team constructed foundations for 34 buildings, two gas turbines and a single steam turbine, in addition to four cofferdams to ensure the safety of operatives on-site.
Our foundation works required the installation of more than 1,400 piles, 5,700m of temporary sheet piling and 600m2 of permanent sheet piles. The 3m deep steam turbine base used more than 1,200m3 of concrete, and was constructed following our open-cut excavation works.
The turbine table was constructed on 12m high columns, ranging from 1m2 to 1.5m2, and ranged between 3 and 4.5m deep. It contained 286t of reinforcing steel and required a continuous 17-hour pour of 1,800m3 of concrete.
We undertook all pours relating to the turbines monolithically and maintained a close monitor of the concrete temperature using themocouples to ensure that the temperature of the curing concrete never exceeded the optimal temperature. The three transformer bases were poured to a tolerance of +-3mm, ensuring an even surface for the transformer.
The foundations for two boilers consisted of two 1,800m3 monolithic concrete pours to a depth of 1.5m. In addition to these works, we also laid 27,000m of drainage ranging from 100-600mm in diameter, alongside waterproof ducts for services ranging from 100-900mm.