Renè Tkáčik, 44, died when nearly a tonne of wet concrete poured onto him.
The two other incidents saw a worker injured when a tipper truck crushed his leg, while another man was injured when a high pressure mixture struck him.
The companies admitted the health and safety breaches at Southwark Crown Court.
BFK - joint venture contractors comprising of BAM Nuttall, Ferrovial Agroman (UK) and Kier Infrastructure and Overseas - were fined £300,000 in relation to Mr Tkáčik; £600,000 for the serious leg injuries to Terrence Hughes and £165,000 for the injuries Alex Vizitiu who hurt his head and suffered hip injuries.
They were taken to court by the Health and Safety Executive (HSE).