The firm picked up an £80m job to build the Croxley Rail link for joint clients Network Rail and the Greater London Authority.
It also bagged a £141m Energy Recovery Centre at St Austell for SITA to secure top ranking for new orders during April.
Mace came in second place after converting a project management role on the £150m commercial development at the Commonwealth Institute in Kensington into a main contract.
It also proved a good month for Balfour Beatty, which won the £127m extension of Midland Metro for Centro putting it into the top three contractors.
The top five places for the rolling 12-month remains mostly unchanged with Balfour Beatty leading the pack and Morgan Sindall jostling with Laing O’Rourke over second and third place.
Sir Robert McAlpine has dropped out of the top five to be replaced by Bam after its US Embassy contract secured just over a year ago drops out of the 12-month haul of contracts.
The tables can be found in the Contracts Spy section of the website listed at the top of this page.