She left last week after completing a disposal programme at the group which has returned the business to profitable growth led by the remaining core operation Mabey Hire.
The disposal programme saw Mabey exit wind turbine construction and earlier this year sell its loss-making pre-engineered modular bridges division to Acrow.
Last week the disposal plan completed with the sale of Australian and New Zealand Mabey operations to a local management buy-out.
As a consequence, the role of group chief executive came to a natural end, said a spokeswoman for the firm.
Mabey Hire, which designs and installs temporary works and infrastructure monitoring services, remains under Mabey family shareholder ownership in the UK.
The company said: “The strong national leadership team for Mabey Hire, led by Gordon MacDonald, will ensure that the business continues to develop and hold its important position serving construction and infrastructure clients with its engineering and operational excellence.
“The board and shareholders thank Juliette for her valuable contribution and wish her well for the future.”