The company said the strategy had worked as it announced that pre-tax profit had risen from £32.4m to £38.8m, despite wobbles in the global economy. Group turnover rose 22% from £1.7bn to £2.1bn.
Chief executive Peter Mason said: "Amec's growth in client support services has established a more predictable base of earnings, which is underpinning our performance."
Support services turnover increased from £605m to £858m after acquisitions in the USA and Amec's increased shareholding in French rail and utilities firm Spie. Support services made a contribution to operating profit of £35.9m, or 56% of group profit, and had a margin of 4.5%.
Mason said Amec no longer did "hard bid" construction work in the UK. All the work was now partnered on a design-and-build or design, build and manage basis.
He said: "We've abandoned the bumps and horrors of the traditional construction market. We continue to be very selective in the capital projects we want."
Despite the focus shift from traditional construction, Mason said there were no plans to relist on the stock exchange as a support services company. He added that Amec's construction order book was likely grow as a result of increased government spending in the UK and USA on infrastructure.
Mason said: "There is uncertainty out there but we are confident. Infrastructure spending will help."
The company said its construction management order book was £500m lower after the planned reduction in capital projects, which was started last year. The business has made losses in recent years, but there has been an improvement in its margins over the past six months from –8% to –1%.
Amec is bidding for 10 UK public–private partnership contracts including a Docklands Light Railway extension in London and the Manchester Metrolink.
Mason added that demand was holding up in the oil and gas market, which bolstered the group's prospects.