The firms will carry out construction works connected with public infrastructure improvements for the phase 1 of the huge housing development.
This includes highways improvements, strengthening river walls and refurbishing the existing bridge in a package of works worth around £4m.
Developer Crest Nicholson plans to create a new urban quarter, eventually building up to 2000 houses at the derelict 18ha site on the edge of the city.
Buro Happold is the engineer for the project with Davis Langdon on board as project QS.
The site has recently secured planning permission paving the way for enabling and infrastructure works to start.
National housing and regeneration agency the Home and Communities Agency has invested around £6m in the Bath Western Riverside site, taking the total amount it has spent in unlocking activity around the development to more than £8m in recent months.
The latest investment enables the delivery of almost 200 new homes on the 44-acre site, half of which will be affordable and funded by the HCA.
Of the 100 affordable homes due to be built in this phase, 64 will be available to rent and 36 to buy or part own. A further 99 homes will be built for private sale as part of this phase of development.