After 5 revisions that lasted 5 months the Main design have finally been approved. Two months after that the Engineer stop our works and is requesting us to engage a third party to do the revision of the approved design. Can he do it? What shall the Contractor do in this case?
The Engineer’s involvement in the design process under the Yellow Book should be minimal, just enough to ensure that it meets the Employers Requirements/technical objectives of the project. If it is later found that it does not meet this threshold then yes the Engineer can identify that issue and require redesign. However, if the Engineer/Employer want to change the underlying objectives/requirements then yes they can do this but it will be a variation for which time and delay will be recoverable by the contractor.