Network Rail said everything had been done to cause the least amount of disruption to the fewest number of people.
Replacement bus services will be in operation between Birmingham New Street and Lichfield Trent Valley.
“There is never a good time for closures like this and I am sorry for the inconvenience, but school holidays and summer breaks means passenger numbers are lower at this time of year,” said Denise Wetton, Network Rail’s central route director.
At 24 metres high, the new structure will be the tallest in a one-mile stretch of new viaducts carrying high-speed trains into Birmingham. The curved design will feature a unique light installation, set to become a new landmark on the city’s skyline.