Construction Manager Canary Wharf Group declined to reveal the value of the job.
Harrington will start on site this month pouring the equivalent of 11 Olympic-sized swimming pools into the building’s foundations.
The concrete will be supported by 6,000 tonnes of steel reinforcements sourced from Nottingham steel works. The largest single pour is around 2,300 cubic metres.
The Walkie Talkie is being jointly developed by Land Securities and Canary Wharf Group.
Completion to ground floor is planned for February 2012 and final completion is anticipated in 2014.
Approximately 165 people, including three apprentices, will work for Harrington on the concrete works. The entire project is supporting around 3,000 jobs throughout construction.
Cormac MacCrann, Executive Director of Canary Wharf Contractors Limited said “20 Fenchurch Street has come a long way in a short space of time.
“Since construction began in January we have put in over 300 piles, finished the excavation, installed cranes and we’re rapidly preparing for the first of the concrete pours.
“We are doing our bit for the economy by sourcing locally where possible and it is great to welcome P.C. Harrington onto the team.”