Structure design for adding storeys of Harbin Nangang Hall

To solve the problem of that the construction process for original buildings story-adding prevents its usual work, taking Harbin Nangang Hall as demonstration, the adding project of huge frame including main frame around old buildings and sub frame is studied. The vertical load is transmitted from sub frame to main frame by the davit. The main frame is composed by prestressed concrete beams with encased H-steel and angle-steel concrete columns, and the sub frame is composed by encased steel beams hanging and encased steel columns over the huge frame. Design and construction methods of self-supporting concrete structure are presented to ensure that original building works as usual during the construction.