Analysis on Stiff Frame in Replacement of Closure Segment for Prestressed Concrete Cable-stayed Bridges

Stiff frame was the important structural member in construction of replacement of closure segment for prestressed concrete cable-stayed bridges. To establish the design calculation method of it and reveal its variation of internal forces with construction stages of replacement, some configurations and its working process of stiff frame was introduced. Based on construction stage analysis of replacement, calculation methods of its strength and stability were given. Through FEM results, influence of stiff frame to structural dynamic property and global stability of whole bridge were described. Analysis results showed, it was appropriate to consider each section steel of stiff frame as eccentric compression member. During construction, the transversal global property of stiff frame and the security of its link with main girder must be valued. Construction results also proved, the theoretical calculation method could reflect the actual structural state of stiff frame, and its result was conservative. Analysis on stiff frame was an important part of replacement of closure segment, and could provide ways and references for construction control of replacement of closure segment.