Abstract：The failure mechanism and prevention countermeasures of the closure segment bottom slab cracks of longspan P.C. box girders during symmetric cantilever construction were investigated. The destruction styles of the closure segment bottom slab were classified as local bursting, global tearing and global bursting. Based on three classic destruction examples, a whole structural construction simulation analysis with spatial solid elements was conducted. The analysis results show that local bursting belongs to shear destruction, and global tearing belongs to tension destruction with global bursting caused by creep compression. Two countermeasures of reducing action effects and improving structural capacity were proposed. As a constitution solution, transverse stirrup for bottom slab was suggested to enhance the carrying capacity under threedimensional stress.
2013, Vol. 34 
