THE INFLUENCE OF INITIAL IMPERFECTIONS ON THE ULTIMATE BEARING CAPACITY OF SUPER-LARGE HYPERBOLIC COOLING TOWERS

摘要

The uncontrollable factors such as construction error,material inhomogeneity,etc. will inevitably lead to a certain initial imperfection. This paper mainly studies the initial defects of cooling tower structure influencing on the ultimate bearing capacity in the elastic-plastic stage. Through elastic buckling analysis and the self-vibration characteristics of analysis,the buckling modes and the vibration modes are introduced into the structure as the initial defects of hyperbolic cooling towers,taking into account the nonlinear material under the premise of the modified arc-length method in order to amend the elastoplastic ultimate bearing capacity of the structure. The numerical results show that: the hyperbolic cooling tower structure belongs to the imperfection sensitivity structure. The initial defects reduce the ultimate bearing capacity,and the largest drop is 46.6%.The superlarge hyperbolic cooling tower with mode shape initial imperfections is more sensitive than with buckling mode initial imperfections.