This paper studies the fire resistance of the mega-columns in a super high-rise building and proposes an optimized fire protection design.The simplified analysis model is determined by using the equivalent effective length method.Based on the ISO834 standard process exposed to fire

an initial fire protection design is proposed by analyzing and comparing the relevant design codes and reference materials.Finite element analysis program LS-DYNA is then employed to obtain the temperature distribution of typical mega-column sections in fire and also used to perform structural fire analysis.The analysis result shows that under the specified protection scheme

the mega-columns can achieve a fire resistance of no less than 4.9h

which can satisfy the code requirement.To study the real structural behavior in fire

a real fire of 20 hduration including a heating phase and a cooling phase is established and the stability of the mega-columns in the real fire is analyzed.The results validate the proposed fire protection scheme

but also indicate that the inner temperature of the mega-columns continues to increase during the cooling phase

which might make a dire threat to the structural safety.Structural fire safety evaluation based on the ISO834 standard fire will not be able represent the real fire performance of mega-columns.