Comparison of Building Analyses Assuming Rigid or Flexible Floors

The main purpose of this paper is to investigate the difference between the rigid-floor and flexible-floor analyses of buildings. The finite-element method is used to analyze the buildings with and without shear walls. From a number of response-spectrum analyses, the rigid-floor model was found to be accurate enough for regular and nonregular buildings without shear walls. However, the difference between the rigid-floor and flexible-floor analyses can be large for the buildings with shear walls. Thus, an error formula is generated using the regression analysis of the rigid-floor and flexible-floor analyses from 520 rectangular, U-shaped, and T-shaped buildings. Using this formula, one can estimate the error of the structural analysis of a building with shear walls when the rigid-floor assumption is used.