Effect of Second Order Analysis on the Drift Reliability of Steel Buildings

摘要

Serviceability limit state is an important limit state in the reliability analysis of building structures. One of the serviceability limit states to consider in the design is the lateral displacement or drift check. Excessive static lateral displacement can cause visible damage to nonstructural components, cladding separation or leakage, racking of doors and windows. Furthermore controlling lateral displacements could reduce the second order effects in the tall buildings. Due to the uncertainties in the cross-sectional dimensions and the mechanical properties of materials, the lateral drift of structures is a random variable. Second order effects also amplify the lateral displacements and are a function of gravity loads and lateral displacements. Gravity loads act on lateral displacements and produce overturning moments that amplify the lateral displacements, so the lateral drifts are functions of gravity loads as well. In this study the drift reliability of steel frames and the effects of second order analysis are investigated using geometric nonlinear analysis and Monte Carlo simulation technique. The results show that gravity loads' uncertainties do not affect the reliability index for lateral displacement. In addition, the effect of flexibility uncertainty in the reliability index is small in comparison to the load uncertainty.