Second-order and advanced analysis of structures allowing for load and construction sequences

The advantage of second-order nonlinear analysis lies on its capacity to model actual structural response instead of making assumption on the structural behavior such as the arbitrary assumption of effective length factor. Considering the construction process of a structure, it may become a sway frame from a non-sway frame when a story is added or, on the contrary, to convert to a non-sway frame from a sway frame when bracings or infill walls are constructed and this makes the first-order linear analysis extremely inconvenient to use. Further, the deformation and load distributions of the structures considering the construction sequence can be much different from those obtained by assuming all structural elements share loads simultaneously. This paper proposes an advanced simulation-based design using an improved second-order analysis for structures accounting for both local and global imperfections, sequential loads and construction process. The technique for such an analysis is described and the error for ignoring the effects of sequential loads and construction procedure is quantified. Both the elastic and the plastic second-order analyses are used for comparison.