Analysis of Steel Frames Under Seismic Loads Accounting for Imperfections
| dc.contributor.advisor | Bedilu, Habte (PhD) | |
| dc.contributor.author | Mekuriaw, Mihrete | |
| dc.date.accessioned | 2020-03-04T12:52:27Z | |
| dc.date.accessioned | 2023-11-11T12:56:29Z | |
| dc.date.available | 2020-03-04T12:52:27Z | |
| dc.date.available | 2023-11-11T12:56:29Z | |
| dc.date.issued | 2019-10 | |
| dc.description.abstract | The study presented here is focused on the seismic analysis of moment-resisting steel frames accounting for imperfections. Geometrical and material nonlinear effects are considered in the modeling of steel frames. The objectives of this research are to identify the main parameters affecting the response of moment-resisting steel frames under seismic actions. The effects of modeling problems and their accuracy in analyzing isolated imperfect columns and a simple imperfect steel portal frame were also examined by varying the number of elements per member. Two types of seismic analyses have been carried out by OpenSees for the steel frames considered in this research, these are nonlinear static and nonlinear dynamic analysis. Force-based distributed plasticity approaches were used for modeling of beam-column elements and fiber sections were assumed for modeling steel sections. Initial sway imperfections, residual stresses, and geometric nonlinear effects were considered for the global analysis of frames. The effects of lateral load distributions on the results of nonlinear static analysis have also been investigated by considering three different patterns of lateral load distribution: linear, modal and triangular. The results of the pushover analysis for the frames under consideration show that the lateral load distribution patterns have a greater effect than the magnitude of the loads applied to the structure. The effects of imperfections for moment-resisting sway frames are less than that of the second-order effects. Three verification examples are performed to demonstrate the capability of the OpenSees program in solving nonlinear problems in comparison with experimental results. These examples were analyzed by both OpenSees and SeismoStruct and the results were presented against experimental results. The second-order elastic analysis results for isolated columns show that the number of elements needed per member to model the cantilever column is lower than the pin ended column. A simple portal frame analyzed by modeling imperfections directly to the frame geometry and by replacing imperfections to equivalent lateral loads has no considerable difference between the results from these types of modeling imperfections. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/20846 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Seismic Loads | en_US |
| dc.subject | Steel Frames | en_US |
| dc.subject | Imperfections | en_US |
| dc.title | Analysis of Steel Frames Under Seismic Loads Accounting for Imperfections | en_US |
| dc.type | Thesis | en_US |