Soil-Structure Interaction Effects on Seismic Fragility Curves of Steel Mrf Structures


Abstract eng:
Seismic loss estimation of structures rested on soil is inevitably influenced by soil-structure interaction (SSI). To evaluate this fact, the present study is focused on seismic damage assessment of low-rise steel moment resisting frames (MRFs) incorporating SSI effects. To this end, incremental dynamic analyses (IDAs) are performed using a suit of real ground motion records. A five-story MRF structure is selected as representative of building inventory in Iran. The structure is supported by single footings. To evaluate the SSI effects, four cases are compared including (i) fixed base, (ii) linear SSI and uncoupled footings (i.e. without tie beams), (iii) nonlinear SSI and uncoupled footings, and (iv) nonlinear SSI and coupled footings (i.e. with tie beams). The SSI effect is represented by modified Beam-on-nonlinear Winkler foundation (BNWF) model. An appropriate structural damage index based on summation of cumulative plastic hinges’ rotations is employed. The seismic fragility curves of the structures are derived and compared for the above-mentioned cases. The results show that nonlinear SSI has significant effects on seismic fragility curves and consequently the overall amount of seismic loss estimation. Evidently, these effects are mitigating especially in case of footings with tie beams. However, some adverse displacements (i.e. foundation uplifting) are expected in case of footings without tie beams through which the local instabilities would be probable during the excitation period. As another consequence, excessive residual foundation tilting especially in exterior footings could lead to serious problems in serviceability of the structure after a strong event. Overall, based on findings of this study, the obtained modified fragility curves are supposed to be helpful for the earthquake engineers to conduct more realistic loss estimations considering SSI effects. These modification factors need to be generalized with respect to a variety of structural systems, site types and foundation configurations.

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Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
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Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 3051.:
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