Optimal damper placement in steel frames by the Endurance Time method

Abstract

Performance‐based optimal seismic design of structures requires repetitive and massive dynamic analyses. In the Endurance Time (ET) method, structures are subjected to specially designed intensifying acceleration functions and their response at various excitation levels is estimated by each single response‐history analysis, thus, significantly reducing the required computational demand. In this paper, the ET method is utilized to acquire optimal placement of viscous dampers in short steel frames with the target of obtaining the desirable performance in two hazard levels simultaneously. In the optimization procedure, the damping coefficients of the added dampers are treated as design variables and assigned such that the total damping coefficients used in the structure would be minimal. Moreover, the performance of the structures before and after damper placement has been evaluated using ground motions. The sensitivity of the results to the selection of a particular set of ground motions is also investigated. Nonlinear models of steel frames have been investigated and the optimization procedures are conducted with genetic algorithm. Recommendations of ASCE/SEI 41‐06 code are followed in setting the performance design criteria. Copyright © 2011 John Wiley & Sons, Ltd.

Optimal placement of metallic dampers for seismic upgrading of multistory buildings based on a cost‐effectiveness criterion using genetic algorithm

“…In general, two types of earthquake ground motions have been used for time history analysis in previous studies on ODP problems, that is, the real ground motion and the spectrally matched ground motion, where the former is recorded by seismometers whereas the latter is generated by spectral matching techniques . Although most previous studies on ODP problems have adopted the real ground motion for time history analysis, the spectrally matched ground motion has drawn increasing attention and was also adopted for time history analysis in ODP problems in recent years …”

“…Comparison between the Bouc-Wen model and the bilinear model motion, where the former is recorded by seismometers whereas the latter is generated by spectral matching techniques. [35] Although most previous studies on ODP problems have adopted the real ground motion for time history analysis, [11][12][13][21][22][23][24][25][26] the spectrally matched ground motion has drawn increasing attention and was also adopted for time history analysis in ODP problems in recent years. [36,37] In engineering practice, most seismic design codes require that the spectrum of the earthquake ground motion should have a good fit with the design spectrum at certain period points or within certain period range.…”

Application of endurance time method in performance-based optimum design of structures

“…In the ET method, the structure which is to be assessed is analyzed subjected to specially designed intensifying acceleration functions instead of a set of progressively scaled up ground motion records, and its performance is assessed based on its response at different excitation levels in a single response-history analysis. Therefore, the required computational demand is considerably reduced while the major benefits of a complete response history analysis, i.e., accuracy and insensitivity to model complexity, are maintained [21]. Application of the ET method in loss assessment and LCC analysis is formulated in a work by Basim and Estekanchi [10].…”

Seismic collapse assessment of reinforced concrete moment frames using endurance time analysis

“…It also eliminates complications for selecting proper ground motions for IDA. Accuracy of ET method is evaluated by comparing its results with linear static analysis, linear spectral analysis, linear time history analysis, pushover analysis, nonlinear time history analysis, and IDA in previous studies (Estekanchi et al ., , ; Riahi et al ., , , ; Riahi and Estekanchi, ; Estekanchi and Basim, ; Amouzegar et al ., ; Hariri‐Ardebili et al ., ; Valamanesh and Estekanchi, ). In this paper, sidesway collapse of reinforced concrete moment‐resisting frames is assessed using ET analysis.…”