Residual drift demands in moment-resisting steel frames subjected to narrow-band earthquake ground motions

2013 ◽  
Vol 42 (11) ◽  
pp. 1583-1598 ◽  
Author(s):  
Edén Bojórquez ◽  
Jorge Ruiz-García
Keyword(s):  
Narrow Band ◽  
Ground Motions ◽  
Steel Frames ◽  
Residual Drift ◽  
Earthquake Ground Motions ◽  
Moment Resisting

scholarly journals Improving the Structural Reliability of Steel Frames Using Posttensioned Connections

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Edén Bojórquez ◽  
Arturo López-Barraza ◽  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz ◽  
Jorge Ruiz-García ◽  
...  
Keyword(s):  
Ground Motion ◽  
Structural Reliability ◽  
Narrow Band ◽  
Steel Frames ◽  
Steel Structures ◽  
Incremental Dynamic Analysis ◽  
Spectral Acceleration ◽  
Residual Drift ◽  
Interstory Drift ◽  
Moment Resisting

In this paper, various moment-resisting steel frames (MRSFs) are subjected to 30 narrow-band motions scaled at different ground motion intensity levels in terms of spectral acceleration at first mode of vibration SaT1 in order to perform incremental dynamic analysis for peak and residual interstory drift demands. The results are used to compute the structural reliability of the steel frames by means of hazard curves for peak and residual drifts. It is observed that the structures exceed the threshold residual drift of 0.5%, which is perceptible to human occupants, and it could lead to human discomfort according to recent investigations. For this reason, posttensioned connections (PTCs) are incorporated into the steel frames in order to improve the structural reliability. The results suggest that the annual rate of exceedance of peak and residual interstory drift demands are reduced with the use of PTC. Thus, the structural reliability of the steel frames with PTC is superior to that of the MRSFs. In particular, the residual drift demands tend to be smaller when PTCs are incorporated in the steel structures.

On the Use of Vector-Valued Intensity Measure to Predict Peak and Cumulative Demands of Steel Frames under Narrow-Band Motions

2014 ◽  
Vol 595 ◽  
pp. 137-142 ◽  
Author(s):  
Edén Bojórquez ◽  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz
Keyword(s):  
Narrow Band ◽  
Ground Motions ◽  
Steel Frames ◽  
Spectral Shape ◽  
Intensity Measure ◽  
Intensity Measures ◽  
Energy Demands ◽  
Long Duration ◽  
Story Drift ◽  
Vector Valued

In this study, various alternative vector-valued ground motion intensity measures (IMs) are used to estimate maximum inter-story drifts and hysteretic energy demands of steel framed buildings under long duration narrow-band ground motions. The vectors are based on the spectral acceleration at first mode of the structure as first parameterSa (T1). As the second parameter of the vector,IMsrelated to peak, integral and spectral shape parameters are selected. It is concluded that spectral-shape-based vector-valuedIMshave the best relation with maximum inter-story drift and energy demands in steel frames subjected to narrow-band earthquake ground motions.

scholarly journals Reduction of Maximum and Residual Drifts on Posttensioned Steel Frames with Semirigid Connections

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Arturo López-Barraza ◽  
Edén Bojórquez ◽  
Sonia E. Ruiz ◽  
Alfredo Reyes-Salazar
Keyword(s):  
Seismic Performance ◽  
Ground Motions ◽  
Soft Soil ◽  
Steel Frames ◽  
Time History ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Steel Buildings ◽  
Earthquake Ground Motions ◽  
Semirigid Connections

The aim of this paper is to study the seismic performance of self-centering moment-resisting steel frames with posttensioned connections taking into account nonlinear material behavior, for better understanding of the advantages of this type of structural system. Further, the seismic performance of traditional structures with rigid connections is compared with the corresponding equivalent posttensioned structures with semirigid connections. Nonlinear time history analyses are developed for both types of structural systems to obtain the maximum and the residual interstory drifts. Thirty long-duration narrow-banded earthquake ground motions recorded on soft soil sites of Mexico City are used for the analyses. It is concluded that the structural response of steel buildings with posttensioned connections subjected to intense earthquake ground motions is reduced compared with the seismic response of traditional buildings with welded connections. Moreover, residual interstory drift demands are considerably reduced for the system with posttensioned connections, which is important to avoid the demolition of the buildings after an earthquake.

Seismic Behavior of Dual Systems with Column Hinging

2001 ◽  
Vol 17 (4) ◽  
pp. 657-677 ◽  
Author(s):  
Mário S. Lopes ◽  
Rita Bento
Keyword(s):  
Ground Motions ◽  
Nonlinear Dynamic Analysis ◽  
Capacity Design ◽  
Dual Systems ◽  
Structural Walls ◽  
Design Procedures ◽  
Earthquake Ground Motions ◽  
Codes Of Practice ◽  
Moment Resisting ◽  
Ductile Behavior

In order that moment-resisting frames exhibit adequate ductile behavior under seismic actions, it is necessary that inelastic deformations spread throughout the height of the frames. It is widely accepted that this is only possible if vertical members remain essentially elastic, such as enforced in the most advanced codes of practice. The results of nonlinear dynamic analysis shown in this work demonstrate that this is not the case if frames resist earthquake ground motions together with structural walls. This was attributed to the fact that these elements prevent the development of sidesway mechanisms even if plastic hinges form at all column extremities at a given floor. As a consequence, it is proposed to relax the capacity design procedures for design of ductile frames that resist earthquake ground motions together with structural walls.

scholarly journals Influence of P-Delta Effect on Ductility and Vulnerability of SMRF Steel Buildings

2015 ◽  
Vol 9 (1) ◽  
pp. 351-362 ◽  
Author(s):  
Juan Carlos Vielma Pérez ◽  
Manuel Antonio Cando Loachamín
Keyword(s):  
Seismic Behavior ◽  
Ground Motions ◽  
Steel Frames ◽  
Order Effect ◽  
Second Order ◽  
Steel Buildings ◽  
Strong Ground Motions ◽  
Earthquake Resistant ◽  
Moment Resisting ◽  
Strong Ground

Current earthquake-resistant procedures prescribe generic values for the response reductions factors, regardless of the configurational characteristics of the designed buildings. It is well know that these response reduction factors values reflect the expected behavior of the structures when they are under strong ground motions, being this seismic behavior usually evaluated through ductility and over-strength. In this work calculated values of the ductility of special moment-resisting steel frames with different span lengths and designed according the Ecuadorian Construction Code are presented. Results show that the buildings’ ductility is strongly influenced by the spans length and they would reach inadequate values if the second-order effect P-Δ occur, and then indicating that the structures are more vulnerable than structures not affected by P-Δ effect.

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