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Effect of damping and yielding on the seismic response of 3D steel buildings with PMRF.

Reyes-Salazar A, Haldar A, Rodelo-López RE, Bojórquez E - ScientificWorldJournal (2014)

Bottom Line: The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion.It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation.Much more research is needed to reach more general conclusions.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Ciudad Universitaria, 80040 Culiacán, SIN, Mexico.

ABSTRACT
The effect of viscous damping and yielding, on the reduction of the seismic responses of steel buildings modeled as three-dimensional (3D) complex multidegree of freedom (MDOF) systems, is studied. The reduction produced by damping may be larger or smaller than that of yielding. This reduction can significantly vary from one structural idealization to another and is smaller for global than for local response parameters, which in turn depends on the particular local response parameter. The uncertainty in the estimation is significantly larger for local response parameter and decreases as damping increases. The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion. It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation. Moreover, the effect of yielding should be explicitly calculated by using complex 3D MDOF models instead of estimating it in terms of equivalent viscous damping. The findings of this paper are for the particular models used in the study. Much more research is needed to reach more general conclusions.

Show MeSH
Local damping reduction factor for element forces, Model EQ1.
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Related In: Results  -  Collection


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fig7: Local damping reduction factor for element forces, Model EQ1.

Mentions: The RζG,EQ parameter is used to represent the global damping reduction factors for the equivalent (EQ) 3D models. The results for interstory shears are presented in Figure 6 for Models EQ1 and EQ2 and the N-S direction. As for the 3D models with PMRF (SAC Models), the reduction factors significantly vary from one earthquake to another and from one story to another reflecting the effect of earthquake frequency contents and the contribution of several modes of vibrations. From a comparison of all the plots, it is noted that the major observations made for the SAC Models also apply the EQ Models; the only additional observation that can be made is that the reduction values are slightly larger for the SAC Models. The local damping reduction factors for the EQ Models (RζL,EQ) for both axial loads and bending moments are given in Figure 7 for Model EQ1 and the N-S direction. The results resemble those of the SAC Models in the sense that the reduction of the response is larger for local than for global parameters, larger for axial loads than for bending moments, and that the variation of the reduction factors from one column to another, which decreases as damping increases, is smaller for bending moment than for axial load. For a given earthquake, the bending moment reductions, for the 2–5 or 5–10 range, are essentially the same for all the columns under consideration.


Effect of damping and yielding on the seismic response of 3D steel buildings with PMRF.

Reyes-Salazar A, Haldar A, Rodelo-López RE, Bojórquez E - ScientificWorldJournal (2014)

Local damping reduction factor for element forces, Model EQ1.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4109077&req=5

fig7: Local damping reduction factor for element forces, Model EQ1.
Mentions: The RζG,EQ parameter is used to represent the global damping reduction factors for the equivalent (EQ) 3D models. The results for interstory shears are presented in Figure 6 for Models EQ1 and EQ2 and the N-S direction. As for the 3D models with PMRF (SAC Models), the reduction factors significantly vary from one earthquake to another and from one story to another reflecting the effect of earthquake frequency contents and the contribution of several modes of vibrations. From a comparison of all the plots, it is noted that the major observations made for the SAC Models also apply the EQ Models; the only additional observation that can be made is that the reduction values are slightly larger for the SAC Models. The local damping reduction factors for the EQ Models (RζL,EQ) for both axial loads and bending moments are given in Figure 7 for Model EQ1 and the N-S direction. The results resemble those of the SAC Models in the sense that the reduction of the response is larger for local than for global parameters, larger for axial loads than for bending moments, and that the variation of the reduction factors from one column to another, which decreases as damping increases, is smaller for bending moment than for axial load. For a given earthquake, the bending moment reductions, for the 2–5 or 5–10 range, are essentially the same for all the columns under consideration.

Bottom Line: The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion.It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation.Much more research is needed to reach more general conclusions.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Ciudad Universitaria, 80040 Culiacán, SIN, Mexico.

ABSTRACT
The effect of viscous damping and yielding, on the reduction of the seismic responses of steel buildings modeled as three-dimensional (3D) complex multidegree of freedom (MDOF) systems, is studied. The reduction produced by damping may be larger or smaller than that of yielding. This reduction can significantly vary from one structural idealization to another and is smaller for global than for local response parameters, which in turn depends on the particular local response parameter. The uncertainty in the estimation is significantly larger for local response parameter and decreases as damping increases. The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion. It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation. Moreover, the effect of yielding should be explicitly calculated by using complex 3D MDOF models instead of estimating it in terms of equivalent viscous damping. The findings of this paper are for the particular models used in the study. Much more research is needed to reach more general conclusions.

Show MeSH