Resumo

GODINEZ DOMINGUEZ, Eber Alberto. Influence of concentric x-bracing or chevron inverted v-bracing on the nonlinear behavior of ductile moment-resisting reinforced concrete frames. Ing. sísm [online]. 2014, n.91, pp.1-30. ISSN 0185-092X.

In this paper the author summarize the results of a study devoted to evaluate, using nonlinear static analyses, the influence of two different bracing configurations on the behavior of low to medium rise ductile moment-resisting reinforced concrete concentric braced frames structures (RC-MRCBFs), as well as its impact in some specific design parameters. RC-MRCBFs height ranges from 4 to 20 stories, using both chevron and X-steel bracing. From the results obtained in this study it is possible to conclude that overstrength reductions factors (R) are dependent on the bracing configuration, therefore equations for the estimation of R factors for each studied bracing configuration are proposed. A story drift limit for service purposes, independent of bracing configuration, is proposed. It was also found that the peak story drift limit proposed in NTCS-04 is suitable for both bracing configurations. For the two bracing configurations, an equation to estimate the minimum shear strength provided by the columns of the RCMRCBFs as a function of the slenderness ratio of the building is proposed. Finally, it was observed that if proposed capacity design methodology is used, it is possible to design low and medium rise ductile RC-MRCBFs when the columns of the moment frames resist at least 50% of the total seismic shear force, obtaining a collapse mechanism that correlate reasonably well with the expected failure mechanism of strong column-weak beam-weaker brace.

Palavras-chave : ductile braced frames; chevron bracing; X bracing; reinforced concrete frames; capacity design; nonlinear static analysis.