دانلود رایگان مقاله انگلیسی ارزیابی ایمنی احتمالاتی قاب فولادی مهاربندی شده خود متمرکز - اشپرینگر 2017

ABSTRACT

The main drawback of conventional braced frames is implicitly accepting structural damage under the design earthquake load, which leads to considerable economic losses. Controlled rocking self-centering system as a modern low-damage system is capable of minimizing the drawbacks of conventional braced frames. This paper quantifies main limit states and investigates the seismic performance of self-centering braced frame using a Probabilistic Safety Assessment procedure. Margin of safety, confidence level, and mean annual frequency of the self-centering archetypes for their main limit states, including PT yield, fuse fracture, and global collapse, are established and are compared with their acceptance criteria. Considering incorporating aleatory and epistemic uncertainties, the efficiency of the system is examined. Results of the investigation indicate that the design of low- and mid-rise self-centering archetypes could provide the adequate margin of safety against exceeding the undesirable limit-states.

6 Summary and conclusions

Self-centering special concentrically braced frame is known as low-damage system that can concentrate damage on replaceable fuses. This paper quantified main limit states of PT yield, fuse fracture, and global collapse limit states for self-centering archetypes. In addition, the safety performance of 12 low- and mid-rise self-centering braced frames with different frame types (space/perimeter) and seismic design categories (SDC Dmax/SDC Dmin) were determined using safety margin ratio, confidence level and mean annual frequency measures. The investigation resulted in the following main conclusions: 1) The mean values of spectral capacity intensities (S^LS) for the PT yield, fuse fracture, and global collapse limit states ranged from 0.67 g to 1.04 g, 0.73 g to 1.25 g, and 0.85 g to 1.75 g, respectively, and mean of the corresponding maximum inter-story drift ratios (IDRmax) ranged from 0.32 to 0.38, 0.43 to 0.45, and 0.53 to 0.88, respectively. Moreover, based on defined performance levels for self-centering braced frames, IDRmax equal to 2%, 3%, and 8% were determined for performance limits of immediate occupancy, life safety, and global collapse, respectively. Furthermore, it was indicated that the mean spectral capacities of archetypes depends on modeling parameters and SDC.