There are special guidelines to design the structures resistant to earthquake forces; parameters such as conditions of the site, seismicity of the site, importance of the structure and the type of the structure are the main effective factors. Consideration of these parameters in calculation and distribution of the earthquake forces are significantly different in various design codes. In most of these design codes, the computation and distribution of earthquake forces are based upon the elastic structural analysis. In this approach, the real behavior of structure is not considered and it may consequently sustain big displacements and irretrievable damages. Therefore, a new design method has been utilized in this paper by which the base shear and its distribution in the height of the structure are calculated according to the plastic behavior of structure and takes advantage of energy balance. The latter is known as performance-based plastic design method. The study of the behavior of eccentrically braced frames with vertical links while undertaking earthquake loads using performance-based plastic design method is the main purpose of this study. It is also worthy of notion that the frames are designed using a capacity design method. In addition, the results are compared with those of the International Building Code 2009 method; the results demonstrate that the plastic hinges, the interstory drifts and plastic rotation of links are distributed more uniformly in the height of frames designed by the suggested method compared to International Building Code 2009.
Most structural design codes use elastic analysis to calculate and distribute seismic base shear over the height. This may lead to unsuitable design and may cause undesirable damages to the structure. To solve this problem, in recent years the Performance-based Plastic Design (PBPD) method which considers the plastic behavior of the structure, has been proposed. In this study, the PBPD method is extended to the dual system of moment and eccentrically braced frames. As a code requirement, in dual systems the moment frame must be able to resist at least 25 percent of the base shear. In the proposed PBPD method, the shear resistance of each system is selected at the beginning of design process and this criterion can be contributed to the design process directly. In this regard, three 6, 12 and 20 story structures are designed based on PBPD and conventional method. To assess the behavior of each system, nonlinear pushover and time history analysis are conducted. Results show that dual frames that are designed by PBPD method have less stiffness and strength than frames that are designed by ordinary method. However the yield mechanism is controllable and plastic deformation capacity of structures are better conducted to design in PBPD method. The results also show that the collapse probability of frames that are designed by PBPD method is acceptable.
A total of 240 white Shaver laying hens from 22 to 34 weeks of age were assigned to 3 treatments and 5 replications. The treatments included: i) Conventional (hens were kept in experimental building without access to outdoor area and fed with the conventional diet), ii) Semi-organic (hens were kept in experimental building with access to outdoor area and fed with the organic diet plus amino acids and vitamin-minerals supplement), and iii) Organic (hens were kept in experimental building with access to outdoor and fed with the organic diet). The results showed statistically significant differences in the feed intake, egg production, egg mass, egg weight, and change body weight(g) means among the treatments (p < 0.05). The hens kept in the organic treatment had fecal highest contain of oocytes coccidia (p < 0.05). The yolk color index and shell strength in the organic treatment significantly increased in comparison with that of other treatments (p < 0.05). The highest HDL was in the semi-organic and organic treatments (p < 0.05). The lowest egg yolk cholesterol concentration was found in hens kept in the semi-organic and organic treatments (p < 0.05). It is concluded that organic production system is useful for improving egg quality.
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