Kumbasaroglu, Atila; Korkmaz, Emre

In this study, the effect of hollows passing through reinforced concrete (RC) beams in the longitudinal direction on flexural strength was examined. 4 RC beams were designed to satisfy the conditions for implementation. One of the beams was fabricated as a reference specimen and 3 of the remaining beams were fabricated with total of 5 pipes in the tension, neutral axis and compression regions. All experimental beam specimens were subjected to 4-point axial flexural tests with the request for constant flexural moments at the limits of loading. Experimental beams with pipes in the compression region, tensile region and neutral axis regions were confronted with the reference beam in terms of initial stiffness, ductility, load-bearing capacity and energy absorption capacity. It was verified that to provide that both the sufficient stiffness and sufficient ductility conditions for the reinforced concrete beams, do not establish any structural discontinuity, the longitudinal orbicular cross-section hollows created by pipes should be passed through the neutral axis region as much as possible. The results of the present study not only align with those of previous research (e.g., the correlative results) but also extend the current state of research (e.g., the revealed differences) and provide starting points for future research. Conclusions are drawn from these results at the end of the paper.

Kumbasaroglu, Atila

User-defined plastic hinge properties obtained experimentally are used to examine the structural behavior of bare, infilled walled frames with and without anchor bars in reinforced concrete (RC) buildings. Experimentally obtained moment-curvature relationships of structural members (i.e., beams and columns) are used to determine the plastic hinge properties of each section. Three building frames are modeled and examined for time-history analysis using 20 ground-motion records. Seismic performance levels of three buildings are analyzed to determine the effects of anchor bars. Limit states at each performance level are defined, and the multi-record incremental dynamic analysis curves are obtained; 16%, 50%, and 84% fractal curves are obtained for each case. Cumulative distribution functions are constructed to summarize the varieties in the roof-drift ratios of three RC buildings with different frame types for design-based and maximum-considered earthquake hazards. It is found that, with an increased spectral acceleration of ground motions, the probability of exceeding the performance levels of infilled walled frames in reinforced buildings is reduced with the help of anchor bars. The increased stiffness of RC buildings with infilled wall frames exhibiting lower ductility is re-gained by the absorption energy of the anchor bars.