mohammadsadegh shahidzadeh

The panel zone is the central part of the beam and column joint in the frame. The purpose of this article is to investigate the effect of panel zone modeling on the behavior of concrete moment resistance frames. For this purpose, two 8- and 12-story concrete moment resistance frames are modeled using OpenSees software and the results of nonlinear cyclic static analysis, nonlinear dynamic analysis and nonlinear incremental dynamic analysis, with and without consideration of panel zones are compared to each other. In all cases, the degradation has been considered based on the Ibarra, Medina and Krawinkler model. The results show that the in the static analyses, the differences in the results of the models are very small. In the dynamic analyses, the effect of the panel zone is significant. The fragility curves of the structures indicate that the models with the panel zones reached the collapse threshold at lower intensity levels. Also, in the non-linear time history analysis of the structural response, it was observed that when the structures have linear behavior, the effects of modeling of the panel zones are insignificant, but when the structure enters the non-linear region, the displacements are greater in the presence of the panel zones.

Self-compacting concrete is one of the newest types of concrete due to its durability, stability, flowability and resistance. Nowadays, one of the most important concerns in the environment is solid waste disposal. Plastic packaging belts are one of the plastic materials that are thrown away after use and are known as waste, also iron smelting factories are the main source of iron oxide waste production. In this research, based on the idea of using plastic packing belts and iron oxide waste in the design of self-compacting concrete mix with different percentages (0, 0.5, 1, 1.5, 2 percent compared to the weight of cement) and ( 0, 5, 10, 15, 20% relative to the weight of sand) was added as an additive. For fresh and hardened properties of self-compacting concrete tests with and without fibers and iron oxide, slump flow tests, V funnel, L box, J ring, U box and compressive strength, tensile strength, ultrasonic pulse speed, Schmidt hammer, temperature effect They were evaluated on compressive strength and permeability. The results of the tests showed that with the increase in the percentage of fibers and iron oxide waste in self-compacting concrete for cubic samples, respectively, the compressive strength, ultrasonic pulse speed, Schmidt hammer and the effect of temperature on the 1-day compressive strength in 28-day processing from the range of 1.61% - 72.57%, 10% - 57.5%, 3.27% - 9.27% and 5.22 – 20.64% increased compared to self-compacting concrete (control) and also the tensile strength of cylindrical samples in 28 days processing.

Reinforced concrete tall building failure, in residual areas, can cause catastrophic disaster if they can’t survive during the destructive earthquakes. Hence, determining the damage of these buildings in the earthquake and detecting the probable mechanism formation are necessary for insurance purposes in urban areas. This paper aims to determine the failure modes of the moment resisting concrete frames (MRFs) according to the damage of the beam and column.  To achieve this goal, a 15-storey moment resisting reinforced concrete frame is modeled via IDARC software, and nonlinear dynamic time history analysis is performed through 60 seismic accelerograms. Then the collapse and non-collapse vectors are constructed obtaining the results of dynamic analysis in both modes. The artificial neural network is used for the classification of the obtained modes. The results show good agreement in failures classes. Hence it is possible to introduce the simple weight factor for frame status identification.