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Showing 6 results for Concrete
Shape memory alloys and the possibility of supplying ultra elastic property in reinforced concrete structures
Hamidreza Ashrafi, Peyman Beiranvand,
Volume 1, Issue 1 (9-2017)
Abstract
The effect of shape memory and super-elastic property are two exclusive features in shape memory alloys. In order to exploit the properties of shape memory effect, alloy needs to be heated but super-elastic property in these alloys will be proposed automatically in case suitable conditions. In case of using shape memory alloys as Longitudinal armatures in reinforced concrete structures considering them buried in concrete, exploitation of shape memory property will have its particular problems that these problems won’t happen about super-elastic property. Considering the high rate of strain capacity 3% to 8% in memory alloys with super-elastic behavior and the limitation of this capacity in concrete, conditions are necessary to be prepared in a way that memory alloy has the opportunity to propose super-elastic property. In this study, with simulating short-square reinforced concrete column experimental model in software ANSYS and in multi-level and increasing process, longitudinal armatures with shape memory alloy material will replace steel armatures with super-elastic behavior will be investigated with making shape memory alloy kind as variable (Copper and nickel-based alloys), the opportunity of super-elastic property emergence in these alloys and with playing the role of longitudinal armature in reinforced concrete column.

Investigation the behavior of strengthen RC deep beam with web openings with ACI code
Fatemeh Rahimi,
Volume 1, Issue 2 (12-2017)
Abstract
At this paper, Non-linear FE models were used to stimulate strengthened deep beams with opening. Since the regulation, the analysis and designing of deep beams with opening in truss model has doubted, so FE models are the best option in terms of deep beam behavior. One web opening do not turbulent loads transfer path, whereas deep beams with 2 opening can clip the path of strut and decrease shear capacity. The comparison between experimental results and FE model with the ACI outcome, are representing accurate modeling in RC deep beams. Parametric analysis results indicate, when opening cut the strut path, shear strength will be limited. Specimens were retrofitted in perpendicular direction to plastic strain had the most shear strength.

A review of the process of formation and development of self-sensing concrete
Mohammad Rezaei, Ebrahim Khalilzadeh Vahidi,
Volume 1, Issue 2 (12-2017)
Abstract
Self-sensing concrete (ISSC) refers to a structural material that can be monitored without the need for a sensor or remote control. By measuring the electrical resistance of the ISSC, stress, strain, cracks and damage can be monitored in situ. Compared to conventional structural materials that require additional sensors for monitoring or tracking, ISSC has the advantage of: high sensitivity, good mechanical properties, natural compatibility, durability, easy installation and maintenance. The ISSC can be used to monitor structural health, tracking traffic and border and military security. In this paper, we describe the ISSC research advances in terms of its composition, construction methods, sensory signal testing methods, sensory properties, and manufacturing mechanism and structural applications. future challenges in the development and application of ISSCs will also be discussed.

The study of reinforced concrete under loading system and investigation of resistance variations
Amin Faghrian, Akbar Ghanbari,
Volume 1, Issue 3 (3-2018)
Abstract
Explosion phenomenon has been most attractive subject for researchers during different era, from innovation of gunpowder to these days. The biggest of these researchers has been done during WW2. At last years, many terrorist attacks have been done by using explosion materials and bombs. Explosion is a chemical reaction; it finishes in some mill-second. During reaction a huge amount of energy release in the atmosphere and cause a pressure wave by high speed. Wave attacks building, impacts and forces them. In general, RC buildings have better reaction to explosion wave, because of their high mass. In this study, main goal is to observe the RC building under explosion load and finding ways to reduce or prevent damages. To model the RC building the ABAQUS Finite Element software has been used. For modeling it has been tried to make the model very close to the reality and to cover the proper details. The results show that distance has significant effect on reducing the explosion wave pressure and consequently on applied explosion loading.

The effects of soil-structure interaction on the displacement magnification factor of concrete shear wall dual system
Mehdi Atayi, Fereydoon Rezaei,
Volume 2, Issue 2 (9-2018)
Abstract
In an analysis of the seismic behavior of a structure, an excitation applied from the ground to the structure for the case where the structure relies heavily on the earth, it is the same stimulus that existed before the construction of the structure at that point of the earth, However, if the structure depends on the soft soil, significant changes will occur in the seismic input of the structure . Therefore, the structure with the surrounding soil will be in operation and will make changes in the base movements Consequently, taking into account the effects of interaction between the soil and structure can accurately increase the natural periodicity and thus reduce the coefficient of earthquake in design and consequently reduce costs. In this study, the resonant coefficients of displacement of fifteen flexural concrete frame with shear wall were resilient and non-reactive analysis. The studied frames are varied in the number of 5, 10, 15, 20, and 25 in 5 openings And the effect of the soil-structure interaction on the magnitude of the displacement coefficient and its comparison with the stationary foot state has been investigated. Each frame was modeled using nonlinear static analysis using the SAP2000 software . The Springer Wincher method has been used for substructure soil model. The results show that the magnitude of displacement coefficient in states with regard to the interaction of soil and structure is higher, regardless of the interaction of soil and structure.
Evaluation of Nonlinear Static Analysis Methods in Seismic Analysis of Concrete Frames with Shear Wall
Shamsedin Hashemi, Reza Kiani Zadegan,
Volume 2, Issue 4 (3-2019)
Abstract
In this paper, the reinforced concrete frames with concrete shear walls are studied from the perspective of the performance-based design method. The shear wall is modeled as an equivalent column with a rigid beam on its top and its hinges are assigned to the equivalent column depending on the moment or the shear governing the behavior of the wall. For this purpose, two-dimensional models of three reinforced concrete frames with concrete shear walls are created. Models with 5, 10 and 15 floors are created to represent the low-rise, mid-rise and high-rise buildings. The models are investigated using the traditional pushover analysis in SAP software. Moreover, adaptive analyses including force-based adaptive pushover (FAP) and displacement-based adaptive pushover (DAP) are conducted using SEISMO STRUCT software.
To investigate the validity, the results of the pushover analysis are compared with the results of nonlinear time history analysis. For nonlinear time history analysis, 7 far field earthquake records which were recorded from soils with shear wave velocities between 175 to 375 meters per second at a distance of approximately 20 km far from the epicenter of the earthquakes are selected.
The results of these investigations show that, for the high-rise and mid-rise buildings, the traditional pushover analysis results in more displacement and stresses in comparison to the nonlinear time history analysis. Also, the first mode pattern causes more drift than the other patterns. Adaptive analysis which was thought to be based on a stronger logic resulted in more inaccurate responses compared to the traditional pushover analysis. Significantly, DAP analysis failed to meet expectations. The results also show that structures with shear walls and matching the correct design based on linear analysis are resistant to phase shift and do not collapse. Another important result is that the buildings designed based on linear analysis of the Iran 2800 code perform well for non-linear analysis and practically never approach life safety, which is a performance level of Iran 2800 code. This study demonstrates that the frame-shear wall system is very effective in reducing the level of performance and is able to hold a building at low performance levels.
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