behzad ayoobi
Abstract
One of the challenges of using reinforced concrete structures is the corrosion of reinforcements in aggressive and corrosive environments such as offshore structures, stairs, etc., which will eventually lead to the destruction of concrete structures. To solve the corrosion problem in this category of ...
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One of the challenges of using reinforced concrete structures is the corrosion of reinforcements in aggressive and corrosive environments such as offshore structures, stairs, etc., which will eventually lead to the destruction of concrete structures. To solve the corrosion problem in this category of structures, experts turned to the use of rebars with epoxy coating as a suitable alternative to conventional rebars. Most FRP rebars on the market today are made of high-performance continuous fibers such as glass, carbon and aramid, which are embedded in a polymer substrate by various composite production methods. FRP amplifiers are commonly used in various forms in the form of networks, rebars, textiles or cables. In this research, the numerical behavior of FRP hybrid reinforced concrete compression members and its modeling under concentric loading is investigated. All modeling is performed in ABAQUS finite element software and is evaluated using nonlinear analysis.
Alireza Doroudian Homayouni; Abbas Ghasemi
Abstract
The direct displacement-based design method introduced and expanded by Priestley et al. is one of the functional methods that has the ability to replace the force-based design method. Estimation of hysteresis damping and displacement of yielding are among the key parameters of this method, the error ...
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The direct displacement-based design method introduced and expanded by Priestley et al. is one of the functional methods that has the ability to replace the force-based design method. Estimation of hysteresis damping and displacement of yielding are among the key parameters of this method, the error in their estimation leads to the overall error in the estimation of base shear. In this study, 10 bending steel frames with vestibular braces and short and medium zippers have been investigated and evaluated for tremors. With a wide range of analyses, including non-linear dynamic analyses of time history based on natural accelerometers, as well as wear analysis based on different patterns, yielding displacement, damping, effective cycle time, secant cycle time and base shear of the steel bending frames with the above-mentioned hip brace and zipper are analysed. And the relationships presented in the DBD regulations have been verified. Finally, by proposing relationships for damping and displacement of yielding, in relation to improving the performance of the direct design method based on displacement in steel bending frames, it has been done as follows. Given that increasing damping, it underestimates the forces applied to the structure. It seems that Priestley's formula is presented with a higher reliability factor and results in the design of harder and heavier structures, in terms of the amount of steel consumption. The amount of damping is not very sensitive to the changes in the number of openings and in the worst case, the damping has a difference of 3% with the increase in the number of openings.
Hojjatullah Vakili Nusratabad
Volume 2, Issue 4 , July 2020, , Pages 64-76
Abstract
In recent decades, the need for tall towers with different uses has increased day by day. The proper performance of these towers against earthquakes is of great importance due to the volume of investments and their residents. In high-rise structures, one of the problems that makes it difficult to use ...
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In recent decades, the need for tall towers with different uses has increased day by day. The proper performance of these towers against earthquakes is of great importance due to the volume of investments and their residents. In high-rise structures, one of the problems that makes it difficult to use the structure is the high displacement values of the floors, including the roof of the structure. Therefore, in this study, by calculating the values of floor and roof displacement and comparing it with the allowable structural values, the need to use new methods such as long braces, truss belts and seismic isolation system is investigated. In this paper, first, using a selected laboratory sample from the frame, how to model and validate the results of nonlinear static analysis in the SAP software is discussed. Then, by modeling the 18, 22, 26 and 30 floor samples and performing nonlinear and dynamic static analysis of nonlinear time history, the seismic performance of the system has been investigated. And their behavioral curves are presented. Finally, the results of comparing seismic parameters and displacement values in different samples are presented. The results indicate poor bending system performance in high-rise structures, making it difficult to use the building normally.
