Macroscopic Modelling of the Concrete Shearwall with Asymmetrical Openings

Document Type : Original Research

Authors
M. Rezapour
M. Ghassemieh
School of Civil EngineeringUniversity of Tehran
10.22034/23.5.4
Abstract
So far, various elements have been introduced for modeling concrete shear walls, which are classified into two general categories: microscopic and macroscopic. Compared to microscopic elements, macroscopic elements have less degrees of freedom and therefore require less time for analysis. This is the main advantage of these elements. In this article, a special type of macroscopic elements called Multiple-Vertical-Line-Element-Model (MVLEM) is used to model the concrete shear wall. These elements simulate the behavior of simple shear walls well, but when the opening is embedded in the wall, it does not work satisfactory. In this article, the modified MVLEM is used to model the concrete shear wall with asymmetric openings. For this purpose, an experimental concrete shear wall with asymmetric openings was selected and verified using the microscopic finite element method in Abaqus software. After validation, the shear wall was subjected to macroscopic modeling in Abaqus software. In this model, a method for macroscopic modeling of the coupling beam was proposed, which is based on the moment distribution diagram in the beam. When the wall is subjected to lateral loading, due to its geometric shape, the amount of moment on

one side of the beam is almost zero and on the other side it is maximum. In simple concrete shear walls under lateral load, the amount of moment at the top of the wall is zero and at the bottom is maximum too. Therefore, the coupling beam can be considered as a simple shear wall. In the shear wall with asymmetric openings, the coupling beams are modeled as simple shear wall whose base is connected to the main wall. After modeling the coupling beam, three different methods were proposed to connect this beam to the main body of the wall. This research includes a microscopic wall with asymmetric openings, three macroscopic walls. The main difference between the macroscopic walls is in the way of connecting the beam to the shear wall, which is based on the difference in the stiffness of the connection. In order to check the accuracy of the proposed models, macroscopic and microscopic walls were subjected to static and quasi-dynamic loading. Based on the results of the aforementioned analyses, the models showed acceptable behavior. The amount of connection stiffness caused the behavior of macroscopic models to be different from each other. Based on the results, as the stiffness of the beam to the wall increases, the bearing capacity and elastic stiffness of the model increases and the ductility decreases. The degree of stiffness of the connection also affects the cyclic behavior of the wall. In such a way that the higher the stiffness of the connection, the greater the loss of carrying capacity is observed in cyclic loading. In the model whose stiffness is higher than the other models, it experiments a large resistance drop in the ninth and tenth cycles. In the model whose stiffness is less than the others, less drop is observed and it shows a soft behavior. The model in which the connection stiffness was in the middle level showed the most accuracy compared to other models.

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Modares Civil Engineering journal
Volume 23, Issue 5
November and December 2023
Pages 35-49