Document Type : Research Article
Authors
1
Ph.D. Candidate, Department of Civil Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran
2
Ph.D. Candidate of Earthquake Engineering , Department of Civil Engineering, Iran University of science and technology, Tehran, Iran
3
M.Sc. Graduate of Earthquake Engineering, Department of Civil Engineering, , South Tehran Branch, Islamic Azad University, Tehran , Iran
4
Associate Professor, Structural Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
Abstract
Earthquake damage in concretre structures has led to the development of new methods for the design and construction of earhquake resistant concrete structures. However, recent earthquakes have shown that concrete structures are damaged by earthquakes, making them very difficult and even impossible to repair. For this reason, after relatively severe earthquakes, these buildings have been damaged and destroyed, and in order to reuse the structure, it is necessary to spend a lot of time and money due to the extent of damage to the structure, and this issue creates a new idea to limit damage to specific points of the structure. In this way, buildings can be exploited more quickly by replacing damaged elements. One of the new methods to improve the seismic performance of concrete buildings is the use of systems that limit damage to the structure. Among these methods, we can mention systems with rocking motion. In these systems, the main building behaves elastically so that the energy absorption and the nonlinear performance occur only in certain parts of the building that have been predicted. Therefore, in this study, a new system has been developed that transmits damage to fuses by using Rocking shearwall system, and make the concrete structure safe during and after the earthquake by making a very easy repair. Details of connections and design of this system are done in ABAQUS software and nonlinear analysis of the structure equipped with rocking shear wall has been performed in SAP2000 software under seven seismic near field records. The solid element was used to model the rocking system in Abaqus and concrete damage palsticity model was used for modeling the concrete, which is used to model the nonlinear behavior of concrete. The contact between the steel bolts and the concrete shear wall is simulated using contact element. The concrete shear wall in this method remains in the elastic range, but the dampers connected to the shear wall due to the elevation of the shear wall absorb most of the seismic force. The results shown that the use of rocking shear wall compared to the concrete structure without it has effectively reduced the damage to the structure due to seismic records and the concrete structure equipped with it has remained intact. Also, the functional levels of the structure equipped with rocking shear wall has remain in immidiate occupancy but in the concrete structure without it, plastic hinges have even entered the collapse area. Improving the seismic behavior of a structure equipped with rocking shear wall about 30 percent more than a sismilar structure without it. The use of a controlled rocking motion system significantly reduces axial force in structural members by about 25 percent and post-tensioned cables in the cradle drive system have a more than 70% effect in reducing the deformation of the structure and then the yielding damper is placed. The amount of vertical displacement on the sides of rocking concrete shear walls should be less than 5 cm. The use of a new repairable shear wall with rocking motion has caused the vibration mode to dominate the structure of the first vibration mode and the distance between the torsion mode and the first and the second modes are very large.
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