1- Civil Engineering Dept., Islamic Azad University, Kerman Branch , tabatabaei@iauk.ac.ir
2- Islamic Azad University of Kerman
Abstract: (15 Views)
The effective design of structures resistant to seismic vibrations is one of the main concerns of structural engineers to deal with damages caused by earthquakes, which can withstand more earthquake forces with methods such as energy dissipation. Recent earthquake records show that the earthquake record characteristic of the near area differs from the earthquake records of the far area. Among these characteristics, it can be mentioned that the pulse-type state of these records, as well as the high maximum speed and ground displacements. For this reason, these types of records increase the seismic requirements of the structure compared to normal earthquakes. The map of faults and seismic zoning of Iran shows that important urban points such as Tehran, Tabriz, etc. have high seismicity and are located near the fault. Therefore, it is necessary to design and build structures that can properly withstand the features of near-fault earthquakes, this issue reveals the understanding and recognition of the behavior of structural systems and the structure's response to the special features of near-fault earthquakes. This article first investigated the seismic evaluation of three existing 4, 8, and 12-story steel structures with lateral load-resisting systems. Then the desired structure was strengthened using a friction damper, and finally, the acceleration recorder was applied to the structure in the near- and far-fault earthquake zone case study. The seismic demand of the retrofitted structure was investigated in ANSYS Workbench finite element software, which was done in the form of modal analysis, floor drift displacement, structure acceleration response, and von Mises stress. For seismic validation, a two-story, single-span steel frame has been used. The dynamic load used was 0.5g based on the north-south component of the El Centro earthquake (1940) with a maximum acceleration scaled to 50 cm/s. To validate the numerical results, the horizontal displacement of two points on the first and second floor was compared with experimental data, and an acceptable accuracy was obtained. The results of the maximum acceleration at the highest point of the building showed that in a far-fault earthquake zone, the best effect of dampers was on 8-story buildings with a 77% decrease, and in a near-fault earthquake zone, it was related to a 4-story building with a 66.4% decrease in acceleration. Stress in near- and far-fault earthquake zones, the best effect of dampers was on 4-story buildings with 83% and 84% reduction, respectively. In a far-fault earthquake zone, the best effect of dampers was on 8-story buildings with a 44% reduction in maximum displacement, and in a near-fault earthquake zone, it was related to a 4-story building with a 61% reduction in acceleration.
Article Type:
Original Research |
Subject:
Earthquake Received: 2024/01/9 | Accepted: 2024/11/20