Techno Press
Tp_Editing System.E (TES.E)
Login Search
You logged in as...

eas
 
CONTENTS
Volume 28, Number 4, April 2025
 

Abstract
Studies conducted on the effect of earthquakes in concrete structures are based on the structure's behavior versus these stimulations by common regulations generally. In the desired structural model, the shear walls are considered as lateral resistance elements, and considering the stiffness and strength assigned to these elements, the torsional and displacement responses are investigated. Finally, the vulnerability of structures by using fragility curves and surfaces and changing the centers of stiffness and strength relative to the center of mass and creating 7 different modes are discussed. Furthermore, the nonlinear incremental dynamic analysis (IDA) method has been used by OpenSees software. In total, 21 earthquake records, which are mostly based on FEMA P695 criteria, are employed for this analysis. The results indicate if stiffness and strength centers are located on both sides of the center of mass, which is called the symmetric model in this study, the minimum torsional response and, consequently, the least structure probability of damage is created. Also, for models that have asymmetry of stiffness and strength centers to the center of mass (asymmetric models), torsional responses, displacement, and consequently vulnerability increased at lower spectral acceleration. The proximity of stiffness and strength centers to stiff (left) or soft (right) edges and considering performance levels causes a change in the vulnerability of one edge relative to the other edge. Due to the overlap of some of the graphs obtained through fragility curves, using the fragility surfaces results to represent the extent of probability of damage more accurately was on the agenda.

Key Words
fragility curve; fragility surfaces; incremental dynamic analysis; irregular structures; stiffness and strength dependence; stiffness and strength eccentricity

Address
Yousef Mardani Kachooei and Gholamreza Atefatdoost: Department of Civil Engineering, Estahban branch, Islamic Azad University, Estahban, Iran
Hasanali Tavazo: Department of Civil Engineering, Zarghan branch, Islamic Azad University, Zarghan, Iran
Leila Shahryari: Department of Civil Engineering, Shiraz branch, Islamic Azad University, Shiraz, Iran

Abstract
This paper presents a comparative analysis of the seismic performance of two tall steel buildings employing different dual systems: the Special Concentrically Braced Frame (SCBF) and the Buckling Restrained Braced Frame (BRBF). The study investigates the behavior of two 30-story structures subjected to ground motions from 15 far-field and 15 near-field earthquake records, using Incremental Dynamic Analysis (IDA). Additionally, fragility curves are developed to evaluate structural damage probabilities at Immediate Occupancy (IO) and Collapse Prevention (CP) performance levels. Seismic loss estimation is conducted using the FEMA P-58 methodology, providing a comprehensive assessment of economic implications at two intensity levels, corresponding to mean return periods of 475 and 2475 years. The outcomes emphasize the critical influence of near-field ground motions, which impose greater demands on structural performance compared to far-field scenarios. The results reveal that BRBF systems consistently outperform SCBFs in terms of economic efficiency and seismic resilience. At intensity level 1, median repair costs for SCBFs are 24.7% and 30.4% of the total replacement cost under far-field and near-field conditions, respectively, compared to 20.7% and 25.6% for BRBFs. These cost advantages persist at intensity level 2, where BRBF repair costs are 31.7% and 36.4%, significantly lower than the 33.9% and 42.5% for SCBFs. These findings confirm the superiority of Buckling Restrained Braced Frames in reducing repair costs, minimizing damage probabilities, and enhancing the seismic resilience of tall steel buildings, regardless of ground motion characteristics.

Key Words
buckling restrained barce; FEMA; high-rise building; incremental dynamic analysis; loss estimation; performance based design

Address
Behrouz Asgarian and Farnaz Abediyan: Department of Civil Engineering, K.N.Toosi University of Technology, Mirdamad Ave, Tehran, 19697-64499, Tehran, Iran
Sara Amerinia: Department of Civil Engineering, Memorial University of Newfoundland, Livingston St, St. John

Abstract
This study involves an analytical investigation of the earthquake performance of Technological Friction Damper Systems-TFDS and the novel Technological Base Isolator System-TBIS in steel structures. The earthquake performance of a 5-story steel structure, which is considered within the scope of this study, was analyzed using both the pushover method and the time history analysis method in accordance with the Turkish Building Earthquake Code 2018 TBEC-2018. The pushover analysis method was chosen for retrofitting with the TFDS, while time history analysis methods were selected for the retrofitting study involving TBIS and the hybrid system. 11 scaled earthquake records were utilized for history analysis. It was observed that no damage occurred in the structure after retrofitting with TFDS. Furthermore, FEM analyses also corroborated this finding. On the other hand, when the reference structure was analyzed using the time history analysis method with 11 scaled earthquake records, it was noted that 36% of the ground floor columns did not meet the TBEC 2018 limit conditions. However, damage was prevented when TBIS and TBIS-TFDS-Hybrid were used together. Additionally, it was observed that the TBIS system reduced the roof's relative displacement of the structure by 54%, and the hybrid system reduced it by 61%.

Key Words
base isolator; damper and base isolator; earthquake; friction damper; hybrid system

Address
Civil Engineering, Bahriye Ucok 9674 street No:24 Karabaglar Izmir, Türkiye

Abstract
Scrap tyres, a significant source of environmental pollution, have been identified as excellent materials for vibration isolation. The steel cords in the tyres provide vertical stiffness, while the rubber offers lateral flexibility, making them suitable for base isolation. However, variations in tyre sizes, pad thickness, steel strand arrangements, and properties under different loading directions and pressures present practical challenges. This paper investigates the basic strength properties of scrap tyre pads to assess their suitability for base isolation. Key factors influencing the structural properties of scrap tyre pad isolators are identified. Tyres of size 175/65/R14 are chosen for the study. Structural properties are estimated through experimental and finite element modelling. A detailed parametric study examines the effects of secondary shape factor, loading direction, vertical pressure, and tyre layer thickness and arrangement. The study reveals that secondary shape factor and vertical pressure predominantly control the structural properties of unbonded scrap tyre pad isolators. A Design Aid is developed, showing the structural parameters of isolators with different configurations under varying pressures. The design aid's application is demonstrated in designing base isolators for a two-story masonry building.

Key Words
base isolation; masonry building; scrap tyre pad isolator; sustainability

Address
1) Department of Civil Engineering, TKM College of Engineering, Kollam 691005, Kerala, India, 2) APJ Abdul Kalam Technological University, Thiruvananthapuram 695016, Kerala, India

Abstract
Earthquakes, as a major cause of excitation and damage to structures, have always posed one of the most significant challenges in structural design. Consequently, various methods have been proposed to mitigate the impact of seismic events. Seismic isolators, as a subset of structural control methods, represent an effective solution by being placed between the superstructure and substructure to alter the input vibrations from destructive to non-destructive. Among the various types of seismic isolators, frictional pendulum isolators are widely used, while suspended pendulum isolators, a more recent development by the authors, offer an alternative approach. This paper presents a comparison of the two types of isolators, evaluating their performance, benefits, and limitations under different seismic conditions. Challenges associated with frictional pendulum isolators, such as the existence of a non-periodic region near the center, permanent displacements, and the inability to effectively isolate seismic forces under low acceleration loads, are examined. In this research, a friction pendulum seismic isolator with different friction coefficients and a suspended pendulum seismic isolator with different damping have been modeled and investigated. The models have been subjected to several seismic loadings, and the system response has been obtained. Fast Fourier transform analysis has been performed on the results. It is demonstrated that these issues can lead to fatigue and damage to non-structural components under cyclic loading. Furthermore, the study highlights that frictional pendulum isolators may not adequately isolate seismic loads with low acceleration, which can negatively affect the overall performance of seismic isolation systems. Cyclic loading results showed that the efficiency of the friction pendulum isolator in terms of energy dissipation is very low compared to the suspended pendulum isolator, and the resonance in the friction pendulum isolator is not fully controlled.

Key Words
earthquake; frictional pendulum; isolators; suspended pendulum; vibration

Address
Department of Structural Engineering, University of Tabriz, 29 Bahman Boulevard, Tabriz, Iran

Abstract
A new structural wall system has been proposed to enhance the seismic performance of reinforced concrete walls. The new wall system is slotted vertically along the central axis unlike the conventional reinforce concrete wall. Metallic plates, featuring a series of parallel diamond-shaped holes, are strategically employed to connect the two inner sides of the slit wall. To further enhance ductility and energy dissipation capacity, a yielding scheme has been specifically designed for the metallic plates. The configuration and design methodology of the slit wall are established accordinA new structural wall system has been proposed to enhance the seismic performance of reinforced concrete walls. The new wall system is slotted vertically along the central axis unlike the conventional reinforce concrete wall. Metallic plates, featuring a series of parallel diamond-shaped holes, are strategically employed to connect the two inner sides of the slit wall. To further enhance ductility and energy dissipation capacity, a yielding scheme has been specifically designed for the metallic plates. The configuration and design methodology of the slit wall are established according to its lateral deformation. Finally, numerical simulations are conducted to validate the design method of the metallic damper and the slit wall. The analysis results have shown that the new structural wall system can achieve a desirable performance of energy dissipation.g to its lateral deformation. Finally, numerical simulations are conducted to validate the design method of the metallic damper and the slit wall. The analysis results have shown that the new structural wall system can achieve a desirable performance of energy dissipation.

Key Words
energy dissipation; high ductility; metallic damper; reinforced concrete wall; slit wall

Address
Ming Fang, Zhipeng Li and Miao Zhang: Shipbuilding and Ocean Engineering Experiment Centre, College of Shipbuilding Engineering, Harbin Engineering University, Harbin, China
Shuo Xing: College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin, China
Jian Wang: School of Civil Engineering, Harbin Institute of Technology, Harbin, China

Techno-Press: Publishers of international journals and conference proceedings.       Copyright © 2025 Techno-Press ALL RIGHTS RESERVED.
P.O. Box 33, Yuseong, Daejeon 34186 Korea, Email: admin@techno-press.com