Seismic Performance of Ductile Steel Moment-Resisting Frames Subjected to Multiple Strong Ground Motions

2019 ◽  
Vol 35 (1) ◽  
pp. 289-310 ◽  
Author(s):  
Randy Tenderan ◽  
Takanori Ishida ◽  
Yu Jiao ◽  
Satoshi Yamada
Keyword(s):  
Ductile Fracture ◽  
Ground Motion ◽  
Seismic Performance ◽  
Ground Motions ◽  
Cumulative Damage ◽  
Response Analysis ◽  
Steel Moment Resisting Frames ◽  
Strong Ground Motions ◽  
Moment Resisting ◽  
Strong Ground

This study evaluates the seismic performance of steel moment-resisting frames (SMRFs) under multiple strong ground motions. The cumulative damage of beam members is used as the main damage index. A cumulative damage formula is generated based on the experimental results of the steel beam-to-column connection test considering the ductile fracture. Local buckling of members is not considered in this study. Six SMRF models with two parameters (the number of stories and the strength of the column base) are analyzed by conducting an inelastic response analysis. Three different ground motion intensities (peak ground velocity = 0.5 m/s (design level), 0.75 m/s, and 1.0 m/s), each with five repeated excitations are used in the inelastic response analysis to simulate the occurrence of multiple strong ground motions. Stable behavior with a linear increment in cumulative damage is found in most cases, especially when the ground motion intensity is equal to the design level. However, when the intensity is greater than the design level, both ductile fracture and weak story collapse are observed in several cases.

Seismic risk analysis of concrete moment-resisting frames against near-fault earthquakes

2020 ◽  
pp. 1748006X2094047
Author(s):  
Ehsan Khojastehfar ◽  
Farzad Mirzaei Aminian ◽  
Hamid Ghanbari
Keyword(s):  
Risk Analysis ◽  
Seismic Risk ◽  
Ground Motions ◽  
Seismic Risk Analysis ◽  
Strong Ground Motions ◽  
Near Fault ◽  
Moment Resisting Frames ◽  
Short Period ◽  
Moment Resisting ◽  
Strong Ground

Characteristics of earthquake strong ground motions play an important role in the calculation of seismic-induced risk imposed on the structures. Distinguished features exist in movements recorded near seismic sources, as a result of a substantial amount of energy in a short period of record arrival time. In this article, seismic risk analysis of concrete moment-resisting frames due to near-fault strong ground motion is calculated and compared with that of caused by far-field strong ground motions. To achieve this goal, three moment-resisting frames with 4, 6, and 10 stories were designed based on international seismic design code. These frames are modeled applying modified Ibarra–Krawinkler moment–rotation nonlinear model in which strength and stiffness deterioration are involved. Seismic risk analysis of the frames is implemented using the Pacific Earthquake Engineering Research Center approach. Through this approach, probabilistic seismic hazard, probabilistic structural demand, probabilistic structural damage, and probabilistic loss curves are combined. Mean annual frequency of exceedance of seismic-induced losses presents probabilistic seismic risk of the sampled frames. According to the achieved results, the four-story frame (representative of low-rise frames) is more prone to be affected by near-fault strong ground motions in view of calculated seismic-induced risks.

The Simulation of Strong Ground Motion Using Empirical Green Function and Stochastic Method for Southern Taiwan Area

2018 ◽  
Author(s):  
Tsung-Jen Teng ◽  
Pei-Ting Chen ◽  
Ting-Wei Chang ◽  
Yuan-Sen Yang ◽  
Chien-Kuo Chiu ◽  
...  
Keyword(s):  
Green Function ◽  
Ground Motion ◽  
Strong Ground Motion ◽  
Ground Motions ◽  
Large Earthquake ◽  
Green Function Method ◽  
Strong Ground Motions ◽  
Empirical Green Function ◽  
Southern Taiwan ◽  
Strong Ground

This study presents strong ground motion simulation methods for the future fragility study of a power plant in Southern Taiwan. The modified stochastic method and empirical Green function method are utilized to synthesize the strong ground motions of specific events. A modified physical random function model of strong ground motions for specific sites and events is presented in this study with verification of sample level. Based on the special models of the source, path, and local site, the random variables of the physical random function of strong ground motions is obtained. The inverse Fourier transform is used to simulate strong ground motions. For the empirical Green function method, the observed site records from small earthquake events occurring around the source area of a large earthquake are collected to simulate the broadband strong ground motion from a large earthquake event. Finally, an application of proposed two simulated methods of this study for simulating the ground motion records of Nishi-Akashi Station at 1995 Kobe earthquake and 2006 Southern Taiwan PingDong earthquake are presented.

On the Seismic Response of the Faculty of Architecture and Engineering Building at Tohoku University

2016 ◽  
Vol 32 (1) ◽  
pp. 523-545 ◽  
Author(s):  
Ying Wang ◽  
Enrique Villalobos ◽  
Santiago Pujol ◽  
Hamood Al-Washali ◽  
Kazuki Suzuki ◽  
...  
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Structural Damage ◽  
Ground Motions ◽  
Strong Ground Motions ◽  
First Motion ◽  
Strong Ground

The Faculty of Architecture and Engineering Building at Tohoku University survived two strong ground motions. This is not surprising because the structure was stiff and strong. What is surprising is that the first ground motion did not cause severe structural damage but the second one caused so much structural damage that the building had to be evacuated and demolished. The damage occurred despite two key facts: (1) the intensities of the mentioned ground motions are understood to have been similar and (2) the building was strengthened after the first motion (and before the second) following stringent standards.

Simplified R-Factor Relationships for Strong Ground Motions

2003 ◽  
Vol 19 (1) ◽  
pp. 25-45 ◽  
Author(s):  
Isabel Cuesta ◽  
Mark A. Aschheim ◽  
Peter Fajfar
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Structural Systems ◽  
Code Design ◽  
Frequency Content ◽  
Design Spectrum ◽  
Strong Ground Motions ◽  
R Factor ◽  
N2 Method ◽  
Strong Ground

Recent studies have demonstrated the need to consider the ground motion frequency content in the development and use of R−μ−T relationships. Results from two different approaches to determining these relationships are unified in the present paper. Two bilinear R−μ−T/Tg relationships are recommended for most strong ground motions and structural systems. One is more accurate, while the other, more conservative relationship is used in FEMA 273, ATC-32, and the simple version of the N2 method. Both relationships are indexed by the characteristic period of the ground motion, Tg. Simple methods to determine Tg from smoothed design spectra and recorded ground motions are provided. Neither recommended relationships are applicable to the nearly harmonic ground motions that may be generated at sites containing soft lakebed deposits. An example illustrates the application of these relationships to a code design spectrum in both the acceleration-displacement and yield point spectra formats.

Empirical Relationships for Frequency Content Parameters of Earthquake Ground Motions

2004 ◽  
Vol 20 (1) ◽  
pp. 119-144 ◽  
Author(s):  
Ellen M. Rathje ◽  
Fadi Faraj ◽  
Stephanie Russell ◽  
Jonathan D. Bray
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Earthquake Ground Motion ◽  
Rupture Directivity ◽  
Frequency Content ◽  
Deep Soil ◽  
Empirical Relationships ◽  
Strong Ground Motions ◽  
Site Classes ◽  
Strong Ground

The frequency content of an earthquake ground motion is important because it affects the dynamic response of earth and structural systems. Four scalar parameters that characterize the frequency content of strong ground motions are (1) the mean period (Tm), (2) the average spectral period (Tavg), (3) the smoothed spectral predominant period (To), and (4) the predominant spectral period (Tp). Tm and Tavg distinguish the low frequency content of ground motions, while To is affected most by the high frequency content. Tp does not adequately describe the frequency content of a strong ground motion and is not recommended. Empirical relationships are developed that predict three parameters (Tm, Tavg, and To) as a function of earthquake magnitude, site-to-source distance, site conditions, and rupture directivity. The relationships are developed from a large strong-motion database that includes recorded motions from the recent earthquakes in Turkey and Taiwan. The new relationships update those previously developed by the authors and others. The results indicate that three site classes, which distinguish between rock, shallow soil, and deep soil, provide a better prediction of the frequency content parameters and smaller standard error terms than conventional “rock” and “soil” site classes. Forward directivity significantly increases the frequency content parameters, particularly Tm and To, at distances less than 20 km. Each of the frequency content parameters can be predicted with reasonable accuracy, but Tm is the preferred because it best distinguishes the frequency content of strong ground motions.

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