Inverse optimal damper placement via shear model for elastic–plastic moment-resisting frames under large-amplitude ground motions

2022 ◽  
Vol 250 ◽  
pp. 113457
Author(s):  
Hiroki Akehashi ◽  
Izuru Takewaki
Keyword(s):  
Large Amplitude ◽  
Ground Motions ◽  
Shear Model ◽  
Elastic Plastic ◽  
Moment Resisting Frames ◽  
Moment Resisting

scholarly journals Seismic collapse safety of reinforced concrete moment resisting frames with/without beam-column joint detailing

2021 ◽  
Vol 54 (1) ◽  
pp. 1-20
Author(s):  
Naveed Ahmad ◽  
Muhammad Rizwan ◽  
Muhammad Ashraf ◽  
Akhtar Naeem Khan ◽  
Qaisar Ali
Keyword(s):  
Reinforced Concrete ◽  
Ground Motions ◽  
Seismic Intensity ◽  
Shear Reinforcement ◽  
Dynamic Reliability ◽  
Moment Resisting Frames ◽  
Collapse Probability ◽  
Seismic Collapse ◽  
Moment Resisting ◽  
Column Joint

FEMA-P695 procedure was applied for seismic collapse safety evaluation of reinforced concrete moment resisting frames with/without beam-column joint detailing common in Pakistan. The deficient frame lacks shear reinforcement in joints and uses concrete of low compressive strength. Shake-table tests were performed on 1:3 reduced scale two-story models, to understand the progressive inelastic response of chosen frames and calibrate the inelastic finite-element based models. The seismic design factors i.e. response modification coefficient, overstrength, ductility, and displacement amplification factors (R, W0, Rμ, Cd) were quantified. Response modification factor R = 7.05 was obtained for the frame with beam-column joint detailing while R = 5.30 was obtained for the deficient frame. The corresponding deflection amplification factor Cd/R was found equal to 0.82 and 1.03, respectively. A suite of design spectrum compatible accelerograms was obtained from PEER strong ground motions for incremental dynamic analysis of numerical models. Collapse fragility functions were developed using a probabilistic nonlinear dynamic reliability-based method. The collapse margin ratio (CMR) was calculated as the ratio of seismic intensity corresponding to the 50th percentile collapse probability to the seismic intensity corresponding to the MCE level ground motions. It was critically compared with the acceptable CMR (i.e. the CMR computed with reference to a seismic intensity corresponding to the 10% collapse probability instead of MCE level ground motions). Frame with shear reinforcement in beam-column joints has achieved CMR 11% higher than the acceptable thus passing the criterion. However, the deficient frame achieved CMR 29% less than the conforming frame. This confirms the efficacy of beam-column joint detailing in reducing collapse risk.

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.

A database of seismic designs, nonlinear models, and seismic responses for steel moment-resisting frame buildings

2020 ◽  
pp. 875529302097120
Author(s):  
Xingquan Guan M.EERI ◽  
Henry Burton M.EERI ◽  
Mehrdad Shokrabadi
Keyword(s):  
Nonlinear Models ◽  
Ground Motions ◽  
Structural Models ◽  
Service Level ◽  
Data Driven ◽  
Seismic Responses ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Nonlinear Structural ◽  
Moment Resisting

A number of simplified methodologies have been developed and used to estimate seismic drift demands in buildings. However, none of them have been systematically tested against a large number of buildings subjected to a diverse set of ground motions. This is partly attributed to the lack of existing databases of building designs, nonlinear structural models, and simulated seismic responses. This article introduces the development of a comprehensive database, which includes 621 special steel moment-resisting frames designed in accordance with modern codes and standards and their corresponding nonlinear structural models and seismic responses (i.e. peak story drifts, peak floor accelerations, and residual story drifts). The seismic responses for a subgroup of 100 steel moment-resisting frames subjected to three groups of site-specific ground motions (with 40 records each), at the service-level, design-based, and maximum considered earthquakes, are also included. The database has been utilized by the authors (in a separate study) to evaluate the performance of existing methods and develop data-driven and hybrid (combination of mechanics-based and data-driven) models for estimating seismic structural drift demands. The database can also be utilized in the development and implementation of a performance-based analytics-driven seismic design methodology.

Amplified Seismic Loads in Steel Moment Frames

2016 ◽  
Vol 847 ◽  
pp. 222-232
Author(s):  
Bora Aksar ◽  
Selcuk Dogru ◽  
Bulent Akbas ◽  
Jay Shen ◽  
Onur Seker ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Ground Motions ◽  
Time History ◽  
Load Level ◽  
Steel Buildings ◽  
Moment Frames ◽  
Axial Loads ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Moment Resisting

This study focuses on exploring the seismic axial loads for columns in steel moment resisting frames (SMRFs) under strong ground motions. For this purpose, the increases in axial loads are investigated at the maximum lateral load level and the corresponding lateral displacement. The results are presented in terms of maximum amplification factors (Ω0) of all frame columns under the selected ground motions and axial load-moment levels in columns. four typical steel moment resisting frames representing typical low, medium and high rise steel buildings are designed based on the seismic design requirement in ASCE 7-10 and AISC 341-10 . An ensemble of ground motions range from moderate to severe are selected to identify the seismic response of each frames. Two sets of ground motions corresponding to 10% and 2% probability of exceedance are used in nonlinear dynamic time history analyses.

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