The Effect of Post-Earthquake Fire on the Performance of Steel Moment Frames Subjected to Different Ground Motion Intensities

2021 ◽  
Author(s):  
Peyman Pourkeramat ◽  
Vahed Ghiasi ◽  
Benyamin Mohebi
Keyword(s):  
Ground Motion ◽  
Moment Frames ◽  
Steel Moment Frames

Required Column Overdesign Factor of 3D Steel Moment Frames with Square Tube Columns

2018 ◽  
Vol 763 ◽  
pp. 235-242
Author(s):  
Iathong Chan ◽  
Yuji Koetaka
Keyword(s):  
Plastic Deformation ◽  
Bearing Capacity ◽  
Ground Motion ◽  
Seismic Design ◽  
3D Analysis ◽  
Horizontal Load ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Load Bearing Capacity ◽  
Load Bearing

Steel moment frames are designed to ensure sufficient energy absorption capacity by achieving an entire beam-hinging collapse mechanism against severe earthquakes. Therefore, the column overdesign factor is stipulated in seismic design codes in some countries. For example in Japanese seismic design code, the specified column overdesign factor is 1.5 or more for steel moment frames with square tube columns. And this paper describes seismic response by 3D analysis of steel moment frames, and presents seismic demand for the column overdesign factor to keep the damage of square tube columns below the specified limit of plastic deformation. The major parameters are column overdesign factor, horizontal load bearing capacity, shape of frames and input direction of ground motion. In order to investigate 3D behavior of frames and correlation between plastic deformation of columns and column over design factor, apparent column overdesign factor, which is defined as the ratio of full plastic moment of the column (s) to the full plastic moment of the beam (s) projected in the input direction of the ground motion, is introduced. From the earthquake response analysis, it is clarified that the profile of maximum value of cumulative plastic deformation of columns to apparent column overdesign factor, with the similar horizontal load bearing capacity, are nearly identical regardless of number of stories, floor plan, and input direction of ground motion. As a result, the required column overdesign factor to keep the damage of columns below the limit of plastic deformation is proposed under the reliability index of 2.

Seismic Energy Demands in Steel Moment Frames

2016 ◽  
Vol 847 ◽  
pp. 210-221
Author(s):  
Selcuk Dogru ◽  
Bora Aksar ◽  
Bulent Akbas ◽  
Jay Shen ◽  
Onur Seker ◽  
...  
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Seismic Energy ◽  
Degree Of Freedom ◽  
Nonlinear Time History Analysis ◽  
Input Energy ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Energy Parameters ◽  
Energy Demands

This study presents an energy approach to the seismic evaluation of steel moment resisting frames. A structure subjected to strong ground motion is supposed that it shows nonlinear behavior. Energy parameters is a way to specify the structural damage. Input energy is depend on the characteristics of the structure and ground motion. Structural design can be defined as the equilibration of the input energy and the energy dissipation capacity of the structure. Structures subjected to eartquake are supposed to dissipate all the input energy. Studies based on energy concepts are usually applied to single-degree-of-freedom (SDOF) system. For multi-degree-of-freedom (MDOF), more researches and new simpler methodologies are still needed in performance based evaluation including energy parameters. In this study , low – medium and high rise steel moment frames and will be studied in linear and nonlinear time history analysis. The results obtained from these analysis are reviewed for seismic energy demands.

Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

2006 ◽  
Vol 22 (2) ◽  
pp. 367-390 ◽  
Author(s):  
Erol Kalkan ◽  
Sashi K. Kunnath
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
High Amplitude ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Damage Potential ◽  
Near Fault ◽  
Forward Directivity ◽  
Fling Step ◽  
Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

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