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.

Seismic vulnerability assessment of multi-degree-of-freedom systems based on total input energy and momentary input energy responses

2008 ◽  
Vol 35 (1) ◽  
pp. 41-56 ◽  
Author(s):  
J. Vaseghi Amiri ◽  
G. Ghodrati Amiri ◽  
B. Ganjavi
Keyword(s):  
Reinforced Concrete ◽  
Ground Motion ◽  
Short Duration ◽  
Structural Damage ◽  
Degree Of Freedom ◽  
Input Energy ◽  
Concrete Frames ◽  
Reinforced Concrete Frames ◽  
Total Input ◽  
Mdof Systems

In energy-based seismic evaluation and design, input energy as a seismic demand parameter and hysteretic energy are two important factors. Previous studies for seismic assessment and design based on energy approach have been generally limited to single-degree-of-freedom (SDOF) structures. The purpose of this paper is to find a suitable energy-based parameter for estimation of the damaging potential of ground motion in reinforced concrete frames of multi-degree-of-freedom (MDOF) systems. In this regard, 40 common reinforced concrete frames subjected to four different earthquakes have been analyzed. The results indicate that maximum momentary input energy is a more appropriate parameter than maximum total input energy for estimation of structural damage in short-duration earthquakes or those in which the major damage to structures happens within a short duration of ground motion. In addition, in earthquakes with a wide frequency range, the predominant period of ground motion in Fourier spectrum is shown to be the period corresponding to maximum input energy.

scholarly journals Hysteretic Energy Demands in Multi-Degree-of-Freedom Systems Subjected to Earthquakes

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 220
Author(s):  
Emrah Erduran
Keyword(s):  
Ground Motion ◽  
Energy Demand ◽  
Relative Strength ◽  
Degree Of Freedom ◽  
Special Focus ◽  
Hysteretic Energy ◽  
Demand Distribution ◽  
Single Degree ◽  
Energy Demands ◽  
Energy Based Design

Reliable estimation of energy demands imposed on a structure by a design ground motion is a key component of energy-based design. Although several studies have been conducted to quantify the energy demands in single-degree-of-freedoms systems, few have focused on multi-degree-of-freedom systems. This study aims to build on the knowledge from previous studies on multi-degree-of-freedom systems with special focus on the distribution of hysteretic energy demands among the components of the structure. Nonlinear response history analyses conducted under ground motion sets representing three different hazard levels show that the total input and hysteretic energy demands of multi-degree-of-freedom systems can be accurately estimated from equivalent single-degree-of-freedom systems for low- and medium-rise buildings. The distribution of hysteretic energy demands over the height of the multistory structures has been shown to vary significantly from ground motion to ground motion. Analyses results also show that the relative strength of adjoining beams and columns has a significant influence on the hysteretic energy demand distribution. On the other hand, the energy distribution is relatively insensitive to the damping model used in the analysis of the multi-degree-of-freedom system.

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.

scholarly journals Bidirectional Seismic Energy Input to an Isotropic Nonlinear One-Mass Two-Degree-of-Freedom System

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 143
Author(s):  
Kenji Fujii
Keyword(s):  
Nonlinear System ◽  
Ground Motion ◽  
Energy Input ◽  
Degree Of Freedom ◽  
Half Cycle ◽  
Input Energy ◽  
Peak Displacement ◽  
Seismic Input ◽  
Total Input ◽  
Two Degree Of Freedom

The test results obtained for reinforced concrete columns by several studies have revealed that the peak displacement and cumulative hysteresis energy are important parameters for evaluating the damage of columns under horizontal bidirectional and unidirectional loading. Therefore, the seismic parameters related to the nonlinear peak displacement and cumulative hysteresis energy with regard to horizontal bidirectional seismic input should be investigated. In this study, the bidirectional seismic input to an isotropic nonlinear one-mass two-degree-of-freedom system was evaluated. First, a dimensionless parameter γ, which controls the low-cycle fatigue effect, was formulated as a function of two energy input parameters (the maximum momentary input energy and total input energy) and a nonlinear system (ductility and normalized hysteresis energy absorption during a half cycle). Then, the maximum momentary input energy and total input energy were evaluated according to the ground motion characteristics (Fourier coefficient of horizontal ground motion components) and system properties. Finally, the nonlinear peak displacement and parameter γ of the nonlinear system were evaluated on the basis of the maximum momentary input energy and total input energy. The results revealed that the nonlinear peak displacement and parameter γ can be properly evaluated using two energy parameters.

The Morgan Hill Earthquake of April 24, 1984—Performance of Three Engineered Structures

1985 ◽  
Vol 1 (3) ◽  
pp. 579-593 ◽  
Author(s):  
Simin Naaseh
Keyword(s):  
Structural Damage ◽  
Shear Walls ◽  
Lateral Load ◽  
San Jose ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Long Period ◽  
Steel Building ◽  
Engineered Structures ◽  
Different Characteristics

The performance of three engineered buildings in San Jose during the 1984 Morgan Hill earthquake is reviewed. The lateral-load-resisting systems for these buildings are: (1) concrete shear walls, (2) concrete shear walls and moment frames in two orthogonal directions, and (3) perimeter steel moment frames. The concrete buildings performed satisfactorily with no damage. The steel building oscillated for a long period of time with low damping. There was some nonstructural and content damage and very limited structural damage to this building. The recorded responses of these buildings also showed excitations from two events with different characteristics.

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