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Structural Engineering and Mechanics
  Volume 54, Number 4, May25 2015, pages 809-827
DOI: http://dx.doi.org/10.12989/sem.2015.54.4.809
 


Evaluation of energy response of space steel frames subjected to seismic loads
Kadir Ozakgul

 
Abstract
    In this paper, seismic energy response of inelastic steel structures under earthquake excitations is investigated. For this purpose, a numerical procedure based on nonlinear dynamic analysis is developed by considering material, geometric and connection nonlinearities. Material nonlinearity is modeled by the inversion of Ramberg-Osgood equation. Nonlinearity caused by the interaction between the axial force and bending moment is also defined considering stability functions, while the geometric nonlinearity caused by axial forces is described using geometric stiffness matrix. Cyclic behaviour of steel connections is taken into account by employing independent hardening model. Dynamic equation of motion is solved by Newmark\'s constant acceleration method in the time history domain. Energy response analysis of space frames is performed by using this proposed numerical method. Finally, for the first time, the distribution of the different energy types versus time at the duration of the earthquake ground motion is obtained where in addition error analysis for the numerical solutions is carried out and plotted depending on the relative error calculated as a function of energy balance versus time.
 
Key Words
    seismic energy response; inelastic steel structure; earthquake ground motion; Ramberg-Osgood equation; independent hardening model; stability functions
 
Address
Kadir Ozakgul: Department of Civil Engineering, Istanbul Technical University, Maslak 34469, Istanbul, Turkey
 

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