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.

Even though some empirical formulas for hysteretic energy (E H ) to energy input (E I ) ratio have been proposed in the literature, they all assume that this ratio is the same for any period range and do not consider either the ground motion properties or the structural properties. This paper presents a study on E H /E I in inelastic single-degree-of-freedom (SDOF) systems and relates it to the inelastic multidegree-of-freedom (MDOF) systems subject to severe earthquake ground motions. The response analyses are carried out through nonlinear dynamic time-history (NDTH) analyses on SDOF systems and steel moment resisting frames as MDOF systems for ninety EQGMs recorded on different soils. A spectrum for E H /E I ratio with different strength indices in SDOF systems is proposed based on the analyses results. Keywords

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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