Application of Lower Grade Steel on Dynamic Behavior of X-braces in Shear Part 2: Advanced Nonlinear Static and Incremental Dynamic Analyses (IDA)

Document Type : Research Article


1 Department of Civil Engineering, Shahr-e-Qods Branch, Islamic Azad University, Tehran - Iran

2 M.Sc. in Earthquake Engineering, Tehran, Iran


In the first part of this paper, the theory of design of X-braces using different steel grades was introduced and its effects on different frames verified using nonlinear static analyses. It was found that using lower grade steel in X-braces increases the stiffness, energy absorption capacity, damping, and ductility of the system and decreases its lateral drift. To completely investigate the behavior of steel structures with X-bracing systems in design with different steel grades and consider their dynamic behavior, the frames with different stories studied using advanced nonlinear static and Incremental Dynamic Analyses (IDA). The results are presented as comparative diagrams and tables. The near and far-field earthquakes used for dynamic analysis of sand and their seismic performance were studied. Therefore, this research can lead to a better investigation of the seismic behavior of X-braced systems in design with different steel grades. The proposed theory along with analyses shows that building codes and steel seismic design specifications can consider the effects of steel grades in seismic parameters definition of structures. The comparative diagrams and tables show that the seismic behavior of X-braces designed with lower-grade steel improves considerably. Also, the response of structures under near field earthquakes is bigger than related parameters under far-field earthquakes. Also, with an increase in height of the frames and governing bending behavior (relative to shear behavior) and more effects of columns in lateral deflection of frames, the effects of lower-grade steel in the overall behavior of taller buildings decreases gradually.


Main Subjects

[1] C. Comartin, R. W. Niewiarowski, S. A. Freeman, F. Turner, Seismic Evaluation and Retrofit of Concrete Buildings: A Practical Overview of the ATC 40 Document, 2000.
[2] F.E.M. Agency, NEHRP Guidelines for the Seismic Rehabilitation of Buildings, 2000.
[3] S. Antoniou, R. Pinho, Development and verification of a displacement-based adaptive pushover procedure, Journal of Earthquake Engineering, 8(5) (2004) 643-661.
[4] S. Antoniou, R. Pinho, Advantages and limitations of adaptive and non-adaptive force-based pushover procedures, Journal of Earthquake Engineering, 8(4) (2004) 497-522.
[5] P. Fajfar, A Nonlinear Analysis Method for Performanceā€Based Seismic Design, Earthquake Spectra, 16(3) (2000) 573-592.g20
[6] D. Vamvatsikos, C.A. Cornell, Incremental dynamic analysis, Earthquake Engineering & Structural Dynamics, 31(3) (2002) 491-514.
[7] D. Vamvatsikos, C.A. Cornell, Applied Incremental Dynamic Analysis, Earthquake Spectra, 20(2) (2004) 523-553.
[8] B. Asgarian, A. Sadrinezhad, P. Alanjari, Seismic performance evaluation of steel moment resisting frames through incremental dynamic analysis, Journal of Constructional Steel Research, 66(2) (2010) 178-190.
[9] M. Dolsek, Incremental dynamic analysis with consideration of modeling uncertainties, Earthquake Engineering & Structural Dynamics, 38(6) (2009) 805-825.
[10] D. Vamvatsikos, C.A. Cornell, Direct Estimation of Seismic Demand and Capacity of Multidegree-of-Freedom Systems through Incremental Dynamic Analysis of Single Degree of Freedom Approximation1, Journal of Structural Engineering, 131(4) (2005) 589-599.
[11] D. Vamvatsikos, M. Fragiadakis, Incremental dynamic analysis for estimating seismic performance sensitivity and uncertainty, Earthquake Engineering & Structural Dynamics, 39(2) (2010) 141-163.
[12] M. Mofid, P. Zarfam, B.R. Fard, On the modal incremental dynamic analysis, The Structural Design of Tall and Special Buildings, 14(4) (2005) 315-329.
[13] P. Zarfam, M. Mofid, On the modal incremental dynamic analysis of reinforced concrete structures, using a trilinear idealization model, Engineering Structures, 33(4) (2011) 1117-1122.
[14] P. Ebadi, H.R. Shokrghozar, M. Moradi, Case study on advanced nonlinear static procedures with adaptive pushover methods in analysis of steel frames with X-bracing system, in:  3th International Congress on Civil Engineering, Architecture and Urban Development, Tehran-Iran, 2015.
[15] B. Gupta, S. K. Kunnath, Adaptive spectra-based pushover procedure for seismic evaluation of structures, Earthquake Spectra, 16(2) (2000) 367-392.
[16] M. A. Hadianfard, H. Rahnema, Advanced nonlinear time-history analysis of partially restrained steel frames by using integrated equations of motion, in:  The International Conference on Computing in Civil and Building Engineering, Nottingham University, 2010.
[17] AISC360, Specification for Structural Steel Buildings, 2010.
[18] AISC341, Seismic Provisions for Structural Steel Buildings, 2010.
[19] Nazri, F. M., Tahar, S., Saruddin, S. N. A., & Shahidan, S., Seismic Fragility Curves of Industrial Buildings by Using Nonlinear Analysis. In MATEC Web of Conferences (Vol. 103, p. 02017). EDP Sciences.‏