An Investigation on the Effect of Infill Walls on the Fundamental Period of Moment-Resisting Steel Frames with Consideration of Soil-Structure Interaction

Document Type : Original Article


1 M.Sc. of structural engineering, Department of Civil Engineering, Islamic Azad University, Najafabad, Iran.

2 Assistant Professor, Department of Civil Engineering, Islamic Azad University, Najafabad, Iran


One of the most critical parameters in process of analysis and design of structures is determination of the fundamental period of vibration. The fundamental period depends on the distribution of the mass and stiffness of the structure. Therefore, the building codes propose some empirical equations based on the observed period of real buildings during an earthquake as well as ambient vibration tests. These equations are usually a function of type and height of the buildings. Differences in the fundamental period of buildings determined by the code equation and analytical methods are due to elimination of the effects of non-structural elements in the analytical methods. For this reason, the presence of non-structural elements such as infill panels, which may produce a variation in these properties, should be carefully considered. Another effective parameter on the fundamental period is the influence of Soil-Structure Interaction (SSI). It is obvious that soil flexibility increases the fundamental period of the structure. The current research deals with the effect of infill panels on the fundamental period of moment resisting frames considering the influence of soil-structure interaction (SSI). For this purpose, 3, 6, 9, 12, 15 and 18 stores 2-D frames were investigated with different configuration of infill panel in the plan and also various percentage of infill openings. The studied frames were modelled and analyzed in Seismo Struct software. The calculated values of the fundamental period are compared with those of obtained from proposed equation in the seismic code. From the analysis of the results it has been found that the number of stores, the infill opening percentage, the stiffness of the infill panels and the soil type are crucial parameters that influence the fundamental period of steel building frames.


[1]- UBC97, 1997, Uniform building Code, International Conference of Building Officials, California, Wilier.
[2]-Code 2800, 2015, Iranian Code of Practice for Seismic Resistant Design of Buildings, Center for Construction and Housing Researches of Iran., Standard No.2800, 4th edition. 2015.
[3]- National Building Code of Canada, 1953, Canadian Commission on Building and Fire Codes, National Research Council Canada, National Research Council Canada, National Research Council of Canada, & National Research Council of Canada.
[4]-FEMA-450, 2003, NEHRP recommended provisions for seismic regulations for new buildings and other structures, Part 1: Provisions, Washington (DC), Federal Emergency Management Agency.
[5]-Eurocode 8, 2003, Design of Structures for Earthquakes Resistance _ Part 1: General Rules, Seismic Actions and Rules for Buildings. Pr‐EN 1998‐1 Final Draft. Comité Européen de Normalisation. December 2003.
[6]-Goel, R. K. and Chopra, A. K, 1997, Period formulas for moment-resisting frame buildings, Journal of Structural Engineering, ASCE, 123(11), 1454-1461.
[7]-Chopra, A. K. and Goel, R. K., 2000, Building period formulas for estimating seismic displacements, Earthquake Spectra, 16(2), 533-536.
[8]-Hong, L. L. and Hwang, W. L., 2000, Empirical formula for fundamental vibration periods of reinforced concrete buildings in Taiwan, Earthquake Engineering and Structural Dynamics 29, 327–337.
[9]- Paolo, R., Verderame, G. M. and Manfredi, G., 2011, Analytical investigation of elastic period of infilled RC MRF buildings, Engineering Structures, 32, 2, 308-319.
[10]-Elgohary, H., 2013, Empirical formula for the fundamental period of vibration of multi-storey RC framed buildings, Proceeding of Vienna Congress on Recent Advances in Earthquake Engineering and Structural Dynamics Vienna, Austria August.
[11]-Asteris, P. G., Antoniou, S. T., Sophianopoulos, D. S. and Chrysostomou, C. Z., 2011, Mathematical macro modeling of infilled frames: State of the art, Journal of Structure Engineering, ASCE, 137, 12, 1508-1517.
[12]-Asteris, P. G., Cotsovos, D. M., Chrysostomou, C. Z., Mohebkhah, A. and Al-Chaar, G. K., 2013, Mathematical micro modeling of infilled frames: State of the art, Engineering Structure, 56, 1905-1921.
[13]-Asteris, P. G., Repapis, C. C., Tsaris, A. K., Di Trapani, F., and Cavaleri, L., 2015, Parameters affecting the fundamental period of infilled RC frame structures, Earthquakes and Structures, 9, 5, 999–1028.
[14]-Asteris, P. G., 2005, Closure to Lateral stiffness of brick masonry infilled plane frames, Journal of Structure Engineering, ASCE, 131(3), 523-524.
[15]-Asteris, P. G., 2008, Finite element micro-modeling of infilled frames, Electronic Journal of Structural Engineering, 8, 8, 1-11.
[16]-SeismoSoft, 2018, SeismoStruct - A computer program for static and dynamic nonlinear analysis of framed structures, [online], Seismosoft Ltd., Pavia, Italy.
[17]-Crisafulli, F. J., 1997, Seismic behaviour of reinforced concrete structures with masonry infills, Ph.D. Dissertation, University of Canterbury, New Zealand.
[18]-Asteris, P. G., 2003, Lateral stiffness of brick masonry infilled plane frames, Journal of Structural Engineering, ASCE, 129, 8, 1071-1079.