Trends in Applied Sciences Research1819-35792151-7908Academic Journals Inc.10.3923/tasr.2012.221.230JamshidiMortezaMajidTaksiah A.DarvishiAmirRamajiAmin Esmaeil3201273Space trusses have become widely popular, particularly in large areas such as sport center, exhibition halls and airport hangars. Base on their high degree of indeterminacy and great stiffness, the seismic designs of space trusses are neglected. Despite the earlier assumption, recent studies show that in the area which, the strong earthquakes are probable; these structures are vulnerable to seismic failures. As dynamic behavior of the structures is a function of the mass and stiffness matrixes, so in this study, the effects of structural geometry on the natural period of vibration which is depended to these two matrixes, are studied. The results show that the natural period of vibration and dynamic behavior of the double layer lattice domes depended on the geometry of these structures, especially on the span and finally, the natural period of vibration of the double layer lattice domes can be estimated by using this mentioned geometric parameter.]]>Adedeji, A.A. and S.P. Ige,2011Alsulayfani, B.J. and T.E. Saaed,2009Amiri, G.G., H.H. Jamnani and B. Mohebi,2008Bagherzadeh, A. and B. Ferdowsi,2009Cai, J.C., J. Feng, Y. Chen and L.F. Huang,2008Chopra, A.K.,1995Coan, C.H. and R.H. Plaut,1983David, F.N.,2009El-Kafrawy, O. and A. Bagchi,2007Ghasemi, M., M.R. Davoodi and S.A. Mostafavian,2010Ishikawa, K., S. Okubo, Y. Hiyama and S. Kato,2000Jamshidi, M., T.A. Majid and A. Darvishi,2011Kawaguchi, K.,1997Koohestani, K. and A. Kaveh,2010Marsh, C.,2000Moghaddam, H.A.,2000Nadhim, A.M.M.,2006Nezamabadi, M.F., A.S. Moghadam and M. Hosseini,2008Rezaiee-Pajand, M., M. Kadkhodayan, J. Alamatian and L.C. Zhang,2011Sadeghi, A.,2004Sasan, M. and S. Mohammadsadegh,2011Weaver, W. and P.R. Johnston,1987Zhang, Y. and T.T. Lan,2000