Initially the differential equation of this equivalent sandwich beam is written; shape functions for each storey can then be obtained by the solution of differential equations.
By using boundary conditions and storey transfer matrices obtained from these shape functions, system modes and periods can be calculated. The reliability of the study is shown using several examples. A computer program has been developed in MATLAB and numerical samples have been solved for demonstration of the reliability of this method. The results of the samples show the agreement between the present method and other methods given in the literature.
Under horizontal loads, wall-frame buildings demonstrate neither Timoshenko beam nor Euler– Bernouilli beam behavior. The behavior of high-rise buildings is equivalent to a sandwich beam which denotes the total of these two types of behavior (Figure 1). Initially the differential equation of this equivalent sandwich beam can be written. The ? exural rigidity of the sandwich beam contains the sum of the ? exural rigidity of shear walls and columns; the shear rigidity of the sandwich beam is equal to the sum of the shear rigidities of frames and the sum of the connecting beam shear rigidities.Elastic analysis of asymmetric tall building structures. Structural Design of Tall Buildings 10: 245–261.
Hoenderkamp JCD. 2002. A simpli? ed analysis of high-rise structures with cores. Structural Design of Tall Buildings 11: 93–107.
Kuang JS, Ng SC. 2000. Coupled lateral-torsion vibration of asymmetric shear wall structures. Thin Walled Structures 38(2): 93–104.
Li GQ, Choo BS. 1996. A continuous–discrete approach to the free vibration analysis of stiffened pierced walls on ? exible foundations. International Journal of Solids and StructuresMichel C, Hans S, Gueguen P, Boutin C. 2006. In situ experiment and modelling of RC structure using ambient vibration and Timoshenko beam.
In First European Conference on Earthquake Engineering and Seismology, Geneva, Switzerland, 3–8 September. Miranda E. 1999. Approximate lateral drift demands in multi-story buildings subjected to earthquakes. Journal of the Structural Division, ASCE 125(4): 417–425. Miranda E, Reyes JC.
2002. Approximate lateral drift demands in multi-story buildings with nonuniform stiffness. Journal of the Structural Division, ASCE 128(7): 840–849. Miranda E, Taghavi S. 2005.
Approximate ? oor acceleration demands in multistorey buildings I: Formulation. Journal of the Structural Division, ASCE 131(2): 203–211. Nollet JM, Stafford Smith B. 1993. Behavior of curtailed wall-frame structures. Journal of the Structural Division, ASCE 119(10): 2835–2853.
Potzta G, Kollar LP. 2003. Analysis of building structures by replacement sandwich beams. International Journal of Solids and Structures 40: 535–553. Rafezy B, Zare A, Howson PW. 2007.
Coupled lateral-torsional frequencies of asymmetric, three dimensional frame structures. International Journal of Solids and Structures 44: 128–144.
