Abstract—Seismic qualification testing for equipments to be mounted on upper storeys of buildings is very demanding in terms of floor spectra. The latter is characterized by high accelerations amplitudes within a narrow frequency band. This article presents a method which permits to cover specified required response spectra beyond the shaking table capability by amplifying the acceleration amplitudes at an appropriate frequency range using a physical intermediate mounted on the platform of the shaker. Keywords—floor spectra, response spectrum, seismic qualification testing, shaking table I. INTRODUCTION HE early 1970s saw the first inclusion for nonstructural provisions other than walls, parapets, and chimneys. The provisions have grown to include a wide variety of nonstructural components and building systems since the mid- 1970s, but the seismic codes have yet to recognize the need for qualification of owner-supplied equipment that is not fixed to the building. The codes have also yet to come to grips with systems qualification and continued performance for facilities. Qualification involves the acceptance of components and systems for use in a seismic environment and compliance with code requirements. There are numerous methods by which seismic qualification can be realized. Each method has a narrow window of applications for effective seismic qualification [1,2]. The method based on dynamic testing using shaking table is one of the most reliable methods. In general, the dynamic excitations for seismic qualification tests of equipments are defined in terms of response spectra or modulated sinusoidal waves, specified according to the environmental conditions: seismo-geologic context or the type of the building and the height of the floor [3]. Obviously the seismic qualification tests of equipments cannot be carried out if the required response spectrum (R.R.S) is not covered by the performance curve of the shaking table. The R.R.S. are dominated by low frequencies and sometimes may go beyond the system capacity. In order to overcome this problem, a procedure for spectra transformation is developed to amplify the acceleration at the base of the specimen at low frequencies to cover the required response spectra. N. Bourahla is with the University Saad Dahlab, Blida, Algeria (phone: 213 21 552895; fax: 213 21 404920; e-mail: nbourahla@univ-blida.dz). F. Bouriche was with National Earthquake Engineering Centre, Algiers, Algeria. He is now with SCE Engineering ltd, Algiers, Algeria (e-mail: bourichefarid2002@yahoo.fr). Y Benghalia is with the University of Hassiba Benbouali, Chlef, Algeria (e-mail: ybenghalia@yahoo.fr). The procedure is based on introducing a physical interface between the shaking table and the specimen. The interface is a support capable to carry the equipment and transmit the vibrations from the shaking table to the specimen. The design and the limitation of this method are presented below.. II. PROCEDURE FOR SPECTRUM TRANSFORMATION To perform the qualification tests for equipments, the required response spectrum RRS needs to be determined on the basis of the environmental conditions of the equipment site. In case that the RRS is not totally covered by the performance curve of the shaking table, therefore a physical amplifier support may be used as described hereafter. It should be noted however that this method is first developed for rigid specimen. The spectrum transformation procedure as shown on Fig. 1 can be carried out in three steps: Fig. 1 Illustration of the procedure of the spectrum transformation Nouredine Bourahla, Farid Bouriche and Yacine Benghalia Response Spectrum Transformation for Seismic Qualification Testing T Shaking Table Support Specimen GSR A. Transfer function f(ξ,ω n ) R.R.S Equipment World Academy of Science, Engineering and Technology International Journal of Civil and Environmental Engineering Vol:5, No:11, 2011 595 International Scholarly and Scientific Research & Innovation 5(11) 2011 scholar.waset.org/1307-6892/4927 International Science Index, Civil and Environmental Engineering Vol:5, No:11, 2011 waset.org/Publication/4927