340 A.F. Hameed and A. Pavic 34.6 Conclusions The dynamic properties of a floor comprising hollow-core precast planks and undergoing a massive refurbishment process have been identified using MIMO modal testing. The measured FRFs have certain level of noise which has not affected the measurement significantly. This is clearly shown by checking the reciprocity plots where there is a good level of match between corresponding references. The FRF-estimated vertical modes are showing a noticeable degree of complexity. These complex mode shapes were to be expected due to the possibility of the floor featuring non-proportional damping, low signalto-noise ratio and noisy measured FRFs. The test, which is the first in a series, will be used as a platform to assess different vibration serviceability related issues and will published in due course. Acknowledgements The paper was prepared with the financial and technical support of the University of Exeter and Engineering and Physical Sciences Research Council (EPSRC) grant reference EP/K03877X/1 for which the writers are grateful. The financial support of The Higher Committee for Education Development in Iraq (HCED IRAQ scholarship reference GD-13-5) is highly appreciated as well. WSP-Parsonsj Brinckerhoff, and ISG plc are acknowledged for allowing access to the site during construction. References 1. Brownjohn, J.M.W., Pan, T.-C., Middleton, C.J., Tan, S.C., Yang, G.: Floor vibration serviceability in a multistory factory building. J. Perform. Constr. Facil. 04014203-1-14 (2014) 2. Pavic, A., Reynolds, P., Prichard, S., Lovell, M.: Evaluation of mathematical models for predicting walking-induced vibrations of highfrequency floors. Int. J. Struct. Stab. Dyn. 3, 107–130 (2003) 3. Pavic, A., Willford, M.R.: Vibration serviceability of post-tensioned concrete floors - CSTR43 App G, Appendix G in Post-Tensioned Concrete Floors Design Handbook. Technical Report 43, pp. 99–107 (2005) 4. Willford, M.R., Young, P.: A design guide for footfall induced vibration of structures - CCIP-016. The Concrete Centre, Slough (2006) 5. Murray, T.M., Allen, D.E., Ungar, E.E.: Floor vibrations due to human activity - AISC DG11 (2003) 6. Smith, A.L., Hicks, S.J., Devine, P.J.: Design of floors for vibration - a new approach SCI P354, revised Ed. The Steel Construction Institute, Ascot (2009) 7. Pavic, A., Miskovic, Z., Živanovic´, S., Zivanovic, S.: Modal properties of beam-and-block pre-cast floors. IES J. A Civ. Struct. Eng. 1, 171–185 (2008) 8. Instruction manual, Electro-seis, Model 113 Shaker (1996) 9. Instruction manual, Electro-seis, Model 400 Shaker (2013) 10. I. Honeywell International, QA-750 Accelerometer Datasheet (2005) 11. E. Corporation, endevco model 7754A-1000 Datasheet 12. Ewins, D.J.: Modal testing: theory, practice and application. Research Studies Press, Baldock (2000) 13. Vibrant Technology Inc., ME’Scope VES 6.0 (2015) 14. Imregun M, Ewins DJ.: Complex modes: origins and limits. In: Proceedings of the 13th International Modal Analysis Conference, pp. 496–506. Society for Experimental Mechanics, Inc., Nashville (1995)
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