30 Vibration Transmission Through Non-Structural Partitions Between Building Floor Levels 301 The model without partitions is characterised by higher accelerations on the load floor level but relatively little transmission of vibration (ratio of peak floor level 2 acceleration to floor level 1 acceleration) to the floor above. In the absence of partitions the level of transmission is 1.8 % compared to 9 % when partitions are included. 30.5 Discussion of Results The experimental and numerical investigations into vibration transmission between floor levels discussed above seek to explore the contribution of non-structural partitions to such transmission. Both sets of investigations show that excitation on a given floor level can be expected to produce a vibration response on the floor above. In the case of the numerical simulations the presence of the partitions results in a stiffer system which is consistent with prior experimental modal studies [7] which showed that nominally identical floors in the absence of partitions had increased frequencies and altered modes of vibration once the partitions were added. Hence with partitions included although the vibration levels (Fig. 30.5 and Table 30.1) identified on the floor along which walking was simulated are lower the extent of transmission to the floor above is higher—the upper floor vibration level is predicted to be of the order of 9 % of those on the excited floor compared to only 1.8 % in the absence of the partitions. This constitutes a fivefold increase in transmission from one floor to the next due to the presence of partitions. While it was not possible to undertake the experimental test programme with and without partitions the extent of transmission was at least as pronounced, being in the range of 10–65 % over the duration of the test. Vibration transmission of the order of 10 % is considered significant and implies that the actual vibration response on a given floor level is likely to be due to the activity on that floor level itself and also to some not insignificant level of transmission from the floors below. This is currently not acknowledged in any code of practice for floor vibration serviceability assessment and is in the authors’ opinions an area of research that requires further investigation. 30.6 Conclusions Experimental and numerical studies have shown that there is transmission of vibration from one floor to the next. The extent of transmission along a partition line was measured to be in the range of 10–65 % for a recently constructed reinforced concrete building with different partition layouts on each floor level. Numerical models of the test structure indicate that the extent of transmission is increased, a fivefold increase in this case, due to the presence of partitions. It follows that building floor vibration serviceability assessment should account for this transmission. Currently this in not the case and further research work, preferably experimentally based, on full scale structures with and without internal partitions, is required. Acknowledgements The authors wish to express their gratitude to (1) the Irish Research Council for Science, Engineering & Technology for their financial support, (2) the Vibration Engineering Research Section of Sheffield University for use of their equipment at the time the testing was undertaken, and (3) the Buildings Office at University College Dublin (UCD) for access to the Charles Institute at UCD. References 1. Pavic, A., et al.: Critical review of guidelines for checking vibration serviceability of post-tensioned concrete floors. Cem. Concr. Compos. 23(1), 21–31 (2001) 2. Pavic, A., Miskovic, Z., Reynolds, P.: Modal testing and finite element model updating of a lively open-plan composite building floor. J. Struct. Eng. 133(4), 550–558 (2007) 3. Pavic, A., Widjaja, T., Reynolds, P.: The use of modal testing and FE model updating to investigate vibration transmission between two nominally identical building floors. In: Proceedings of the International Conference on Structural Dynamics Modeling-Test, Analysis, Correlation and Validation. pp. 347–355. Instituto Superior Tecnico Lisbon, Lisbon (2002) 4. Nyawako, D., Reynolds, P., Hudson, M.: Findings with AVC design for mitigation of human induced vibrations in office floors. In: Catbas, F.N., Pakzad, S., Racic, V., Pavic, A., Reynolds, P. (eds.) Topics of Dynamics in Civil Structures, vol. 4, pp. 37–44. Springer, New York (2013) 5. Reynolds, P.: The effects of raised access flooring on the vibrational performance of long-span concrete floors. PhD Thesis, University of Sheffield (2000) 6. Miskovic, Z., Pavic, A., Reynolds, P.: Effects of full-height nonstructural partitions on modal properties of two nominally identical building floors. Can. J. Civil Eng. 36(7), 1121–1132 (2009)
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