serviceability design of floor structures | i8 Bibliography: Ebrahimpour, A., Hamam, A., Sack, R., & Patten, W. (1996). Measuring and modeling dynamic loads imposed by moving crowds. Journal of Structural Engineering, 122 (12), 1468-1474. Galbraith, G., & Barton, W. (1970). Ground loading from footsteps. Journal of the Acoustical Society of America, 48, 1288- 1292. Murray, T. M., Allen, D. E., & Ungar, E. E. (1997). Design guide 11: Floor vibrations due to human activity. Ungar, E. E., Zapfe, J. A., & Kemp, J. D. (2004). Predicting footfall-induced vibrations of floors. Sound and Vibration, 16-22. Figure 7 Velocity response for a central point due to a slow walking path 330 mm thick slab Figure 8 Velocity response for a central point due to a fast walking path 330 mm thick slab Velocity responses due to footfall are measured at nine locations and evaluated using both the AISC and finite element methods. The maximum response is found to be at the center of the 330 mm concrete slab panel. Time history response at this location is shown in Figure 7 and Figure 8 for the slow and fast walking paths, respectively. Using the AISC equation, the maximum calculated velocity for a slow walking path is 47 μm/s, which is in line with the maximum vibration velocity calculated using the time history method (43 μm/s). The slab thicknesses are optimized to the nearest centimeter to satisfy a vibration velocity limit of 50 μm/s with 330-mm thick slab and 430-mm thick drop panel. A more stringent vibration velocity limit of 25 μm/s is achievable using a 400-mm thick flat slab as shown in Figure 9 and Figure 10. Applying the AISC equation, the maximum calculated velocity is 21 μm/s, which is in line with the maximum vibration velocity calculated using the time history method (23 μm/s). Figure 9 Velocity response for a central point due to a slow walking path 400 mm thick slab Conclusion For vibration velocities between 25 μm/s and 50 μm/s, it is recommended to maintain the column grid spacing in the range of 6 m x 9 m. The anticipated slab thickness will vary between 330 mm and 400 mm. Smaller column grids in the range of 6 m x 6 m are recommended for a vibration velocity limit of 12 μm/s. For velocity limits in the range of 3 μm/s to 6 μm/s, it is advisable to place such equipment at grade level with complete isolation from the surrounding structure. Figure 10 Velocity response for a central point due to a fast walking path 400 mm thick slab 43