Abstract
This paper proposes a reliability based design for limiting floor slab vibration due to human walk. The reliability index β can predict the stochastic vibration performance of any floor slabs, independent of the dynamic characteristics of the slabs. Then the reliability design method was applied to an actual floor slab design and its validity was confirmed by hammering tests and a one person walking test using the actual building floor slabs.
The second moment method was used in formulating the reliability based design. The serviceability limit state was defined based on previous experimental data by other researchers. The serviceability limit is one at which acceleration “isn't unpleasant“. This was deemed as a log-normal distribution with the median of 4cm/s2 (or mean 5.28cm/s2) and coefficient of variance 0.8. From this work, “the walking vibration V-value response spectrum” is proposed first as the loading effect. A relationship between the reliability index β based on formulation, V-value (the corrected response acceleration considering human perception) and the perception probability mentioned above, was formulated using a single degree of freedom system. It was shown that a relationship between reliability index β and V-value is almost independent of the dynamic characteristics of the floor slab.
Finally, the reliability based design was applied to an actual floor slab with an intention of realizing a certain value of β against one person walking. The effectiveness of the design was verified through the fact the targeted β and experimentally obtained one were almost identical. The latter value of β was estimated using the data from a hammering tests and a one person walking tests on a slab in an actual building.
The following conclusions were obtained.
1 Formulation of the reliability based design method for limiting floor slab vibration due to human walking was proposed using the authors' walking vibration V-value response spectrum.
2 This reliability based design method considered the effects of prediction errors in the vibration characteristics of the floor slab, such as the first natural frequency, damping coefficient, modal mass and individuality of walkers. It was also expanded to the multi degree of freedom system.
3 The reliability index β could almost uniquely determine a stochastic behavior of habitability performance for any floor slabs. This fact was empirically reduced, through various calculation model cases, where various combinations of reliability index β and vibration characteristics of the floor slabs were tried.
4 An application example of the reliability based design of floor vibration due to human walking was shown, and design objectives were verified based on the field experiment including hammering tests and a one person walking test on the designed actual slabs.
