![]() Typically this is achieved by designing staircases for a limiting multiplying factor of 32 for light use (such as offices) or 24 for heavy use (such as public buildings and stadia) under single person excitation using the Fourier terms given above. Also give guidance on the acceptability criteria for staircases, and their research indicates that for multi-person excitation, a maximum mul- tiplying factor of 64 applies. No specific analysis is given by Bishop et al for the impulsive loads that will be experienced by staircases with natural frequencies that exceed the up- per limits of the Fourier terms given in ISO 10137.įurther Fourier coefficients (up to the 6th harmonic) are presented in the paper these could be used to determine a more comprehensive response.Acceptability criteriaBishop et al. ISO 10137: 2007 (Bases for design of structures – Serviceability of buildings and walkways against vibrations) reproduces the worst case of these in Table A.4, and these are also given in Table 3.2 of P354:In P354 floors are categorised as either low-frequency or high-frequency, the latter case responding to impulsive excitations rather than responding reso- nantly. These Fourier coefficients are given in Human induced loading of flexible staircases (Bishop, Willford & Pumphrey, 1995 and Kerr & Bishop, 2001), and depend on the speed of ascent or descent. The peak amplitude of the load in each mode is generally given in terms of Fourier coefficients, αn, which represent the proportion of a person’s weight that is acting at each harmonic of the activity frequency. The general approach outlined in Chapter 6 of SCI P354 can be used to determine the dynamic behaviour of the staircase, but clearly the applied forces will be different for people travelling up and down staircases than for walking across floors, and acceptable levels of vibration also differ.Applied LoadsIn P354, the response is determined from the modal properties of the staircase (frequencies, modal masses and mode shapes) and the frequency and ampli- tude of the applied vertical load. ![]()
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