Design of floors for vibration quiz

Please answer the following 10 multiple choice questions, then click 'submit' to check the result. The pass mark for a CPD certificate is 8 out of 10, and you may retake the quiz as many times as you wish, but the questions will vary! Please note that one, two, three or all of the possible answers presented for each question may be right, and to gain a mark for that question all correct answers must be identified.

Good luck

Design of floors for vibration

Where is the magnitude of damping of most importance?

Floors with low frequency
Floors with low frequency
Resonant floors
Floors subject to group activities

When assessing vibrations in a floor, appropriate acceptance criteria can be referenced from where (more than one may apply)?

BS 5950: Structural use of steelwork in building
BS 6472: Guide to evaluation of human exposure to vibration in buildings
SCI publication P354 “Design of Floors for Vibration: a New Approach”
BS 6399: Loadings for buildings

What is a reasonable frequency range caused by walking?

2 Hz to 3 Hz
1 Hz to 2 Hz
2.8 Hz to 3.2 Hz
1.8 Hz to 2.2 Hz

Human perception to vibration depends on the direction of incidence of the acceleration relative to the human body. In the basicentric coordinate system, the z-axis corresponds to the direction of the human spine. In which of the situations below is the human body more sensitive to vibration?

Walking (z-axis perpendicular to the floor)
Lying down (z-axis parallel to the floor)
Sitting
Standing

Which of the statements below are true with respect to the Variable Dose Value (VDV) method?

VDV’s can be used for hospital operating theatres
They relate the response factor or multiplying factor to the intermittency of vibration
VDV’s are independent of walking path length
Give the number of times that an activity can take place in a given exposure period

Which of the following statements is incorrect? Human perception to vibration:

Depends on the frequency of the vibration
Depends on the direction of vibration relative to the spine
Is higher for intermittent vibrations
Is higher with vibrations having a frequency between of 4 and 8 Hz

When assessing the frequency of a floor, which elements of the floor must the designer check?

The slab
The secondary beam
The primary beam
All of the above, both individually and collectively

Which of the following statements is incorrect?

If the beams of a floor have a natural frequency of 4Hz or higher, then the floor performance is satisfactory for vibration
The frequency of the system (composed of primary and secondary beams plus slab) should be higher than 3Hz
Both primary and secondary beam mode shapes should be investigated and the mode which gives the higher deflection is more critical
If component frequencies are known then Dunkerley’s equation may be used to calculate the frequency of the system

Which of the following statements are true?

The response factors or multiplying factors given in BS 6472 are “for a low probability of adverse comment”
Multiplying factors are for exposure to continuous vibration
Multiplying factors are for a 16 hour exposure period during the day
Multiplying factors are for an 8 hour exposure period during the night

Which statement below does NOT describe a characteristic of a low frequency floor?

Has a fundamental frequency greater than 3 Hz but less than 10Hz
Exhibits a near resonant response
Both steady state and transient response must be checked
Has a fundamental frequency greater than 10Hz