Floor System Frequency Of Vibration Calculation

The natural frequency of the floor system may then be estimated by the following formula 2 3 f 0 18i g aj ag 3 for concrete floor systems sup ported on walls 4gmay.

Floor system frequency of vibration calculation.

Both human comfort and the need to. Supporting the floor system also af fects the natural frequency of the floor system. If the forcing frequency is close to the natural frequency of the system and the system is lightly damped huge vibration amplitudes may occur. The simple spandeflection ag of the floor girder may be calculated in the same manner as a.

Is the natural frequency of the floor system βis the modal damping in the floor system and w is the effective weight that moves because of the excitation. Design for sensitive equipment. P o is 65 lb for office. Where f is the natural frequency of the considered mode k mod is the modal stiffness m.

False floor l spread of energy throughout the whole structure. Hz 1 3 13 2 1 2 1 2 1 g w kg. Damping by furniture and finishing e g. In reality only f n and w require calculations.

At first glance the criteria might look a bit formidable it certainly is different than the older criteria. Try this test for each type of excitation. Observe the behavior when the excitation frequency coincides with the natural frequency of the system. Coil spring isolators are available in up to 3 static deflection.

Require the calculation of the first natural frequency of the floor system and the maximum amplitude of acceleration. For floor vibrations to be acceptable the peak acceleration of the floor system which is a function of the floor system s natural frequency damping and effective weight must be less than or equal to the recommended acceleration which is equal to 0 5 percent of the acceleration of gravity for office and residential occupancies. Floor systems and footbridges for vibration serviceability due to human activities. A beam may be thought of as a series of mass spring models joined together to form a continuous system.

The system has a fundamental frequency which corresponds to the first lowest mode of vibration. 6 floor vibration continuous systems a beam has a mass stiffness and boundary conditions at the supports that define its behaviour. People are often annoyed by and are very sensitive to vibrations in the 8 10 hz range. This calculator gives the fundamental vibration frequency of a floor joist girder and the combined floor system.

The natural frequency of the system assuming a single degree of freedom can be calculated by. Watch what the system is doing. Unlike the sdof system which has a single natural frequency and corresponding mode of vibration a continuous system theoretically has an infinite number of natural frequencies and associated modes. The additional benefit of making it easy to calculate the system natural frequency.

For best results the frequency should be 15 hz or higher.