Input requirements for DG11 floor vibration
General
The simplified method for the analysis of the vibration of floors given in the AISC Publication DG11, on which on which the Tekla Structural Designer check is based, is only applicable to regular structures which, by and large, are created from rectilinear grids.
Of course the floor layouts of 'real' multistorey buildings are rarely uniform and Tekla Structural Designer therefore provides you with the opportunity to select the more irregular floor areas to be assessed with grids that are other than rectilinear.
In so far as the selection of the beams and girders to be used in the analysis is concerned, only beams or girders with NonComposite, Steel Joist or Composite attributes are valid for selection and, within these confines, the user should be able to:
 select a single beam or girder
 select a girder span as critical plus an adjoining span (in a two or three span configuration)
In all cases, and subject to the above restrictions, which beams and girders from the selected area of floor are chosen is entirely at your discretion and under your judgment, but it is expected that the beams and girders chosen will be those that are typical, common or the worst case. Irrespective,Tekla Structural Designer will take these beams as those that form the idealized floor layout. There is no validation on what the you select (although there is some validation on which beams and girders are selectable i.e. those which have no slab for part of their length, those from angle sections, those with no adjoining span when a 2span configuration is chosen, and those with no adjoining span at both ends when a 3span configuration is chosen will not be selectable).
Data Derived from Tekla Structural Designer
Note that, where appropriate, the derived data is for each design combination under SLS loads only.
Unit supported weight
The unit supported weight is used to establish the 'effective panel weight'  that is the weight of the floor and its permanent loading that has to be set in motion during vibration of the floor. It is taken as the slab selfweight (and to be accurate, the beam selfweight), other permanent 'Dead' loads and the proportion of the 'Live' loads (expressed as a percentage) that can be considered as permanent.
The unit supported weight is obtained by summing all the loads (or the appropriate percentage in the case of live loads) that act over or in the selected area. This includes any blanket, area, line and spot loads that are present within the selected area. The component of any of these load types that lie outside of the selected area are ignored. Nodal loads directly on columns are also ignored. The total load is then divided by the area selected.
The slab selfweight will usually be in the Slab Dry loadcase  note that in the case of composite slabs this includes the weight of decking. The beam selfweight is in a separate protected loadcase. For simplicity this component of the unit supported weight is ignored. This leads to a slight inaccuracy in the participating mass that is conservative (more mass is advantageous).
Note that the use of live load reductions has no effect on the floor vibration check.
Slab data
If there are more than one set of slab attributes in the selected area then you have to choose which of these it is appropriate to use. From the designated slab attributes the following information/data is obtained,
 the transformed inertia in mm^{4} per mm width [in^{4}/ft].
 the shortterm modular ratio for normal or lightweight concrete as appropriate.
If the designated slab attributes are for a 'generic' slab, then you are asked for the transformed inertia and the dynamic modular ratio.
Beam data
When these are noncomposite beams, the inertia is obtained from the sections database. When these beams are of composite construction the inertia is the gross, uncracked composite inertia based on the dynamic modular ratio that is required. Steel joist inertias from the database are assumed to be 'gross' inertias of the chords and are editable. Following guidance contained in AISC Steel Design Guide 11 ^{Ref. 1}, section 3.5, the gross steel joist inertia is factored by quantity C_{r} and displayed as the 'effective' inertia in the results viewer. C_{r} is derived from the following formulas,
For joists with angle web members: 

C_{r}  =  0.90*(1  e^{0.28(L/D)})^{2.8}  ≤ 0.9  valid for 6 ≤ L/D 


For joists with rod web members: 

C_{r}  =  0.721 + 0.00725*(L/D)  ≤ 0.9  valid for 10 ≤ L/D 
where  
L  =  Joist span  
D  =  Joist nominal depth 
The span of the critical/base beam and the adjoining beams is required.
The deflection of the critical beam under the permanent loads is required. To calculate this value, the deflection under the Dead loads and the appropriate percentage of the Live load deflection is summed.
Girder data
The same data is required as that for the beams.
Floor plate data
The dimensions of the floor plate in the idealized cases are defined in one direction by the number of beam bays and in the orthogonal direction by the number of girder bays. In practice, given that the idealized case may not attain, the floorplate dimensions are derived from the slab items you select as participating in the mass.
User Input Data
Secondary Beam Spacing
You must confirm the spacing of the secondary beams  an average value when the spacing is nonuniform.
Permanent Live Loads
You are required to specify the proportion of the permanent live loads that are to be used in the vibration analysis as a percentage of the live load.
Beam Continuity Factor
This has a value of either 1.0 or 1.5 and you are offered the choice when a two or three span beam configuration is selected. The default value is 1.0.
Girder Continuity Factor
This has a value of either 1.0 or 1.5 and you are offered the choice when a two or three span girder window is selected. The default value is 1.0.
This factor is not generally applicable for girders as they usually frame directly into columns and this potential increase in the effective panel weight does not apply under those circumstances.
Beam and Girder location
You are required to specify whether the beam and the girder under consideration is an "internal" location or an "internal edge" location. This information is required to set the constants that are used in calculating the effective widths of the beam and girder panel modes.
Number of bays used to establish effective panel weight
You are required to specify the number of bays in the direction of the beam span, nj, and the number of bays in the direction of the girder span, ng, that are to be used to establish the effective panel weight. The number of bays ranges from 1 to 4 for both directions.
Damping ratio
Floors do not vibrate as a free mass but have some damping i.e. dissipation of the energy in the system. Values of the damping ratio for individual components, β_{i} are recommended in DG11 as,
Recommended Component Damping Values  

Component  Ratio of Actual DampingtoCritical Damping, β_{i} 
Structural System 
0.01 
Ceiling and ductwork 
0.01 
Electronic office fitout 
0.005 
Paper office fit out 
0.01 
Churches, schools and malls 
0.0 
Lightly furnished quiet spaces  0.005 
Fullheight dry wall partitions in bay 
0.02 to 0.05* 
*Depending on the number of partitions in the bay and their location; near the center of the bay provides more damping. 
For example, a floor with ceiling and ductwork supporting an electronic office area has β = Σβ_{i} = 0.01 (floor) + 0.01 (ceiling and ductwork) + 0.005 (electronic office area) = 0.025, or 2.5% critical damping.
Since an even higher damping ratio might be justified for storage floors for example, a range of up to 10% is offered.
Acceleration limit
You must enter acceleration limits appropriate to the floor under consideration, one limit for floors with frequencies in the range 39 Hz and a separate limit for High Frequency floors (in the range 915 Hz). These limits will be based on your engineering judgement and the advice given in DG11  which gives a range of values between 0.5% and 5.0% depending on structural form (for building floors see the table below).
Table 41. Recommended Tolerance Limits for Building Floors  

Occupancy 
Acceleration Limit a_{o}/g x 100% 
Offices, residences, churches, schools and quiet areas 
0.5% 
Shopping Malls 
1.5% 
Footstep frequency
You should enter the footstep frequency to be used if a high frequency floor is detected. The range being 1.2 Hz to 2.2 Hz.
Sensitive use
You have to specify the Use case and walking speed if this analysis is performed. See: Sensitive use analysis DG11