Sensitive use analysis DG11
The vibration check calculations can be performed for sensitive equipment & occupancy if required.
These calculations make use of Chapter 6 of DG11 2nd Edition (2016) with revisions and errata of 27 July 2018. They only cover ⅓ octave spectral velocity and acceleration.
For these calculations the mode shape factors ɸE and ɸW are taken as 1.0. i.e. it is conservatively assumed that the walker and sensitive equipment or sensitive occupant are both at mid-bay.
Use Case - Sensitive Equipment
If walking speed = Very Slow ,
fstep |
|
1.25 Hz |
|
[Table 6-1] |
V1/3 |
|
(250 * 106) / (β * W) * (fstep2.43 / fn1.8) * (1 - e-2*π*β*fn / fstep) |
|
[Eqn 6-3a] |
A1/3/g |
|
(100 * 4.2) / (β * W) * (fstep2.43 / fn0.8) * (1 - e-2*π*β*fn / fstep) |
|
[Eqn 6-8a] |
Else if walking speed = Slow , or Moderate or Fast
fstep , fL , fU and γ as appropriate to selected walking speed |
|
[Table 6-1] |
If fn ≤ fL
V1/3 |
|
(175 * 106) / (β * W * fn0.5) * (e-γ*fn) |
|
[Eqn 6-3b]1 |
A1/3/g |
|
(100 * 6.4) / (β * W) * (e-γ*fn) |
|
[Eqn 6-8b]1 |
If fn ≥ fU
V1/3 |
|
(250 * 106) / (β * W) * (fstep2.43 / fn1.8) * (1 - e-2*π*β*fn / fstep) |
|
[Eqn 6-3b]2 |
A1/3/g |
|
(100 * 4.2) / (β * W) * (fstep2.43 / fn0.8) * (1 - e-2*π*β*fn / fstep) |
|
[Eqn 6-8b]2 |
Else if fL < fn < fU
For V1/3
- evaluate [Eqn 6-3b]1 with fn = fL , then
- evaluate [Eqn 6-3b]2 with fn = fU , then
- linear interpolate for actual fn
For A1/3/ g
- evaluate [Eqn 6-8b]1 with fn = fL , then
- evaluate [Eqn 6-8b]2 with fn = fU , then
- linear interpolate for actual fn
Use Case - Sensitive Occupancy
These modification factors are derived from consideration of the differences between ⅓ octave spectral Velocity equations for Sensitive Equipment and Sensitive Occupancy, which are given explicitly in DG11 2nd Edn.
If walking speed = Very Slow ,
fstep |
|
1.25 Hz |
|
[Table 6-1] |
V1/3 |
|
(200 * 106) / (β * W) * (fstep2.43 / fn1.8) * (1 - e-2*π*β*fn / fstep) | [Eqn 6-9a] | |
A1/3/g |
|
(200/250)*(100 * 4.2) / (β * W) * (fstep2.43 / fn0.8) * (1 - e-2*π*β*fn / fstep) | [Eqn 6-8a] modified |
Else if walking speed = Slow , or Moderate or Fast
fstep , fL , fU and γ as appropriate to selected walking speed |
|
[Table 6-1] |
If fn ≤ fL
V1/3 |
|
(120 * 106) / (β * W * fn0.5) * (e-γ*fn) |
|
[Eqn 6-9b]1 |
A1/3/g |
|
(120/175)*(100 * 6.4) / (β * W) * (e-γ*fn) | [Eqn 6-8b]1 modified |
If fn ≥ fU
V1/3 |
|
(200 * 106) / (β * W) * (fstep2.43 / fn1.8) * (1 - e-2*π*β*fn / fstep) |
|
[Eqn 6-9b]2 |
A1/3/g |
|
(200/250)*(100 * 4.2) / (β * W) * (fstep2.43 / fn0.8) * (1 - e-2*π*β*fn / fstep) | [Eqn 6-8b]2 modified |
Else if fL < fn < fU
For V1/3
- evaluate [Eqn 6-9b]1 with fn = fL, then
- evaluate [Eqn 6-9b]2 with fn = fU , then
- linear interpolate for actual fn
For A1/3/ g
- evaluate [Eqn 6-8b]1 modified with fn = fL , then
- evaluate [Eqn 6-8b]2 modified with n = fU , then
- linear interpolate for actual fn