vibrations in buildings induced by small-scale turbines for ......moreover, vibrations in buildings...

Bauhaus Summer School Forecast Engineering: From Past Design to Future Decision

22 August - 2 September 2016, Weimar, Germany

Vibrations in buildings induced by small-scale turbines for urban

wind harvesting: a case study

LUČIĆ Sanda

Graduate student, Josip Juraj Strossmayer University of Osijek

KRAUS Ivan

Dr.Sc., Josip Juraj Strossmayer University of Osijek

Abstract

Vibrations induced by machinery, traffic and other stochastic frequency-rich sources may cause

deformations and cracks on both structural and non-structural elements but also fatigue related

problems. Moreover, vibrations in buildings may cause discomfort for people and animals. On the

other hand, wind turbines may often be found in urban areas surrounded by buildings or placed a top

of a building. Although the turbines support green engineering and production of clean energy, they

also produce vibrations that may negatively influence the behaviour of both structures and living

beings. This paper aims to investigate effects of vibrations generated by small-scale wind turbines

placed on buildings in urban areas. A platform for this research is a soil-structure-wind turbine system,

where the structures selected for this case study are typical buildings that can be found in city of

Osijek. The aim of this research is to set the stage for a small-scale wind turbine that will harvest green

energy in Osijek in near future. Numerical analysis was performed using software Ashes 1.2 and

SAP2000, while program SeismoSignal was employed for interpretation of analysis results.

Parametric analysis provides results in the light of displacement response spectrums and acceleration

response spectrums taken from characteristic structural elements on different floors compared with

code-based thresholds. In addition, parametric study provides transfer functions calculated by dividing

output (structural vibration) and input (vibration of the top of the turbine) signals pointing out

amplified frequencies by structural members.

1. Introduction

Development of industry, traffic and modern technologies results in environmental pollution that leads

to global warming. Moreover, taking into account decrease of supplies of fossil fuels, society had to

increase interest in developing energy sources that will not be harmful to the environment such as

wind, hydropower, solar, geothermal. For the past few decades, renewable energy sources have been

in a state of continual growth. Among all renewable energy branches, one of the most popular and

fastest growing sources is wind energy. Use of this type of energy eliminates emission of CO2, SO2

and other harmful gases. According to Tong (2010), in 2009, global annual installed wind generation

capacity reached 37 GW, bringing the world total wind capacity in 2010 to 158 GW. Taking into

account that this “green” energy source is the most promising and reliable, wind power is believed to

play a critical role in global power supply in the 21st century.

Wind turbine technology has gained great development over the last decades. Traditional windmills

have been used for centuries, but owning to discovery of internal combustion engine and development

of electrical technology, traditional windmills started to disappear and development of modern wind

turbines began. Nowadays, it is not unusual to use wind turbines for electricity production. While wind

turbine technology is mainly concentrated on large turbines and offshore wind farms, this paper aims

to emphasize the importance of development and installation of small wind turbines which are

LUČIĆ Sanda, KRAUS Ivan / FE 2016 2

adequately safe and easy to run and maintain on individual buildings for independent power

production. Unlike large wind turbines, small wind turbines can be installed in urban areas, near to

buildings or at the top of them. These machines are operating in areas where people work and live thus

strict requirements concerning the safety of people and serviceability of the structure must be fulfilled.

Small wind turbines are usually designed with high tip-speed ratio hence their rotational speed

becomes very high. They also usually have fixed pitch type blades while their rotational surface can be

furled upward or side wards to prevent the over-rotation. As a result, these ferocious green energy

collectors can often be noisy and dangerous under strong winds. They also produce vibrations which

can be harmful for both structures and living beings (Ameku et al., 2008).

2. Vibrations

Vibrations in structures can have negative impact on both living beings and structures - they can cause

serviceability problems reducing comfort of people inside the building to an unacceptable level or

safety problems with danger of collapse of either structural or non-structural elements. Vibrations may

be caused by many different sources: human body motions, wind flow, traffic, working machines etc.

In this paper, only dynamic actions induced by rotating machines (wind turbines) are considered.

Vibrating machines, such as wind turbines, can affect different parts of engineering structures:

foundations, slabs, beams or even the whole structure. Operating machines can cause dynamic forces

that primarily depend on the type of the motion the machine describes – in case of wind turbine it is

rotation. Effects of machine-induced vibrations can be various; they can affect structures and structural

elements or people and other living beings. Effects on structures may include appearance of cracking,

crumbling plaster, loss of load-bearing capacity, fatigue problems. People, who spend time near to

machines emitting vibrations could be affected in various degrees - the intensity may range from

barely perceptible to slightly or strongly disturbing to harmful and they can manifest in three different

ways: as mechanical effects (vibration of floors or ceilings), an acoustic effects (noise from

installations or equipment motion) or as optical effects (visible motion of building elements of other

objects inside the building). Tolerable values of vibrations are different for different criteria:

structural, psychological and production-quality criteria. Vibration can be limited by given values of

physical quantities such as displacement amplitude, velocity amplitude and acceleration amplitude or

by other quantities such as KB intensity defined in German standard (Bachmann et al., 1994).

2.1. Human response to vibrations

All living beings are highly sensitive to vibration. People can sense vibration displacement amplitudes

as low as 0,001 mm, while finger-tips are even 20 times more sensitive. Human reaction to vibrations

is individual and depends on personal attitude and situation in which a person is. For instance, level of

discomfort is different while reading from driving in public transport. Sensitivity depends on many

different circumstances like personal dedication to a task, position (standing, sitting..), personal

activity, age, direction of incidence with respect to the spine, frequency of occurrence, time of day and

many others (Bachmann et al., 1994).

Table 1. Human perception of vibration level (The Engineering ToolBox, 2016)

Vibration level – acceleration [m/s2] Human Perception

< 0,315

0,315 – 0,63

0,50 – 1,00

0,80 – 1,60

1,25 – 2,50

> 2,00

Not uncomfortable

A little uncomfortable

Fairly uncomfortable

Uncomfortable

Very uncomfortable

Extremely uncomfortable


The intensity of perception is depended upon displacement, velocity and acceleration amplitudes,

duration of exposure and vibration frequency. According to Bachmann et al. (1994), perceptibility in

the range 1 to 10 Hz is proportional to acceleration, while in the range 10 to 100 Hz perceptibility is

proportional to velocity. Human perception of vibration depending of peak acceleration amplitude is

shown in Table 1.

2.2. Building response to vibrations

Vibrations in engineering structures are restricted by serviceability limit states. Recommended values

are mainly given for particle velocity. Those values are empirical and they depend on the type of the

structure, type of soil, type of excitation, frequency content and duration of exposure. Tolerable values

vary for different countries and structures and there is no criterion that can satisfy all requirements.

Most of the criteria reduce probability of appearance of damage to acceptably low levels but do not

guarantee total absence of it. Examples of recommended values are shown in Tables 2 and 3.

Table 2. Standard values for piling, sheet piling, vibratory compaction and traffic (Bachmann et al., 1994)

Building class

Frequency range where the

standard value is applicable

[Hz]

Max. resultant

velocity vi

[mm/s]

Estimated max. Vertical

particle velocity vmax

[mm/s]

Class 1 – Industrial buildings

of reinforced concrete, steel

construction

Class 2 – Buildings on

concrete foundation with

concrete or brick walls

Class 4 – Buildings with brick

cellar walls, upper apartment

floors on wooden beans

Class 4 – Especially sensitive

buildings and historical

buildings

10-30

30-60

10-30

30-60

10-30

30-60

10-30

30-60

12

12-18

8

8-12

5

5-8

3

3-5

7,2-12

7,2-18

4,8-8

4,8-12

3-5

3-8

1,8-3

1,8-5

Table 3. Recommended values for vibratory compactor (Bachmann et al., 1994)

Maximum vertical particle

velocity [mm/s] Effect on building

2

5

10

10-40

Risk of damage to ruins and buildings of great historical value

Risk of cracking in normal residential buildings with plastered walls and ceilings

Risk of damage to normal residential buildings (no plastered walls and ceilings)

Risk of damage to concrete buildings, industrial premises, ect.

3. Material

Floor and roof slabs and frame elements (beams and columns) were made from normal conventional

C30/37 concrete with characteristic compressive cylinder strength at 28 days fc = 30 N/mm2, secant

modulus of elasticity Ecm = 32 000 N/mm2 and density ρc = 2 400 kg/m

3 (CSI, 2009).

Tower of the wind turbine is made from normal conventional C40/50 concrete with characteristic

compressive cylinder strength at 28 days fc = 40 N/mm2, secant modulus of elasticity Ecm = 35 000

N/mm2 and density ρc = 2 400 kg/m

3 (CSI, 2009). Poisson’s ratio is taken equal to 0,2 (CEN 2002).


4. Geometry

Geometry of structural elements is provided in Table 4. Floor and roof solid reinforced concrete slabs

are 18 cm thick. Height of each level is equal 3 m while total height of structure is 33 m. Plan

dimensions of square plan shaped structure are 18x18 m (building Q) while rectangular shaped

structure has plan sides ratio 1:2,5 (18x45 m – building R).

Table 4. Geometry of structural elements

Element Geometry [cm]

Beam bb/hb

Beam length

Column bb/hb

Column height

Wind turbine’ pole Dbottom;Dtop

Wind turbine’ pole height

Slab thickness

30/50

300

50/50

300

40;20

300

18

5. Loading

5.1. Dead load

The structural analysis program SAP2000 (CSI, 2009) calculates the self weight of all structural

elements. Weight of floor layers for floor slabs was taken into account by uniformly distributed load

equal to 2,5 kN/m2, while uniformly distributed load added on roof slab is 4 kN/m

2. Those values are

taken as proposed by Džakić, Kraus and Morić (2012).

5.2. Live load

Live loads are also taken as suggested by Džakić, Kraus and Morić (2012). Characteristic values of

uniformly distributed load are determined according to category of use - 3 kN/m2 for floor slabs

(classrooms and offices) and 0,75 kN/m2 for roof slab.

5.3. Wind turbine loads

Wind turbine selected for this project is Bergey Excel 1kW wind turbine with power rating of 1000 W

and 2,5 m diameter. It is horizontal, upwind and has three fixed pitch fibreglass blades. Blades are

exceptionally strong because they are densely packed with glass reinforcing fibers that run the full

length of the blade (Bergey, 2003). Major components of the Excel 1 wind turbine are shown in Figure

1 and main characteristics of turbine are shown in Table 5. Turbine is mounted on concrete pole and

the rotational centre of the turbine blades is 3 m above the roof of the building.

Figure 1. Major components of Bergey Excel 1kW (Bergey, 2003)


Table 5. Characteristics of Bergey Excel 1kW (Bergey, 2003)

Bergey Excel 1 kW

Start-up wind speed

Cut-in wind speed

Cut-out wind speed

Max. design wind speed

Rated rotor speed

Rated power

Type

Rotor diameter

Turbine weight

Blade pitch control

Overspeed protection

3 m/s

2,5 m/s

None

54 m/s

490 RPM

1000 kW

3 blade upwind

2,5 m

34 kg

None, fixed pitch

AUTOFURL

Process of wind turbine modelling consists of several stages. Primarily, it was necessary to make a

model of wind turbine which was done using program Ashes 1.2 (Simis, 2013). Main purpose of wind

turbine modelling was to get output signal in form of time history which will be applied at the top

node of the wind turbine’ pole placed a top of the structure. Output signal generated in program Ashes

1.2 was in form of acceleration in time with time step of 0,1 s for two different wind load cases (Table

6). Both load cases are defined as recommended by CEN (2006) to assess dynamic behaviour of the

turbine in order to ensure that the system does not exhibit excessive vibrations. The input signal for

each load case is filtered so it covers frequency range of possible vibrations produced by small-scale

urban wind turbines. This way we cover all possible vibrations that may result from vibration of the

pole, vibration of the blades or wind flow.

Table 6. Wind turbine load cases

Load Case Wind Speed [m/s] Time of Simulation [s]

Case 1- normal operating wind speed

Case 2 – maximum wind speed

5

20

300

300

Wind turbine operating load is applied on the top node of the wind turbine pole placed on the building

roof. Input signal for SAP2000, generated using Ashes 1.2, was defined by records of acceleration in

time for three different directions. For the sake of brevity, Figures 2 and 3 show time histories for

direction x and z. Flow of wind in direction x is of particular interest since that is the direction of

attack of wind while the vibrations acting in z direction influence the behaviour of slabs and thus

influence humans.

Figure 2. Displacement of top node of tower for Case 1: direction x

-4

-3

-2

-1

0

1

2

3

0 5 10 15 20 25 30 35 40 45 50 55 60

Dis

pla

cem

ent [

mm

]

Time [s]


Figure 3. Displacement of top node of tower for Case 1: direction z

6. Numerical models

The numerical analysis of structures and soil-structure-wind turbine system was performed using

structural analysis program SAP2000. Buildings selected for this project are two eleven-story frame

structures regular in plan and elevation (Image 4). The buildings are shallow-founded and modelled as

linear-elastic. The foundation ground is modelled in two ways, namely by using: i) springs and ii) the

fixed-base assumption. Soil modelled by fixed supports represents soil category A (solid rock) while

the one modelled by springs correspond to the ground category C. Vertical and horizontals springs are

defined using expressions given by Gazetas (1983). Moreover, two cases of live loads are considered:

live load in 50% and 100% amount.

Figure 4. Cases modelled in SAP2000

In further text, results will be presented for different models named e.g. RF50 or QS100, where first

letter indicates plan shape of building (Rectangular or Quadratic), the second one marks foundation

model or type of the soil (Fixed or Spring), while the number corresponds to amount of live load

applied on model (50% or 100%).

-0,004

-0,0035

-0,003

-0,0025

-0,002

-0,0015

-0,001

-0,0005

0

0 5 10 15 20 25 30 35 40 45 50 55 60

Dis

pla

cem

ent [

mm

]

Time [s]

Model structure

Building Q

Soil A; 100% live load


Soil C; 100% live load


Building R






7. Results and discussion

Parametric analysis provides results in light of displacement response spectrums and acceleration

response spectrums taken from characteristic structural elements (slabs) on different floors. In this

chapter, characteristic values for nodes shown at Figure 5 are presented and compared with code-

based thresholds.

Figure 5. XY view (top) and XZ view (bottom) of building


7.1. Resulting vibrations for Load Case 1

Considering that acceleration values (Figure 6) in nodes “A” are higher than in nodes “B”, it can be

concluded that vibrations caused by wind turbine are more disturbing for people near building edges.

However, this does not apply on QF50 and RF50 models. In these two cases, acceleration values are

getting higher while approaching the centre of the building. In all modelled cases, vibrations are the

strongest in 10th floor, second from the top.

Figure 6. Maximum acceleration values

Red line (see Figure 6) represents limit value of 0,315 m/s2. For acceleration amplitude bigger than

this value, living beings are feeling a small degree of discomfort. However, maximum amount for Q

shaped model on springs with full amount of live load does exceed value of 0,5 m/s2 – value that

represents boundary between small and fairly amount of discomfort (see Table 1).

Figure 6 shows that vibration level is higher for buildings based on soft ground. Also, it can be noted

that for Q shaped building based on solid rock with decrease of live load amount, vibrations are

raising, while for same shape structure based on soil category C decreasing amount of live load

implicates lower particle acceleration values. For R shaped structure, regardless of the soil type,

vibrations are more disturbing for people for lower-intensity load.

Values of velocity amplitude are presented on Figure 7. As well as in case of acceleration, the highest

values for each node are recorded at 10th floor. Red line (see Figure 7) marks maximum tolerable value

of particle velocity. Maximum velocity for Q shaped structure on springs with full amount of live load

goes beyond 10 m/s which means that this kind of vibrations are dangerous for structure and its

structural and non-structural elements. Irrespective of soil category, higher amount of load acting on

structure influences differently on structures with different plan shape: for Q shaped building, velocity

drops while for R shaped structure velocity values are raising.

0,21

0,26

0,57

0,38

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65

Max

imum

acc

eler

atio

n [m

/s²]

Q-fixed-100 - A2 Q-fixed-50% - B2Q-spring-100% - A2 Q-spring-50% - A2

Q Building

0,09

0,16

0,25 0,25

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65

R-fixed-100 - A2 R-fixed-50% - B2

R-spring-100% - A2 R-spring-50% - A2

R Building

0,21

0,26

0,57

0,38

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65

Max

imum

acc

eler

atio

n [m

/s²]

F100 F50 S100 S50


Figure 7. Maximum velocity values

Elastic acceleration spectra in view of plan shape and soil category for z direction and full amount of

live load for Load Case 1 are presented at Figures 8 and 9. It can be generally noticed that acceleration

values are higher for structures based on soft soil when compared to the counterpart founded on rock.

Considering the fact that frequency is inversely proportional to period, these graphs can be used to

discuss sensitivity of structural elements to vibrations of certain frequency. These spectra show that

slabs on same verticals are sensitive to similar frequencies. Figure 8 (left, soil category A) shows that

“A” slabs (those near building edges) are particularly sensitive to frequency of 2,5 Hz while for “B”

slabs peak acceleration value is reached at approximately 1 Hz. “A” slabs of building based on soft

ground (Figure 8, right) will be most affected by vibrations with frequency value of 1,67 Hz and for

“B” slabs the critical value is 2,5 Hz.

Figure 8. Spectrum for building Q with 100% load: soil category A (left), soil category C (right)

4,64 4,51

15,11

10,18

0

2

4

6

8

10

12

14

16

Max

imum

vel

ocit

y [m

m/s

]

Q-fixed-100 - A2 Q-fixed-50% - B2

Q-spring-100% - B2 Q-spring-50% - A2

Q Building

1,75

3,60

6,01

8,13

0

2

4

6

8

10

12

14

16

R-fixed-100% - A2 R-fixed-50% - B2

R-spring-100% - A2 R-spring-50% - B2

R Building

0,21

0,26

0,57

0,38

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65

Max

imum

acc

eler

atio

n [m

/s²]

F100 F50 S100 S50

0

200

400

600

800

1000

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

on

[mm

/s²]

Period [s]

0

500

1000

1500

2000

2500

3000

3500

4000

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Akc

ele

raci

ja [m

m/s

²]

Period [s]

A1

A2

A3

B1

B2

B3


Figure 9. Elastic spectrum for building R with 100% load: soil category A (left), soil category C (right)

Figure 9 shows nearly equal critical values for both verticals and for both ground types: for soil

category A relevant value is 2,5 Hz, while the corresponding value for soil category C is around 1,67

Hz.

Further, elastic acceleration spectra for nodes A1, A2 and A3 for different soil categories and different

live load amount in z direction and Load Case 1 are presented at Figures 10 and 11. It can be seen that

critical values are different for different soil categories what demonstrates importance of soil type and

its impact on building behaviour. Structure founded on solid ground modelled by fixed joints has

higher stiffness value when compared to the same building model on soil of category C which is

modelled using springs. Due to higher stiffness, vibrations are less perceptible; therefore acceleration

values are significantly lower. Also, apart from Q shaped structure with half amount of live load, peak

acceleration for fixed based structure is reached by lower value of period, hence higher frequency,

than in case of structure on springs.

Figure 10. Elastic spectrum for building Q on A and C soil category: 100% live load (left), 50% live load (right)

Figure 11. Elastic spectrum for building R on A and C soil category: 100% live load (left), 50% live load (right)

0

100

200

300

400

500

600

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

on

[mm

/s²]

Period [s]

0

200

400

600

800

1000

1200

1400

1600

1800

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Period [s]

A1

A2

A3

B1

B2

B3

0

500

1000

1500

2000

2500

3000

3500

4000

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

on

[mm

/s²]

Period [s]

0

500

1000

1500

2000

2500

3000

3500

4000

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Akc

ele

raci

ja [m

m/s

²]

Period [s]

A1 (F)

A2 (F)

A3 (F)

A1 (S)

A2 (S)

A3 (S)

0

200

400

600

800

1000

1200

1400

1600

1800

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

on

[mm

/s²]

Period [s]

0

200

400

600

800

1000

1200

1400

1600

1800

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Akc

ele

raci

ja [

mm

/s²]

Period [s]

A1 (F)

A2 (F)

A3 (F)

A1 (S)

A2 (S)

A3 (S)


In Figure 11 it can be seen that spectra for building with R shaped plan based on soft soil are different

for different load amount applied on slabs, while for building on solid rock amount of load does not

significantly impact on spectral acceleration values or spectrum shape. Even though acceleration

values for model on springs are generally higher for higher load, for period of 0,8 s, acceleration is

lower for building with higher load value while at period of 1 s, acceleration values are the same for

both load amounts.

7.2. Comparison of Load Case 1 and Load Case 2

Observing the resulting vibrations for two load cases defined in Table 6, it can be concluded that

values of both acceleration and velocity are multiple rising with increasing of wind speed. Figure 12

provides comparison of maximum acceleration values for two different wind speeds: 5 m/s (Load Case

1) and 20 m/s (Load Case 2). In cases where values are crossing over the red line, vibrations are

extremely uncomfortable for human beings.

Figure 12. Comparison of maximum acceleration values: Load Case 1 (left) and Load Case 2 (right)

Figure 13 shows maximum velocity values for mentioned load cases for fixed base structure. Load

Case 1 gives acceptable results from the standpoint of the serviceability with maximum velocity value

significantly below the permissible level. Analysis for wind speed of 20 m/s gives more than six times

higher value of particle velocity than allowed hence there is a serious danger of failure of structure

exposed to wind turbine operating load.

Figure 14 provides transfer functions for node with maximum recorded acceleration values – node A2

on Q shaped building with full amount of load based on soft soil. Functions for each direction are

calculated by dividing output (structural vibration) and input (vibration of the top of the turbine)

signals pointing out amplified frequencies by structural members. The effect of amplification is

extremely high in vertical direction and it is most prominent for frequencies near to 1 Hz. For x

direction, vibrations of the top of the tower are lower or the same as the vibrations of the slabs, while

amplification for y direction rises until reaching the period value of 0,6 s (1,67 Hz), than drops till 1 s

period (1 Hz), and after this point, it keeps raising with increasing the period value.

0,21 0,26

0,090,16

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

Max

imum

acc

eler

atio

n [m

/s²]

Q-fixed-100 - A2 Q-fixed-50% - B2

R-fixed-100% - A2 R-fixed-50% - B2

5 m/s

3,39

4,29

1,40

2,55

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

Q-fixed-100 - A2 Q-fixed-50% - B2R-fixed-100% - A2 R-fixed-50% - B2

20 m/s

0,21

0,26

0,57

0,38

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65M

axim

um a

ccel

erat

ion

[m/s

²]

QF100 QF50 RF100 RF50


Figure 13. Comparison of maximum velocity values: load Case 1(left), load Case 2 (right)

Figure 14. Amplification of frequency for node A2: x and y direction (left), z direction (right)

8. Conclusion

Although wind turbine installation in urban areas contributes to production of “clean” energy, this

trend has its undesirable consequences too. Owning to its high tip-speed ratio, therefore high rotational

speed, small wind turbines can be dangerous at high wind speed conditions. Additionally, they often

produce loud noise and cause vibrations of structure elements. In this case study, we have come to a

conclusion that vibrations caused by only one small-scale wind turbine placed on the roof edge of 11

story building can cause serious problems for both structure and people who spend time inside it. For

normal operational wind speed (5 m/s), vibration will not have significant negative effect on people

but they will cause serviceability problems in structure. However, by increasing wind speed, vibration

level will also get higher. In case that wind turbine operates at maximum wind speed given for Osijek

4,64 4,511,75

3,60

0

10

20

30

40

50

60

70

80

Max

imum

vel

ocit

y [m

m/s

]


5 m/s

74,6473,33

28,58

59,32

0

10

20

30

40

50

60

70

80

Max

imum

vel

ocit

y [m

m/s

]


20 m/s

0,21

0,26

0,57

0,38

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0,45

0,5

0,55

0,6

0,65

Max

imum

acc

eler

atio

n [m

/s²]

QF100 QF50 RF100 RF50

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

ons

rat

io

Period [s]

X direction Y direction

0

2000

4000

6000

8000

10000

12000

14000

0 0,4 0,8 1,2 1,6 2 2,4 2,8

Acc

ele

rati

on

+s

rati

o

Period [s]

Z direction


area, it will generate vibrations seriously harmful for people as well as for the structure and its

structural and non-structural elements. Vibrations caused by small wind turbine are most disturbing for

people who are on 10th floor, second from the top. Also, vibration level rises while approaching edges

of building. They are generally more noticeable for building with Q shaped plan and for buildings

based on soft soil. Since vibration level for maximum wind speed (20 m/s) is overly high, it is

necessary to discuss and install optimal type of damper device in order to decrease vibration level to

acceptable level. In order to fully define all consequences of wind energy harvesting in urban areas

and the way each of them affect buildings and people, it is necessary to carry out further researches

varying different parameters such as soil type, plan shape, wind speed, position of wind turbine.

Acknowledgment

Authors of this paper would like to express their gratitude to COST Action TU1304 (WINERCOST)

for their support and for creating opportunities for research in the field of wind power technology.

Furthermore, thanks to Dr. Thomassen who generously allowed the use of program Ashes 1.2.

Without their support, this research would not be possible.

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http://www.engineeringtoolbox.com/people-vibration-d_1292.html

vibrations in buildings induced by small-scale turbines for ......moreover, vibrations in buildings...

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