1. No category

Applied Acoustics
Urban Sound Planning
– Focus on road traffic noise
Jens Forssén
Teknisk akustik, Chalmers
[email protected]
Presentation: Miljöbalksdagarna 2015
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
•  Tänk vid stadsplanering – SONORUS-projektet
(Wolfgang Kropp & Jens Forssén)
•  Åtgärder – HOSANNA-projektet
•  Planeringsverktyg – Auralisering och interaktiva
kartor (SONORUS)
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
SONORUS
Exempel Berlin :
245000 invånare har LDEN > 65 dB
27% av de större vägarna är inkluderade i en “noise action plan”.
Befolkningen antas växa med 7 % t o m 2030
Verktyg:
Maxhastighet 30km/h under natten
Vägbeläggningar / trafikåtgärder / skärmar
Slutsats: Det tar mer än 60 år för att åtgärda problem för de 245000
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
SONORUS
Vad gör en Urban Sound Planner?
Planering av den akustiska kvaliteten in en urban miljö
Helhetssyn (holistic) och långsiktig
•  Masterplan för en stad som definierar den akustiska kvaliteten
som man ska behålla och den kvalitet som ska åstadkommas
•  Del av planeringsprocessen från början
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
I dag:
•  Vi pratar buller och inte akustiska kvaliteten
•  Vi löser problem i ett mycket begränsat område
•  Vi löser de med ett korttidsperspektiv (lösningen behövs nu)
•  Huvudsakligen fokus på kostnader men inte på kvaliteten
•  Vi kommer sent in i planeringsprocessen
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
Urban Sound Planning
• 
• 
• 
Training network for young researcher
Sweden, United Kingdom, Belgium, Italy, Switzerland, Germany,
Netherlands
Test sites: Rome, Berlin, Antwerp and Brighton, Göteborg
14 young researchers - ITN financed by the EC €3.7M
www.fp7sonorus.eu
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
SONORUS
•  Planering
•  Verktyg/åtgärder
•  Acceptans för att ljudmiljön är en mycket viktig faktor
för ett urbant områdes funktioner:
o  Upplevelse av ett urbant område
o  Människors välbefinnande och hälsa
Jens Forssén
Department of Civil and Environmental Engineering
Applied Acoustics
Upplevelse/funktion?
Jens Forssén
Department of Civil and Environmental Engineering
Chalmers University of Technology
Verktygslåda för minskat
trafikbuller i stadsmiljö
Toolbox for reduced traffic
noise in urban environments
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Verktygslåda för minskat
trafikbuller i stadsmiljö
Toolbox for reduced traffic
noise in urban environments
•  Noise sources in the urban area
•  Distribution of road traffic, calming of road traffic, etc.
•  Compact or sprawled cities
•  Planning of buildings
•  Ground treatments
•  Materials (soil and recycled)
•  Barriers and berms
•  Trees
•  Greening buildings
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Vägtrafikbullerkällor – åtgärder
Motorljud – förbränningsmotor
(under 30 km/h, lätta fordon)
(under 60-70 km/h, tunga fordon)
• Ljuddämpare
• Inkapsling
• Körning
Däck-vägljud
• Däck: konstruktion (styvhet, mönster,…)
• Däck: bredd
• Vägbeläggning (absorption/stenstorlek, etc.)
Ø  Lokala inköp: el- och hybridbussar till lokaltrafik, tystare personbilar, etc.
Ø  Buller från motorfordon kommer inte ändras nämnvärt under närmaste 15-20 åren
Ø  Finns dock teknisk potential om 5-10 dB* (se även Quieter cities...-rapporten**)
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Reduction Potential of Road Traffic Noise
A PILOT STUDY
– 1 – Jens Forssén and Lars Ivarsson
Wolfgang Kropp, Tor Kihlman,
*Kropp, W., Kihlman, T., Forssén, J., Ivarsson, L. (2007). Reduction potential of road traffic noise – A Pilot Study. Applied
Acoustics, Chalmers University of Technology, February, 2007.
Teknisk akustik
**Kihlman et al. (2014)
http://www.ljudlandskap.acoustics.nu/
publikationer.php?
kapitel=ovrigt&rubrik=quieter_cities
Jens Forssén
Chalmers University of Technology
Distribution of road traffic,
calming of road traffic, etc.
•  Spatial redistribution
•  Temporal redistribution
•  Removal (and tunnels)
•  Calming: Driving speed, Acceleration
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Distribution of road traffic,
calming of road traffic, etc.
•  Spatial redistribution
•  Temporal redistribution
•  Removal (and tunnels)
•  Calming: Driving speed, Acceleration
Urban morphology
•  Compact or sprawled cities
•  Planning of buildings (quiet side)
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Reduction methods during
sound propagation
HOSANNA project
www.greener-cities.eu
•  Edition of summary brochure
•  European workshops (Dec 2012–Jan 2013)
•  Making available engineering prediction tools
•  Publishing of Handbook:
Environmental Methods for Transport Noise Reduction
(Taylor & Francis)
Chalmers University of Technology
Verktygslåda för minskat
trafikbuller i stadsmiljö
Toolbox for reduced traffic
noise in urban environments
•  Noise sources in the urban area
•  Distribution of road traffic, calming of road traffic, etc.
•  Compact or sprawled cities
•  Planning of buildings
•  Ground treatments
•  Materials (soil and recycled)
•  Barriers and berms
•  Trees
•  Greening buildings
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Bättre mark?
Teknisk akustik
Jens Forssén
The Open University, UK: A$enborough, K., University
Taherzadeh, S., et al. Chalmers
of Technology
Soft strips and patches (gravel or soft grass land)
A−weighted sound pressure level, dB
90
80
70
grass, 50 m range
60
50
40
30
SPL reference:
SPL abatement:
Insertion Loss:
20
10
Teknisk akustik
SPL reference
SPL abatement
63
125
250
61.0 dB(A)
55.7 dB(A)
5.3 dB(A)
500
1000
Frequency, Hz
2000
4000
Jens Forssén
The Open University, UK: A$enborough, K., University
Taherzadeh, S., et al. Chalmers
of Technology
Soft strips and patches (gravel or soft grass land)
A−weighted sound pressure level, dB
90
80
70
grass, 50 m range
60
50
40
30
SPL reference:
SPL abatement:
Insertion Loss:
20
10
Teknisk akustik
SPL reference
SPL abatement
63
125
250
61.0 dB(A)
53.0 dB(A)
8.0 dB(A)
500
1000
Frequency, Hz
2000
4000
Jens Forssén
The Open University, UK: A$enborough, K., University
Taherzadeh, S., et al. Chalmers
of Technology
Ground roughness [Attenborough et al., Euronoise 2012]
ca. 3 dB
!
Teknisk akustik
!
Jens Forssén
The Open University, UK: A$enborough, K., University
Taherzadeh, S., et al. Chalmers
of Technology
Low, parallel walls (0.3 m high)
!
Soft strips and patches (gravel or soft grass land)
+ ground
resonators…
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Input data and models from
Bradford University
(Kirill Horoshenkov, Amir Khan, Hadj Benkreira)
(b)
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Low maintenance high performance low density soil – acousAc models Low density soil High porosity and low flow resisAvity increases sound absorpAon performance of low density soil. Summary of soil properAes Soil type
Substratum
Clay based
Teknisk akustik
Normal garden soil – Clay based Flow resistivity
(exp.)
(Pa.s/m2)
Flow resistivity
(theor.)
(Pa.s/m2)
Porosity
(exp.)
Porosity
(theo.)
Tortuosity
(exp.)
Tortuosity
(theo.)
Thickness
(exp.)
(m)
Thickness
(theo.)
(m)
7,600
566,350
7,218
620,650
0.76
0.39
0.76
0.39
-
1.36
2.05
0.07
0.10
0.08
0.04
Jens Forssén
Chalmers University of Technology
ApplicaAons of recycled materials in noise barriers Sound absorbing and soil reten?on applica?ons Sound transmission applica?ons A vegeta(ve wall: composi(on (le4); installa(on (right). Could also be used indoors to improve air quality. Teknisk akustik
Jens Forssén
Bättre skärmar?Chalmers University of Technology
CSTB, France: Defrance, J., Jean, P., Baulac, M., et al. Gabions
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Example: low, absorptive/green barriers

EURONOISE 2012
10–13 June, Prague


Van Renterghem et al.: Low vegetated barriers in streets
!
Teknisk akustik
Figure 1. Geometrical setup of the street canyon configuration under study with indication of dimensions, location of
receiver lines and screens, and different materials considered.
Jens Forssén

Chalmers University of Technology
Skog/träd/buskar
•  Mark
•  Motverkar negativ vindeffekt
• Absorption genom ljudspridning (scattering), ovan ca 1 kHz
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Trees
Ghent University/iMinds (formerly IBBT),
Belgium: Van Renterghem, T., Botteldooren,
D., et al.
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Tree belts
How to increase shielding ?
Teknisk akustik
How to decrease
stem cover
fraction without
affecting
shielding (too
much)?
Jens Forssén
Chalmers University of Technology
Tree belts
Teknisk akustik
Jens Forssén
University of Technology
[HOSANNA, FP7Chalmers
project, www.greener-cities.eu]
Greening buildings
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Greening buildings
Yuliya Smyrnova, Jian Kang (USFD), Timothy Van
Renterghem (IBBT), Maarten Hornikx (CTH/TUE)
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Case: single street
Vegetation in street canyon
Ref. case: no vegetation:
that consist of plants, growing medium packed into
geotextiles or pots and a supporting structure may be
applied. The noise reduction potential of vegetation
including substrate placed on street canyon facades
is affected by canyon width, vegetation and substrate
placement, and receiver position. The noise absorption effect is more efficient in narrower canyons and
the extra attenuation provided by placing vegetation
with substrate or other absorbing surfaces on facades
increases with greater source–receiver distance. Adding vegetation to facades in traffic-bearing streets is
more effective for higher receiver positions. Vegetation absorbs and scatters sound mainly at mid and
high frequencies, so the acoustic effectiveness of
greening facades will be lower at low frequencies.
To illustrate the effect of facade vegetation, noise
reduction was calculated for a single street with
19-m-high facades on both sides, assuming nonvegetated facades with very low noise absorption.
The acoustic treatment consisted of a supporting
system, soil, and vegetation. The calculated predictions suggested that a noise reduction of 2–3 dB(A)
may be obtained at a height of 1.5–4 m if all facades
are covered with vegetation, compared with non-
Receivers at1.5 m and 4 m height on
Teknisk akustik
the façade
Noise reduction for cases with
green wall substrate:
Vegetated facades in urban squares
VEGETATED FACADES IN URBAN SQUARES
As in the case of urban streets, the noise reduction
potential of vegetated facades is greater for narrower
squares and for receivers situated further from traffic sources. Note that if traffic runs through the
square itself, the vegetation will reduce the noise
by less than if the traffic runs on a side street.
The effect of green wall treatments on facades was
predicted for a square with a street on one side, assuming non-vegetated facades with very low noise absorp-Jens
tion. Averaged over 1.5-m-high receivers, a reduction of
Reduction: 2-3 dBA
Forssén
Chalmers University of Technology
Case: street canyon and
courtyard
Vegetated courtyard facades
Teknisk akustik
VEGETATED COURT YARD FACADES
VEGETATED OPENINGS TO COURT YARDS
Having a quiet side bordering a dwelling would
be useful to reduce the adverse effects of noise,
such as annoyance and sleep disturbance. Methods that reduce noise in courtyards can therefore
be valuable as a complement to noise reduction on
the most noise-exposed facades of buildings.
Noise levels in courtyards are lower with higher
facade absorption coefficients. Vegetated facades in
courtyards reduce noise from all sources situated outside the courtyard, and vegetated facades are also beneficial for noises originating from inside the courtyard.
The effect of vegetated courtyard facades is greatest at the highest frequencies and for lower receiver
positions, with an average reduction of 4 dB(A),
Openings to courtyards can transmit noise, reducing the relative quietness of the non-exposed sides of
dwellings. Compared with an enclosed courtyard, an
opening facing a busy street can increase the average noise level in the courtyard by up to 15 dB(A) for a
3-m-high opening and 18 dB(A) for a building-height
opening of 19 m. In the case of an opening facing
a non-trafficked street crossing a busy street, the
noise level increases by approximately 6 dB(A) and
10 dB(A) for opening heights of 3 and 19 m, respectively. The noise level differences are relative to road
traffic noise originating from the main street only,
considering that no noise is coming from side roads.
Vegetating openings leading to courtyards can
Jens Forssén
Chalmers University of Technology
vegetated façades of the
courtyard
Noise reduction with vegetated walls on facades in the
courtyard: 3.5 dBA
Noise reduction for vehicle speed averaged over: 30–70 km/h.
Teknisk akustik
Jens Forssén
Chalmers University of Technology
Absorbing entrance to the
courtyard
!
Teknisk akustik
Opening height
3m
Reduction
4.5 dBA
9.2m
4.1 dBA
Jens Forssén
Chalmers University of Technology
vegetated roofs
Green roofs with short vegetated roof-edge barriers
ROOF BARRIERS
Teknisk akustik
A vegetated roof barrier positively affects the sound
field in the courtyard by the presence of absorption at
the diffraction edges. For example, a vegetated lowheight barrier can be installed along the edges of flat
roofs nearest the courtyard, nearest the street canyon,
or along both edges. When a barrier is placed along
the roof edge nearest the canyon or the courtyard, the
average noise reduction is approximately 1 dB(A) for
a 0.6-m-high barrier. Placing low barriers along both
sides of the central building reduces the noise by an
average of 3 dB(A). For a narrow configuration with
a street width of 10 m, the noise is reduced slightly
more, by an additional approximately 1 dB(A). Note
that low-height barriers without vegetation have an
insignificant effect in terms of noise reduction.
Jens Forssén
Chalmers University of Technology
Example
!
Teknisk akustik
Jens Forssén
Chalmers University of Technology
vegetated roofs
Noise reduction:
3 dBA
7.4 dBA
7 dBA
8 dBA
Flat roof performs better without vegetation
Teknisk akustik
Jens Forssén
Nyttokostnadsanalyser (Ronny Klæboe et al., TOI)
För att skatta nyttan av åtgärden vs kostnaden
Exempel: Enkelt grönt tak, nyttokostnadskvot ca 2
Chalmers University of Technology
Upplevd förbättring
Example: field studies including perception
[Nilsson, M. et al., Stockholm University]
Perceived annoyance
(magnitude estimation scale,)
60
No barrier
Barrier
55
50
45
40
35
30
25
20
63
65
67
69
71
73
75
77
79
81
83
A-­‐weighted sound pressure level (dBA, LAeq,4s)
Teknisk akustik
Jens Forssén
HOSANNA – combining abatements
Illustration, !
T. Hennix, HOSANNA!
Chalmers University of Technology
Sammanfattning
•  Var med tidigt i processen
•  Använd alla verktyg
Teknisk akustik
Jens Forssén