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Assessment of Environmental Effects: Vibrations
State Highway 3,
Awakino Tunnel Bypass
Peter Cenek
© Opus International Consultants Ltd 2017
Prepared By Opus International Consultants Ltd
Peter Cenek Opus Research
Research Manager, Engineering Sciences 33 The Esplanade, Petone, 5012
PO Box 30 845, Lower Hutt 5040
New Zealand
Reviewed By Telephone: +64 4 587 0600
Paul Carpenter Facsimile: +64 4 587 0604
Vibrations Specialist
Date: 24 August 2017
Reference: 2-32705.00 Task 51AVT
Status: Final
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Executive Summary
This report presents an assessment of ground-borne vibrations resulting from construction works
associated with the State Highway 3 (SH3) Awakino Tunnel Bypass Project and from traffic once
the Project is completed. The Project involves realigning SH3 to the north bypassing the tunnel,
requiring two bridges and a relatively complex retaining wall.
Particular emphasis has been placed on determining critical separation distances between
construction and Heavy Goods Vehicle (HGV) traffic vibration sources and receivers to ensure the
generated vibrations are not problematic from the perspectives of annoyance and structural
damage.
The assessment has been based on a desk study that involved the application of predictive models
in conjunction with specific inputs to estimate ground vibrations from road construction activity
and HGV traffic and how these vibrations attenuate with distance.
The estimated vibration levels were assessed from the perspectives of human comfort and cosmetic
building damage using guidelines given in:
• British Standard BS 5228 2:2009, Code of practice for noise and vibration control on
construction and open sites – Part 2: Vibration;
• German Standard DIN 4150-3:1999, Structural vibration – Part 3: Effects of vibration on
structures; and
• The Transport Agency’s State Highway Construction and Maintenance Noise and Vibration
Guide (2013).
The primary conclusions and recommendations arising from this assessment of ground vibrations
generated by the construction and operation of the proposed realignment of SH3 in the vicinity of
Awakino Gorge are as follows:
1. Vibration levels generated by construction are likely to be higher than those from traffic.
However, these construction-related vibrations will be temporary and of a limited duration.
2. The occupants of the dwelling closest to the earthworks and road construction (i.e. OTS
House 1) are likely to experience vibration levels from these activities that may cause
complaint but not damage to the dwelling. Therefore, because complaints typically arise
from interference with people’s activities or fear of property damage, it is important that the
contractor establishes open communication with the occupants so that any issues can be
identified and addressed expeditiously. However, the contractor should ideally take all
practicable measures to avoid excessive earthworks and road construction induced
vibrations near OTS House 1.
3. The analysis has identified that there is the potential for piling to cause damage to the
existing Awakino tunnel.
4. The adverse effects from construction can be appropriately mitigated through a
Construction Vibration Management Plan as the mitigation measures relate to selection of
equipment and processes and the location and operation of the equipment. In the unlikely
event of there being no practicable means for achieving the construction vibration criteria
stipulated in the Construction Vibration Management Plan, pre- and post-construction
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inspections of at risk structures and buildings will need to be performed and any damage
rectified.
5. A key aspect of this Construction Vibration Management Plan is for piling operations to be
used on the project to be trialled before construction proper commences to ensure short-
term vibration damage guidelines given in German Standard DIN 4150-3 are complied with
at the existing Awakino tunnel.
6. Once operational, traffic induced vibrations are unlikely to be perceived if the proposed
chipseal road surface can be laid so that it satisfies the Transport Agency’s roughness
specification of 70 NAASRA counts per km for new pavement construction. Furthermore, at
the closest separation distance from a dwelling of approximately 87 m, vibrations are
unlikely to be felt by occupants even when the road surface roughness reaches 110 NAASRA
counts/km, the Transport Agency’s trigger for road smoothing for roads classified as Rural,
Regional Strategic.
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Contents
Executive Summary .................................................................................................... i
1 Introduction ........................................................................................................1
2 Project Description ............................................................................................ 2
2.1 Overview ................................................................................................................................ 2
2.2 Key considerations from a vibrations perspective .............................................................. 3
3 Assessment Criteria ........................................................................................... 4
3.1 Background ............................................................................................................................ 4
3.2 Human Comfort .................................................................................................................... 4
3.3 Building Damage ................................................................................................................... 5
3.4 Vibration Guidelines Used by the Transport Agency ......................................................... 6
3.5 Screening Criteria Applied to Project .................................................................................. 8
4 Methodology ...................................................................................................... 9
4.1 Overview ................................................................................................................................ 9
4.2 Method for Calculating Attenuation Coefficient ................................................................. 9
4.3 Vibration as a Function of Distance ..................................................................................... 9
4.4 Predictor Equations ............................................................................................................ 10
5 Results .............................................................................................................. 12
5.1 Soil Attenuation .................................................................................................................... 12
5.2 Critical Separation Distances .............................................................................................. 12
6 Assessment of Effects ........................................................................................14
6.1 Existing Environment ..........................................................................................................14
6.2 Construction Vibrations ....................................................................................................... 15
6.3 Operational Vibrations ....................................................................................................... 18
6.4 Mitigation Measures ........................................................................................................... 18
7 Conclusions and Recommendations .................................................................. 21
8 References ....................................................................................................... 22
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1 Introduction
This report presents the results of a desk study to calculate likely maximum ground vibrations
expected to occur in the vicinity of the State Highway 3 (SH3) Awakino Tunnel Bypass project (the
Project). The effects of these calculated vibrations on the existing Awakino Tunnel and nearby
dwellings and their occupants were assessed so that appropriate mitigation actions can be
implemented if necessary.
The vibration sources considered were:
• The operation of machinery during earthworks and laying of the road surface associated
with the construction of the realigned SH3;
• Piling associated with the construction of the two new bridges, which will cross the Awakino
River; and
• Operational road vehicle traffic on SH3, following the completion of the project.
The study involved the application of predictive models in conjunction with New Zealand specific
inputs to estimate ground vibration from road construction activity and traffic, and how these
vibrations attenuate with distance. Typically, this approach produces conservative estimates of the
maximum probable ground vibrations. Therefore, the output from the study can be regarded as
representing the upper value of expected vibration levels.
The estimated vibration levels were assessed from the perspectives of human comfort and cosmetic
building damage using guidelines given in:
• British Standard BS 5228 2:2009, Code of practice for noise and vibration control on
construction and open sites – Part 2: Vibration;
• German Standard DIN 4150-3:1999, Structural vibration – Part 3: Effects of vibration on
structures; and
• The New Zealand Transport Agency’s State Highway Construction and Maintenance Noise
and Vibration Guide (2013).
The report has been structured as follows:
• Section 2 presents an overview of the project and key aspects of the project from a
vibrations perspective.
• Section 3 details the criteria by which the estimated construction and traffic related
vibrations were evaluated from the perspectives of human comfort and cosmetic building
damage.
• Section 4 describes the methodology used for determining construction and operational
vibrations.
• Section 5 summarises the key findings from the vibration analysis undertaken.
• Section 6 identifies problematic vibrations and associated mitigation measures.
• Section 7 presents the main conclusions and recommendations resulting from the
assessment.
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2 Project Description
2.1 Overview
The SH3 Awakino Tunnel Bypass project is located 50 km south of Te Kuiti, roughly half way
between Hamilton and New Plymouth, in the Waikato Region. The project will reduce fatal and
serious crashes and road closures, as well as improve the performance of the network. Parts of the
site are highly constrained by poor access, steep terrain and the narrow existing highway, as well as
the meandering Awakino River. The proposed two lane realignment to the north of the existing
single lane Awakino Tunnel will be about 2 km long (i.e. approximate start at SH3 RS133-B/0.4
and approximate end at SH3 RS118-B/13.07).
The preliminary design of the realignment involves:
• Approximately 2.3 km of new two lane road typically 10 m wide (plus batter slopes), which
bypasses the existing single lane Awakino Tunnel;
• Approximately 675 m of northbound passing lane and two truck pull off areas (one in each
direction);
• Two new bridges across the Awakino River;
• Approximately 190,000 m3 of earthworks cut up to about 30 m high, covering about 400 m
length of the new highway;
• Approximately 600 m length of embankment up to about 6 m high, including a section of
fill supported on timber piles due to underlying soft ground;
• Approximately 600 m length of new retaining walls up to about 8 m high at various
locations along the realigned highway;
• Changes to existing farm entrances and access tracks, including provision of a new farm
underpass;
• A rest area with a footpath to the tunnel and access to the river; and
• Landscape treatment and ecological enhancement planting.
At the time of preparing the report, there were no plans to employ blasting in making the 50 m
length of cut in the limestone at the southern end of the Project. However, if the successful
contractor wanted to do things differently, he/she would still need to comply with the vibrations
related criteria specified in the Construction Vibration Management Plan (CVMP) as well as any
vibrations related conditions that may be placed on the designation. Recommend criteria for
managing the effects of construction vibration and airblast are provided in the Transport Agency’s
“State Highway construction and maintenance noise and vibration guide” (NZTA, 2013), which has
been reproduced as Table 3.3 in this report for ready reference. Therefore, for the purposes of this
assessment of vibration effects, it has been assumed that no blasting will be employed for the
Project.
The existing alignment has an annual average daily traffic of 2269 vehicles per day (two way flow)
of which heavy commercial vehicles comprise 20% (i.e. 450 HCV’s per day). These traffic
characteristics are not expected to change as a result of the Project, with the exception of growth
estimated at 0.8% per annum based on historic trending and a maximum rate of 2.2% per annum
based on the last 5 years.
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2.2 Key considerations from a vibrations perspective
The key considerations of the project from a vibrations perspective are as follows:
2.2.1 Operational Traffic
The Project will have an 80 km/h speed limit in place, which is 20 km/h less than the open road
(100 km/h) for the existing alignment of SH3. Therefore, a deterioration of the existing traffic-
induced vibration conditions can only occur if the Project brings traffic closer to neighbouring
buildings.
2.2.2 The Bridge Elements
The two new bridges have the potential to generate problematic vibrations from a number of
aspects:
• Ground improvement may be required to protect against liquefaction subsidence and
lateral spreading at the bridge abutments. A method, which is commonly used is
compacted or rammed stone columns. This may result in large ground vibrations,
depending on the energy required to ram the stone columns.
• Construction of the bridge piers will necessitate vibration inducing piling operations, which
have the potential to cause damage to nearby buildings because of the large impact forces
involved.
• Once operational, large ground vibrations will result if the transitions at the bridge
abutments and expansion joints aren’t sufficiently smooth to limit impact wheel loading
from heavy commercial vehicles.
2.2.3 General Road Construction
Typical road construction activity such as ground excavation and compaction has the potential to
cause problematic vibrations if it takes place in close proximity to buildings and structures.
2.2.4 Wooden piles – Hammonds Corner
Wooden piles may be used around the area of the realigned Hammonds Corner. These wooden
piles are expected to only be driven until they hit rock and as such are expected to generate smaller
vibration levels than possible piling activities related to bridge construction. As the location of the
wooden piles is further from the sensitive receivers than the bridge construction activities, it can be
expected that vibrations generated from the wooden piles will be of a low level, provided the
calculated vibration levels from piling related to bridge construction are acceptably low.
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3 Assessment Criteria
3.1 Background
The Project covers land areas under the jurisdiction of the Waitomo District Council and the
Waikato Regional Council. The only specific reference to vibrations is made under clause 20.5.1.6
of the Waitomo District Plan-March 2009, Part 3: Section 20: Noise1. Under the Waitomo District
Plan, the Project area is zoned rural and the following rules apply:
While Waitomo District Plan vibration related rules do not directly apply to the designation, they
provide guidance as to the community’s expectations of what is reasonable vibration. Therefore,
any standards based criteria used to evaluate the significance of the calculated maximum probable
ground vibrations in the vicinity of the Project should ideally be consistent with the vibration
related rules contained in the Waitomo District Plan.
Current standards and guidelines considered appropriate in assessing the effects of vibration
caused by the Project from the perspectives of human comfort and damage to buildings are
discussed below. These standards and guidelines generally state ground vibrations in terms of
peak particle velocity (PPV) for the assessment of effects on humans and structures.
3.2 Human Comfort
The British Standard, BS 5228.2, 2009, “Code of practice for noise and vibration control on
construction and open sites – Part 2: Vibration,” is a current standard that is commonly adopted in
New Zealand to provide guidance on the response of humans to vibration levels. Guidance on
effects of vibration levels from BS 5228.2 is reproduced below as Table 3-1 for ready reference. The
vibration levels in Table 3-1 are in terms of PPV, which is the vibration parameter routinely
measured when assessing potential building damage.
1 http://www.waitomo.govt.nz/Documents/Documents/District%20Plan/Part%20Three_General%20Provisions.pdf
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Table 3-1: Guidance on effects of vibration levels (from British Standard BS 5228-2:2009, Annex B)
Vibration level Effect
0.14 mm/s
Vibration might be just perceptible in the most sensitive situation for most vibration
frequencies associated with construction. At lower frequencies, people are less
sensitive to vibration.
0.3 mm/s Vibration might be just perceptible in residential environments.
1.0 mm/s It is likely that vibration of this level in residential environments will cause complaint,
but can be tolerated if prior warning and explanation has been given to residents.
10 mm/s Vibration is likely to be intolerable for any more than a very brief exposure to this
level.
3.3 Building Damage
The German Standard DIN 4150-3 (1999) “Structural vibration – Part 3: Effects of vibration on
structures” provides guideline vibration levels which, “when complied with, will not result in
damage that will have an adverse effect on the structure’s serviceability.” For residential buildings,
the standard considers serviceability to have been reduced if:
• Cracks form in plastered surfaces of walls.
• Existing cracks in the building become enlarged.
• Partitions become detached from load bearing walls or floors.
These effects are deemed ‘minor damage’ in DIN 4150-3.
The DIN 4150-3 (1999) guideline values for evaluating short-term and long-term vibration on
structures are given in Table 3-2, where short-term vibrations are defined as those that do not
occur often enough to cause structural fatigue and do not produce resonance2 in the structure
being evaluated and long-term vibrations are all the other types of vibration.
With reference to Table 3-2, the German Standard DIN 4150-3 (1999) recognises commercial
buildings can withstand higher vibration levels than residential and historic buildings. Also, the
guideline values for short-term vibration increase as the vibration frequency increases.
2 Resonance is the condition occurring when a vibrating system is subjected to a periodic force that has the same frequency as the natural vibrational frequency of the system. At resonance, the amplitude of vibration is a maximum.
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Table 3-2: Vibration guidelines from DIN 4150-3:1999 for assessing effects of vibrations on buildings
Type of Structure
Vibration Thresholds for Structural Damage, PPV (mm/s)
Short-Term Long-Term
At Foundation Uppermost
Floor
Uppermost
Floor
0 to 10
Hz
10 to 50
Hz
50 to 100 Hz
All Frequencies
All
Frequencies
Commercial /industrial
20 20 to 40 40 to 50 40 10
Residential 5 5 to 15 15 to 20 15 5
Sensitive/Historic 3 3 to 8 8 to 10 8 2.5
Note: When a range of velocities is given, the limit increases linearly over the frequency range.
3.4 Vibration Guidelines Used by the Transport Agency
3.4.1 Construction Related Vibrations
Vibration criteria given in the State Highway Construction and Maintenance Noise and Vibration
Guide (NZTA, 2013) have been used as a basis to manage construction related vibrations. These
criteria are reproduced in Table 3-3 below.
Table 3-3: Construction Vibration Criteria from NZTA, 2013
Receiver Details Category A Category B Location
Occupied
dwellings
Daytime 6: am to 8:00 pm 1.0 mm/s PPV 5.0 mm/s PPV Inside the
building Night time 8:00 pm to 6: am 0.3 mm/s PPV 1.0 mm/s PPV
Other
occupied
buildings
Daytime 6: am to 8:00 pm 2.0 mm/s PPV 10.0 mm/s PPV
All buildings Transient vibration 5.0 mm/s PPV BS 5228.2
Table B2 values
Building
foundation
Continuous vibration BS 5228.2
50 percent
Table B2 values
Underground
Services
Transient vibration 20mm/s PPV 30 mm/s PPV On pipework
Continuous vibration 10mm/s PPV 15 mm/s PPV
Table 3-3 refers to values from BS 5228.2 Table B2, which is reproduced below as Table 3-4 for
ease of reference.
With reference to Table 3-3, if measured or predicted vibration levels exceed the Category A criteria
then a suitably qualified expert shall be engaged to assess and manage construction vibration to
comply with the Category A criteria. If the Category A criteria cannot be practicably achieved, the
Category B criteria shall be applied.
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If measured or predicted vibration levels exceed the Category B criteria, then construction activity
shall only proceed if there is continuous monitoring of vibration levels and effects on those
buildings at risk of exceeding the Category B criteria by suitably qualified experts.
Table 3-4: BS 5228.2 Table B2 values
Type of building Peak component velocity in frequency range of
predominant pulse
4 to 15 Hz 15 Hz and above
Reinforced or framed structures
Industrial and heavy commercial
buildings
50 mm/s 50 mm/s
Unreinforced or light framed
structures
Residential or light commercial
buildings
15 mm/s at 4 Hz
increasing to 20 mm/s at 15 Hz
20 mm/s at 15 Hz
increasing to 50 mm/s at 40
Hz and above
3.4.2 Operational Vibrations
For perception of traffic vibration, the criteria commonly used is taken from Annex B, table B.1 of
the Norwegian Standard NS 8176.E (2005) “Vibration and shock: Measurement of vibration in
buildings from land-based transport and guidance to evaluation of its effects on human beings.”
For new roads, the criterion for class C buildings is applied as it corresponds to the recommended
limit value for vibration in new residential buildings and in connection with planning and building
of new transport infrastructures. This criterion is in terms of statistical maximum value for
weighted velocity (Vw,95) and has a value of 0.3 mm/s. Weighted velocity is the root-mean-square
value (r.m.s) of vibration velocity measured by using a frequency weighting filter corresponding to
whole-body vibration in buildings, where the weighting is about 1 over the frequency range 1 to 80
Hz. The r.m.s integration time is 1 second and the statistical maximum is derived from the mean
and standard deviation of a minimum of 15 single passes of a Heavy Goods Vehicle (HGV) at a
measurement location.
Because of this need to apply a weighting, the class C and D building criteria of NS 8176.E (2005)
can only be applied to measurements of traffic-induced vibrations, not values calculated from
predictive models.
NS 8176.E states that about 15% of the affected persons in class C dwellings can be expected to be
disturbed by traffic induced vibration.
For existing roads, the criterion for class D buildings is applied as it corresponds to vibration
conditions that ought to be achieved in existing residential buildings. This criterion is in terms of
statistical maximum value for weighted velocity (Vw,95) and has a value of 0.6 mm/s.
NS 8176.E (2005) states that about 25% of the affected persons in class D dwellings can be
expected to be disturbed by traffic induced vibration.
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3.5 Screening Criteria Applied to Project
To identify where construction and operation of the Project may create significant adverse impact,
the following criteria has been applied to the output of modelling used to provide estimates of
ground-borne vibrations:
• 0.3 mm/s PPV for disturbance of building occupants.
• 1 mm/s PPV for complaint by building occupants.
• 2.5 mm/s PPV for damage to buildings arising from traffic (i.e. long term vibration).
• 5 mm/s PPV for damage to buildings arising from construction (i.e. short term vibration).
These criteria have been derived from BS 5228.2, 2009 and DIN 4150-3 (1999) and have
deliberately been made more stringent than the criteria used by either the Waitomo District
Council or the Transport Agency because they are being applied to modelled estimates of ground
vibrations and not measured ground vibrations. This approach will yield slightly more conservative
effects assessments, which is considered preferable.
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4 Methodology
4.1 Overview
The methodology adopted in making the assessment involved the application of predictive models
in conjunction with specific inputs to estimate ground vibrations from road construction activity
and HGV traffic and how these vibrations attenuate with distance. These predictive models are
detailed below.
4.2 Method for Calculating Attenuation Coefficient
The soil attenuation coefficient, α, is used as a measure of the decrease in measured vibration with
increasing distance from the road.
With reference to Cenek et al (2012), maximum scala readings have been shown to be very good
predictors of soil attenuation. Therefore, estimates of soil attenuation coefficient were calculated
from scala readings presented in the 2017 SH3 Awakino Tunnel Bypass DBC Geotechnical Factual
Report used in combination with equation 4-1, taken from Cenek et al (2012).
�(5��) = 0.0351 ��.����������� (Equation 4-1)
where: �(5��) = soil attenuation coefficient (m-1) for a frequency of 5Hz
������� = maximum scala reading (blows/50mm)
Attenuation of vibrations is dependent on the frequency of the vibrations. Equation 4-2 can be used
to convert the attenuation coefficient to a frequency independent value relating to the soil type.
fπ
αρ = (Equation 4-2)
where: α is the attenuation coefficient [m-1]
ρ is the frequency independent material property of the soil [s/m]
f is the dominant frequency of the ground vibration [Hz]
4.3 Vibration as a Function of Distance
The soil attenuation coefficient derived as outlined in section 4.2 can be used to estimate the
magnitude of ground vibrations at any distance from source using equation 4-3 below, taken from
Cenek et al (2012). This allows estimation of critical separation distances required to ensure that the
guideline vibration levels for human comfort and building damage given in BS 5228-2:2009 and DIN
4150-3:1999 are not exceeded.
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!� = !" #$"$�%�.& �α(')×()*�)+) (Equation 4-3)
where: V" = the measured or estimated peak particle velocity (mm/s) at distance R" (m)
V� = the peak particle velocity (mm/s) at distance R� (m) from source
�(.) = soil coefficient for the dominant frequency . (Hz)
4.4 Predictor Equations
4.4.1 Vibrations from Heavy Commercial Vehicles
The probable maximum ground vibrations 2m from the lane edge arising from HCV traffic were
calculated using an approach developed for the US Federal Highway Administration (FHWA) by
Rudder (Rudder, 1978). This allows the effect of vehicle speed, vehicle mass, vehicle suspension
type, surrounding soil type and road roughness on the calculated ground vibration level to be
investigated.
For the project, the following inputs were used with the FHWA model:
• Mass of vehicle = 50 tonnes
• Suspension = leaf spring/walking beam
• Speed = 80 km/h
• Road roughness:
Minimum = 70 NAASRA counts/km
Maximum = 110 NAASRA counts/km
The minimum roughness value coincides with the Transport Agency’s roughness specification for
the construction of new chipseal surfaces (NZTA, 2006).
The maximum roughness value coincides with target maximum values adopted by the Transport
Agency for state highways classified as “Regional Strategic.”
4.4.2 Vibrations from Road Construction Equipment
Table 4.1 in NZTA Research Report 485 “Ground vibration from road construction” (Cenek et al,
2012) summarises ground vibration data from construction sites throughout New Zealand acquired
for representative mechanised construction equipment operating on a range of soil types. The
specific equipment monitored comprised, twelve rollers, three dozers, two excavators, one grader
and one stabiliser. This table was used to identify the type of mechanical plant that would generate
the highest magnitude vibrations when operating on soil types expected along the route of
Section C.
For the Project, the source vibration representing construction activity for use with equation 4-3
was taken to be a Sumitomo SH120 Excavator, giving a vibration level of 5.4 mm/s PPV at a
distance of 10 m, with a frequency of 20 Hz. With reference to the vibration levels from mechanical
plant given in Cenek et al 2012, a vibration level of 5.4 mm/s PPV corresponds to the 80th
percentile value, i.e. only 20% of the mechanical plant monitored generated a vibration level
greater than 5.4 mm/s PPV at a distance of 10 m.
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4.4.3 Piling Operations
Predictor equations provided in Table E.1 of BS 5228-2:2009 for vibrated stone columns,
percussive (drop mass) piling and vibratory piling have been used. These have been reproduced
below for ready reference. In all cases, the 5% scaling factor has been adopted, so there is only a 5%
probability of the predicted value being exceeded.
Vibrated stone Vibrated stone Vibrated stone Vibrated stone columnscolumnscolumnscolumns !=>? = 95A".B (Equation 4-4)
where: !=>? = predicted resultant peak particle velocity (mm/s) with 5% probability of value being exceeded
A = distance measure along the ground surface (m), 8≤ A ≤100 m
VibratVibratVibratVibratory pilingory pilingory pilingory piling (all operations)(all operations)(all operations)(all operations) !=>? = 266A".B (Equation 4-5)
where: !=>? = predicted resultant peak particle velocity (mm/s) with 5% probability of value being exceeded
A = distance measure along the ground surface (m), 1≤ A ≤100 m
PercussivePercussivePercussivePercussive pilingpilingpilingpiling (a(a(a(at refusal)t refusal)t refusal)t refusal) !=>? ≤ 5 L√NO".� P (Equation 4-6)
where: !=>? = predicted resultant peak particle velocity (mm/s)
N = nominal hammer energy , in joules (J), 1,500≤W≤85,000
O = slope distance from pile toe (m), where O� = �� + A�
�, pile toe depth (m) (1≤ �≤27) and
A, distance measured along the ground surface (m) (1≤ A≤111)
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5 Results
5.1 Soil Attenuation
Results of the soil attenuation coefficients for the 3 locations where scala penetrometer readings
were made from the surface are given in Table 5-1. Because of the small variability in the
maximum scala readings over the 3 locations, a ρ value of 1.40×10-3 s/m was adopted for the
project, this being the average.
Table 5-1: Soil Attenuation Estimates along Project Route
Test Pit ID
SCALAmax
(blows/50mm) α(5Hz) ρ
AS201 1.5 0.0246 1.57E-03
AS202 2 0.0219 1.39E-03
AS203 2.5 0.0195 1.24E-03
Av 2 0.0220 1.40E-03
With reference to Table 5-2 below, a ρ value of 1.40×10-3 s/m corresponds to weak or soft soils.
This is consistent with the Project’s Geotechnical Factual Report, which shows that the soil to a
depth of 2.5 m comprises of silt and fine to medium sand.
Table 5-2: Attenuation Characteristics of Various Soil Types (adapted from Amick, 1999)
5.2 Critical Separation Distances
Table 5-3 tabulates the calculated critical separation distances for key construction operations and
HGV traffic once the Project becomes operational. The vibration levels corresponding to
perception, complaint, damage from long term vibrations and damage from short term vibrations
are as presented in section 3.5.
The estimates of critical separation distance given for percussive piling in Table 5-3 assumes the
maximum hammer energy permitted for use with Equation 4-6, i.e. 85,000 J, and a pile toe depth
of 12 m. To put these two values in context, the hammer energy of 85,000 J corresponds to a 9
tonne hammer with an approximately 1m drop height. Such energy was considered to be sufficient
Class Description of Soil Attenuation Coefficient,
αααα, at 5 Hz (m-1)
Frequency Independent
Soil Property, ρρρρ (s/m)
I
Weak or soft soils (soil penetrated easily); loess soils, dry or partially saturated peat and muck, mud, loose beach sand and dune sand, recently ploughed ground, soft spongy forest or jungle floor, organic soils, topsoil
0.01 - 0.03 6x10-4 - 2x10-3
II Competent soils (can dig with shovel): most sands, sandy clays, silty clays, gravel, silts, weathered rock
0. 003 - 0.01 2x10-5 - 6x10-4
III
Hard soils (cannot dig with shovel, must use pick to break up): dense compacted sand, dry consolidated clay, consolidated glacial till, some exposed rock
0.0003 - 0.003 2x10-5 - 2x10-4
IV Hard, competent rock (difficult to break with a hammer): bedrock, freshly exposed hard rock
< 0.0003 < 2x10-5
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to drive a concrete plug at the base of piles for the Wigram Magdala Link Bridge, which was part of
the Christchurch Southern Motorway project (Hayes, 2015).
For the Project, the retaining walls at the western tie-in are bored concrete piles into the underlying
rock. Similarly, the bridge piles will be bored piles into the underlying rock. Construction of these
bored piles may involve temporary steel casings. The methodology for driving the casing is
undetermined at this stage so could be either vibratory, percussive or a combination of both so
both piling options have been considered in Table 5-3.
It should be noted that critical separation distances tabulated in Table 5-3 for damage are
indicative only as no account has been taken of the dominant frequency of the ground vibrations.
Table 5-3: Estimated Critical Separation Distances for Key Construction Activities and HGV Traffic
Vibration Source
Separation Distance from Vibration Source (m)
Perception Complaint Damage
(Long Term Vibrations)
Damage (Short Term Vibrations)
50T Truck @ 80km/h, 70 NAASRA counts/km
4.2 0.5 <0.1 -
50T Truck @ 80 km/h, 110 NAASRA counts/km
7.7 1.2 0.2 <0.1
Excavator 43.8 28.4 - 10.7
Vibrated Stone Columns 61.0 25.8 - 8.1
Vibratory Piling 127.3 53.9 - 17.1
Percussive Piling 683.8 270.6 - 77.7
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6 Assessment of Effects
6.1 Existing Environment
There are only two dwellings in the vicinity of the Project located within 100 m of each other.
These two dwellings will be referred to as OTS House 1 and OTS House 2 for consistency with the
Noise Assessment Report. OTS House 1 is to the north of OTS House 2, the approximate location
of these 2 dwellings along SH3 being RS 118-B/14.008 (OTS House 1) and RS 118-B/14.108 (OTS
House 2). Figure 6-1 shows an aerial view of the two dwellings and their proximity to SH 3.
Figure 6-1: Aerial image of the only dwellings in vicinity of the project
The average lane roughness levels of SH3 along the frontages of these two properties as measured
on 23rd of November 2016 as part of the Transport Agency’s annual high speed condition survey
was 65 NAASRA counts/km in the near (southbound) lane and 88 NAASRA counts/km in the far
(northbound) lane.
OTS House 1 is setback from the edgeline of SH3 by about 33 m whereas OTS House 2 is setback
even further at 55 m. Therefore, with reference to the HGV vibration data provided in Table 5-3, it
can be inferred that vibrations presently induced by SH3 traffic are unlikely to be perceived by
occupants of either OTS House 1 or OTS House 2.
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6.2 Construction Vibrations
6.2.1 Background
The operation of construction equipment causes ground vibrations that spread through the ground
and diminish in strength with distance. Buildings and structures in the vicinity of the construction
site respond to these vibrations with varying results ranging from no perceptible effects at the
lowest levels, perceptible vibrations at moderate levels and slight damage at the highest levels
(Hanson et al, 2006). Construction equipment that generate little or no ground vibrations are air
compressors, light trucks, hydraulic loaders etc. whereas construction activities that typically
generate the most severe vibrations are pile-driving, vibratory compaction, and drilling or
excavation in close proximity to vibration sensitive structures.
With regard to the Project, the six construction activities that have the most potential to generate
troublesome vibrations are:
i. bored piling associated with the construction of the bridge piers,
ii. bored piling associated with the retaining walls at the western tie-in;
iii. ground improvement that may involve vibrated stone columns;
iv. wooden piling associated with Hammonds corner;
v. general road construction; and
vi. construction machinery startup and shutdown in set-down areas.
These are expanded on below after a consideration of distances between the various vibration
sources and the critical receivers. For this Project, the critical receivers with regard to vibrations
are the two OTS houses shown in Figure 6-1. Also, the Awakino tunnel could be considered a
critical receiver as it is unlined and if large vibrations were to be created nearby, there could be
some risk of increased rockfall from slopes in the vicinity of the tunnel.
6.2.2 Building and Tunnel Setbacks
The distances of the nearest occupied buildings and the Awakino tunnel to
earthworks/piling/blasting associated with the Project, as determined from Google Earth, are
summarised in Table 6-1. Figure 6-2 spatially shows how the location of the two dwellings are
related to the key construction activities.
By comparing the distances against the critical separation distances provided in Table 5-3, the
expected construction vibration effects can be readily inferred.
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Table 6-1: Nearest Scaled Distances
Vibration Source Receiver Estimated Nearest Distance
(m)
Piling:
Western tie-in
Awakino Tunnel 90
Nearest OTS House 630
Piling:
Bridge Abutments/Pylons
Awakino Tunnel 35
Nearest OTS House 300
Timber Piling: Hammonds Corner
Awakino Tunnel 1,100
Nearest OTS House 450
General Construction Awakino Tunnel 35
Nearest OTS House 30
Site Storage Awakino Tunnel 110
Nearest OTS House 220
Figure 6-2: Aerial image showing the approximate location of the various construction activities: (A) Possible piling activities related to bridge construction. (B) Nearest earthworks activities to a dwelling (C) Nearest road construction/sealing activities to a dwelling. (D) Possible wooden piles associated with realignment of Hammonds Corner.
6.2.3 Earthworks and General Road Construction
The minimum separation distance between where earthworks and road construction is indicated to
take place and the two dwellings is 30 m (OTS House 1) and 70 m (OTS House 2). It is therefore
unlikely that the occupants of OTS House 2 will be able to distinguish vibrations generated from
earthworks and road construction activity from ambient vibrations as, with reference to Table 5-3,
a separation distance of less than 44 m is required for these vibrations to be perceived. However,
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at OTS House 1, vibration levels will approach the level that will cause complaint in residential
environments. Therefore, because complaints typically arise from interference with people’s
activities or fear of property damage, it is important that the contractor establishes open
communications with the occupants so that any issues can be identified and addressed
expeditiously. As a minimum, this communication should include written information on the
planned works (nature, working hours, and anticipated duration) plus a helpline to respond to
queries and complaints.
Ideally, the contractor should take all practicable measures to avoid using earthworks and road
construction equipment near OTS House 1 that generate excessive ground vibrations.
The Awakino tunnel is 35 m away at its closest from earthworks and road construction activity. As
a consequence, the magnitude of ground vibrations induced by this activity will be insufficient to
cause damage to the tunnel or soil settlement in its vicinity.
6.2.4 Piling
The two dwellings are at least 300 m away from any piling operations and stone column based
ground improvement works. Therefore, irrespective of what piling technique is used, this distance
is more than sufficient to prevent annoyance of the occupants and damage to the buildings.
Regarding the Awakino tunnel, the closest piling operations are likely to get to the Awakino Tunnel
from Table 6-1 is 35 m. With reference to Table 5-3, no damage is expected to occur if vibratory
piling is selected for driving steel casings or the concrete piles associated with the construction of
the bridge. However, if percussive piling is selected instead, there is a possibility that vibrations
could cause damage depending on the hammer energy used and the structural integrity of the
tunnel.
For example, the estimated critical separation distance for avoiding damage from percussive piling
of 78 m given in Table 5-3 has been predicated on a maximum hammer energy of 85 kJ and the
Awakino tunnel having reduced integrity so that it approximates a residential building. If we
assume the structure has adequate structural integrity so that it approximates a commercial
building, the vibration level for onset of damage increases from 5 mm/s PPV to 20 mm/s PPV
allowing the critical separation distance to reduce from 78 m to 27 m, if a maximum hammer
energy of 85 kJ is assumed.
Because of the uncertainties associated with the method of piling and the structural condition of
the Awakino Tunnel and its sensitivity to soil settlement, it will be prudent to treat the Awakino
Tunnel as a vibration sensitive structure. This will require pre and post construction condition
surveys of the Awakino Tunnel and possibly monitoring of ground vibrations during the
construction period to ensure the magnitude and frequency of the resulting ground vibrations in
the vicinity of the tunnel are as expected.
6.2.5 Equipment Storage Areas
As powered construction equipment starts up or shuts down, the vibrations generated change
frequency. As a result, the vibration levels at start up and shut down may be considerably higher
than under normal running. Therefore, it is advisable to carefully plan where construction
equipment should be left parked.
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With reference to Table 5-3, start-up and shut-down of equipment is unlikely to cause problematic
vibrations if this can take place at least 45 m away from the two occupied dwellings or the Awakino
tunnel. The indicated storage areas for the project are at least 110 m from the Awakino tunnel and
220 m from the dwellings so the critical separation distance of 45 m is exceeded by some margin.
6.3 Operational Vibrations
Both the dwellings and the Awakino tunnel will be at least 30 m way from the realigned SH3.
Therefore, if the proposed chipseal road surface can be laid so that it satisfies the Transport
Agency’s roughness specification of 70 NAASRA counts per km for new pavement construction3
then traffic induced vibrations are unlikely to be perceptible at these locations. Furthermore,
vibrations are unlikely to be felt in the dwellings or the Awakino tunnel even when the road surface
roughness reaches 110 NAASRA counts/km, the Transport Agency’s trigger for road smoothing for
roads classified as Rural, Regional Strategic. The modelling assumes a maximum vehicle mass of
50 tonnes and a vehicle speed of 80 km/h, so high productivity motor vehicles (HPMV’s) have been
covered.
6.4 Mitigation Measures
6.4.1 Piling and General Construction
The analysis has identified that there is the potential for percussive (i.e. drop mass) piling to cause
damage to the existing Awakino tunnel. Therefore, it is recommended that if percussive piling is
used on the Project, appropriate trials be carried out to ensure vibrations at the Awakino tunnel
will comply with the short-term vibration guidelines given in DIN 4150-3 and reproduced in
Table 3-2 of this report.
This will place more certainty around the impact of the percussive piling operations as the
assessment in this report is based on a predictor equations which does not take into account soil
characteristics. However, vibration amplitudes and the predominant frequencies are influenced
significantly by soil type and stratification. The lower the stiffness and damping of the soil, the
higher the vibration.
The Project will also entail a significant amount of compaction work, with conventional sheepsfoot
compaction of the silty soils expected for the embankments and vibratory compaction of granular
soils expected for retaining wall backfill and pavements. Like percussive piling, compaction has
the potential to generate large magnitude ground vibrations. Furthermore, there is considerable
variability in the magnitude and frequency of ground vibrations generated between different makes
and models of equipment used for compaction. Therefore, before commencing construction, it will
be prudent that the contractor performs trials with the compaction equipment to demonstrate that
the short-term vibration guidelines given in DIN 4150-3 will be complied with at the Awakino
tunnel and disturbance of the occupants of OTS House 1 is minimised.
These trial measurements should be performed either at an off-site location with soil properties
that are similar to the construction site or preferably on-site during first use of the equipment with
the on-site location of first use being chosen to be least sensitive to adjacent land uses.
3https://www.nzta.govt.nz/assets/resources/roughness-requirements-finished-pavement/docs/guide.pdf
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Both the piling and compaction trials can be best addressed through a Construction Vibration
Management Plan (CVMP), which recognises the Awakino tunnel as a vibration sensitive structure.
The CVMP’s objective is to minimise annoyance and damage due to construction vibration by all
reasonable and feasible means possible. Therefore, it should specifically address:
a. The procedure for measuring vibrations.
b. The criteria for assessing vibrations.
c. Hours of operation, including times and days when high-vibration machinery would be
used.
d. List of machinery to be used.
e. Requirements for vibration measurements of relevant machinery prior to construction or
during their first operation, to confirm that the vibrations they generate will not be
problematic.
f. Requirements for building condition surveys of critical dwellings prior to and after
completion of construction works and during the works if required.
g. Requirements for identifying any existing infrastructure assets (services, roads etc) which
may be at risk of vibration induced damage during construction.
h. Roles and responsibilities of personnel on site.
i. Construction operator training procedures, particularly regarding the use of excavators and
vibratory compactors.
j. Construction vibration monitoring and reporting requirements.
k. Mitigation options, including alternative strategies where full compliance with the Project
Criteria cannot be achieved.
l. Methods for receiving and handling complaints about construction vibration.
m. Procedures for managing vibration damage to existing services such as roads and
underground pipelines.
Guidance on preparing a CNVMP is provided in the Transport Agency’s publication “State highway
construction and maintenance noise and vibration guide.”4
6.4.2 Bridge Joints
Bridge joints can be problematic because of the vibration generated by vehicles traversing the joint,
which is transferred to the surrounding ground via the bridge’s piers and also felt by occupants of
the vehicles. This vibration is caused by impact loads generated by vehicles encountering a
localised discontinuity in road surface level at the joint.
Bridges and associated joints are usually immediately above water or other roads, and the footprint
of embankments and slip lanes can create separation between joints and the nearest dwellings. In
these cases, while cars and trucks traversing bridge joints may cause vibration to be felt inside the
vehicles, there is a relatively limited effect experienced in the wider environment.
4 https://www.nzta.govt.nz/assets/resources/sh-construction-maintenance-noise/docs/construction-maintenance-noise-vibration-guide.pdf
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In the case of the proposed 2 bridges over the Awakino River, the nearest existing dwelling is some
300 m away. Therefore, ground vibrations generated by HGV traffic passing over the bridge joints
will not be an issue and so no specific mitigation measures are needed. However, if in the future
residential dwellings are to be constructed in close proximity (20 m) to the bridge, it would be
desirable to have any surface discontinuities as small as practicably possible.
Application of a theoretical method provided in Nelson (1987) for estimating vibration from a
surface discontinuity indicates that the difference in levels between the road and abutment should
be kept below 2 mm for vibrations to be below the perception threshold of 0.3 mm/s PPV and
7 mm to be below the complaint threshold of 1 mm/s PPV for HGV traffic travelling at 80 km/h.
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7 Conclusions and Recommendations
Vibrations have been assessed in the vicinity of the SH3, Awakino Tunnel Bypass Project through a
desktop study. The vibration sources under consideration include earthwork and piling operations
during the construction of the Project, and operational road vehicle traffic following the completion
of the Project. The key conclusions and recommendations arising from this assessment are as
follows:
1. Vibration levels generated by construction are likely to be higher than those from traffic.
However, these construction-related vibrations will be temporary and of a limited duration.
2. The occupants of the dwelling closest to the earthworks and road construction (i.e. OTS
House 1) are likely to experience vibration levels from these activities that may cause
complaint but not damage to the dwelling. Therefore, because complaints typically arise
from interference with people’s activities or fear of property damage, it is important that the
contractor establishes open communication with the occupants so that any issues can be
identified and addressed expeditiously. However, the contractor should ideally take all
practicable measures to avoid excessive earthworks and road construction induced
vibrations near OTS House 1.
3. The analysis has identified that there is the potential for piling to cause damage to the
existing Awakino tunnel.
4. The adverse effects from construction can be appropriately mitigated through a
Construction Vibration Management Plan as the mitigation measures relate to selection of
equipment and processes and the location and operation of the equipment. In the unlikely
event of there being no practicable means for achieving the construction vibration criteria
stipulated in the Construction Vibration Management Plan, pre and post construction
inspections of at risk structures and buildings will need to be performed and any damage
rectified.
5. A key aspect of this Construction Vibration Management Plan is for piling operations and
compaction equipment to be used on the project to be trialled before construction proper
commences to ensure short-term vibration damage guidelines given in German Standard
DIN 4150-3 are complied with at the existing Awakino tunnel.
6. Once operational, traffic induced vibrations are unlikely to be perceived if the proposed
chipseal road surface can be laid so that it satisfies the Transport Agency’s roughness
specification of 70 NAASRA counts per km for new pavement construction. Furthermore, at
the closest separation distance from a dwelling of approximately 87 m, vibrations are
unlikely to be felt by occupants even when the road surface roughness reaches 110 NAASRA
counts/km, the Transport Agency’s trigger for road smoothing for roads classified as Rural,
Regional Strategic.
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8 References
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Conference on Current Developments in Vibration Control for Optomechanical Systems, Denver,
Colorado, July 20, 1999. Retrieved from http://www.vulcanhammer.net/geotechnical/Amick-
SPIE99.pdf
British Standard, BS 5228.2:2009. Code of practice for noise and vibration control on construction
and open sites – Part 2: Vibration.
British Standard, BS 7385:Part2:1993. Evaluation and measurement for vibration in buildings, Part
2. Guide to damage levels from ground-borne vibration.
Cenek, P.D., Sutherland, A.J. and McIver, I.R. (2012) Ground Vibration from Road Construction,
NZ Transport Agency Research Report 485, downloadable from:
http://www.nzta.govt.nz/resources/research/reports/485/index.html
Dowding, C.H. (2000) Construction Vibrations. Second Edition. ISBN 0-99644313-1-9. Prentice
Hall Engineering/Science/Mathematics, Upper Saddle River, NJ.
German Standard, DIN 4150-3:1999. Structural Vibration – Part 3: Effects of vibration on
structures.
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Assessment. Report FTA-VA-90-1003-06, Office of Planning and Environment, Federal Transit
Administration.
Hayes, G. (2015) Wigram Magdala Link: Vibration Assessment
Hunaidi, O. (2000) Traffic Vibrations in Buildings. Construction Technology Update No. 39.
Institute for Research in Construction, National Research Council of Canada. ISSN 1206-1220.
Nelson, P. M. (1987) Transportation Noise. Reference Book, Butterworth & Co (Publishers), Ltd.
Norwegian Standard NS 8176.E:2005 Second Edition Vibration and Shock. Measurement of
vibration in buildings from landbased transport and guidance to evaluation of its effects on human
beings, Standards, Norway, 2005. English translation version, 2006.
NZTA (2006). Network Operations Technical Memorandum No: TNZ TM7003 v1, Roughness
Requirements for Finished Pavement Construction.
NZTA (2013). State Highway Construction and Maintenance Noise and Vibration Guide,
downloadable from: https://www.nzta.govt.nz/resources/sh-construction-maintenance-noise/
Opus (2017). Geotechnical Factual Report No HA16/031 – SH3 Awakino Tunnel Bypass DBC.
Rudder,F.F. (1978) Engineering Guidelines for the Analysis of Traffic-Induced Vibration. Report
No FHWA-RD-78-166, US Department of Transportation, Washington, D.C.