Holroyd to Rookwood Road cable REF - TransGrid

CONSTRUCTION NOISE & VIBRATION Page 6 42.6590.R1:CFCD5 

QUALITATIVE ASSESSMENT Rev04 

330kV ELECTRICITY CABLE 

HOLROYD to ROOKWOOD ROAD January 2012 

Where construction activities extend and affect sensitive receivers for more than three (3) 

weeks, the ICNG recommends that construction noise should generally not exceed the 

background LA90 noise level by more than 10dB at residences during standard 

construction hours and 5dB outside of standard construction hours, with the 

implementation of all feasible and reasonable control measures. 

Standard construction hours are defined as: 

o 7.00am to 6.00pm Monday to Friday; 

o 8.00am – 1.00pm Saturday; and 

o no work on Sundays or Public Holidays. 

Other potentially sensitive land uses within the immediate proximity of the proposed 

cable route include schools, commercial premises, industrial premises and areas of 

passive and active recreation. The ICNG recommends to following noise management 

levels, where construction activities are likely to affect a receiver for more than three (3) 

weeks, for the respective uses as follows: 

Schools LAeq,15min 45dB(A) (internal) 

Commercial premises LAeq,15min 70dB(A) 

Industrial premises LAeq,15min 75dB(A) 

Active recreation LAeq,15min 65dB(A) 

Passive recreation LAeq,15min 60dB(A) 

3.2 Ground Vibration 

Trenching and tunnelling activities associated with the construction of the 330kV 

electricity cable route would be required and could generate ground vibration. The effect 

of vibration on humans and structures is normally considered and evaluated in terms of 

annoyance and structural damage. 

3.2.1 Annoyance 

The DECCW, Assessing Vibration: a technical guideline and Australian Standard 

AS 2670.2-1990 recommend goals for assessing potential disturbance to the 

PERRAM & PARTNERS ATKINS ACOUSTICS





occupants of buildings. Table 1 presents a summary of vibration levels (mm/s) for 

the assessment of human comfort, derived from AS 2670.2-1990. In terms of 

overall ground vibration levels, Appendix C of Assessing Vibration: a technical 

guideline recommends criteria for exposure to continuous vibration associated 

with construction activities, specifically: 

Place Day Night 

Residence 0.2-0.4mm/s 0.14-0.28mm/s 

Offices 0.4-0.8mm/s same 

Workshops 0.8-1.6mm/s same 

Table 1: Vibration Levels for Assessment of Human Comfort 

Vibration Level (mm/s) 

Frequency 

(Hz) 

Continuous Vibration Intermittent Vibration 

Day Night Day Night 

1 3.2 2.2 95 31 

1.25 2.3 1.6 68 22 

1.6 1.6 1.1 47 15 

2 1.1 0.8 33 11 

2.5 0.8 0.6 24 8.0 

3.15 0.6 0.4 17 5.8 

4 0.4 0.3 19 4.0 

5 0.3 0.2 9.5 3.2 

6.3 0.3 0.2 7.6 2.5 

8 0.2 0.1 6.0 2.0 

10 0.2 0.1 6.0 2.0 

12.5 0.2 0.1 6.0 2.0 

16 0.2 0.1 6.0 2.0 

20 0.2 0.1 6.0 2.0 

25 0.2 0.1 6.0 2.0 

31.5 0.2 0.1 5.4 1.8 

40 0.2 0.1 6.0 2.0 

50 0.2 0.1 6.0 2.0 

63 0.2 0.1 6.0 2.0 

80 0.2 0.1 6.0 2.0 






AS 2670.2:1990 recommend that vibration generated from construction activities 

should be less than the allowable goals set for intermittent or impulsive 

vibrations. Where the levels exceed the goals set for continuous vibration, the 

DECCW recommends that activities be restricted to between 7.00am and 6.00pm 

Monday to Friday and 8.00am and 1.00pm Saturday. 

3.2.2 Perception 

For comparison of vibration in terms of human response, Table 2 presents a 

summary of levels referenced to degrees of perception. 

Table 2: Human Perception of Vibration 

Ref: German Standard DIN 4150 (1986) 

Vibration Levels 

mm/sec 

Likely Perception 

0.15 Perception Threshold 

0.35 Barely Noticeable 

1.0 Noticeable 

2.2 Easily Noticeable 

6.0 Strongly Noticeable 

14.0 Very Strongly Noticeable 

Figure 2 shows human response to vibration levels of varying duration. It can be 

seen that short duration vibration levels are less perceptible than those with long 

transient and continuous levels. Figure 1 also shows consistency with the data 

presented in Table 2. 






Figure 1: Human Response to Vibration 

3.2.3 Structural Damage 

German Standard DIN4150 Part 3 (1986) provides guidelines for evaluating the 

effects of vibration on structures. The values recommended in the standard are 

summarised in Table 3. The values are the maximum vibration levels measured in 

any direction at the building foundation. These are limits up to which damage due 

to vibration effects has not been identified for the referenced class of building. 

Table 3: Safety Limits for Structural Damage 

Type of Structure 

Commercial/industrial buildings or 

buildings with similar design 

Dwellings and buildings of similar 

design and/or use 

Structures of great intrinsic value 

(eg. buildings under preservation) 

Ref: German Standard DIN4150 

Vibration Level (mm/s) 

10Hz 10Hz to 50Hz 50Hz to 100Hz 

20 20 to 40 40 to 50 








4.0 CONSTRUCTION NOISE and VIBRATION ASSESSMENT 

4.1 Sensitive Receivers 

A review of provided aerial photographic information, route plans, descriptions and 

details have confirmed that receivers located adjacent the proposed route include: 

residential dwellings; 

vacant land subject to approval for residential development; 

schools; 

commercial / industrial premises; 

passive/active recreation areas; 

heritage sites; and, 

other infrastructure. 

Typical distance separation from the envisaged construction activities ranges from a 

minimum of six (6) metres, to more than fifty (50) metres. There are a number of 

residences located in the order of six (6) to ten (10) metres of the proposed route, for 

which noise and vibration impacts will be managed. 

Discussions with Perram & Partners confirmed there may be a number or heritage items 

or similar sensitive structures within close proximity of the proposed route. Subject to the 

construction and condition of these items, careful methodology may need to be developed 

to minimise ground vibration and potential cosmetic or structural damage. 

4.2 Existing Noise Environment 

Due to the typically short duration of the construction works at any one location (





roads. Therefore it is anticipated that daytime background noise levels along the route 

could range from the order of LA90 40dB(A) up to 55-60dB(A). 

4.3 Construction Activities and Noise Sources 

4.3.1 Trenching and Pipe Laying Activities 

The construction methods envisaged during trenching and cable laying between 

Holroyd and Rookwood Road are commonly used and should not present unusual 

difficulties to a competent contractor. The following plant schedules have been 

nominated to represent typical activities for the purpose of the noise assessment. 

Table 4: Typical Trenching and Construction Equipment 

Equipment Activity Usage 

Backhoe Clearing, excavation Intermittent use, full time 

Excavator Excavation Intermittent use, part time 

Rock Breaker 

(Hydraulic) 

Rock and concrete excavation possible part time use 

Trucks Removal of spoil and equipment 

deliveries 

multiple intermittent movements 

Plate Compactor Compaction of backfill material intermittent use, full time 

Concrete Truck Concrete supply, backfilling multiple intermittent deliveries 

Concrete Pump Concrete pumping possible part time use 

Dewatering Pump Dewatering of excavations possible part time use 

Generator & 

Compressor 

General use around site possible part time use 

Jack Hammer Rock excavation and concrete 

demolition 

possible part time use 

Bobcat General earthworks intermittent use, full time 

Crane Raising and lowering of materials intermittent use, full time 

Welder Fabrication and erection of 

steelwork 

intermittent use, part time 

Vibrator Concrete compaction intermittent use, full time 

4.3.2 Micro Tunnelling 

A number of entry sites have been identified where micro tunnelling (directional 

drilling) could be undertaken. TransGrid will determine final construction 

methods for particular locations in consultation with the contractor and 

landowner. There is adequate space for the envisaged works at proposed sites, 






nevertheless, special care will need to be exercised in order to minimise noise 

impacts on residential properties. 

For the purpose of the noise assessment the following plant schedules have been 

nominated to represent typical plant and activities. 

Table 5: Typical Micro Tunnelling Equipment 

Equipment Activity Usage 

Hercules Drilling Rig and 

power pack 

Drilling continuous 

Austin Western 4 x 4 crane Loading drill rig intermittent use, full time 

Gardiner Denver Mud Pump Water pumping continuous 

Mud processing equipment Water processing continuous 

Sideboom tractor General intermittent use/ full time 

Front end loader General activities intermittent use/ full time 

Truck General activities intermittent use/ full time 

4.4 Plant and Equipment 

For the assessment of noise emanating from the envisaged construction activities, the 

following range of sound pressure levels have been considered in the noise modelling. 

Table 6: Plant and Equipment 

dB(A) re: 20 x 10 -6 Pa. 

Item Plant Description Sound Pressure Level 

@ 7 metres 

Front End Loader Wheeled 90 

Jack Hammers Silencing bags 85 

Compactor Caterpillar 815 85 

Compactor Caterpillar 825 89 

Compactor Vibrating Plate 92 

Water Cart 88 

Excavator Kato 750 86 

Rock breaker Hydraulic, or excavator KATO 750 97 

Crane Truck mounted 85 

Compressor 600 CF 75 

Compressor 1500 CFM 80 

Backhoe 88 

Spreader Asphalt, concrete 70 

Asphalt Truck 92 

Tip Truck 83 






Table 6: Plant and Equipment (cont.) 

dB(A) re: 20 x 10 -6 Pa. 

Item Plant Description Sound Pressure Level 

@ 7 metres 

Generator Diesel 79 

Spraying Machine 75 

Mechanical Broom 83 

Concrete Truck 83 

Concrete Pump 84 

Concrete Vibrators 80 

Concrete Saw 93 

Welders 85 

4.5 Construction Noise Assessment 

4.5.1 Trenching and Cable Work 

It is envisaged that the main trenching and cable laying activities will be 

undertaken during normal daytime working hours, being between 7.00am and 

6.00pm Monday to Friday, and 7.00am to 1.00pm Saturday. Due to site 

constraints some night-time or weekend works may be necessary. In these 

situations notification would be provided to residents, Council and DECCW prior 

to conducting the works. 

Noise levels resulting from the envisaged construction activities during the 

trenching and cable laying will vary due to the transient nature and range of plant 

and equipment. Considering the likely worse case scenario, Table 7 presents the 

results of the noise level predictions for the five (5) main stages of the 

construction works. Under most situations however, construction noise levels will 

be less than those presented below. As the activities are short term and transient 

any likely noise impacts would be considered to be minimal. 






Table 7: Predicted Noise Levels from Construction Activities 

L10 dB(A) re: 20 x 10 -6 Pa 

Distance from 

Sound Pressure Level 

Construction 

dB(A) 

Activity Concrete Rock breaker Trenching Cable Backfilling 

(m) 

Saw 

Laying 

15 87 91 85 79 86 

40 78 82 76 70 77 

80 72 76 70 64 71 

100 70 74 68 62 69 

150 67 71 65 59 66 

300 61 65 59 53 60 

4.5.1(a) Assessment 

The noise levels predicted for the trenching and cable laying activities (Table 7) 

would exceed a normal ICNG qualitative noise management level for activities 

three (3) weeks or longer, of LA90 +10dB at residential properties within 150 

metres of the construction activities. As the typical cable laying construction 

activities are transient are not expected to exceed 4 - 5 days in total at any one 

location, any noise impact would likely be managed. Where practical and 

feasible, engineering noise controls and work practices will be considered to 

minimise noise impacts (Section 5). 

The construction activities would normally be restricted to the daytime hours 

7.00am to 6.00pm. Monday to Friday, and 7.00am to 1.00pm Saturday. For any 

construction activities outside normal daytime hours, notification will be provided 

to residents, Council and DECCW prior to commencing the works. 

4.5.2 Micro Tunnelling 

Noise levels from the micro tunnelling activities will vary due to the nature of the 

activities and range of plant and equipment that could be used. Considering the 

envisaged activities, Table 8 presents a summary of the predicted noise levels for 

each phase of the micro tunnelling operations. 






Table 8: Predicted Noise Levels from Micro Tunnelling 

L10 dB(A) re: 20 x 10 -6 Pa 

Distance from 

Sound Pressure Level 

Construction 

dB(A) 

Activity 

(m) 

Site 

Establishment 

Drilling Cable Laying 

15 85 87 79 

40 76 78 70 

80 70 72 64 

100 68 70 62 

150 65 67 59 

300 59 61 53 

4.5.2(a) Assessment 

The predicted noise levels for the micro tunnelling activities exceed a noise 

management goal of LA90 +10dB (50-60dB(A)) for activities three (3) weeks or 

longer at residential properties within 150 metres of the construction activities. 

Depending on the final selection of the drilling rig some engineering noise 

controls may be feasible. Where feasible and practical, engineering noise controls 

and work practices will be considered to minimise noise impacts (Section 5). 

Directional drilling activities will be restricted to the daytime hours of 7.00am to 

6.00pm Monday to Friday, and 7.00am to 1.00pm Saturday. It is not envisaged 

that micro tunnelling will be undertaken outside normal daytime hours, however 

if it is required, notification will be provided to residents, Council and DECCW 

prior to commencing the works. 

Where directional drilling or micro tunnelling is required, construction activities 

are not expected to exceed three (3) weeks at any one location, this noise impact 

would likely be acceptable. Albeit night time work may be required when located 

within close proximity to main roads or railways. 






4.6 Construction Vibration 

During the excavation and construction activities it will be necessary to use plant and 

equipment that will generate ground vibration. To evaluate the likely effects of the 

construction activities, the following vibration levels have been considered. 

Table 9: Typical Plant Vibration Levels 

Plant Description 

Vibration Levels 

mm/sec 

5 metres 20 metres 40 metres 

Rock-breaker (large) 5 0.5 0.3 

Rock-breaker (small) 2 0.09 0.06 

Jack-hammer 2 0.09 0.06 

Truck 1 0.05 0.02 

Compactor 4 0.5 0.2 

4.6.1 Assessment of Vibration 

The main source of ground vibration that has been identified in this assessment is 

associated with rock breakers. Ground vibration from breakers could range up to 

0.5mm/sec at a distance of twenty (20) metres, and would be below 0.3mm/sec at 

forty (40) metres. The ground vibration level at these distances generally satisfies 

the recommended assessment goals, and would be expected to be acceptable from 

both human disturbance and structural damage points of view. Geotechnical 

investigations are to be undertaken in order to ensure sensitive items in proximity 

to the cable alignment (e.g. heritage items) are not impacted. 

However, the selection of smaller equipment will ensure that at distances less 

than twenty (20) metres from the source, ground vibration levels are minimised 

and controlled to satisfy the recommended assessment goals. Notwithstanding 

potential use of large rock-breakers, the assessment has shown a level of 5mm/sec 

that satisfies the structural damage criteria for typical dwellings as referenced in 

German Standard DIN 4150. 






The proposed route will be in reasonably close proximity to the Sydney Water 

pipeline, with offset distances in the order of five (5) metres. The specific 

requirements for the assessment and management of vibration within Sydney 

Water land in the vicinity of the pipeline and associated infrastructure has been 

determined through consultation between TransGrid and Sydney Water. 

Construction methodologies to be employed must be within agreed vibration 

limits, with the aim of minimising vibration where possible. 

A portion of the proposed cable route will be laid adjacent to the former Prospect 

Canal, which has largely been backfilled, covered and currently utilised as a 

cycleway. This canal is classified as a local heritage structure and accordingly 

will be subject to more stringent ground vibration limits. The location of the cable 

route may be in the order of one (1) metre from the canal, hence subject to the 

proposed methodology and equipment used in this area, the 3mm/sec structural 

damage criteria for structures of intrinsic value referenced in German Standard 

DIN 4150 may be exceeded. It is recommended that geotechnical investigations 

be undertaken and include assessment of the Prospect Canal and determine 

ground vibration limits to ensure its integrity. Where practical, the size of 

equipment utilised adjacent the canal should be minimised, and the distance 

separation maximised. Where concrete is being removed to enable the installation 

of the cable, we recommend saw cutting concrete into small manageable segments 

and removal by small excavator or bobcat, to avoid use of excavators / rock 

breakers. 

Within some areas of the route, residential and commercial buildings are located 

in the order of six to eight (6-8) metres of the proposed excavation works. In these 

areas careful planning should be adopted to determine the means of excavation 

and establish if ground vibration generating plant and equipment would be 

required (e.g rock hammer). Where residences are located within ten to twenty 

(10-20) metres of the route and vibration generating plant were proposed, 

alternative methods of excavation may need to be considered e.g. saw cutting. 






5.0 CONSTRUCTION NOISE and VIBRATION MANAGEMENT 

Noise during the construction works associated with the electricity cable will be managed 

utilising the work practices as outlined in the Interim Construction Noise Guideline Section 

5.2 

. The ICNG practices include, but not necessarily limited to: 

contact potentially noise affected neighbours in advance of the works occurring; 

advising residents of construction activities and schedule of timing when different 

activities would occur; 

consult with affected schools to ensure that noise generating construction works 

in the vicinity of affected school buildings are not scheduled to occur during 

examination periods, unless other arrangements (such as relocation to an 

alternative location) acceptable to the affected school/s can be made; 

keep potentially noise affected neighbours up to date on progress of the 

construction activities; 

provision of site contact details for public / residents seeking information or to 

lodge a complaint; 

site inductions and personnel/contractor training in correct use of plant and 

equipment; 

a site noise and vibration training and awareness program for all staff and 

contractors engaged during construction 

selection of plant and equipment to take into account acoustic performance where 

practical; 

siting of fixed plant and equipment shall be in order to maximise distance 

separation and natural shielding to residential dwellings. Consideration of 

localised temporary acoustic shielding for fixed plant where feasible and 

reasonable (e.g. directional drilling/micro tunnelling); 

reduce operating speed of plant and equipment where practical and switch off idle 

plant when not in active use; 






co-ordinate flow movement of vehicles within the proposed easements during 

construction to minimise the use of reversing alarms on vehicles and mobile 

plant; 

where feasible and reasonable, replace ‘beeper’ style reversing alarms with broad 

band variable level ‘quacker’ reversing alarms or equivalent, ensuring that the 

OH&S legislation requirements are complied with; 

ensure that construction activities are conducted within the standard hours*: 

o 7.00am to 6.00pm Monday to Friday 

o 8.00am to 1.00pm Saturday; 

* unless under special circumstances (ICNG Section 2.3) 

where night work near residences cannot be feasibly or reasonably avoided, 

restrict the number of nights per week and/or the number of nights per calendar 

month that the works are undertaken, in consultation with residents who will be 

most affected; 

examine and implement, where feasible and reasonable, the option of relocating 

noise affected occupants for short periods of time, such as when high noise levels 

from construction occur at night and there are no feasible and reasonable ways of 

reducing noise levels. e.g. proponent offer alternative accommodation or other 

respite options (movie tickets, dinner vouchers), where mitigation is sought and 

there are no feasible and reasonable work methods available; 

noise and vibration monitoring shall be conducted in response to community 

complaints and at the request of a regulatory authority. Reports of investigations 

shall be provided to the relevant regulatory authority upon request. 

5.1 Noise and Vibration Monitoring 

Noise and vibration monitoring will be undertaken as agreed between Sydney Water and 

Transgrid. Impacts of vibration will also be monitored along the LPCR given its heritage 

sensitivity. Due to the generally short duration of the works, it is not proposed to conduct 

scheduled noise or vibration monitoring. Where complaints are received, the source of the 

noise and/or vibration complaint will be identified and ameliorative measures considered if 

required. Noise and / or vibration monitoring would be considered in response to receipt of 






repeated complaints. Following audits, control measures will be reviewed should additional 

ameliorative measures be required. 

Albeit a review of the proposal has identified that in some areas of the route ground vibration 

generating equipment may need to be utilised within ten (10) metres of residential buildings. 

It is been recommended that alternative methods be considered for these areas. If alternative 

methods are not feasible, it is recommended that dilapidation reports be prepared prior to and 

after the works, whilst during the works ground vibration monitoring should be conducted. 


Appendix F 

ELECTRIC AND MAGNETIC FIELDS 

PERRAM & PARTNERS 

Holroyd to Rookwood Road Underground Cable January 12 

Review of Environmental Factors 132R1

1. Fields in Everyday Life 

ELECTRIC AND MAGNETIC FIELDS 


Power frequency electric and magnetic fields are produced by virtually all electrical 

equipment and occur wherever electricity is being used. Due to the large number of 

potential electric and magnetic field (EMF) sources in a modern industrialised 

society, people are regularly exposed to different sources of EMF. 

In a rural area, away from dwellings, workshops, power lines and other electrical 

equipment, power frequency electric and magnetic fields are negligible. In an 

industrial environment, electric and magnetic fields would be largely determined by 

the electrical equipment in use, with negligible background fields. 

In dwellings, the background electric field would normally be negligible and the 

background magnetic field would normally be less than one milligauss (mG) in the 

case of a rural dwelling and between 2 to 4 mG in an urban dwelling, school or shop. 

Background magnetic fields of tens of milligauss are sometimes experienced in parts 

of urban dwellings, due primarily to the influence of electric currents that can flow in 

water pipes and safety earthing connections in some residential areas. The magnetic 

fields in the vicinity of a selection of appliances are indicated in Table F.1. 

Table F.1 TYPICAL MAGNETIC FIELD AT NORMAL USER DISTANCES 

FROM AUSTRALIAN APPLIANCES 

Typical Magnetic Typical Magnetic 

Appliance 

Field 

Field Range 

(mG) 

(mG) 

Electric Range 6 2-30 

Computer 5 2-20 

Television 1 0.2-2 

Electric Blanket 20 5-30 

Hair Dryer 25 10-70 

Refrigerator 2 2-5 

Toaster 3 2-10 

Electric Kettle 3 2-10 

Portable Fan 

Notes: 

1 0.2-2 

Owing to variations in the design of electrical appliances and the ways they are used, the levels of 

magnetic fields can vary from those shown. 

The above table is based on a consistent set of measurements undertaken by power authorities in 

Australia using similar techniques to overseas measurements. Because of differences in appliance 

designs and voltages overseas, fields shown in overseas publications can differ from the above. 


Review of Environmental Factors 132R1 

F.1

2. Electric and Magnetic Fields associated with the Cable Project 


As with other types of electrical equipment, electricity transmission cables produce 

electric and magnetic fields. However, due to the conductor being totally enclosed 

within an earthed metal sheath, the levels of electric fields produced are negligible 

outside the cables themselves. 

The magnetic field external to a power cable depends on the size of the current 

flowing in the cable and decreases with distance from the cable. The magnetic field 

strength at any point near the cable is affected by a number of factors including: 

the distance from the cable; 

the total electrical current (amps) flowing at that particular time; 

the size, layout and configuration of the cable installation; and 

the interaction of the cable with other cables or equipment 

3. Overview of EMF and Human Health 

3.1 General 

The possibility of adverse health effects due to the electric and magnetic fields 

associated with electrical equipment has been the subject of extensive research 

throughout the world. To date, adverse health effects have not been established, but 

the possibility that they may exist has not been ruled out. 

While EMFs involve both electric and magnetic components, electric fields are 

relatively constant over time, are readily shielded and, in the health context, are 

generally no longer associated with the same level of interest as magnetic fields. The 

bulk of the electric and magnetic fields/health research over the past 15 years has 

been directed towards magnetic rather than electric fields. As indicated above, 

owing to the shielding inherent in their construction, underground cables do not 

produce external electric fields. Accordingly, the major focus of the remainder of this 

section is on magnetic fields. 

Research into EMFs and health involves many scientific disciplines including 

biology, physics, chemistry, medicine, biophysics and epidemiology. Many of the 

health issues of interest to researchers are quite rare. In this context, it is well 

accepted by scientists that no study considered in isolation will provide a meaningful 

answer to the question of whether or not EMFs can contribute to adverse health 

effects. In order to make an informed conclusion from the research, it is necessary to 

consider the science in its totality. Over the years, governments and regulatory 

agencies around the world have commissioned independent scientific review panels 

to provide such overall assessments. 



F.2


The most recent scientific reviews by authoritative bodies are reassuring for most 

potential health issues. However, statistical associations 1 between prolonged 

exposure to elevated magnetic fields and childhood leukaemia have persisted. This 

led the International Agency for Research on Cancer (IARC) in 2001 to classify 

magnetic fields as a "possible carcinogen". 2 

The fact that, despite over 20 years of laboratory research, no mechanism for an effect 

has been established, lends weight to the possibility that the observed statistical 

associations reflect some factor other than a causal relationship. This point is made in 

the 2001 report of the UK National Radiological Protection Board's (NRPB) Advisory 

Group, chaired by eminent epidemiologist, the late Sir Richard Doll. 

"in the absence of clear evidence of a carcinogenic effect in adults, or of a plausible 

explanation from experiments on animals or isolated cells, the evidence is currently 

not strong enough to justify a firm conclusion that such fields cause leukemia in 

children" (page 164). 

3.2 Health Standards 

Until a few years ago, the relevant Australian health standard was the document 

called ‘Interim Guidelines on Exposure to 50/60 Hz Electric and Magnetic Fields’ 

(1989), issued by the National Health and Medical Research Council (NHMRC) and 

based on international guidelines. As the NHMRC has not updated its guidelines 

since their original issue, they have lapsed. The Australian Radiation Protection and 

Nuclear Safety Agency (ARPANSA) is currently developing a new standard. 

In December, 2006, ARPANSA issued a draft standard on “Exposure Limits for 

Electric and Magnetic Fields (0Hz to 3kHz)” for public comment. The draft standard 

proposes a 24-hour magnetic field exposure limit (reference level) for the general 

public of 1000 mG (the corresponding occupational exposure limit is 5000mG). This 

is identical to both the previous (Australian) NHMRC guidelines and the current 

version of the international guidelines, upon which they were based. 

1 

Statistical association does not necessarily indicate a cause and effect relationship. 

2 

IARC publishes authoritative independent assessment by international experts of the carcinogenic 

risks posed to humans by a variety of agents, mixtures and exposures. These agents, mixtures and 

exposures are categorised into 5 groups, namely: 

Group 1 -the agent is carcinogenic to humans-108 agents are included in the group, including 

asbestos, tobacco and ultra violet radiation; 

Group 2A - the agent is probably carcinogenic - 66 agents have been included in this group, 

including diesel engine exhaust, creosotes and PCBs; 

Group 2B - the agent is possibly carcinogenic to humans - 248 agents have been included in 

this group, including coffee, gasoline, lead, nickel, petrol engine exhaust and extremely low 

frequency magnetic fields; 

Group 3 - the agent is not classifiable as to carcinogenicity - 515 agents have been included in 

this group, including caffeine, coal dust and extremely low frequency electric fields; 

Group 4 - the agent is probably not carcinogenic to humans - only 1 agent (caprolactam) has 

been included in this group. 



F.3


In the absence of a current Australian standard, TransGrid has taken the view that 

the 2006 ARPANSA draft standard is the most appropriate “standard” to apply to 

the current assessment, noting the similarity of its limits to those in both the previous 

NHMRC and the current international guidelines. 

In applying the ARPANSA draft standard, it is important to recognise that the 

numerical limits (1000mG for the general public) are based on “established biological 

effects”. The foreword to the draft standard notes that: 

“..data regarding biological effects, at levels below the limits specified in the 

Standard, are incomplete and inconsistent. The health implications for these data 

are not known and such data could not be used for setting the levels of the Basic 

Restrictions in the Standard.” 

Being based on “established biological effects” (which occur at field levels much 

higher than those normally encountered in the vicinity of electrical equipment), the 

(numerical) exposure limits in the draft standard cannot be said to define safe limits 

for possible health effects, should these exist, from fields at levels normally 

encountered in the vicinity of electrical equipment. Nevertheless, in the foreword to 

the ARPANSA draft, the CEO of ARPANSA, Dr John Loy notes “the incorporation of 

arbitrary additional safety factors beyond the limits of the Standard is not supported.” 

It is in this context that precautionary measures such as “Prudent Avoidance” have 

arisen. 

3.3 Prudent Avoidance 

While compliance with the relevant guideline is important in protecting people from 

established health effects from magnetic fields, it does not necessarily address 

possible health effects, should they exist, from fields at the lower levels normally 

encountered in the vicinity of electrical equipment. The possibility of such effects 

has been comprehensively studied over several decades worldwide but, to this day, 

there is no clear understanding of whether or not electric or magnetic fields at low 

levels can pose a threat to human health. 

Since the late 1980s, many reviews of the scientific literature have been published by 

authoritative bodies. There have also been a number of inquiries such as those by Sir 

Harry Gibbs in NSW and Professor Hedley Peach in Victoria. These reviews and 

inquiries have consistently found that: 

adverse health effects have not been established; 

the possibility cannot be ruled out; and 

if there is a risk, it is more likely to be associated with the magnetic field than 

the electric field. 

Both Sir Harry Gibbs and Professor Peach recommended a policy of prudence or 

prudent avoidance, which Sir Harry Gibbs described in the following terms: 



F.4


“…. [doing] whatever can be done without undue inconvenience and at modest 

expense to avert the possible risk …” 

In 1999, the (US) National Institute of Environmental and Health Sciences (NIEHS) 

found: 

“In summary, the NIEHS believes that there is weak evidence for possible health 

effects from ELF 3-EMF exposures, and until stronger evidence changes this 

opinion, inexpensive and safe reductions in exposure should be encouraged.” (page 

38) 

The practice of ‘prudent avoidance’ has been adopted by the (Australian) Energy 

Networks Association (ENA) and most Australian power utilities, including 

TransGrid. 

In the Australian context, the draft ARPANSA standard addresses the matter of 

prudent avoidance in an annex entitled “A Public Health Precautionary Approach to 

ELF Fields”. The annex states: [prudent avoidance] “does not imply setting exposure 

limits at an arbitrarily low level, and requiring that they be achieved regardless of cost, but 

rather adopting measures to reduce public exposure to ELF fields at modest cost.” 

Section 5.7 of the draft addresses “Protection of the General Public” and relevantly 

stipulates “measures for the protection of the general public who may be exposed to ELF 

and/or static fields due to their proximity to high ELF and/or static sources must include the 

following: Minimising, as appropriate, ELF and/or static electric and magnetic field exposure, 

provided this can be readily achieved without undue inconvenience and at reasonable expense. 

Any such precautionary measures should follow good engineering and risk minimisation 

practice. ……………The incorporation of arbitrary additional prescriptive safety factors 

beyond the exposure limits of this Standard is not supported.” 

Internationally, the World Health Organisation has also addressed the notion of 

prudence or precaution on several occasions, including in its 2007 publication 

Extremely Low Frequency Fields: Environmental Health Criteria, Vol 238, which 

states “the use of precautionary approaches is warranted. However, it is not recommended 

that the limit values in exposure guidelines be reduced to some arbitrary level in the name of 

precaution. Such practice undermines the scientific foundation on which the limits are based 

and is likely to be an expensive and not necessarily effective way of providing protection.” 

Also, “provided that the health, social and economic benefits of electric power are not 

compromised, implementing very low-cost precautionary procedures to reduce exposure is 

reasonable and warranted.” 

Given the inconclusive nature of the science, it is considered that a prudent approach 

continues to be the most appropriate response in the circumstances. Under this 

approach, subject to modest cost and reasonable convenience, power utilities should 

design their facilities to reduce the intensity of the fields they generate, and locate 

them to minimise the fields that people, especially children, encounter over 

prolonged periods. While these measures are prudent, it cannot be said that they are 

essential or that they will result in any benefit. 

3 ELF = extra low frequency 



F.5

4. Preliminary Study of Cable EMFs 

4.1 Cable Loadings used for Modelling 


The magnetic fields from electrical equipment depend on the electric current flowing 

at that particular time. Accordingly, in characterising the magnetic fields from the 

proposed cables, it is necessary to make practical assumptions regarding the cable 

loadings. 

During a typical day, the amount of load current passing through an electricity 

network will vary substantially between a daily minimum, generally in the early 

hours of the morning and a daily maximum at times of peak demand. Loadings also 

vary seasonally during the year, generally reaching peaks in summer and winter. 

Epidemiological associations which underpin community interest regarding 

magnetic fields tend to relate to elevated "average" magnetic fields. For this reason 

the most meaningful hypothetical conditions one could select for magnetic field 

characterisation is to take the long term average load and link this to conservative 

assumptions regarding other factors. Magnetic fields derived under these conditions 

are the most appropriate for consideration in the context of the magnetic field/health 

literature. 

In this regard, it is normal practice to calculate the magnetic fields at the 85th 

percentile forecast loads for a particular item of electrical infrastructure. The 85th 

percentile loading is defined as the loading which is exceeded for no more than 15% 

of the year and is commonly available from utility forecasts. 

The load modelling for the cables has been based on the maximum cable loading 

over the coming 10 years allowing for the planned developments of the 330kV 

system. Modelling indicates that the 85th percentile load will be approximately 

325MVA. 



F.6

4.2 Modelling of the Magnetic Field Contribution of the Proposed Cables 


Based on the available design and loading information, the magnetic field 

contribution expected from the proposed underground cables has been modelled. 

Fields have been calculated at a height of one metre above ground level in 

accordance with international practice. 

4.3 Predicted Magnetic Fields under Normal Operating Conditions 

The predicted contribution from the proposed cable installation to the existing 

magnetic field environment is shown below in figures F.1 and F.2 for 325 MVA per 

cable circuit. 

Magnetic Field (mG) 

250 

200 

150 

100 

50 

0 

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 

Distance from trench centreline (m) 

Flat formation (300mm spacing, 1m depth) Double bank (700mm spacing, 1m and 1.5m depth) 

Double bank (500mm spacing, 1m and 1.3m depth) 

Figure F.1 - Predicted magnetic field contribution for 325 MVA per circuit 



F.7

Magnetic Field (mG) 

25 

20 

15 

10 

5 

0 

Predicted magnetic field contribution for 325MVA per feeder 

4 5 6 7 8 9 

Distance from trench centreline (m) 

Flat formation (300mm spacing, 1m depth) Double bank (700mm spacing, 1m and 1.5m depth) 

Double bank (500mm spacing, 1m and 1.3m depth) 

Figure F.2 - Predicted magnetic field contribution for 325 MVA per circuit 

(expanded scale between 4 and 10 m) 


The following observations are made in respect of the results shown in figures F.1 

and F.2: 

For the flat formation trench configuration, the cable’s contribution to the 

magnetic field environment directly above the centre of the trench is 

predicted to be approximately 170 mG. This will decrease to less than 43 mG 

at a distance of three metres from the centre of the trench, and less than 8 mG 

within six metres. 

For the most closely spaced double bank formation trench configuration, the 

cable’s contribution to the magnetic field environment directly above the 

centre of the trench is predicted to be approximately 80 mG. This will 

decrease to less than 17 mG at a distance of 3 metres from the centre of the 

trench, and less than 4 mG within six metres. 

Where the proposed cable route passes residential or commercial buildings or school 

boundaries, the separation from the trench centreline to the residential or commercial 

building or school boundary is 7.5 metres or more. 

4.4 Magnetic Fields under Infrequent High Load or Emergency Conditions 

While the field levels presented in Section 4.3 are the most relevant in the public 

health context, the possibility should be recognised that fields up to twice those 

shown in Figure F.1 could be produced by the cables for short periods should 

emergency loading be necessary. Such situations would rarely arise, if ever, and 

would not be expected to be of prolonged duration. 



F.8 

10


5. Compliance with EMF Standards and Prudence / Precautionary 

Principles 

As noted in Section 4.3, the predicted magnetic field contribution of the proposed 

cables, occurring directly over the cables at one metre above ground level, is 

generally expected to range from 100 to 200 mG (10-20% of the relevant public health 

guideline). The actual field will depend on trench configuration at that location and 

loadings at that time. These peaks are generally expected to reduce to less than 

15 mG within 5 metres of the centre of the cable trench, (see Table F.1) which is less 

than 1.5% of the relevant health guideline (reference level) for the general public 

(refer to section 3.2). 

6. Assessment against Prudent Avoidance Principles 

As noted in Section 3.3, given the inconclusive nature of the science, it is considered 

that a prudent avoidance approach continues to be the most appropriate response in 

the circumstances. Under this approach, subject to modest cost and reasonable 

convenience, power utilities should design their facilities to reduce the intensity of 

the fields they generate, and locate them to minimise the fields that people, especially 

children, encounter over prolonged periods, provided this can be achieved without 

undue inconvenience and at reasonable expense. 

Along with other members of ENA, TransGrid has adopted the policy of prudent 

avoidance and is applying it to this project. In this regard, TransGrid has 

incorporated the following measures into the design of the cable installation: 

selected a route that avoids close proximity to residences, schools and other 

locations where people may be present for extended periods of time; 

adopted a cable spacing and phasing arrangement for the two cables that 

results in a reduced contribution to the magnetic field environment; and 

provided information to the public regarding the EMF/health issue and the 

proposed facilities. 



F.9

Appendix G 

PROSPECT CANAL GEOTECH 

INVESTIGATION 



Review of Environmental Factors 132R1

Transgrid LPCR Transmission 

LineTransgrid LPCR Transmission 

LineTransgrid Cycleway Channel 

Transmission Line 

26 October 2011 

LPCR - U/G Transmission 

Line - Potential Construction 

Impacts 

Desktop Investigation Prepared for Transgrid

AECOM Transgrid LPCR Transmission LineTransgrid LPCR Transmission LineTransgrid 

Cycleway Channel Transmission Line 

LPCR - U/G Transmission Line - Potential Construction Impacts 


Desktop Investigation Prepared for Transgrid 

Prepared for 

Mr Kek Tang - Transgrid 

Prepared by 

AECOM Australia Pty Ltd 

17 Warabrook Boulevarde, Warabrook NSW 2304, PO Box 73, Hunter Region MC NSW 2310, Australia 

T +61 2 4911 4900 F +61 2 4911 4999 www.aecom.com 

ABN 20 093 846 925 

26 October 2011 

60157132 

AECOM in Australia and New Zealand is certified to the latest version of ISO9001 and ISO14001. 

© AECOM Australia Pty Ltd (AECOM). All rights reserved. 

AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly stated in the document. No other 

party should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor accepts any responsibility, to any 

third party who may rely upon or use this document. This document has been prepared based on the Client’s description of its requirements and 

AECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in accordance with sound professional 

principles. AECOM may also have relied upon information provided by the Client and other third parties to prepare this document, some of which 

may not have been verified. Subject to the above conditions, this document may be transmitted, reproduced or disseminated only in its 

entirety.AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly stated in the document. 

No other party should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor accepts any 

responsibility, to any third party who may rely upon or use this document. This document has been prepared based on the Client’s description of 

its requirements and AECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in accordance with 

sound professional principles. AECOM may also have relied upon information provided by the Client and other third parties to prepare this 

document, some of which may not have been verified. Subject to the above conditions, this document may be transmitted, reproduced or 

disseminated only in its entirety.AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly 

stated in the document. No other party should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor 

accepts any responsibility, to any third party who may rely upon or use this document. This document has been prepared based on the Client’s 

description of its requirements and AECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in 

accordance with sound professional principles. AECOM may also have relied upon information provided by the Client and other third parties to 

prepare this document, some of which may not have been verified. Subject to the above conditions, this document may be transmitted, reproduced 

or disseminated only in its entirety." "" 

\\ausyd1fp001\Projects\60157132_TG_330kV_Cable\6. Draft docs\6.1. Reports\Heritage Culvert Transgrid Implications 

Report.docxC:\Mark F Files\Projects\Holroyd to Rookwood\Cycleway Channel\Transgrid Implications Report.docx 

Revision 01 - 26 October 2011




Quality Information 

Document LPCR - U/G Transmission Line - Potential Construction Impacts 

Ref 60157132 

Date 26 October 2011 

Prepared by Mark Ferfolja 

Reviewed by Brian Parker 

Revision History 

Revision 

Revision 

Date 

Details 

Authorised 

Name/Position Signature 

01 26-Oct-2011 Issued for Information Brian Parker 

Technical Director 







Table of Contents 

Executive Summary i 

1.0 Purpose of Report 1 

2.0 Background 1 

3.0 Referenced Documents 1 

4.0 Observations 1 

4.1 Canal 1 

4.2 Surrounding Area 2 

5.0 Understanding of Proposed Project 2 

6.0 Discussion of Implications 2 

6.1 Methodology for Assessing Impact of Loadings 2 

6.2 Concrete Truck on Cycleway Slabs 3 

6.3 Concrete Truck on Channel and Linings 3 

6.4 Excavator on Channel 3 

6.5 Access for Cycleway Slabs 3 

6.6 Access Over Channel Walls 3 

7.0 Exclusions / Clarifications / Omissions 4 

8.0 Conclusion 4 

Appendix A 

Historical Documents A 

Appendix B 

Typical Corridor Cross Section B 

Appendix C 

Geotechnical Pressure Bulbs C 

Appendix D 

Assumed Excavator Specifications D 







Executive Summary 

AECOM P/L were commissioned by Mr Kek Tang of Transgrid to undertake a desktop study of the likely impacts 

of the construction of an underground electrical transmission line on an existing heritage listed canal and 

cycleway slab located within the Lower Prospect Canal Reserve (LPCR). 

The study was based on limited information and does not include rigorous historical investigation, geotechnical 

boreholes or destructive testing of the cycleway slabs, original sandstone channel walls or linings. 

Performance of the channel wall was analysed assuming standard construction equipment and typical material 

properties. 

It was found that impacts to the wall could be minimised by locating concrete supply trucks a sufficient distance 

away from the edge of the channel wall toward the centre of the existing channel and controlling the method of 

excavation of the transmission trench located outside the channel wall. 

Additional certainty around the impacts of construction could be ascertained once the Contractor’s construction 

methodology was determined and after additional studies provided relevant information on geotechnical and 

structural properties of the canal and its surroundings. 



Revision 01 - 26 October 2011 

i




1.0 Purpose of Report 

The purpose of this report is to comment on the likely effects of construction operations during the installation of 

Transgrid’s underground electrical transmission line parallel, and adjacent to, the Lower Prospect Canal Reserve 

(LPCR). The underground transmission line will be located immediately adjacent to the LPCR cycleway channel 

which is a heritage listed item. It is believed that Transgrid will use this report as the basis for discussion with the 

successful Contractor to better understand his approach to minimising impacts on the channel. 

2.0 Background 

The LPCR traverses through a densely populated area of Western Sydney. The corridor stretches for 

approximately 7.7 kilometres from Prospect Reservoir to Sydney Water Pipehead at Albert Street, Guildford and 

varies in width from 40 metres to 100 metres covering an area of approximately 54.6 hectares 

The channel within the LPCR was built in 1880 from sandstone masonry. Between 1907 and 1912 it was relined 

with pre-cast concrete “Monier Plates”. The relining raised the height of the canal walls and thus increased the 

capacity from a total volume of 395ML to 450ML. 

The canal ceased to be a conveyance of water in 1995. In 2001 work commenced on filling the canal and 

converting the corridor into a public space. August 2003 saw the reserve opened to the community with a 

cycleway / walkway running its full length. 

Transgrid representative Paul Henry met with the author on Monday 24 October 2011 to “walk the site” and 

describe the features of the canal and the anticipated construction method likely to be employed during project 

execution. It is understood that the construction phase of project is currently at tender at the time of writing of this 

report. 

3.0 Referenced Documents 

The following documents were referenced in this desktop assessment: 

Lower Prospect Canal Reserve – Canal Reserve Action Group. Untitled. Accessed at: 

http://www.canalreserve.org/reserve/reserve.html. Appendix A. 

Historical signage erected along the canal walk. Refer photos Appendix A. 

Geotechnical “pressure bulb” diagrams supplied by Douglas Partners. Appendix C. 

Komatsu PC220 / PC220LC excavator specifications. Appendix D. 

4.0 Observations 

4.1 Canal 

Visual remnants of the canal are clearly evident. During the inspection the following were noted: 

The canal is approximately 7.7km long and has follows a general alignment of SE to NW, 

Precast concrete “Monier Plates” protrude from the earth to a height of approximately 0.3m above 

finished surface level, 

Precast concrete thrust blocks approximately 0.25m x 0.4m at 1.2m centres are placed behind the 

“Monier Plates”, 

At many locations the “Monier Plates” have rotated forward from the thrust blocks presumably as a result 

of unbalanced earth pressure. This would not have been an issue duration operation of the channel as 

hydrostatic water pressure would have counter-acted this effect, 

The canal has been filled to a level approximately 0.3m beneath the height of the “Monier Plates”, 




1




A concrete bike path approximately 2.0m wide has been constructed in the centre of the filled channel. 

The cycleway slab is regularly jointed however the thickness is unknown. In addition the quality and 

compactive effort used in placing the fill is unknown, 

Chainages for the bike path have been marked on the concrete slabs at 50m intervals, 

At major crossing locations such as the Cumberland Hwy, the channel crosses beneath the road, 

From Ch690 - Ch1220 & Ch1320 - Ch1380 the channel construction appears to change from “Monier 

Plate” linings to an insitu concrete structure. Note – there is no historical evidence to describe this 

change in construction form, and little else is known about the channel at these locations. 

4.2 Surrounding Area 

The LPCR corridor is described as follows: 

Varying in width from approximately 40m to 100m in some locations, 

In narrow areas, generally having a flat mowed nature strip approximately 4.0m – 5.0m wide with nearby 

ground sloping at approximately 2H:1V on the South Western side of the corridor. It is assumed that 

material excavated during the construction of the original canal would have been placed on the South 

Western side of the canal to form the 4.0m – 5.0m level embankment adjacent to the channel, 

The nature of the fill suspected to be on the South Western side of the channel and surrounding insitu 

soils is unknown, 

In many locations, residential properties abut the corridor. 

5.0 Understanding of Proposed Project 

It is understood that the successful Contractor will be required to excavate a trench adjacent to the canal and 

install electrical transmission lines on behalf of Transgrid. It is also understood that the canal is heritage listed and 

as such, the project must be completed without causing damage to the canal, its linings or any related structures. 

As the project has been let as a “Design & Construct” contract, the detail related to cable arrangement and trench 

size and location is unknown at this stage. Transgrid representative Paul Henry provided an opinion on what the 

Contractor may propose as the preferred installation solution. Mr Henry suggested that the Contractor may 

propose a trench approximately 3.0m wide and 1.3m deep should the required 6 cables be laid flat, otherwise the 

trench could be 1.6m deep and 1.5m wide if the cables are installed in a 2 x 3 arrangement. Cable jointing pits 

approximately 15m - 20m long, 2.0m deep and 3.0m wide would also be required approximately 500m – 1000m 

apart at locations to be determined by the Contractor. 

It is assumed that a 20T – 25T excavator would be used to dig the trench. An excavator of that size may impose a 

load directly beneath the caterpillar tracks of approximately 75kPa – 100kPa depending on reach, payload and 

other operational factors. The excavator specification used in the author’s calculations is shown in Appendix D. 

It is assumed that concrete would be trucked to location and delivered to a concrete pump by chute. The 

Contractor may require longer pump lines in areas where the corridor, topography or other constraints prohibit 

access by truck. 

It is understood that one of the conditions of contract is that pedestrian and cyclist access must be maintained 

during construction. 

6.0 Discussion of Implications 

6.1 Methodology for Assessing Impact of Loadings 

The “pressure bulb” diagram provided by Douglas Partners which converts vertical force to horizontal stress has 

been used in the assessment of the adequacy of the existing sandstone channel and linings. The “pressure bulb” 

is shown in Appendix C of this document. 

Assumptions: 




2




Concrete strength of Monier Plates assumed to be 20MPa. Flexural tensile strength of 2.6MPa, 

Concrete strength of the cycleway slab assumed to be 25MPa. Flexural strength of 3.0MPa, 

Cycleway slab assumed to be 150mm thick, 

Sandstone masonry assumed to possess no tensile strength, 

Modulus of subgrade reaction behind the “Monier Plates” = 4E6 N/m 3 , 

Assumed that the concrete truck carries a 6.0m 3 agitator and has dual rear axles (ie minimum of 3 axles 

total for the truck), 

Assumed that the excavator used is a 20T – 25T caterpillar tracked excavator. Refer Appendix D. 

The most effective means of minimising the potential impact of loadings is to arrange the operational area in such 

a manner as to avoid surcharging the original sandstone wall and linings. The “Monier Plates” form a “masonry 

like” structure that is unreinforced and thus lacking in general robustness and strength. 

Appendix B shows a method by which surcharging of the wall could be kept to a minimum and hence reduce the 

potential impacts of an excavator and concrete truck. Positioning surcharge loads remote from the channel wall 

limits the pressure applied to the wall which is a critical consideration given the wall’s relative fragility. 

It is noted that Appendix B represents one of many potential solutions and the Contractor will be required to 

provide a construction management plan as part of his commission. 

6.2 Concrete Truck on Cycleway Slabs 

The assumed concrete truck will be likely to cause cracking of the cycleway slab. To gain access to the point of 

concrete discharge the concrete truck will presumably follow the existing cycleway slab. The quality of the 

material beneath the slab is unknown so to the compaction of that material. Calculations suggest that the flexural 

tensile stress in the bottom fibre of the concrete will be exceeded and as a consequence, cracking of the slabs 

may be initiated. 

Smaller trucks could possibly be used with lesser wheel loads however this needs to be balanced against the 

volume of concrete which needs to be poured and the increased number of truck movements required. 

The size and weight of concrete pump is also unknown. 

6.3 Concrete Truck on Channel and Linings 

The assumed concrete truck is unlikely to cause cracking of the “Monier Plates” lining the original sandstone 

channel provided that the truck remains a minimum distance of 1.5m from the edge of the channel (as shown in 

Appendix B of this report). 

6.4 Excavator on Channel 

The assumed excavator is unlikely to initiate cracking of the “Monier Plates” providing the excavation is properly 

“managed.” The excavator can reduce potential impact on the existing sandstone wall and “Monier Plates” by 

cutting down to a bench then repositioning away from the centre line of the cycleway channel and cutting down to 

the base of excavation as suggested in Appendix B of this report. 

Again, positioning the excavator surcharge loads remote from the channel wall limits the pressure applied to the 

wall which is a critical consideration given the wall’s relative fragility. 

6.5 Access for Cycleway Slabs 

Operationally, as the concrete truck will likely be required to be 1.5m from the edge of the channel wall to 

minimise stress on the wall, the entire slab width will be obstructed by the truck. The contractor will need to make 

alternate provisions to maintain access for pedestrians and cyclists. 

6.6 Access Over Channel Walls 

At locations where trucks are required to cross over the channel walls (which protrude approximately 0.3m above 

the existing ground line), road base or a similar material will be required to ramp over the walls. 




3




7.0 Exclusions / Clarifications / Omissions 

The following list of exclusions and clarifications apply to this desktop study: 

Geotechnical information regarding the nature of the insitu soils, 

Clear identification of the exact route the Contractor proposes for the cables, 

Detailed understanding of the existing sandstone wall construction, 

Detailed understanding of the “Monier Plate” lining of the channel, 

Understanding of why the channel construction appears to change at chainage locations Ch690 - 

Ch1220 & Ch1320 - Ch1380. 

Proper understanding of proposed construction methods including type and size of plant and machinery. 

8.0 Conclusion 

If uncontrolled, negative impacts are likely on the original sandstone walls, linings and cycleway slabs. 

Measures can be taken to reduce the impacts on the existing sandstone wall and linings. These include: 

Managed approach to plant location and operation, 

Sufficient protection of existing precast “Monier Plates” by using roadbase or other material to ramp over 

the wall. 

The existing concrete cycleway slab is likely to be damaged during the contract. Appropriate allowance should be 

made to provide for repair or replacement. 

This desktop study has been conducted using limited information. Estimates of likely impacts can be further 

refined by obtaining better information on the original sandstone channel construction, “Monier Plate” relining, soil 

conditions, Contractor’s program and a list of proposed Contractor plant and machinery. 

A comprehensive and agreed construction management plan addressing protection of the canal walls and 

impacts to the cycleway slabs should be a requirement of the contract with further engineering investigation to be 

undertaken by the Contractor to “proof up” the underlying engineering assumptions used in his plan. 




4




A Appendix A 

Historical Documents 







B Appendix B 

Typical Corridor Cross 

Section 







C Appendix C 

Geotechnical Pressure 

Bulbs

Holroyd to Rookwood Road cable REF - TransGrid

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?