bulk earthworks civil engineering design report

Orange City Council

Bulk Earthworks Civil Engineering Design Report

F3113-16

Orange Regional Sporting Precinct at Jack Brabham Park

June 2021

© Copyright Barker Ryan Stewart Pty Ltd

2021 All Rights Reserved

Project No. 210090R02

Author Scott Brisbin

Checked

Approved Scott Brisbin

Rev No. Status Date Comments

1 For Review 04/06/2021 80% Preliminary Design

COPYRIGHT

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licence or authority is granted by Barker Ryan Stewart to any person or organisation to use any of Barker Ryan Stewart’s documents

for any purpose without the written consent of Barker Ryan Stewart.

REPORT DISCLAIMER

This report has been prepared for the client identified in Section 1.0 only and cannot be relied on or used by any third party. Any

representation, statement, opinion or advice, expressed or implied in this report is made in good faith but on the basis that Barker

Ryan Stewart are not liable (whether by reason of negligence, lack of care or otherwise) to any person for any damage or loss

whatsoever which has occurred or may occur in relation to that person taking or not taking (as the case may be) action in any

respect of any representation, statement, or advice referred to above.

Table of Contents

1 Introduction ......................................................................................................................................................... 5

2 Project Start Up and Existing Site Description .................................................................................................. 6

2.1 Start Up Inspection and Meeting ............................................................................................................. 6

2.2 Existing Site Description .............................................................................................................................. 6

3 Scope of Bulk Earthworks ................................................................................................................................. 12

4 Detailed Site Survey .......................................................................................................................................... 13

5 Utilities Services .................................................................................................................................................. 14

5.1 Dial Before You Dig Information.............................................................................................................. 14

5.2 Communications (AARNet, APT, NBN, Optus and Telstra) .................................................................. 14

5.3 Essential Energy ......................................................................................................................................... 14

5.4 Jemena Gas .............................................................................................................................................. 14

5.5 Orange City Council (Water and Sewer) .............................................................................................. 14

5.6 Proposed Orange City Council Water and Sewer Works .................................................................... 15

5.7 Utility Potholing .......................................................................................................................................... 15

5.8 Summary of Services ................................................................................................................................ 15

6 Geotechnical Works ........................................................................................................................................ 16

6.1 Geotechnical and Pavement Investigation ......................................................................................... 16

6.2 Contamination Investigation .................................................................................................................. 16

7 Bulk Earthworks Design ..................................................................................................................................... 17

7.1 Bulk Earthworks Design ............................................................................................................................. 17

7.2 Maintenance Compound ....................................................................................................................... 18

7.3 Tree Removal ............................................................................................................................................ 18

7.4 Heritage ..................................................................................................................................................... 18

8 Items for Further Discussion/Consideration .................................................................................................... 19

List of Figures

Figure 1 – Plan view of site (via SixMaps) ................................................................................................................. 7

Figure 2 – Aerial image of site (via SixMaps) ........................................................................................................... 7

Figure 3 – Aerial image of site (via NearMap) ........................................................................................................ 8

Figure 4 – View looking north along former fairway parallel to Forest Road ...................................................... 8

Figure 5 – View looking south over former golf green toward Forest Road and Bloomfield heritage gates .. 9

Figure 6 – View looking east with proposed site on the right and existing Jack Brabham Park on the left .... 9

Figure 7 – Semi-formal channel through centre of site and path crossing ....................................................... 10

Figure 8 – View looking west from eastern portion of site .................................................................................... 10

Figure 9 – Maintenance compound at interface of proposed site and Jack Brabham Park ........................ 11

Figure 10 – Bloomfield heritage gates adjoining Forest Road ............................................................................ 11

Figure 11 – Extent of Topographical Survey .......................................................................................................... 13

210090 – Orange Regional Sporting Precinct Bulk Earthworks Design Report

List of Tables

Table 1 - Summary of Known Utility Services ......................................................................................................... 15

Table 2 – Bulk Earthworks Volume Summary ......................................................................................................... 17

Table 3 – Topsoil Volume Summary ........................................................................................................................ 17

Table 4 – Bulk Earthworks Volume Summary ......................................................................................................... 18

Appendix List

Appendix A - Site Masterplan

Appendix B – Detailed Site Survey

Appendix C – Geotechnical Report

Appendix D – Preliminary Contamination Report

Appendix E – Bloomfield Precinct Service Infrastructure Redevelopment

Appendix F – Bulk Earthworks Engineering Drawings


1 Introduction

Barker Ryan Stewart Pty Ltd (BRS) was engaged by Orange City Council (OCC) to prepare a preliminary

bulk earthworks (BEW) design for the proposed Orange Regional Sporting Precinct at Jack Brabham Park

(The Project). The site bulk earthworks will be undertaken ahead of the site’s main civil works package.

Design works have been carried out under Project Number F3113-16. The Project is funded by the NSW

State Government.

The site primarily comprises of a disused golf course with the former fairways and greens overcome with

weed and associated vegetation growth. A number of existing structures and site improvements remain

on the site. Existing sports fields and a maintenance compound are located to the north of the site.

The overall Project includes the following components:

a. Bulk earthworks ‘early works’ package;

b. Main stadium with grandstand and forecourt;

c. Athletics stadium with grandstand;

d. Car parking areas; and

e. Sporting fields for use by cricket, softball, summer football, athletics, rugby league, touch football

and other sports, and community events.

The site will be accessed via Forest Road and Huntley Road. The site is immediately adjacent to the

heritage listed ‘Bloomfield’ gates off Forest Road and the Bloomfield Health Service precinct.

A Masterplan for the site was prepared by Premise Consulting (‘Orange Sporting Precinct Masterplan – Sir

Jack Brabham Park’, Project Number 219058, Set 1F). A copy of the Masterplan is included in Appendix A

and was used to support a Tree Removal Development Application for the site that is currently under

assessment by Council.

The preliminary civil engineering design by BRS adopted the site Masterplan layout as adjusted through

discussions with NSW Heritage Council. The layout and finished surface levels proposed as part of the

main civil works package have been used to inform this bulk earthworks design.

This design report summarises the design approach and methodology for the preliminary bulk earthworks

design of The Project.

This report should be read in conjunction with the bulk earthworks drawings included in Appendix F.


2 Project Start Up and Existing Site Description

2.1 Start Up Inspection and Meeting

A site start-up meeting was held on site on 8 March 2021. The site inspection was undertaken during

daylight hours to observe existing site conditions, project opportunities and project constraints.

The inspection was attended by representatives from:

a. Public Works Advisory of NSW;

b. Barker Ryan Stewart.

Following the inspection, a project kick-off meeting was held in Council’s offices. This meeting was

attended by representatives from:

a. Orange City Council;

b. Public Works Advisory of NSW;

c. Premise Consultants;

d. Barker Ryan Stewart.

2.2 Existing Site Description

The proposed Orange Regional Sporting Precinct at Jack Brabham Park is located approximately 3km

south of the Orange town centre. The site is bound to the north by existing sports fields at Jack Brabham

Park, to the east by Huntley Road, to the south by Bloomfield Health Services and to the west by Forest

Road. The site is known as 1502 Forest Road, Orange and is legally defined as Lot 209 DP42900.

The site has an area of approximately 21.5ha and generally grades from south to north. The site comprises

of a disused golf course with the former fairways and greens overcome with weed and associated

vegetation growth. A number of site improvements remain on the site including structures, paths and

piped channel crossings.

The site includes a large number of trees that line the former fairways. The trees are a mixture of native and

exotic species.

Small dams exist upstream of the site and at the northern boundary of Jack Brabham Park. The dams are

linked by a semi-formal channel that flows north through the proposed site and existing Jack Brabham

Park. The semi-formal channel is not a mapped watercourse.

A number of local and trunk utility services traverse the site. These services primarily comprise of

communications and Council water and sewer assets. Other public utilities are located in the Forest Road

and Huntley Road verges.

Bloomfield Hospital heritage gates are located off Forest Road and form part of State Heritage Register

SHR: 01745. The gates provide access to Bloomfield Hospital and are located beyond the Sports Precinct

boundary.

The existing site is presented in Figure 1 to Figure 10.


Figure 1 – Plan view of site (via SixMaps)

Figure 2 – Aerial image of site (via SixMaps)


Figure 3 – Aerial image of site (via NearMap)

Figure 4 – View looking north along former fairway parallel to Forest Road


Figure 5 – View looking south over former golf green toward Forest Road and Bloomfield heritage gates

Figure 6 – View looking east with proposed site on the right and existing Jack Brabham Park on the left


Figure 7 – Semi-formal channel through centre of site and path crossing

Figure 8 – View looking west from eastern portion of site


Figure 9 – Maintenance compound at interface of proposed site and Jack Brabham Park

Figure 10 – Bloomfield heritage gates adjoining Forest Road


3 Scope of Bulk Earthworks

Bulk earthworks at the site are proposed to be undertaken ahead of the main civil works package.

The scope of works for the proposed bulk earthworks package broadly includes:

a. Removal of trees and vegetation;

b. Demolition of a disused structure and associated infrastructure near future Car Park 1;

c. Demolition of minor site improvements (piped channel crossing, etc) to facilitate bulk earthworks

operations;

d. Management of stormwater around and through the site as appropriate to suit the contractor’s

staging;

e. Adjustment of utility services that will be impacted by the bulk earthworks operations;

f. Relocation of site maintenance compound (if required);

g. Stripping and stockpiling of topsoil;

h. Bulk earthworks cutting, filling, compaction and testing operations;

i. Hydromulch stabilisation of the finished bulk earthworks surface.

The proposed bulk earthworks package does not include:

a. Permanent connections to existing public roads;

b. Construction of road and car park pavements, kerbs, wearing course, etc;

c. Adjustment to existing utility services that are not impacted by bulk earthworks operations;

d. Adjustment of retained utility service pits and surface fittings to suit revised site levels;

e. Installation of new utility infrastructure to service the future sports fields (ie electrical, comms,

water and sewer, etc);

f. Installation of stormwater drainage pits, pipes and culverts;

g. Construction of any structures, including grandstands;

h. Construction of athletics track;

i. Installation of sports field playing surface, including import of specialist growing medium and

amelioration/improvement of site won topsoil;

j. Spreading of topsoil.


4 Detailed Site Survey

Premise Consultants were engaged by Orange City Council to undertake a detailed topographical

survey of the site and the immediately surrounding area. The survey was undertaken in August 2020 is

presented over 6 sheets as part of Job Number 220366.

The survey was undertaken on MGA2020 co-ordinates with levels to AHD. A screen capture of the survey

extents is presented in the Figure below. A full copy of the survey is included in Appendix B.

Figure 11 – Extent of Topographical Survey

The Premise Consulting survey has been adopted as the site’s existing surface for the bulk earthworks

design.


5 Utilities Services

5.1 Dial Before You Dig Information

Dial Before You Dig (DB4YD) plans for the site were requested on 22 March 2021 (Job No 21303286). Utility

assets in the vicinity of the works were identified from the following authorities:

a. AARNet

b. APT Management Services

c. NBN Co

d. Optus

e. Telstra

f. Essential Energy

g. Jemena Gas

5.2 Communications (AARNet, APT, NBN, Optus and Telstra)

Significant copper and fibre optic communications assets exist in both the Forest Road and Huntley Road

verges. Communication assets are also located within the site parallel to Huntley Road. It is noted that

the existing maintenance compound does not appear to have an underground communications

service.

Assets located within the site parallel to Huntley Road will be partially located within future Car Park 3, 4

and 5. It is anticipated communications cabling will be retained and the communication pits will be

adjusted to suit proposed car park levels as part of the future main civil works package.

5.3 Essential Energy

Aerial HV, LV and street lighting assets exist along Forest Road and Huntley Road. Underground HV and

LV assets are located along Forest Road. Aerial assets are not expected to be impacted by the

proposed works.

Underground LV assets exist within the site to service a small building located within the footprint of future

Car Park 1 and the amenities building near future Car Park 5.

Any impacts to underground assets are expected to be limited to future car park connections to Forest

Road and Huntley Road. Any assets that will become redundant as a result of the bulk earthworks (such

as the one servicing the small building at future Car Park 1) will be capped and removed.

5.4 Jemena Gas

A network of DN110 210kPa gas mains exist along Forest Road and Huntley Road. No known gas assets

are present within the site.

Any impacts to existing gas assets are expected to be limited to future car park connections to Forest

Road and Huntley Road.

5.5 Orange City Council (Water and Sewer)

A utility services plan showing stormwater, potable water and sewer assets was provided by Orange City

Council. The plan showed:

a. Stormwater drainage assets to the north of Jack Brabham Park to drain the existing dam near

Huntley Road. Other stormwater assets did not appear to be present on the site.


b. Multiple potable water services traversing the site, generally in a north-south orientation. Assets

included DN200, DN250 and DN375 assets. Portions of these mains will need to be adjusted or

relocated to facilitate the proposed bulk earthworks.

c. A number of sewer assets traverse the site including a DN375 main that discharges north near the

centre of the site and a DN150/DN225 network that runs parallel to Huntley Road. Portions of the

sewer network will need to be adjusted or relocated to facilitate the proposed bulk earthworks.

It is understood that a feeder pipe from the Gosling Creek dam (located about 1.5km south-east of the

site) is located near the future athletics stadium and future Car Park No 3. It is understood that Council is

undertaking investigations as to the viability of utilising the Gosling Creek Feeder pipe as the primary

source of irrigation water for the proposed sporting fields.

5.6 Proposed Orange City Council Water and Sewer Works

It is understood that significant augmentation and adjustments are proposed to Council's water and

sewer assets on and adjoining the sports field site as part of Council’s Bloomfield Precinct service

infrastructure redevelopment. These adjustments and augmentation will relocate a large portion of

Council's assets away from the sports field site.

Timing of the proposed utility adjustment and augmentation works are yet to be confirmed. Following

further discussion with Council, the final utility adjustment strategy will be included on the 100% bulk

earthworks documents.

A copy of the proposed utility strategy is included in Appendix E.

5.7 Utility Potholing

Utility potholing to physically locate assets using non-destructive investigation techniques may be

undertaken as part of future design stages of the project, or as part of the bulk earthworks. Any

potholing works should be undertaken by accredited specialists.

5.8 Summary of Services

A summary of known services is presented in the table below.

Utility Service Information Source Assets Comment

Communications Dial Before You Dig, site

survey

AARNet, APT, NBN, Optus

and Tesltra - fibre and

copper network

Pit adjustment to suit

future car park works

Essential Energy Dial Before You Dig, site

survey

Aerial and underground

HV, LV, street lighting,

Zone Substation

Potentially impacted at

future car park access

points

Jemena Dial Before You Dig, site

survey

DN110 Potentially impacted at

future car park access

points

Water and Sewer Dial Before You Dig, site

survey, Council data

Potable water and sewer Adjustment and

relocations required to

suit bulk earthworks

Table 1 - Summary of Known Utility Services


6 Geotechnical Works

6.1 Geotechnical and Pavement Investigation

Macquarie Geotech was engaged by Orange City Council to undertake geotechnical site investigations

and reporting. Results are presented in the Macquarie Geotech report ‘Sporting Precinct – Geotechnical

Investigation, Report number B20292, Rev 02, dated 04/01/2021.

Pavement thickness recommendations for the future internal roads and car parks have been considered

in the bulk earthworks design.

A copy of the report is included in Appendix C.

6.2 Contamination Investigation

Envirowest Consulting was engaged by Orange City Council to undertake a preliminary contamination

investigation. Results are presented in the Enirowest Consulting report ‘Preliminary Contamination

Investigation - Proposed New Sporting Precinct, Forest Road, Orange’, Report number R12205C, Rev 0,

dated 21/9/2020.

A copy of the report is included in Appendix D.


7 Bulk Earthworks Design

7

7.1 Bulk Earthworks Design

A preliminary site earthworks model was prepared that considered the proposed site grading including:

a. Main fields with grandstands;

b. Main sports fields;

c. Car parks and internal access roads;

d. Adjoining regrade areas.

The earthworks model was prepared in 12D Model software (version 14) with the following assumptions:

a. Existing site surface per Premise Consultants detailed site survey (refer Section 4);

b. Average 150mm topsoil strip across the bulk earthworks footprint based upon the Macquarie

Geotech report (refer Section 6.1);

c. Site layout per BRS concept civil engineering drawing set 210090-01 Rev B;

d. Future finished site levels per BRS concept civil engineering drawing set 210090-01 Rev B;

e. Bulk earthworks levels a specific depth below the future finished surface level as summarised in

Table 2 below. Note BEW = bulk earthworks and FSL = finished surface level.

Location BEW Level

Below

Future FSL

Comment

a. Main League Field -300mm Allows for future import of growing medium

b. 8 Centre Fields and

Athletics Track

-250mm Allows for future placement of ameliorated/improved, site

won topsoil. Stripped topsoil to be stockpiled by BEW

contractor for improvement/placement by main civil

contractor.

c. Athletics Track -500mm Allows for future treatment/import to address reactive

subgrade

d. Car Park 1 and Roads -330mm Allows for future import of pavement materials

e. Car Park 2 N/A Retain existing

f. Car Park 3 and Roads -430mm Allows for future import of pavement materials

g. Car Park 4 and Roads -330mm Allows for future import of pavement materials

h. Car Park 5 and Roads N/A Nil BEW proposed. Undertake as part of main civil works

i. Areas other than those

listed above

-140mm Allows for placement of site won topsoil (typically on

mounds, batters, landscape areas, etc)

Table 2 – Bulk Earthworks Volume Summary

A summary of site topsoil volumes is presented below:

Topsoil Element Value

Strip Volume at 150mm Average Depth 30,800m³

Assumed Stockpile Dimensions (nom.) 110mL x 110mW x 2.5mH

Future Respread Volume by Main Civil

Contractor Over Item b and i Table 2

30,800m³

Table 3 – Topsoil Volume Summary


A summary of the site bulk earthworks volumes, excluding topsoil, is presented below.

Volume

Cut -116,275m³

Fill +116,287m³

Net -12m³ (export)

Table 4 – Bulk Earthworks Volume Summary

The above volumes are preliminary and make no allowance for:

a. Bulking factors;

b. Trench spoil;

c. Grandstand foundation spoil;

d. Unsuitable material.

7.2 Maintenance Compound

A maintenance compound that services the existing Jack Brabham Park is located between the proposed

sports fields and Jack Brabham Park. The compound currently has vehicle access from Huntley Road.

It is preferred to retain maintenance compound without adjustment or relocation. The current bulk

earthworks design shows an earth batter encroaching the fenced compound area. Further, the existing

vehicle access off Huntley Road is likely to require relocation to utilise part of future Car Park No 4.

Impacts to the maintenance compound can not be avoided without installation of a retaining wall about

3m high, or adjustment to the future sports field layout and/or runoff areas.

If the maintenance compound is to be relocated, consideration is required to the timing of the relocation

and if this is undertaken by Council ahead of the bulk earthworks operations, or if its relocation is included

in the bulk earthworks contract.

7.3 Tree Removal

The site includes a large number of trees that line the former fairways. The trees are a mixture of native and

exotic species.

The site Masterplan included in Appendix A included tree removal drawings that were used as part of a

Tree Removal Development Application that is currently under assessment by Council. Trees that are

proposed for removal as part of the Development Application have been duplicated on Sheet 102 and

102 in the bulk earthworks drawing set included in Appendix F.

7.4 Heritage

Bloomfield Hospital heritage gates are located off Forest Road and form part of State Heritage Register

SHR: 01745. The gates provide access to Bloomfield Hospital and are located beyond the Sports Precinct

boundary.

The Bloomfield gates and adjoining heritage precinct that form part of SHR: 01745 are not expected to be

impacted by the proposed bulk earthworks.


8 Items for Further Discussion/Consideration

The engineering drawings included in Appendix F present a 80% complete concept design for the bulk

earthworks design of the project. The list below presents a summary of items that require further discussion

and consideration as part of the next stage of the design:

a. Further adjustment and refinement to the bulk earthworks design to accommodate the design

development of the main civil works package.

b. Further consideration to relocation of existing maintenance compound or adjustment to suit layout

(fields, runoff, retaining walls etc).

c. Confirmation of timing of Bloomfield Precinct service infrastructure redevelopment.

d. Finalisation of utility adjustments to be undertaken as part of the bulk earthworks package, following

completion of Item c above.

e. Consideration to timing of potholing of utility services.


APPENDIX A

Site Masterplan


APPENDIX B

Detailed Site Survey


APPENDIX C

Geotechnical Report


APPENDIX D

Preliminary Contamination Report


APPENDIX E

Bloomfield Precinct Service Infrastructure Redevelopment


APPENDIX F

Bulk Earthworks Engineering Drawings

bulk earthworks civil engineering design report

Documents