海外公路项目投标书

NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

Airport Link & Northern Busway – Project Bid

Preliminary Advice on Northern Busway Pavement

Coffey (Hyder SMEC JV) PV-NB-01 Preliminary 220-PVNB01-00049-C-R 02 30 August 2007 Sven Padina Weeks White Alan Clover Signature: Signature: Signature: CONSULTANT: DESIGN LOT: STAGE: DOCUMENT No.: REVISION No.: ISSUE DATE: AUTHOR: CHECKED: REVIEWED BY:

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

Remove this page when final copy is submitted

Date 22/8/2007 30/8/2007 Revision 01 02 03 Author Sven Padina Sven Padina Checker Weeks White Weeks White

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Review Revision Description Alan Clover First Draft Alan Clover First Issue

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

TABLE OF CONTENTS

Page

1

1.1 1.2 1.3 1.4

CONCEPT DESCRIPTION

Introduction Busway Description

Busway Design Requirements Design Traffic

Brief Requirements for Design Traffic Design Traffic Loads

4

4 4 4 5

5 5

1.4.1 1.4.2

1.5 1.6 1.7 1.8 1.9

Subgrade Conditions

Preliminary Busway Pavement Assessment / Design ( No LRT ): Rigid Pavement Design Review

Preliminary Busway Pavement Assessment / Design ( No LRT ): Flexible Pavement Design Review

Incorporation of Light Rail within Busway Reuse or Rehabilitation of Existing Pavements

6 7 9 11 12

2

2.1 2.2 2.3

ASSUMPTION / DEPARTURES

Design Traffic Loads Subgrade Conditions

Incorporation of Light Rail within Busway

13

13 13 13

3 4 5 6 7 8 9 10 11

RISKS / OPPORTUNITIES OPERATION & MAINTENANCE SAFETY IN DESIGN CONSTRUCTABILITY

ENVIRONMENTAL IMPACTS & APPROVALS ENVIRONMENTALAL SUSTAINABILITY ADVANTAGES / DISADVANTAGES

OUTSTANDING INFORMATION / MATTERS FOR RESOLUTION RECOMMENDATIONS

14 14 14 14 14 14 14 14 15

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

1 1.1

CONCEPT DESCRIPTION Introduction

This report presents preliminary pavement design advice for the Northern Busway (NB) tender design together with a discussion on preliminary assumptions made on design traffic and subgrade conditions. This preliminary advice has been restricted to review and comment on the adequacy of the Request For Proposal (RFP) Brief pavement designs only, presenting two separate design option reviews, one considering Bus only traffic in Busway, and the other considering the possible future inclusion of a Light Rail line within the Busway.

The RFP Exhibit A, Annexure 1 – Part 1 clause 5.3.3(c) presents specific minimum thickness pavement designs to be used for Busway applications. In lieu of developing alternative pavement designs, to support early stage project planning we have only carried out an adequacy assessment of these designs based on the initial traffic and sub grade conditions discussed in Sections 2.2.1 and 2.3.

Additionally it should be noted that this review of RFP pavement designs only provides preliminary LRT pavement advice, and detailed design and modelling calculations are required to more completely assess pavement thickness and reinforcing.

1.2

Busway Description

We understand that the proposed Busway will be developed in two stages as follows; Stage 1 (current development): Construction of the Interim Design comprising the following key elements;

1. A dedicated Busway from the southern connection north to Federation Street, including

bridge and trough structures. 2. Addition of Bus-only lanes to Lutwyche Road, Truro Street and Roblane Street from

Federation Street to Stoneleigh Street. 3. Dedicated Busway tunnel and trough structures from Stoneleigh Street to Gympie Road. Stage 2 (possible future development): Construction of a dedicated Busway tunnel linking 1 and 3 above.

Following completion of Stage 2 works a Light Rail Transport (LRT) line may also be incorporated within the Busway corridor to operate in conjunction with Bus operations. Provisions for LRT are to be included within pavement design and construction of Stage 1 Bridge, Trough and Tunnel structures.

1.3

Busway Design Requirements

The pavement design requirements have been sourced from the following project documents; ? Project Deed.

? Request for Proposal (RFP), 14 June 2007.

? RFP Exhibit A, Performance Specification (including all attachments).

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

1.4 1.4.1

Design Traffic

Brief Requirements for Design Traffic

The key tender requirements with respect to Busway traffic for pavement thickness designs are as follows; Design Life

(RFP Exhibit A Annexure 1 – Part 1 Table A)

? Pavements for Busways, Bus stations, Bus stops, Bus only lanes, Bus lanes (Turo

street only) (other than wearing surfaces) – 40 years. ? Pavement wearing surfaces – 10 years. Design Traffic

PPP Co must design the Busway, Busway Stations, Bus Stops, Bus Lanes (Truro Street only) and Bus-only Lanes for a traffic loading (Nes) = 2.1 x 108 (per lane) which assumes a 40 year Design Life. (RFP Exhibit A Annexure 1 – Part 1 Clause 5.3.3 (b))

PPP Co must design any other lanes which buses may use (other than Truro Street) for the maximum of: (RFP Exhibit A Annexure 1 – Part 1 Clause 5.3.3 (d))

(i) the design requirements of the relevant road authority (i.e. Council or QDMR) over the Design Life; and

(ii) the bus traffic loading as noted above plus the traffic loading as determined from PPP Co’s traffic model assessment of expected other traffic volumes and other vehicle mixes over the nominated Design Life.

PPP Co must make all allowances for the future provision of LRT to operate within the Busway and must design and construct the Project Works to allow for the operation of LRT vehicles in collocation with buses within the Busway at some later date. (RFP Exhibit A Annexure 1 – Part 1 Clause 8.1 (a))

1.4.2

Design Traffic Loads

As the results from the tender design traffic model are not yet available, Design traffic has been derived by only considering the RFP supplied Busway design traffic in dedicated Busway and Bus only lanes. A resulting breakdown of this RFP design traffic for both rigid and flexible pavement design are as follows;

? The number of standard axles of equivalent damage to the sub grade (Nes) = 2.1 x 108

per lane for 40 year Design Life (as specified in the RFP) ? Estimated number of standard axles of equivalent damage to asphalt (Nea) = 2.42 x 108 ? Estimated cumulative heavy vehicles (HV) = 1.9 x 108

? Estimated cumulative heavy vehicle axle groups (HVAG) = 4.4 x 108

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

The assumptions used for this preliminary advice report in calculating the above Nea, HV and HVAG values are as follows:

1) In lieu of project specific Traffic Load Distributions (TLD) for buses (i.e. the

distribution of types of axle groups and the distribution of loads on each type of axle group), the Busway traffic load distribution derived from weigh-in-motion data from a bus-only lane in the ACT has been used. We understand that this TLD has been used for other Busway projects in Brisbane. 2) The number of heavy vehicle axle groups per vehicle (HVAG) is assumed to be 2.33. Based on the presumptive TLD noted above, the number of equivalent standard axles per bus (ESA/CV) is 1.1. When calculated in accordance with the Queensland Department of Main Roads “Pavement Design Manual”, the following ratios are also derived:

? the ratio of the number of standard axles of equivalent damage to the sub grade (Nes)

to the number of ESA is 1.0; ? the ratio of the number of axles of equivalent damage to asphalt (Nea) to the number of

ESA is 1.15. These estimated preliminary pavement design traffic loads may change when project traffic models and TLDs are produced. In accordance with the RFP requirements listed above, the design traffic loading in mixed used lanes (i.e., buses and other vehicles) has to be taken as the sum of the specified bus traffic and the other vehicle traffic and it has been assumed that the latter is small in comparison to the bus traffic and can be ignored for the present. This assumption should be reviewed when the traffic in mixed use lanes is identified.

1.5

Subgrade Conditions

At the present time there is little specific information available on pavement subgrade conditions throughout the study area so the following assumed subgrade design CBR values have been adopted for the purposes of preliminary pavement design; ? Road header tunnels: Bedrock floor, CBR >20%.

? Cut and cover tunnels and trough transition structures: Concrete base slab. ? Natural soils at grade or less than 1m of embankment fill: CBR 3%.

It is assumed that in road header tunnels with a bedrock subgrade, a 300mm thick drainage blanket overlain by geotextile will be constructed beneath the pavement to control groundwater seepage.

In accordance with technical standard PSTS101 “Checking Sub grade: Capping layer; Drainage Layer; Controlled Subgrade; Working Platform; Temporary Pavement; Verge”, where the subgrade has a design CBR less than 3% a capping layer will be required. It is anticipated that for some natural soils the subgrade materials may have to be excavated and replaced with imported materials to form the capping layer; for example a soil with design CBR 2% requires capping 200mm thick. Pavements with capping are designed as having a design CBR value of 3% at the top of the capping layer.

In addition, where the natural soils have a swell (in the CBR test) of greater than 0.5% a controlled subgrade is required with minimum thickness depending on the swell value. For example, for a design swell value greater than or equal to 2.5% and less than 5%, the

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

required thickness of the controlled sub grade is 600mm. The working platform (see Section 6) forms part of the controlled sub grade.

1.6

Preliminary Busway Pavement Assessment / Design ( No LRT ): Rigid Pavement Design Review

The RFP specifies that rigid pavements are to be used in the Busway at the following locations;

? Tunnels and Connection ramps.

? Busway Stations including through lanes, standing lanes and tapered approaches. ? Bus turnaround area at Kedron. ? Federation Street bus stop. ? Bus stops.

The RFP designs have been assessed in accordance with the QDMR design manual and are presented in Tables 1, 2 and 3 following together with our recommended design amendments (highlighted in bold) required for design life and anticipated sub grade conditions. In all cases the minimum pavement thickness nominated in the RFP is satisfactory for the nominated bus traffic loading provided that shoulders are provided as discussed below.

Additional design parameters used in accordance with the RFP and QDMR rigid pavement requirements are as follows; ? Project design reliability = 97.5%

? JRCP dowelled and CRCP pavements, for which the required Load Safety Factor =

1.25 ? Rigid pavements will be provided with shoulders as follows;

?

A shoulder made up of the same concrete and thickness as the trafficked lane base concrete thickness, cast integrally with the trafficked lane concrete base and with a minimum width of 0.6m outside the edge line; or

A shoulder made up of the same concrete and same thickness as the trafficked lane base concrete thickness, cast separately to the trafficked lane concrete base and keyed and tied to the base, with a minimum width of 1.5m outside the edge line.

?

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

Table 1: RFP Busway Pavement Design (No LRT) – Rigid Pavement: Tunnels and

Connection Ramps Layer Thickness (mm) 45 Material Asphalt surfacing CRCP Concrete Base Concrete Sub base Working platform

DG14 Asphalt 240 4.5 MPa characteristic flexural strength 150 Lean mix concrete (PSTS39 Aug 06 to apply) 150mm Unbound granular material (modified and with surface seal in accordance with PSTS101 Aug 06) The actual sub base type in tunnels and ramps will depend on supporting materials, drainage requirements and construction practices and may vary from that shown above. In particular, while not strictly conforming to PSTS39, it is likely that the lean mix concrete sub base will be replaced by no fines concrete where rock is exposed in the floor of the road header tunnel.

Table 2: RFP Busway Pavement Design (No LRT) – Rigid Pavement: Busway

Stations, Kedron Turnaround and Federation Street Bus Stop. Layer Thickness (mm) 240 Material CRCP Concrete Base Asphalt Seal Concrete Sub base Working platform Controlled subgrade 4.5 MPa characteristic flexural strength with dark oxide finish consistent with urban design 30 DG10 Asphalt 150 Lean mix concrete (PSTS39 Aug 06 to apply) 150 Unbound granular material (modified and with surface seal in accordance with PSTS101 Aug 06) Varies See section 1.5 (typically150-300mm)

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

All CRCP concrete bases will have longitudinal and transverse reinforcement. Longitudinal reinforcement should comprise 16mm diameter deformed reinforcing bars spaced at 110mm centres. The amount of transverse reinforcement within the base slab and across longitudinal joints will depend on the location of longitudinal joints, whether barriers will sit on the pavement slab and whether provision for the LRT is required and further advice will be provided when these details are known.

Table 3: RFP Busway Pavement Design (No LRT) – Rigid Pavement: Bus Stops. Layer Thickness (mm) 240 Material JRCP Concrete Base Concrete Sub base Working platform Controlled subgrade

4.5 MPa characteristic flexural strength with dark oxide finish consistent with urban design 150 Lean mix concrete (PSTS39 Aug 06 to apply) 150 Unbound granular material (modified and with surface seal in accordance with PSTS101 Aug 06) See section 1.5 Varies (typically150-300mm) Slab reinforcement will typically comprise F82 mesh (subject to slab length). Transverse joints between slabs will be dowelled with 32mm diameter plain round bars 450mm long at 300mm centres. The amount of transverse reinforcement across longitudinal joints will depend on the location of longitudinal joints, whether barriers will sit on the pavement slab and whether provision for the LRT is required and further advice will be provided when these details are known.

1.7

Preliminary Busway Pavement Assessment / Design ( No LRT ): Flexible Pavement Design Review

The RFP specifies that a granular pavement with an asphalt base and wearing course is to be used at the following locations; ? Busway lanes ? Bus-only lanes ? Turo Street Bus lane

The RFP specifies a flexible granular pavement design, which is presented in Table 4 overleaf together with our preliminary recommended design amendments (highlighted in bold) required for design life and anticipated subgrade conditions. The pavement design has been carried out using extrapolation of the design charts in the Austroads Pavement Design Manual and a mechanistic design will be carried out to confirm thickness requirements.

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

Table 4: RFP Busway Pavement Design (No LRT)– Flexible Pavement: Bus Lanes

(assumed subgrade CBR 3%) Layer Thickness (mm) 40 Material Asphalt wearing course Seal Asphalt base layer OGA 14 asphalt -- Not specified (nominal 50mm) Not specified (620mm total thickness) 150 Not specified (PMB seal with 10mm cover aggregate) Not specified DGA 14 with A15E binder Granular base Type 2 subtype 2.1 unbound granular base materials over Type 2 subtype 2.3 unbound granular sub base materials Not specified (assumed to be Type 2 subtype 2.5 unbound granular material) Required where sub grade is CBR <3%, See section 2 Working platform Capping materials

Varies It is expected that the above granular pavement will require significant maintenance works throughout its 40 year design life and is not recommended due to the potential for early distress. As an alternative, consideration should be give to the use of a Full Depth Asphalt (FDA) pavement instead. For comparison we have prepared a preliminary design profile for such a pavement as presented in Table 5 overleaf.

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

Table 5: Proposed Preliminary Pavement Profile (No LRT) – Flexible Pavement: Full

Depth Asphalt Pavement Layer Thickness (mm) 45 Material Asphalt wearing course Seal Size 14 polymer modified (A15E) DGA (PSTS30 Aug 06) -- Polymer modified seal with 10mm cover aggregate (PSTS11 Aug 06) Size 14 polymer modified (A15E) DGA(PSTS30 Aug 06 Asphalt binder layer Asphalt base layer 45 345mm Size 20mm DGA , class 320 binder (PSTS30 Aug 06) will require sub-layering for construction in accordance with PSTS30 Aug 06. Prime and seal Working platform Controlled sub grade -- To be designated but typically 0.9L/m2 C170 binder with 10mm stone (PSTS101 Aug 06) Unbound granular material modified with 2.0% cement by mass (PSTS101 Aug 06) See section 1.5 150 Varies (typically150-300mm) DGA – Dense Graded Asphalt

1.8 Incorporation of Light Rail within Busway

This preliminary assessment of the pavement requirements for light rail has assumed that, in general, it is undesirable to increase the thickness of the concrete base slab and therefore reinforcement must be provided to carry the additional stresses from the LRT. The basis for design is that the rails for the LRT are supported on the initially constructed pavement, with a topping slab to be applied to set the rails below the slab level and allow co-location of buses and LRT. It is understood that in the bus station area this method of construction will not be feasible and the pavement will be replaced. This discussion has therefore only considered the addition of the LRT on the CRC pavement outside the bus stations where the pavement is in the “with-shoulder” condition.

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

This preliminary design to cater for LRT has been based on the following loading as shown in RFP documents:

? bogie load – 22.2 tonnes maximum; ? two axles per bogie, spaced 1.6m apart;

? three axle groups (i.e., six axles) per vehicle, spacing not documented but assumed at

least 11m centre-to-centre. As the base pavement is CRCP, analysis has been based on consideration of an axle group within a slab (i.e., not close to a transverse joint). Based on the rail loading code for concrete rail sleepers, a dynamic load factor of 2.5 has been adopted. The pavement is designed for an unlimited number of passes of the LRT, based on a combined load and material factor of 2.0.

The stress analysis for this design is modelled as a raft slab supported on a layered elastic continuum, using the computer program FEAR. The sub base and subgrade are modelled as separate layers and the base is modelled as “plate element” finite elements, which can be expected to reasonably model bending behaviour. This model is preliminary in order to obtain indicative reinforcement requirements for preliminary costing purposes.

The maximum sagging bending moments in the base slabs derived from the above model for the 22.2tonne bogie load, are approximately 1.7 x 10-2 MN.m and 1.8 x 10-2 MN.m (per metre width) longitudinal and transverse, respectively. The maximum hogging moments are less than 20% of the sagging moments. When the dynamic load factor is included, the resulting stresses cannot be carried by the concrete tensile strength and so bottom face reinforcement is required.

For preliminary costing purposes, the additional reinforcement implied to cater for the passage of an LRT vehicle comprises 16mm Grade 500 deformed reinforcing bars on the bottom face at about 140mm centres both ways.

1.9

Reuse or Rehabilitation of Existing Pavements

Where it is required to widen existing surface roads the project brief currently requires that existing adjoining pavements are to be structurally strengthened for a design life equal to that of the new pavement. At this stage we understand that clarification is being sought to confirm whether this applies to the addition of a bus lane to existing surface roads pavements.

We recommend that if required, preliminary planning of existing pavement rehabilitation works may be carried out using the following;

? Where existing pavements are visually in good condition, the use of a minimum 85mm

asphalt overlay, preceded by proof rolling and a polymer seal underneath will be required. ? Where existing pavements are in visually poor condition it is expected that deeper

profiling and partial replacement of base course materials will be necessary together with an overlay. The actual design of pavement upgrade or rehabilitation works is based on the results of detailed pavement condition assessment inspections and deflectometer testing. At this stage we are not aware of any such works having been carried out on project roads and an RFI question for this information has already been submitted.

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

2 2.1

ASSUMPTION / DEPARTURES Design Traffic Loads

For specific details on the calculation of design traffic loads with respect to the design brief reference should be made to Section 1.4.1 of this report. In summary the assumption used for preliminary design work are as follows;

? As the results from the tender design traffic model are not yet available, Design

traffic has been derived by only considering the RFP supplied Busway design traffic in dedicated Busway and Bus only lanes. ? As project specific Traffic Load Distributions (TLD) for buses (i.e. the distribution of

types of axle groups and the distribution of loads on each type of axle group), has not been provided, the Busway traffic load distribution derived from weigh-in-motion data from a bus-only lane in the ACT has been used. We understand that this TLD has been used for other Busway projects in Brisbane. ? The number of heavy vehicle axle groups per vehicle (HVAG) is assumed to be 2.33.

2.2

Subgrade Conditions

At the present time there is little specific information available on pavement subgrade conditions throughout the study area so the following assumed subgrade design CBR values have been adopted for the purposes of preliminary pavement design;

? Road header tunnels: Bedrock floor, CBR >20%.

? Cut and cover tunnels and trough transition structures: Concrete base slab. ? Natural soils at grade or less than 1m of embankment fill: CBR 3%.

2.3

Incorporation of Light Rail within Busway

? This preliminary assessment of the pavement requirements for light rail has

assumed that, in general, it is undesirable to increase the thickness of the concrete base slab and therefore reinforcement must be provided to carry the additional stresses from the LRT. ? Spacing of LRT axle groups is not documented but has been assumed at least 11m

centre-to-centre as based on the supplied vehicle layout drawings ? Based on the rail loading code for concrete rail sleepers, a dynamic load factor of

2.5 has been adopted.

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Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

3

RISKS / OPPORTUNITIES

Pavement designs as presented in this report are in accordance with the requirements of the Brief. It is expected that thinner pavement sections may be developed to suit project traffic loadings but these designs will not be in conformance with Project Brief design requirements.

Lighter CRCP pavement reinforcement will be feasible if provision for possible future LRT traffic is not required for proposed Busway pavements.

4

OPERATION & MAINTENANCE

The pavement thickness designs have been checked in accordance with current prescribed design methods. Accordingly, maintenance expectations will be similar to those for the Airport Link concrete pavements which will be discussed in future reports.

5

SAFETY IN DESIGN

Safety issues influenced by the pavement thickness design would potentially relate to the type of surface required for operational purposes. As pavement surfacings have been specified in the Brief, it has been assumed that those surfacings are satisfactory for the Principal’s proposed use.

6

CONSTRUCTABILITY

The pavement thickness designs have been checked in accordance with current prescribed design methods. Accordingly, standard construction methods are expected to be adopted.

7

ENVIRONMENTAL IMPACTS & APPROVALS Nothing to report at this time.

8

ENVIRONMENTALAL SUSTAINABILITY Nothing to report at this time.

9

ADVANTAGES / DISADVANTAGES

The pavement types for Busways are prescribed in the Brief and are similar to those adopted elsewhere. Accordingly, no advantage or disadvantage is seen for these pavements.

10

OUTSTANDING INFORMATION / MATTERS FOR RESOLUTION

Where it is required to widen existing surface roads the project brief currently requires that existing adjoining pavements are to be structurally strengthened/rehabilitated for a design life equal to that of the new pavement. The applicability and extent of such strengthing works where Busway lanes will be added to exiting roads should be confirmed prior to detailed design and costing assessments.

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NorthConnect

Airport Link and Northern Busway Tender Design

Preliminary Advice on Northern

Busway Pavement

HYDER SMEC JV

At the present time there is little specific information available on pavement subgrade conditions throughout the study area. It is understood that limited CBR testing will be included in additional Stage 6 geotechnical investigations.

The assessment of design traffic loads for mixed use lanes, i.e. Busway and general road traffic, will be carried out following the completion of project specific traffic modelling by other members of the tender design team.

It is expected that a project specific Traffic Load Distribution (TLD) for Busway traffic will not be developed during tender works and as such we will continue to use the presumptive TLD as discussed in Section 1.4.2 of this report

11

RECOMMENDATIONS

Not additional to currently report under this heading.

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