City of Mandurah
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of
the Bridge
July 2011
Contents
1.
2.
3.
4.
5.
6.
7.
8.
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Introduction
1
1.1
General
1
1.2
Scope of Report
2
Existing Bridge Information
4
2.1
Existing Bridge Details
4
2.2
Reference Information
4
2.3
Site Inspection
4
2.4
Existing Bridge Condition
5
Details of Refurbishment Works for Each Option
6
3.1
Introduction
6
3.2
Option 1 – Upgrade bridge capacity to 100% T44
6
3.3
Option 2 – Retain existing 17 tonne load limit
9
3.4
Option 3 – Convert to a pedestrian footbridge (5kPa load limit)
10
Future Maintenance Requirements
12
4.1
Expected Remaining Life of Bridge
12
4.2
Specific Future Maintenance Works
12
Cost Estimates
14
5.1
Refurbishment Options
14
5.2
Bridge Replacement
14
Whole of Life Cost Comparison
15
6.1
Introduction
15
6.2
NPV Analysis Qualifications
15
6.3
NPV Analysis Assumptions
16
6.4
Summary of Results
17
Non-Financial Considerations
18
7.1
Heritage
18
7.2
Bridge Standards and Safety
18
7.3
Comparison of Construction Impacts
19
Conclusions
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Figure Index
Figure 1: Locality Plans (not to scale)
Appendices
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A
Schedule of Stringer Repairs
B
Cross-sections for Existing Bridge and Refurbishment
C
Cost Estimates for Refurbishment Options 1, 2 and 3
D
Whole of Life Cost Analysis
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Economic Viability Assessment for Replacement of the Bridge
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1.
Introduction
1.1
General
Bridge No. 230, known as Old Mandurah Traffic Bridge, carries Pinjarra Road over the
Mandurah Estuary providing a link from Mandurah City and Commercial Centre on the
east side to residential and coastal areas on the west side (refer to the location plan
below-left and an enlargement on the right), and is used by approximately 20,000
vehicles per day.
Bridge No. 230
Bridge No. 230
Figure 1: Locality Plans (not to scale)
The existing bridge was constructed in 1953, and has a concrete substructure and a
predominately timber superstructure, except for the navigation spans which consist of
steel beams. The bridge is substandard in relation to current design standards in a
number of areas, including load capacity, traffic lane widths and shared path width.
The bridge is also suffering increasing rates of deterioration to the timber
superstructure and concrete substructure, which may require increasing inspection and
maintenance costs.
The City of Mandurah is planning for replacement of the bridge, and a draft concept
design report has been prepared previously by AECOM, which outlines options for the
replacement of the bridge in order to facilitate stakeholder and public consultation.
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In order to support and further inform the decision making and public consultation
processes, further investigation was required of the available options to refurbish the
existing bridge and extend its service life, including estimation of the associated
construction costs and future maintenance costs to refurbish and maintain the existing
structure. GHD were engaged by the City of Mandurah to carry out an economic
viability assessment for the replacement of the bridge.
1.2
Scope of Report
This report presents the preliminary designs for several options to refurbish the existing
bridge and extend its service life, and compares the estimated costs for these to the
costs associated with a new replacement bridge. The comparison take into account
whole of life costs including estimated on-going maintenance and also the eventual
replacement at the end of the service life for the refurbished bridge. In addition there
are non-financial considerations in comparing the refurbishment against the
replacement of the bridge which are also discussed.
The bridge replacement option used for the cost comparisons is based on the
incrementally launched option from the concept design report by AECOM. This
concept was for a bridge carrying 3 lanes of traffic, which is wider than the existing
bridge and understood to be the preferred configuration for the bridge replacement. An
additional replacement option for a 2 lane bridge as per the existing bridge
configuration has also been included in the whole of life cost comparison, as it provides
a more direct comparison to the existing bridge for assessment of replacement vs
refurbishment.
1.2.1
Preliminary Refurbishment Designs
The preliminary design of the bridge refurbishment has been carried out for 3 options:
Option 1 – Retain the existing bridge and construct a new reinforced concrete
overlay and associated repairs to improve capacity to 100% T44 and Group 1 (road
train) vehicles. Significant ongoing maintenance is also expected for the bridge to
maintain this capacity.
Option 2 – Retain the existing bridge and construct a new reinforced concrete
overlay and associated repairs to maintain the current 17 tonne capacity. Ongoing
maintenance is expected for the bridge to maintain this capacity.
Option 3 – Retain the existing bridge and convert it to a pedestrian-use footbridge
only. Some ongoing maintenance and repairs will still be required.
Full details of the anticipated refurbishment works for each option are included in
Section 3 and future ongoing maintenance in Section 4.
1.2.2
Cost Estimates
For each of these options, cost estimates for the construction of the refurbishment
works have been prepared, as well as cost estimates for anticipated future
maintenance works over the remaining life of the bridge.
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Details of the cost estimates are discussed in Section 5.
1.2.3
Whole of Life Cost Assessments
The costs including ongoing maintenance for each option have been compared to the
cost for replacement of the bridge using a Net Present Value (NPV) analysis. The
NPV analysis has been carried out over a 30 year time period. The details are
discussed in Section 6.
1.2.4
Non-Financial Considerations for Refurbishment vs Replacement
There are many other assessment criteria other than cost on which to compare the
refurbishment options against the replacement of the bridge. Replacement of the
bridge will provide many other benefits in addition to reduction of future maintenance,
and conversely there are also other arguments in favour of retaining the existing
bridge. A brief comparison of the refurbished bridge against a replacement bridge has
been undertaken on several criteria, and is presented in Section 7.
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2.
Existing Bridge Information
2.1
Existing Bridge Details
The existing bridge is approximately 186m long from abutment to abutment and has 23
spans, comprising 21 spans of approximately 7.6m with timber stringers and decking,
and 2 navigation spans of approximately 12m with steel beams supporting timber
bearers and decking. There are a number of timber and steel stringer strengthenings
that have been added over time between the original timber stringers, as well as
replacement steel stringers.
The bridge substructure comprises concrete piles with a concrete headstock at the
piers and concrete walls at the abutments. Fishing platforms located below the bridge
are supported on concrete corbels integrated into the piles.
The deck has an existing reinforced concrete overlay, which according to MRWA
records was constructed in 1987. The overall bridge width is 9.17m, with a road
carriageway width of 6.7m between kerbs, and a separate footpath approximately
1.75m wide. The guardrails comprise w-beam with timber posts for both sides of the
roadway and also at the edge of the footpath.
There are a number of services located on the bridge running below the footpath or
cantilevered from the piers. For the refurbishment of the bridge, these can generally
be retained in their current positions, but they have not been specifically investigated
as part of this report. Confirmation of the services requirements will need to be
obtained prior to detailed design of any major refurbishment works.
The bridge currently has a posted load limit of 17 tonnes.
2.2
Reference Information
The following reference information has been used to develop the refurbishment work
scopes, prepare cost estimates and undertake the NPV analysis.
Project brief issued by email dated 1/11/2010 to M. Jones of GHD;
Concept Report for Replacement of Bridge 230 (Draft), AECOM, September 2010
(Document no. 60103037.215.R01);
Existing bridge drawings supplied by MRWA;
Timber Bridge Detailed Inspection Reports (DIR) prepared by MRWA;
Cost data on previous bridge repairs and maintenance undertaken by City of
Mandurah;
2.3
Site Inspection
An inspection of the bridge was undertaken on the 19th November 2010 by Matthew
Jones and Nicholas Meyer of GHD, following a project kick-off meeting with Michael
Gunton from City of Mandurah.
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The purpose of the inspection was to review the latest MRWA DIR for the bridge while
on site and gain a better understanding of the work scope for the various bridge
refurbishment options.
2.4
Existing Bridge Condition
Based on the site inspection and review of the latest MRWA DIR, the bridge condition
can be summarised as follows:
Several of the timber stringers are showing signs of deterioration, however, based
on the latest MRWA Timber Bridge Detailed Inspection Report (DIR) and
subsequent load rating by MRWA, they are all currently still adequate for the 17
tonne load limit;
The steel beams and bracing in the navigation spans are showing signs of
corrosion and the original protective coating appears to be approaching the end of
its life;
There are numerous observed areas of minor concrete spalling to the piles or
headstocks and cracking to some of the concrete piles. There is no detailed
condition survey or testing information available from which to confirm the likely
cause of cracking or the extent of any chloride contamination of the concrete, and
accordingly the rates for future deterioration can be accurately estimated at this
stage.
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3.
Details of Refurbishment Works for Each Option
3.1
Introduction
The required refurbishment works for each of the three proposed options are listed in
the sections below. The refurbishments works are divided into initial repairs and
refurbishment works, which will comprise the initial capital expenditure to upgrade the
bridge and extend its service life, and future maintenance, which will be required to
keep the bridge in service. Due to the age of the bridge and its nature as a timber
structure, there will be significant ongoing maintenance expenditure required in
comparison to a full replacement structure.
A summary schedule of the anticipated timber stringer replacements that will be
required for each refurbishment option, and possible numbers of replacements in the
future as the bridge continues to deteriorate is included in Appendix A.
Typical cross-section sketches of the existing bridge and the proposed refurbishment
options are included in Appendix B.
It should be noted that the design for the refurbishments has only been carried out to a
preliminary level, in order to develop a scope for the works for the purpose of preparing
comparative cost estimates. Only a few of the spans have been load rated, and
stringer replacements for other spans have simply been estimated by extrapolation.
The extent of concrete substructure repairs has also been assumed based on currently
available visual inspection information. Further investigation of concrete condition and
structural analysis of all spans would be required if any of the refurbishment options
are to be investigated and documented in greater detail.
3.2
Option 1 – Upgrade bridge capacity to 100% T44
This option will provide a replacement of the reinforced concrete overlay(RCO) which
will upgrade and extend the life of the current superstructure, together with
strengthening and replacement of the stringers in the timber spans and the navigation
spans to upgrade the load capacity from 17 tonnes to full capacity for T44 loading and
MRWA Group 1 vehicles (ie road train combinations).
As part of this option, the guardrails will be upgraded to the current standard for
Regular Performance Level to AS5100, and MRWA standard pedestrian balustrade will
be installed along the footpath edge. The width of the road carriageway will also be
increased to 7.2m between kerbs, which will accommodate two 3.0m wide traffic lanes
with 0.6m wide shoulders. Note however, that the current standard width for a new
bridge with around 20,000 vehicles per day would be 3.5m wide lanes and a minimum
width of 8.2m between kerbs, so the upgraded bridge will still be below the standard
required for a replacement bridge. This width cannot be accommodated on the
existing bridge without significant modification and strengthening.
The preliminary design refurbishment works for this option are as follows:
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3.2.1
Substructure Repairs
Reinforced Concrete Piles (including fishing platform corbels)
Construct a reinforced concrete encasement repair to an estimated 22 piles (1 pile
per pier). This is based on the number of piles exhibiting signs of cracking and
spalling, plus allowance for additional piles due to possible chloride contamination
which could result in deterioration in the future (this would need to be confirmed by
detailed condition assessment prior to a detailed design). Each encasement repair
shall extend from 1m below to 3m above the low water level and will also breakout
of defective concrete and installation of a sacrificial anode system to the
reinforcement. Temporary propping at each pier may be required during these
works and has been allowed for in cost estimates.
Some of the piles to be encased may have corbels supporting the fishing platform.
It is assumed that these will generally be recreated as part of the encasement detail
(actual details and modifications to fishing platforms not part of the scope at this
stage).
Apply a silane treatment to 100% of all pile surfaces above the high water level
including 100% of all encasement repair surfaces above the high water level. (This
treatment shall comprise Emer-Stop Crème applied in accordance with
manufacturer’s recommendations or similar).
Reinforced Concrete Capbeams (including stair & stringer corbels)
Conduct concrete patch repairs to an estimated 22m 2 (approximately 0.5m2 on
each side of each headstock beam).
Apply a silane treatment to 100% of all headstock surfaces.
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3.2.2
Superstructure Repairs
Timber Stringers
Replace an estimated 15 timber stringers with new steel beams (410UB60 grade
300), in accordance with MRWA Specification 850 Clause 850.33. New stringers
will generally be supported on existing concrete corbel at each end.
Install an estimated 10 new steel beams (410UB60 grade 300) as additional
strengthening stringers between existing stringers near edges of the carriageway, in
accordance with Specification 850 Clause 850.33.
Navigation Spans
Remove the existing bracing in each of the 2 navigation spans.
Abrasive blast and recoat the existing steel beams with a new protective coating.
Allow for access scaffold and encapsulation during blasting, with construction one
span at a time to allow navigation access. Each beam is a 24”x7.5”x95lbs/ft RSB
and there are 5 beams in each span (10 beams in total). Refer existing drawing for
typical navigation span details.
Install 3 new 700WB150 in each navigation span (6 new beams in total) to
strengthen the spans.
Install new bracing.
Reinforced Concrete Overlay
Demolish the existing overlay and construct the new overlay in two halves, allowing
one lane of traffic to be open at all times.
Remove the timber decking along both edges of the carriageway as per typical
cross-section detail and replace with permanent Bondek formwork. Remove all
timber decking, joists and bearers below the existing footpath overlay and replace
with Bondek formwork.
Prepare the remaining timber decking in accordance with MRWA Specification 850
Clause 850.41. Replace any timber planks that are found to be in a poor condition
after the overlay is removed with Bondek and concrete (replace an estimated 5
planks per span for full width).
Cut-out the top corners of each abutment to allow for the construction of the new
wider RCO.
Construct the new RCO with a minimum thickness of 145mm and a 2-way crossfall.
At each end of the new RCO, remove the last 4 deck planks and construct a new
sill beam to support the end of approach slabs.
Provide a 100mm UPVC downpipe on each side of the carriageway at the mid-span
of each span. Also provide a downpipe for the footpath on each span.
Apply a 40mm asphalt seal on the overlay within the carriageway.
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3.2.3
Approach Slabs and Expansion Joints
Demolish the existing approach slabs and expansion joints and construct the new
approach slabs and expansion joints in two halves, allowing one lane of traffic to be
open at all times.
Construct two new approach slabs, each having a length of 5m. Construct a new
footpath slab alongside each new approach slab.
Include steel nosing along the edges of the two expansion joints and install a Wabo
compression seal or similar in each expansion joint.
Apply 40mm asphalt seal on each approach slab.
3.2.4
Guardrails
Guardrails on the Bridge
The existing timber guardrails shall be upgraded to meet the current MRWA barrier
standards.
Remove the existing timber guardrails on both the carriageway and the footpath.
Install a regular performance level guardrail, with top rails (4 rails in total), on each
side of the carriageway. Mount the guardrails on the top of the kerbs of the new
RCO using cast-in anchor bolts. Guardrails will extend to the end of approach
slabs.
Install a MRWA standard balustrade along the footpath edge to the ends of the
approach slabs.
Guardrails on the Approaches
The new deck is wider than the existing deck, and therefore the existing guardrails on
the approaches will need to be replaced.
Install a W-beam guardrail, with an ET2000 extruder terminal, on each side of each
approach slab. The total length of each approach guardrail shall be 22.5m.
Install thriebeam transition segments to join the bridge guardrail at the end of the
approach slabs, as per MRWA standard drawings.
Alternative guardrail end treatments could also be considered, however the above is a
standard MRWA end treatment which has been used for preliminary costing purposes.
3.3
Option 2 – Retain existing 17 tonne load limit
This option will provide a replacement of the reinforced concrete overlay (RCO) which
will upgrade and extend the life of the current superstructure, however, the current load
capacity of 17 tonnes will be maintained which reduces the extent of stringer
replacement and strengthening works required.
As part of this option, the guardrails will be upgraded to the current standard for
Regular Performance Level to AS5100, and MRWA standard pedestrian balustrade will
be installed along the footpath edge. The width of the road carriageway will also be
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increased to 7.2m between kerbs, which will accommodate two 3.0m wide traffic lanes
with 0.6m wide shoulders. Note however, that the current standard width for a new
bridge with around 20,000 vehicles per day would be 3.5m wide lanes and a minimum
width of 8.2m between kerbs, so the upgraded bridge will still be below the standard
required for a replacement bridge. This width cannot be accommodated on the
existing bridge without significant modification and strengthening.
The preliminary design refurbishment works for this option are as follows:
3.3.1
Substructure Repairs
The same works as for Option 1 applies. Refer Section 3.2.1.
3.3.2
Superstructure Repairs
Stringers
No stringers replacements or additional stringers are required.
Navigation Spans
The same works as for Option 1 applies (refer Section 3.2.2) except that:
No additional steel beams are required.
Retain existing bracing.
Reinforced Concrete Overlay
The same works as for Option 1 applies. Refer Section 3.2.2.
3.3.3
Approach Slabs and Expansion Joints
The same works as for Option 1 applies. Refer Section 3.2.3.
3.3.4
Guardrails
The same works as for Option 1 applies. Refer Section 3.2.4.
3.4
Option 3 – Convert to a pedestrian footbridge (5kPa load limit)
This option will provide a replacement of the reinforced concrete overlay (RCO) which
will upgrade and extend the life of the current superstructure, however, it will not
require any widening and its load capacity can be downgraded for a pedestrian only
structure. A lot of the repair works to deteriorating members from the other options is
still included however, as it is still required to extend the life of the bridge and maintain
it in a serviceable condition.
The preliminary design refurbishment works for this option are as follows:
3.4.1
Substructure Repairs
The same works as for Option 1 applies. Refer Section 3.2.1.
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3.4.2
Superstructure Repairs
Stringers
No stringers require replacement.
No additional steel beams are required.
Navigation Spans
The same works as for Option 1 applies (refer Section 3.2.2) except that:
No additional steel beams are required.
Retain existing bracing.
Reinforced Concrete Overlay
Similar works to Option 1 still applies (refer Section 3.2.2), except that:
The full width of the bridge shall be refurbished in one stage, rather than in two
halves.
No cut-outs of either abutment are required as the width of the existing bridge shall
be maintained.
The new RCO shall have a minimum thickness of 130mm.
No asphalt seal is required.
Details are as per sketch cross-section for Option 3 in Appendix Appendix B.
3.4.3
Approach Slabs and Expansion Joints
No new approach slabs or expansion joint are required after demolition of existing.
3.4.4
Guardrails
A new MRWA standard balustrade shall be installed on each side of the bridge.
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4.
Future Maintenance Requirements
4.1
Expected Remaining Life of Bridge
The remaining life of the existing structure is difficult to estimate without a detailed
condition assessment. With ongoing repairs and maintenance to the piles and
stringers as outlined in this report, the remaining life will be controlled by the timber
decking and replacement overlay, and the portion of the piles below the waterline
which are not encased as part of the repairs.
The piles below the water would be expected to have a reasonably long remaining life,
due to the absence of oxygen at that level. This would need to be confirmed by a
detailed investigation in case there were other issues that are not apparent with the
currently available information.
The superstructure after construction of a new RCO would normally be expected to last
for up to 30 years, subject to detailed inspections every 5 years and
replacement/maintenance of any stringers or other elements that deteriorate over this
time. Further assessment of the remaining life of the decking and RCO beyond 30
years would need to be undertaken at that time.
4.2
Specific Future Maintenance Works
In order to carry out a whole of life cost comparison between the refurbishment options
and a new replacement bridge, estimates have been made of the likely future
maintenance required to keep the refurbished bridge in service over its expected 30
year remaining life.
These estimates assume that the works in Section 3 have already been carried out.
They have been based on estimation of the future rate of deterioration, based on
judgement, previous experience and comparison of stringer conditions in the previous
three MRWA Timber Bridge Detailed Inspection Reports to gauge the previous rate of
deterioration. They should be used for comparative purposes only.
In order to accurately assess the maintenance requirements, a detailed condition
assessment of the bridge components (e.g. type, severity & extent of defects and
quantification of deterioration mechanisms such as rot in timber, carbonation and
chloride penetration in concrete) would be required.
4.2.1
Option 1
Substructure Maintenance
In 10 years’ time, assume:
10 piles will require a concrete encasement repair.
2
22m of capbeam surface concrete will require patch repairs.
In 20 years’ time, assume:
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10 piles will require a concrete encasement repair.
22m2 of capbeam surface concrete will require patch repairs.
Superstructure Maintenance
In 10 years’ time, assume:
30 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
In 20 years’ time, assume:
20 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
The steel beams in the navigation spans will require another blast and re-coat.
4.2.2
Option 2
Substructure Maintenance
See 4.2.1
Superstructure Maintenance
In 10 years’ time, assume:
20 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
In 20 years’ time, assume:
10 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
The steel beams in the navigation spans will require another blast and re-coat.
4.2.3
Option 3
Substructure Maintenance
See 4.2.1
Superstructure Maintenance
In 10 years’ time, assume:
10 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
In 20 years’ time, assume:
10 timber stringers will need to be replaced with new steel beams (410UB60 grade
300).
The steel beams in the navigation spans will require another blast and re-coat.
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5.
Cost Estimates
5.1
Refurbishment Options
Cost estimates have been prepared for the proposed refurbishment option works and
are included in Appendix C. They have been prepared by a Quantity Surveyor and are
based on the costs for similar previous works, with allowance for escalation to 2010. A
contingency amount of approximately 15% is included, and allowances have also been
made for design fees and project management costs.
Cost estimates for anticipated future specific maintenance are also included. Note that
these have all been estimated at 2010 rates.
Conditions and exclusions applicable to the cost estimates are included within the
Appendices.
5.2
Bridge Replacement
The cost of the bridge replacement was estimated as $25 million based on the
incrementally launched, 3-lane option from the AECOM Concept Design Report.
Review of this cost estimate was not part of the scope for this report. The cost for the
2-lane bridge replacement option used as a more direct comparison to the existing
bridge was calculated on a pro-rata basis based on the approximate deck area.
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6.
Whole of Life Cost Comparison
6.1
Introduction
The three refurbishment options outlined in this report have been compared to the
alternative of replacing the bridge with a new incrementally launched structure as per
the AECOM Concept Report. The comparison has been made based on the future
costs associated with each option over a period of 30 years, calculated as a net
present value (NPV) by using appropriate discount & inflation rates.
The basis and qualifications for these calculations are outlined in the following sections
and a summary of the NPV results and sample spreadsheet showing the calculations
for one inflation and discount rate scenario are included in Appendix D.
6.2
NPV Analysis Qualifications
The NPV calculations are directly related to the discount rate of return and inflation rate
applicable over the duration of the analysis. A number of assumptions and
qualifications are used to select the rates used in analysis as detailed below.
According to basic financial theory, projects which yield a negative NPV are generally
rejected. Since an upgrade to or replacement of the existing bridge does not yield a
quantifiable return on the invested capital, the option with the highest/least negative
NPV is considered the optimal.
6.2.1
Inflation Rate
Inflation rates have been assumed by inspection of rates over the last 20 years from
data obtained from the Reserve Bank of Australia. For the majority of the last twenty
years, the inflation rate has been confined to a band of between 2 – 3.5% with
occasional spikes to around 4%.
Since the inflation rate is very difficult to fine-tune within a narrow range, rates of 2%,
2.75% and 3.5% have been used for analysis.
6.2.2
Discount Rate
For the purposes of analysis, the discount rate has been assumed to be constant over
the duration of the NPV analysis.
A typical approach in choosing the discount rate is assessing the opportunity cost. The
discount rate can be considered as the rate at which the capital required for the bridge
could return if invested elsewhere.
Discount rates of 6%, 7.5% and 9% have been used for analysis. It should be noted
that NPV calculations are very sensitive to the discount rate of return used in analysis.
Additionally, the discount rate does not include an adjustment for risk. Therefore, the
lower bound discount rate of 6% is a conservative rate assuming low risk whereas a
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9% discount rate implies that the alternative investment has a more significant degree
of risk attached.
6.2.3
Whole of Life Cost Comparison
The NPV analysis has been conducted over a period of 30 years. Since the discount
and inflation rates are difficult to predict and are unlikely to be constant throughout the
30 year period, a sensitivity analysis has been completed using combinations from the
range of values noted above to produce nine separate scenarios. Conservative
scenarios using the lowest discount rate, highest inflation rate and a decrease in the
capital cost of the bridge replacement, or an increase in the Option 1 and 2
refurbishment and maintenance costs have also been compared as an additional
scenario to test the sensitivity of the NPV to these cash flows. Results are included in
the summary spreadsheet included in Appendix D.
6.3
NPV Analysis Assumptions
6.3.1
Cost of Capital
Option 1: The capital cost comprises substructure repairs, superstructure repairs,
construction of approach slabs and replacement of guardrails. The life of the bridge
after refurbishments is assumed to be 30 years, at which point a new bridge will
need to be constructed at a cost of $25 million as noted in Section 5.2.
Option 2: The capital cost is as above for Option 1, except that slightly reduced
scope and refurbishment costs applies.
Option 3: Since the existing bridge would be converted to a pedestrian-only
footbridge, a traffic bridge would still need to be constructed. For the analysis it has
been assumed that this bridge will cost $25 million and would be constructed in five
years’ time. There has been no reduction in cost for the new bridge by considering
a small reduction in width that could be possible by leaving out a footpath.
Option 4: The capital cost for the new, 3-lane bridge is $25 million as noted in
Section 5.2. The life of the new bridge after completion is assumed to be 100 years.
The AECOM Concept Report details the list of exclusions from the estimated capital
cost (also listed in the NPV analysis spreadsheets). The report notes that this cost
has been assumed from a base rate per square metre for the bridge and is a
preliminary cost estimate only.
Option 5: The capital cost for the new, 2-lane bridge is $19.5 million and was
calculated by applying the square metre rate from the AECOM Concept Report to
the reduced deck area, as noted in Section 5.2. The life of the new bridge after
completion is assumed to be 100 years. The exclusions from capital cost are as per
Option 4 above.
6.3.2
Future Maintenance
Future maintenance works required for the bridge for each option have been detailed
in Section 4 and are based on the assumptions and limitations outlined in that Section.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
16
For Options 1, 2 and 3, additional allowance for routine maintenance expenditure of
$50,000 every 5 years has been made, which would cover inspections, timber
preventative treatment and minor repairs. For Options 3, 4 & 5 some general
maintenance comprising a detailed condition assessment for the new bridge has been
included on a 10 year cycle.
6.4
Summary of Results
It can be seen from the spreadsheet summary table in Appendix D that Option 5
(replacement of bridge with 2-lane structure) has the most favourable (highest) NPV for
a low discount rate and Option 2 (retain bridge at existing capacity) has the highest
NPV for a high discount rate. For the medium discount rate of 7.5%, the NPV of
options 2 and 5 are quite close with Option 2 yielding the highest NPV at lower inflation
rates, and the order reversing for a high inflation rate scenario.
There is also not a great deal of difference between Options 1 and 2 and the decision
between these would come down to the operational desirability of upgrading the bridge
capacity.
Option 4 (replacement 3-lane bridge) has lower NPV than Option 5 in all scenarios due
to the extra cost for the wider bridge, but does become competitive with Options 1 & 2
when using the lowest discount rate and higher inflation as per Scenario 3. For Option
4 to yield the highest NPV with these rates (excluding Option 5), the replacement cost
needs to be reduced to $21 million or the refurbishment and future maintenance costs
for Options 1 & 2 need to be slightly increased.
In every scenario the NPV for Option 3 is the lowest and least competitive.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
17
7.
Non-Financial Considerations
Note this section is not intended to be exhaustive, but is to recognise that there are
many other criteria other than whole of life costs on which to compare the
refurbishment and replacement options, and to prompt further discussions.
7.1
Heritage
A detailed heritage assessment is outside the scope of this report, however, the
existing bridge and fishing platforms have been a long-standing icon for the City of
Mandurah due to its prominent location, and heritage issues will need to be considered
in the final assessment of refurbishment and replacement options.
A further option, which was not considered as part of the whole of life cost assessment
in this report, would be to construct a new bridge but retain several spans of the
existing bridge and fishing platform, together with appropriate interpretation facilities.
It should be noted that after construction of a new RCO, replacement of several
stringers with steel, and upgrade of guardrails and other elements to current standards
as per the scope of Options 1 and 2, the bridge will be significantly modified from its
original state. Retaining several spans as a heritage display (and not a functional
traffic bridge) would provide the opportunity to restore those spans to original condition
with a fully timber superstructure.
7.2
Bridge Standards and Safety
Although the refurbishment options have been directly compared to the replacement
bridge in the whole of life cost analysis, there are significant improvements to the
standards for a new bridge. These should be taken into account when making any
value for money judgements from the net present value analysis results.
The new bridge will have a design life of 100 years minimum compared to only 30
years for the refurbishment of the existing bridge;
The new bridge will be designed to the current design loading from AS5100 Bridge
Design (i.e. full SM1600 traffic loading). A refurbished bridge will only cater for T44
loading which is the standard from the now superseded Austroads 1992 Bridge
Design Code (and this applies for Option 1 only).
The capital expenditure for the new bridge (Option 4) on which the whole of life cost
assessments were based is for a 3 lane structure with standard width 3.5m lanes
which will provide greater traffic capacity. The refurbishment Options 1 and 2 will
provide 2 lanes only with 3.0m wide lanes plus a shoulder. It should be noted that
the option of a new 2-lane bridge (Option 5) was comparable to retaining the
existing structure (Option 2).
The new bridge will provide the opportunity to improve the navigation span
clearances.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
18
The new bridge will be a more modern structure with improved aesthetics, although
this is a highly subjective judgement and there are also heritage issues to be
considered.
7.3
Comparison of Construction Impacts
Construction of the refurbishment works for Options 1 and 2 would require closure of
the road to traffic, or at the very least reduction to a single narrow lane which will still
cause disruption (and be required for a longer construction period than a full closure).
The replacement of the bridge would be on a new alignment which would allow the
existing road and bridge to remain open, except possibly for a short period when tying
in the new alignment to existing approach roads. There would be minimal impacts on
estuarine traffic for the replacement bridge construction as outlined in the AECOM
report.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
19
8.
Conclusions
Preliminary designs for several refurbishment options have been prepared, and
comparatively assessed on a whole of life cost basis to the cost of a new incrementally
launched bridge.
The refurbishment of the existing bridge is expected to result in a remaining life of up to
30 years, subject to detailed inspections every 5 years and ongoing replacement and
maintenance of any stringers or other elements that deteriorate over this time.
The initial capital costs for refurbishment of the existing bridge as per Options 1 and 2
are lower than the cost for a replacement bridge (with either 2 or 3 lanes). When
whole of life costs are taken into account using a net present value analysis, the
difference between refurbishing and replacing is reduced, and replacement with a new
2-lane bridge (Option 5) is shown to be more favourable for scenarios with a low
discount rate, while Options 1 and 2 are still slightly more favourable for scenarios with
a high discount rate. For a unique scenario where the discount rate is low, inflation
rate is high, and refurbishment and maintenance costs are slightly increased above the
current cost estimates, it can be shown that the replacement with a 3 lane bridge
(Option 4) is also more favourable that Option 1 and 2.
Option 3 (constructing a new bridge and maintaining the existing bridge for pedestrian
use only) is significantly less competitive than the others.
The replacement of the existing bridge does offer significant improvements in nonfinancial areas including improved standards for load capacity, traffic capacity in the
case of a new 3-lane bridge, safety, and the reduction in the need for ongoing
inspections, monitoring and maintenance.
The final selection of the preferred bridge upgrade option will depend on an
assessment of all financial and non-financial considerations together with the results of
consultation of the community and relevant stakeholders.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
20
Appendix A
Schedule of Stringer Repairs
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
Old Mandurah Traffic Bridge
Job no.
61/26421
STRINGER REPLACEMENT SCHEDULE
Based on MRWA DIR 11/12/09 and GHD site inspection 19/11/10
Original
Construction
Current
# New steel UBs required
Span
# Timber
# Timber
# Steel UB
# Total
Load Rated
Option 1
T44
Option 2
17t
Option 3
5kPa
Current Poor
Condition
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
10
13
13
11
12
12
11
13
11
10
10
12
10
10
9
12
11
12
13
13
13
3
1
0
3
1
1
1
0
2
1
1
1
1
3
2
0
2
0
1
2
2
13
14
13
14
13
13
12
13
13
11
11
13
11
13
11
12
13
12
14
15
15
Yes
0
0
0
Yes
0
0
0
Yes
Yes
Yes
2
2
2
0
0
0
0
0
0
Yes
0
0
0
2
1
0
0
2
0
1
1
1
5
2
1
2
3
1
3
2
2
6
2
1
189
241
28
6
24
0
0
0
0
Totals:
23
269
Total for 6 rated spans:
Estimated total for 23 spans:
Notes
1
2
The spans that were selected for load rating included the critical stringers that were identified
in the MRWA DIR and from the GHD site inspection
The 'number of new steel UBs required' includes those required for replacement and addition
38
Appendix B
Cross-sections for Existing Bridge and
Refurbishment
Note:
Cross sections are based on preliminary design only and are
intended to indicate the extent of the proposed replacement
reinforced concrete overlays and guardrail arrangement.
Existing or proposed stringer replacements or strengthening
are not shown.
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
Appendix C
Cost Estimates for Refurbishment Options
1, 2 and 3
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
PRELIMINARY COST PLANNING
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
Economic Viability Assessment for Refurbishment
Contract No: Unknown
Job No.: A2448
21 December, 2010
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
Economic Viability Assessment for Replacement
CONDITIONS & EXCLUSIONS
1.00 This Cost Indication is conditioned as follows:
1.01 These prices are current as at January 1, 2010
and are based on the rate currently used in
similar contracts for MRWA
1.02 Escalation of cost has been incorporated up to
December 31, 2009
1.03 This cost indication is accurate within the
following range:
1.04 The percentage cost of General Items Etc is
based on the percentage cost of similar MRWA
Projects over the last 12 Months
1.05 The Percentage cost for Contingencies is
based on a percentage similar to that on similar
MRWA Projects over the last 12 months
2.00 This Cost Indication excludes the cost of the following:
2.01 Removal of asbestos
2.02 Any necessary excavation in rock
2.03 Any removal and replacement of unsuitable materials
2.04 The value of Principal supplied items including
searching for and stockpiling of embankment
construction and pavement construction
materials
2.05 Allowances of accelerated construction periods
2.06 Holding Costs and interest charges
2.07 Time extension costs
2.08 Legal fees
2.09 Relocation of services other than those
indicated in the Cost Indication Details
2.10 Allowances for charges and costs levied by
Authorities, Councils and Service Bodies
* See Below
2.11 Aboriginal heritage, cultural and native title
issues
2.12 Redevelopment work of surplus land prior to
disposal
2.13 Loss of business claims
2.14 Increased costs due to labour shortages in the Region
2.15 Increase in tender prices due to the current over supply of work for Contractors
*
Please note: It is no longer Davson+Ward Pty
Ltd Company Policy to nominate limits of
accuracy due to the current economic climate
DAVSON+WARD Pty. Ltd.
Summary
Quantity Surveyors Construction Cost Consultants
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
Economic Viability Assessment for Replacement
SUMMARY
OPTION 1 - Upgrade bridge capacity to 100% T44
2.1 Substructure Repairs
$2,030,477.70
2.2 Superstructure Repairs
$5,166,404.18
2.3 Approach Slabs and Expansion Joints
$494,159.07
2.4 Guardrails
$921,904.96
$8,612,945.92
2.5 Future Specific Maintenance
2.5.1.1 - Substructure - 10 Years
$658,763.20
2.5.1.2 - Substructure - 20 Years
$658,763.20
2.5.2.1 - Superstructure - 10 Years
$187,357.22
2.5.2.2 - Superstructure - 20 Years
$259,211.06
OPTION 2 - Retain existing 17 tonne load limit
3.1 Substructure Repairs
$2,030,477.70
3.2 Superstructure Repairs
$4,783,694.05
3.3 Approach Slabs and Expansion Joints
$494,159.07
3.4 Guardrails
$921,904.96
3.5 Future Specific Maintenance
3.5.1.1- Substructure - 10 Years
$658,763.20
3.5.1.2 - Substructure - 20 Years
$658,763.20
3.5.2.1 - Superstructure - 10 Years
$124,904.81
3.5.2.2 - Superstructure - 20 Years
$196,758.66
Manduralh Bridge Refurbishment
Summary
$8,230,235.78
DAVSON+WARD Pty. Ltd.
Summary
Quantity Surveyors Construction Cost Consultants
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
Economic Viability Assessment for Replacement
OPTION 3 - Convert to a pedestrian footbridge (5kPa load limit)
4.1 Substructure Repairs
$2,030,477.70
4.2 Superstructure Repairs
$3,985,417.99
4.3 Approach Slabs and Expansion Joints
$163,191.05
4.4 Guardrails
$387,527.25
4.5 Future Specific Maintenance
4.5.1.1- Substructure - 10 Years
$658,763.20
4.5.1.2 - Substructure - 20 Years
$658,763.20
4.5.2.1 - Superstructure - 10 Years
$62,452.41
4.5.2.2 - Superstructure - 20 Years
$196,758.66
Manduralh Bridge Refurbishment
Summary
$6,566,613.99
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
OPTION 1 - Upgrade Bridge Capacity to 100% T44
Item
Description
Unit
Qty
Rate
Amount
No.
22
$8,750.00
$192,500.00
2.1 SUBSTRUCTURE REPAIRS
1.1
2.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
1.2
Allow for temporary propping of each pier
during the pile repairs complete
No.
22
$26,750.00
$588,500.00
1.3
Allow for Silane treatment of all concrete
surfaces above high water level complete
Item
1
$285,000.00
$285,000.00
2.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
1.4
Apply concrete patch repairs to all capbeams
m2
22
$585.00
$12,870.00
1.5
Allow for Silane treatment of all surfaces of
capbeams complete
Item
1
$55,000.00
$55,000.00
SUB-TOTAL
$1,133,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$340,161.00
ADD Contingencies
%
15
$170,080.50
GST EXCLUSIVE AMOUNT
Mandurah Bridge Upgrade
Indicative Cost Indication
$1,644,111.50
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$82,205.58
%
1
$16,441.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$57,543.90
PROJECT MANAGEMENT (City of Mandurah)
%
4
$65,764.46
$1,866,066.55
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
Rate
ESTIMATED GST PAYABLE
OPTION 1 - 2.1 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
Amount
$164,411.15
$2,030,477.70
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
m
113
$465.00
$52,545.00
m
75
$425.00
$31,875.00
Item
1
$8,670.00
$8,670.00
Item
1
$75,000.00
$75,000.00
m
75
$1,275.00
$95,625.00
$25,000.00
$25,000.00
2.2 SUPERSTRUCTURE REPAIRS
1.6
1.7
1.8
2.2.1 Timber Stringers
Galvanised 410UB60 steel section stringers
including all fasteners, bearing brackets and
preparing to receive all as detailed on the
drawings as replacement of removed Stringers
(In No. 15)
New 410UB60 Grade 300 beams complete (In
No. 10)
2.2.2 Navigation Spans
Allow for the removal of existing bracing
complete
1.9
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
1.10
New 700WB150 beams fixed complete (In No.
6)
1.11
Allow for new bracing complete
Item
1
1.12
2.2.3 Reinforced Concrete Overlay
Remove existing bituminous pavement
complete
m2
1,231
$15.00
$18,465.00
1.13
Remove existing concrete overlay complete
m2
1,365
$275.00
$375,375.00
1.14
Remove existing concrete and timber footpath
slab including all timber supports
m2
315
$115.00
$36,225.00
1.15
Remove existing timber balustrade to edge of
footpath complete
m
184
$18.00
$3,312.00
1.16
Remove existing timber decking to edge of
deck and prepare for new formwork
m2
552
$55.00
$30,360.00
1.17
Allow for the removal of existing planks and
replacement with 1mm Bondek and concrete
No.
110
$1,265.00
$15,000.00
Item
1
$965,000.00
$965,000.00
m3
450
$940.00
$423,000.00
1.18
1.19
Falsework
Provision and erection of falsework including
maintenance and removal including provision of
access to carry out repairs
Concrete
Reinforced Insitu Concrete Class S40
Deck slab and Sill Beams
Mandurah Bridge Upgrade
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
1.20
1.21
1.22
Description
Formwork
DECK
Formwork to edge of deck slab
Permanent Steel Formwork
1mm thick Bondek to soffit of deck slab
installed as detailed in the Drawings
1mm thick Bondek to soffit of footpath slab as
detailed in the Drawings
Unit
Qty
Rate
Amount
m2
300
$365.00
$109,500.00
m2
552
$125.00
$69,000.00
m2
432
$125.00
$54,000.00
t
1.5
$33,514.00
$50,271.00
Steel Reinforcement
DECK & SILLS
Reinforcing Bars to AS/NZS 4671 Grade 500N
1.23
Bars less than 16mm diameter in Kerbs
1.24
Reinforcing Fabric to AS 1304
SL81 Reinforcing fabric to deck slab & sills
m2
3900
$60.00
$234,000.00
1.25
SL81 Reinforcing fabric to deck kerbs
m2
650
$65.00
$42,250.00
m2
650
$125.00
$81,250.00
Item
1
$35,600.00
$35,600.00
m²
1,325
$1.20
$1,590.00
m²
1,325
$23.50
$31,137.50
No
42
$500.00
$21,000.00
1.26
1.27
1.28
1.29
1.30
Timber Bridges
TIMBER DECK PREPARATION TO RECEIVE
CONCRETE OVERLAY
Clean & Prepare existing timber decking to
receive concrete overlay, including hessian
covering, fungicide treatments and all other
cast in items not covered in these Bills all as
detailed in the Drawings (PROVISIONAL
QUANTITY)
Allow for cutting at existing abutments to take
new with of reinforced concrete overlay.
Asphalt Surfacing
BRIDGEWORKS
Tack coat
50mm dense graded asphalt on bridge deck
and approach slabs
Scuppers
100mm Diameter UPVC downpipes including
all joiners and fastening cast into the concrete
deck all as detailed on the Drawings
SUB-TOTAL
Mandurah Bridge Upgrade
Indicative Cost Indication
$2,885,050.50
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$865,515.15
ADD Contingencies
%
15
$432,757.58
Rate
GST EXCLUSIVE AMOUNT
Amount
$4,183,323.23
%
5
$209,166.16
%
1
$41,833.23
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$146,416.31
PROJECT MANAGEMENT (City of Mandurah)
%
4
$167,332.93
$4,748,071.86
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
ESTIMATED GST PAYABLE
OPTION 1 - 2.2 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$418,332.32
$5,166,404.18
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
2.3 APPROACH SLABS AND
EXPANSION JOINTS
1.31
Remove existing bituminous pavement
complete
m2
67
$15.00
$1,005.00
1.32
Rip up and remove existing concrete approach
slabs complete
m2
75
$455.00
$34,125.00
Item
1
$35,000.00
$35,000.00
m3
6
$3,100.00
$18,600.00
1.33
1.34
Earthworks
Allow for trimming and compacting the ground
ready to receive concrete including all
necessary topping up of the fill material
Concrete
Plain Insitu Concrete Class N20
50 Blinding layer under approach slab (In 120
m2)
1.35
Reinforced Insitu Concrete Class S40
Approach slab
m3
20
$765.00
$15,300.00
1.36
Formwork
Sides of approach slab
m2
40
$335.00
$13,400.00
1.37
Soffit of approach slab
m2
7
$425.00
$2,975.00
Steel Reinforcement
Reinforcing Bars to AS/NZS 4671 Grade 500N
1.38
Bars less than 16 diameter in approach slab
t
0.40
$4,250.00
$1,700.00
1.39
Bars 16 - 36 diameter in approach slab
t
3.31
$4,250.00
$14,067.50
No.
26
$3,000.00
$78,000.00
m
20
$3,000.00
$60,000.00
Bridge Bearings
1.40
APPROACH SLAB BEARINGS
Approach slab bearing comprising 1000 x 160 x
5 Thick ultra high molecular weight
polyethylene sheet (HDPE), 1000 x 120 x 10
thick rubber bearing pad with 50-60 durometer
hardness, galvanised dowel cap cast into
approach slab and 20 diameter galvanised
dowel 120 long cast into deck slab
Compression Joint Seal
1.41
Compression seal including galvanised
expansion joint edging with anchor straps cast
into concrete and galvanised cover plates (In 2
No. expansion joints)
Mandurah Bridge Upgrade
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
1.42
Asphalt Surfacing
BRIDGEWORKS
Tack coat
m²
72
$1.20
$86.40
1.43
50mm dense graded asphalt on approach slabs
m²
72
$23.50
$1,692.00
SUB-TOTAL
$275,950.90
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$82,785.27
ADD Contingencies
%
15
$41,392.64
GST EXCLUSIVE AMOUNT
$400,128.81
%
5
$20,006.44
%
1
$4,001.29
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$14,004.51
PROJECT MANAGEMENT (City of Mandurah)
%
4
$16,005.15
$454,146.19
ESTIMATED GST PAYABLE
$40,012.88
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.3 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$494,159.07
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
m
368
$25.00
$9,200.00
2.4 GUARDRAILS
1.44
2.4.1 Guardrails on the Bridge
Remove existing guardrail with timber posts
and W Beam
Road Safety Barrier Systems and Traffic
Barriers for Structures
1.45
BARRIER
Galvanised Regular Performance Level barrier
m
370
$850.00
$314,500.00
1.46
BALUSTRADE
Galvanized and painted balustrade
m
204
$560.00
$114,240.00
m
45
$25.00
$1,125.00
m
45
$350.00
$15,750.00
1.47
2.4.2 Guardrails on Approach Slabs
Remove existing guardrail with timber posts
and W Beam
Road Safety Barrier Systems and Traffic
Barriers for Structures
1.48
BARRIER
Galvanised W-Beam barrier
1.49
Galvanised Thriebeam/W-Beam transition
No.
4
$6,500.00
$26,000.00
1.50
Galvanised modified eccentric loader terminal
(ET 2000)
No.
4
$8,500.00
$34,000.00
SUB-TOTAL
$514,815.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$154,444.50
ADD Contingencies
%
15
$77,222.25
GST EXCLUSIVE AMOUNT
$746,481.75
Mandurah Bridge Upgrade
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$37,324.09
%
1
$7,464.82
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$26,126.86
PROJECT MANAGEMENT (City of Mandurah)
%
4
$29,859.27
$847,256.79
ESTIMATED GST PAYABLE
$74,648.18
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.4 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
Rate
Amount
$921,904.96
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
2.5 FUTURE MAINTENANCE
2.5.1 Substructure Maintenance
10 YEARS
1.51
1.52
2.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
2.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
1.53
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.5.1.1 - SUBSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No.
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
20 YEARS
1.54
1.55
2.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
2.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
1.56
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.5.1.2 - SUBSTRUCTURE - TOTAL OF
PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
225
Rate
Amount
2.5.2 Superstructure Maintenance
10 YEARS
1.57
2.2.1 Timber Stringers
Galvanised 410UB60 steel section stringers
including all fasteners, bearing brackets and
preparing to receive all as detailed on the
drawings as replacement of removed Stringers
(In No. 30)
$465.00
$104,625.00
SUB-TOTAL
$104,625.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$31,387.50
ADD Contingencies
%
15
$15,693.75
GST EXCLUSIVE AMOUNT
$151,706.25
%
5
$7,585.31
%
1
$1,517.06
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$5,309.72
PROJECT MANAGEMENT (City of Mandurah)
%
4
$6,068.25
$172,186.59
ESTIMATED GST PAYABLE
$15,170.63
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.5.2.1 - SUPERSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$187,357.22
DAVSON+WARD PTY. LTD.
Option 1
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
150
Item
1
Rate
Amount
20 YEARS
1.67
2.2.1 Timber Stringers
Galvanised 410UB60 steel section stringers
including all fasteners, bearing brackets and
preparing to receive all as detailed on the
drawings as replacement of removed Stringers
(In No. 20)
$465.00
$69,750.00
2.2.2 Navigation Spans
1.68
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
$75,000.00
$75,000.00
SUB-TOTAL
$144,750.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$43,425.00
ADD Contingencies
%
15
$21,712.50
GST EXCLUSIVE AMOUNT
$209,887.50
%
5
$10,494.38
%
1
$2,098.88
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$7,346.06
PROJECT MANAGEMENT (City of Mandurah)
%
4
$8,395.50
$238,222.31
ESTIMATED GST PAYABLE
$20,988.75
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.5.2.2 - SUPERSTRUCTURE- TOTAL OF
PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$259,211.06
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
OPTION 2 - Retain Existing 17 tonne load limit
Item
Description
Unit
Qty
Rate
Amount
No.
22
$8,750.00
$192,500.00
3.1 SUBSTRUCTURE REPAIRS
2.1
3.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
2.2
Allow for temporary propping of each pier
during the pile repairs complete
No.
22
$26,750.00
$588,500.00
2.3
Allow for Silane treatment of all concrete
surfaces above high water level complete
Item
1
$285,000.00
$285,000.00
3.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
2.4
Apply concrete patch repairs to all capbeams
m2
22
$585.00
$12,870.00
2.5
Allow for Silane treatment of all surfaces of
capbeams complete
Item
1
$55,000.00
$55,000.00
SUB-TOTAL
$1,133,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$340,161.00
ADD Contingencies
%
15
$170,080.50
GST EXCLUSIVE AMOUNT
Mandurah Bridge
Indicative Cost Indication
$1,644,111.50
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$82,205.58
%
1
$16,441.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$57,543.90
PROJECT MANAGEMENT (City of Mandurah)
%
4
$65,764.46
$1,866,066.55
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
Rate
ESTIMATED GST PAYABLE
OPTION 2 - 3.1 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
Amount
$164,411.15
$2,030,477.70
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Item
1
Rate
Amount
3.2 SUPERSTRUCTURE REPAIRS
2.6
3.2.2 Navigation Spans
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
$75,000.00
$75,000.00
2.7
3.2.3 Reinforced Concrete Overlay
Remove existing bituminous pavement
complete
m2
1,231
$15.00
$18,465.00
2.8
Remove existing concrete overlay complete
m2
1,365
$275.00
$375,375.00
2.9
Remove existing concrete and timber footpath
slab including all timber supports
m2
315
$115.00
$36,225.00
2.10
Remove existing timber balustrade to edge of
footpath complete
m
184
$18.00
$3,312.00
2.11
Remove existing timber decking to edge of
deck and prepare for new formwork
m2
552
$55.00
$30,360.00
2.12
Allow for the removal of existing planks and
replacement with 1mm Bondek and concrete
No.
110
$1,265.00
$15,000.00
Item
1
$965,000.00
$965,000.00
2.14
Concrete
Reinforced Insitu Concrete Class S40
Deck slab and Sill Beams
m3
450
$940.00
$423,000.00
2.15
Formwork
DECK
Formwork to edge of deck slab
m2
300
$365.00
$109,500.00
m2
552
$125.00
$69,000.00
m2
432
$125.00
$54,000.00
2.13
2.16
2.17
Falsework
Provision and erection of falsework including
maintenance and removal including provision of
access to carry out repairs
Permanent Steel Formwork
1mm thick Bondek to soffit of deck slab
installed as detailed in the Drawings
1mm thick Bondek to soffit of footpath slab as
detailed in the Drawings
Mandurah Bridge
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
t
1.5
Rate
Amount
Steel Reinforcement
DECK & SILLS
Reinforcing Bars to AS/NZS 4671 Grade 500N
2.18
Bars less than 16mm diameter in Kerbs
2.19
Reinforcing Fabric to AS 1304
SL81 Reinforcing fabric to deck slab & sills
m2
2.20
SL81 Reinforcing fabric to deck kerbs
2.21
2.22
2.23
2.24
2.25
Timber Bridges
TIMBER DECK PREPARATION TO RECEIVE
CONCRETE OVERLAY
Clean & Prepare existing timber decking to
receive concrete overlay, including hessian
covering, fungicide treatments and all other
cast in items not covered in these Bills all as
detailed in the Drawings (PROVISIONAL
QUANTITY)
Allow for cutting at existing abutments to take
new with of reinforced concrete overlay.
Asphalt Surfacing
BRIDGEWORKS
Tack coat
50mm dense graded asphalt on bridge deck
and approach slabs
Scuppers
100mm Diameter UPVC downpipes including
all joiners and fastening cast into the concrete
deck all as detailed on the Drawings
$33,514.00
$50,271.00
3900
$60.00
$234,000.00
m2
650
$65.00
$42,250.00
m2
650
$125.00
$81,250.00
Item
1
$35,600.00
$35,600.00
m²
1,325
$1.20
$1,590.00
m²
1,325
$23.50
$31,137.50
No
42
$500.00
$21,000.00
SUB-TOTAL
$2,671,335.50
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$801,400.65
ADD Contingencies
%
15
$400,700.33
GST EXCLUSIVE AMOUNT
Mandurah Bridge
Indicative Cost Indication
$3,873,436.48
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$193,671.82
%
1
$38,734.36
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$135,570.28
PROJECT MANAGEMENT (City of Mandurah)
%
4
$154,937.46
$4,396,350.40
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
Rate
ESTIMATED GST PAYABLE
OPTION 2 - 3.2 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
Amount
$387,343.65
$4,783,694.05
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
3.3 APPROACH SLABS AND
EXPANSION JOINTS
2.26
Remove existing bituminous pavement
complete
m2
67
$15.00
$1,005.00
2.27
Rip up and remove existing concrete approach
slabs complete
m2
75
$455.00
$34,125.00
Item
1
$35,000.00
$35,000.00
m3
6
$3,100.00
$18,600.00
2.28
2.29
Earthworks
Allow for trimming and compacting the ground
ready to receive concrete including all
necessary topping up of the fill material
Concrete
Plain Insitu Concrete Class N20
50 Blinding layer under approach slab (In 120
m2)
2.30
Reinforced Insitu Concrete Class S40
Approach slab
m3
20
$765.00
$15,300.00
2.31
Formwork
Sides of approach slab
m2
40
$335.00
$13,400.00
2.32
Soffit of approach slab
m2
7
$425.00
$2,975.00
Steel Reinforcement
Reinforcing Bars to AS/NZS 4671 Grade 500N
2.33
Bars less than 16 diameter in approach slab
t
0.40
$4,250.00
$1,700.00
2.34
Bars 16 - 36 diameter in approach slab
t
3.31
$4,250.00
$14,067.50
No.
26
$3,000.00
$78,000.00
m
20
$3,000.00
$60,000.00
Bridge Bearings
2.35
APPROACH SLAB BEARINGS
Approach slab bearing comprising 1000 x 160 x
5 Thick ultra high molecular weight
polyethylene sheet (HDPE), 1000 x 120 x 10
thick rubber bearing pad with 50-60 durometer
hardness, galvanised dowel cap cast into
approach slab and 20 diameter galvanised
dowel 120 long cast into deck slab
Compression Joint Seal
2.36
Compression seal including galvanised
expansion joint edging with anchor straps cast
into concrete and galvanised cover plates (In 2
No. expansion joints)
Mandurah Bridge
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
2.37
Asphalt Surfacing
BRIDGEWORKS
Tack coat
m²
72
$1.20
$86.40
2.38
50mm dense graded asphalt on approach slabs
m²
72
$23.50
$1,692.00
SUB-TOTAL
$275,950.90
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$82,785.27
ADD Contingencies
%
15
$41,392.64
GST EXCLUSIVE AMOUNT
$400,128.81
%
5
$20,006.44
%
1
$4,001.29
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$14,004.51
PROJECT MANAGEMENT (City of Mandurah)
%
4
$16,005.15
$454,146.19
ESTIMATED GST PAYABLE
$40,012.88
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.3 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
$494,159.07
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
368
Rate
Amount
3.4 GUARDRAILS
2.39
3.4.1 Guardrails on the Bridge
Remove existing guardrail with timber posts
and W Beam
$25.00
$9,200.00
Road Safety Barrier Systems and Traffic
Barriers for Structures
2.40
BARRIER
Galvanised Regular Performance Level barrier
m
370
$850.00
$314,500.00
2.41
BALUSTRADE
Galvanized and painted balustrade
m
204
$560.00
$114,240.00
m
45
m
45
$350.00
$15,750.00
2.42
3.4.2 Guardrails on Approach Slabs
Remove existing guardrail with timber posts
and W Beam
$25.00
$1,125.00
Road Safety Barrier Systems and Traffic
Barriers for Structures
2.43
BARRIER
Galvanised W-Beam barrier
2.44
Galvanised Thriebeam/W-Beam transition
No.
4
$6,500.00
$26,000.00
2.45
Galvanised modified eccentric loader terminal
(ET 2000)
No.
4
$8,500.00
$34,000.00
SUB-TOTAL
$514,815.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$154,444.50
ADD Contingencies
%
15
$77,222.25
GST EXCLUSIVE AMOUNT
$746,481.75
Mandurah Bridge
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$37,324.09
%
1
$7,464.82
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$26,126.86
PROJECT MANAGEMENT (City of Mandurah)
%
4
$29,859.27
$847,256.79
ESTIMATED GST PAYABLE
$74,648.18
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.4 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
Rate
Amount
$921,904.96
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No.
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
3.5 FUTURE MAINTENANCE
2.5.1 Substructure Maintenance
10 YEARS
2.46
2.47
3.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
3.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
2.48
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.5.1.1 - SUBSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No.
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
20 YEARS
2.49
2.50
3.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
3.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
2.51
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.5.1.2 - SUBSTRUCTURE - TOTAL OF
PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
150
Rate
Amount
3.5.2 Superstructure Maintenance
10 YEARS
2.52
3.2.1 Timber Stringers
Galvanised 410UB60 Grade 300 steel section
stringers including all fasteners, bearing
brackets and preparing to receive all as
detailed on the drawings as replacement of
removed Stringers (In No. 20)
$465.00
$69,750.00
SUB-TOTAL
$69,750.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$20,925.00
ADD Contingencies
%
15
$10,462.50
GST EXCLUSIVE AMOUNT
$101,137.50
%
5
$5,056.88
%
1
$1,011.38
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$3,539.81
PROJECT MANAGEMENT (City of Mandurah)
%
4
$4,045.50
$114,791.06
ESTIMATED GST PAYABLE
$10,113.75
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.5.2.1 - SUBSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
$124,904.81
DAVSON+WARD PTY. LTD.
Option 2
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
75
Item
1
Rate
Amount
20 YEARS
2.53
3.2.1 Timber Stringers
Galvanised 410UB60 steel section stringers
including all fasteners, bearing brackets and
preparing to receive all as detailed on the
drawings as replacement of removed Stringers
(In No. 10)
$465.00
$34,875.00
3.2.2 Navigation Spans
2.54
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
$75,000.00
$75,000.00
SUB-TOTAL
$109,875.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$32,962.50
ADD Contingencies
%
15
$16,481.25
GST EXCLUSIVE AMOUNT
$159,318.75
%
5
$7,965.94
%
1
$1,593.19
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$5,576.16
PROJECT MANAGEMENT (City of Mandurah)
%
4
$6,372.75
$180,826.78
ESTIMATED GST PAYABLE
$15,931.88
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.5.2.2 - SUBSTRUCTURE - TOTAL OF
PRELIMINARY COST INDICATION
Mandurah Bridge
Indicative Cost Indication
$196,758.66
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
OLD MANDURAH TRAFFIC BRIDGE (BRIDGE 230)
OPTION 3 - Convert to a pedestrian footbridge (5kPa Load Limit)
Item
Description
Unit
Qty
Rate
Amount
No.
22
$8,750.00
$192,500.00
4.1 SUBSTRUCTURE REPAIRS
3.1
4.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
3.2
Allow for temporary propping of each pier
during the pile repairs complete
No.
22
$26,750.00
$588,500.00
3.3
Allow for Silane treatment of all concrete
surfaces above high water level complete
Item
1
$285,000.00
$285,000.00
4.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
3.4
Apply concrete patch repairs to all capbeams
m2
22
$585.00
$12,870.00
3.5
Allow for Silane treatment of all surfaces of
capbeams complete
Item
1
$55,000.00
$55,000.00
SUB-TOTAL
$1,133,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$340,161.00
ADD Contingencies
%
15
$170,080.50
GST EXCLUSIVE AMOUNT
Mandurah Bridge Upgrade
Indicative Cost Indication
$1,644,111.50
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
%
5
$82,205.58
%
1
$16,441.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$57,543.90
PROJECT MANAGEMENT (City of Mandurah)
%
4
$65,764.46
$1,866,066.55
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
Rate
ESTIMATED GST PAYABLE
OPTION 2 - 3.1 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
Amount
$164,411.15
$2,030,477.70
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Item
1
Rate
Amount
4.2 SUPERSTRUCTURE REPAIRS
3.6
3.2.2 Navigation Spans
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
$75,000.00
$75,000.00
3.7
4.2.3 Reinforced Concrete Overlay
Remove existing bituminous pavement
complete
m2
1,231
$15.00
$18,465.00
3.8
Remove existing concrete overlay complete
m2
1,365
$275.00
$375,375.00
3.9
Remove existing concrete and timber footpath
slab including all timber supports
m2
315
$115.00
$36,225.00
3.10
Remove existing timber balustrade to edge of
footpath complete
m
184
$18.00
$3,312.00
3.11
Remove existing timber decking to edge of
deck and prepare for new formwork
m2
552
$55.00
$30,360.00
3.12
Allow for the removal of existing planks and
replacement with 1mm Bondek and concrete
No.
110
$1,265.00
$15,000.00
Item
1
$785,000.00
$785,000.00
3.14
Concrete
Reinforced Insitu Concrete Class S40
Deck slab and Sill Beams
m3
420
$940.00
$394,800.00
3.15
Formwork
DECK
Formwork to edge of deck slab
m2
200
$365.00
$73,000.00
m2
552
$125.00
$69,000.00
m2
432
$125.00
$54,000.00
3.13
3.16
3.17
Falsework
Provision and erection of falsework including
maintenance and removal including provision of
access to carry out repairs
Permanent Steel Formwork
1mm thick Bondek to soffit of deck slab
installed as detailed in the Drawings
1mm thick Bondek to soffit of footpath slab as
detailed in the Drawings
Mandurah Bridge Upgrade
Indicative Cost Indication
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
t
1.5
Rate
Amount
Steel Reinforcement
DECK & SILLS
Reinforcing Bars to AS/NZS 4671 Grade 500N
3.18
Bars less than 16mm diameter in Kerbs
3.19
Reinforcing Fabric to AS 1304
SL81 Reinforcing fabric to deck slab & sills
m2
3.20
SL81 Reinforcing fabric to deck kerbs
3.21
3.22
Timber Bridges
TIMBER DECK PREPARATION TO RECEIVE
CONCRETE OVERLAY
Clean & Prepare existing timber decking to
receive concrete overlay, including hessian
covering, fungicide treatments and all other
cast in items not covered in these Bills all as
detailed in the Drawings (PROVISIONAL
QUANTITY)
Scuppers
100mm Diameter UPVC downpipes including
all joiners and fastening cast into the concrete
deck all as detailed on the Drawings
$33,514.00
$50,271.00
1850
$60.00
$111,000.00
m2
500
$65.00
$32,500.00
m2
650
$125.00
$81,250.00
No
42
$500.00
SUB-TOTAL
$21,000.00
$2,225,558.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$667,667.40
ADD Contingencies
%
15
$333,833.70
GST EXCLUSIVE AMOUNT
$3,227,059.10
%
5
$161,352.96
%
1
$32,270.59
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$112,947.07
PROJECT MANAGEMENT (City of Mandurah)
%
4
$129,082.36
$3,662,712.08
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
ESTIMATED GST PAYABLE
OPTION 2 - 3.2 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$322,705.91
$3,985,417.99
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Mandurah Bridge Upgrade
Unit
Qty
Indicative Cost Indication
Rate
Amount
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
4.3 APPROACH SLABS AND
EXPANSION JOINTS
3.23
Remove existing bituminous pavement
complete
m2
67
$15.00
$1,005.00
3.24
Rip up and remove existing concrete approach
slabs complete
m2
75
$455.00
$34,125.00
3.25
Allow for filling behind abutment with pavement
material and Asphalt surfacing
Item
1
$56,000.00
$56,000.00
SUB-TOTAL
$91,130.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$27,339.00
ADD Contingencies
%
15
$13,669.50
GST EXCLUSIVE AMOUNT
$132,138.50
%
5
$6,606.93
%
1
$1,321.39
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$4,624.85
PROJECT MANAGEMENT (City of Mandurah)
%
4
$5,285.54
$149,977.20
ESTIMATED GST PAYABLE
$13,213.85
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 2 - 3.2 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$163,191.05
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
413
m
368
Rate
Amount
4.4 GUARDRAILS
3.26
3.4.1 Guardrails on the Bridge
Remove existing guardrail with timber posts
and W Beam
$25.00
$10,325.00
Road Safety Barrier Systems and Traffic
Barriers for Structures
3.27
BALUSTRADE
Galvanized and painted balustrade
$560.00
$206,080.00
SUB-TOTAL
$216,405.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$64,921.50
ADD Contingencies
%
15
$32,460.75
GST EXCLUSIVE AMOUNT
$313,787.25
%
5
$15,689.36
%
1
$3,137.87
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$10,982.55
PROJECT MANAGEMENT (City of Mandurah)
%
4
$12,551.49
$356,148.53
ESTIMATED GST PAYABLE
$31,378.73
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 3 - 4.4 - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$387,527.25
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No.
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
4.5 FUTURE MAINTENANCE
4.5.1 Substructure Maintenance
10 YEARS
3.28
3.29
3.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
3.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
3.30
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 3 - 4.5.1 - SUBSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
Rate
Amount
No.
10
$8,750.00
$87,500.00
No.
10
$26,750.00
$267,500.00
m2
22
$585.00
$12,870.00
20 YEARS
3.31
3.32
2.1.1 Reinforced Concrete piles
Allow for the removal or breakout of defective
concrete and provide and construct concrete
encasement of piles including all necessary
formwork, reinforcement and dewatering as
required
Allow for temporary propping of each pier
during the pile repairs complete
2.1.2 Reinforced Concrete Capbeams
(including Stair and Stringer Corbels)
3.33
Apply concrete patch repairs to all capbeams
SUB-TOTAL
$367,870.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$110,361.00
ADD Contingencies
%
15
$55,180.50
GST EXCLUSIVE AMOUNT
$533,411.50
%
5
$26,670.58
%
1
$5,334.12
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$18,669.40
PROJECT MANAGEMENT (City of Mandurah)
%
4
$21,336.46
$605,422.05
ESTIMATED GST PAYABLE
$53,341.15
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 1 - 2.5.1.2 - SUBSTRUCTURE TOTAL OF PRELIMINARY COST
INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$658,763.20
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
75
Rate
Amount
4.5.2 Superstructure Maintenance
10 YEARS
3.34
3.2.1 Timber Stringers
Galvanised 410UB60 Grade 300 steel section
stringers including all fasteners, bearing
brackets and preparing to receive all as
detailed on the drawings as replacement of
removed Stringers (In No. 10)
$465.00
$34,875.00
SUB-TOTAL
$34,875.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$10,462.50
ADD Contingencies
%
15
$5,231.25
GST EXCLUSIVE AMOUNT
$50,568.75
%
5
$2,528.44
%
1
$505.69
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$1,769.91
PROJECT MANAGEMENT (City of Mandurah)
%
4
$2,022.75
$57,395.53
ESTIMATED GST PAYABLE
$5,056.88
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 3 - 4.5.1 - SUPERSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$62,452.41
DAVSON+WARD PTY. LTD.
Option 3
Quantity Surveyors and Construction Cost Consultants
Item
Description
Unit
Qty
m
75
Item
1
Rate
Amount
20 YEARS
3.35
3.2.1 Timber Stringers
Galvanised 410UB60 steel section stringers
including all fasteners, bearing brackets and
preparing to receive all as detailed on the
drawings as replacement of removed Stringers
(In No. 10)
$465.00
$34,875.00
3.2.2 Navigation Spans
3.36
Allow for abrasive blasting and recoating of
existing steel beams including all access
scaffolding and encapsulating during the
blasting
$75,000.00
$75,000.00
SUB-TOTAL
$109,875.00
ADD Preliminary items (Includes: Insurances,
Contractor's Superintendence, site
establishment, Contractors site offices and
area, Superintendent's Office Survey costs and
all other items included in the normal Schedule
No. 1 - General Items)
%
30
$32,962.50
ADD Contingencies
%
15
$16,481.25
GST EXCLUSIVE AMOUNT
$159,318.75
%
5
$7,965.94
%
1
$1,593.19
TENDER AND CONTRACT ADMINISTRATION (City
of Mandurah)
%
4
$5,576.16
PROJECT MANAGEMENT (City of Mandurah)
%
4
$6,372.75
$180,826.78
ESTIMATED GST PAYABLE
$15,931.88
SURVEY, DESIGN AND DOCUMENTATION
ETHNOGRAPHIC SURVEYS AND CLEARANCES
OPTION 3 - 4.5.2 - SUPERSTRUCTURE - TOTAL OF PRELIMINARY COST INDICATION
Mandurah Bridge Upgrade
Indicative Cost Indication
$196,758.66
Appendix D
Whole of Life Cost Analysis
Summary of all NPV Results using different discount &
inflation rate scenarios
NPV calculations - Options 1 to 5 for Scenario 3 (as a sample
of calculations done for all scenarios)
61/26421/105205
Old Mandurah Traffic Bridge (Bridge No. 230)
Economic Viability Assessment for Replacement of the Bridge
Old Mandurah Traffic Bridge (Bridge No. 230) over Mandurah Estuary - Summary
Summary of NPV Results from sensitivity analysis using different discount & inflation rate scenarios
Scenario
Discount Rate
Inflation Rate
Option
(refer notes below)
1
2
3
4
5
1
6.00%
2.00%
2
6.00%
2.75%
3
6.00%
3.50%
4
7.50%
2.00%
5
7.50%
2.75%
6
7.50%
3.50%
7
9.00%
2.00%
8
9.00%
2.75%
9
9.00%
3.50%
Lower replace cost
Higher refurb & maintain
6.00%
3.50%
6.00%
3.50%
-13,771
-13,331
-27,157
-19,775
-15,425
-14,902
-14,456
-27,830
-20,362
-15,883
-20,357
-19,882
-27,061
-19,152
-15,049
-23,866
-23,208
-30,697
-22,788
-17,776
Estimated NPV ($ 000's)
-17,700
-17,242
-29,137
-21,484
-16,758
-19,770
-19,304
-29,902
-22,128
-17,261
-22,312
-21,837
-30,697
-22,788
-17,776
-14,775
-14,330
-27,760
-20,301
-15,836
-16,152
-15,700
-28,464
-20,909
-16,310
-17,840
-17,381
-29,193
-21,531
-16,795
-12,847
-12,412
-26,505
-19,200
-14,977
Most favourable (highest) NPV of all options
Most favourable (highest) NPV of Options 1 - 4 only
Summary of assumptions for each option:
Option 1 - Upgrade bridge capacity to 100% T44 & Grp 1 Vehicles
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $8.613 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Replace bridge with new bridge in 30 years at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $200k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $260k as per cost indication.
Carry out routine maintenance over the bridges life, say $50k per 5 year cycle
Option 2 - Retain bridge at existing 17 tonne load capacity
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $8.230 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Replace bridge with new bridge in 30 years at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $130k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $200k as per cost indication.
Carry out routine maintenance over the bridges life, say $50k per 5 year cycle
Option 3 - Convert bridge to pedestrian-only footbridge (5 kPa load capacity)
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $6.567 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Construct new traffic bridge in 2015 at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $70k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $200k as per cost indication.
General maintenance works for the new bridge costing $50k every 10 years are incurred.
Carry out routine maintenance over the old bridges life, say $50k per 5 year cycle
Option 4 - Construct incrementally launched, 3-lane bridge as per AECOM Concept Report
Construct new incrementally launched, 3-lane bridge as per AECOM Concept Report in 2015. Estimated cost is $25 million as specified in this report.
Estimated cost above includes contractor site facilities and overheads, but excludes contingency & risk, contract administration, design & consultancy fees,
road approaches, fishing platform, services relocation and escalation as noted in AECOM report.
Estimated life of new bridge is 100 yrs, with associated maintenance works carried out as per below.
General maintenance works costing $50,000 every 10 years are incurred following completion of the bridge.
Option 5 - Construct incrementally launched, 2-lane bridge (with rates factored down from AECOM Concept Report)
Option included for purposes of direct comparison between upgrade of existing 2-lane bridge, and replacement with new 2-lane bridge.
Construct new incrementally launched, 2-lane bridge (for purposes of comparing new structure of equivalent width to existing structure). Cost is estimated as
$19.5 million by factoring down cost of 3-lane bridge specified in AECOM Concept Report
Estimated cost above includes contractor site facilities and overheads, but excludes contingency & risk, contract administration, design & consultancy fees,
road approaches, fishing platform, services relocation and escalation as noted in AECOM report.
Estimated life of new bridge is 100 yrs, with associated maintenance works carried out as per below.
General maintenance works are estimated at $40,000 every 10 years following completion of the bridge, calculated by factoring down maintenance works for 3-lane bridge.
Additional scenarios to test sensitivity to estimated capital and maintenance costs
Using the most favourable discount rate and inflation rate for Option 4, the following adjustments were made to the cashflow assumptions:
Lower Replace cost
As per Options described above, except cost for new replacement bridge taken as $21 million, in 30 years for Options 1 & 2, and in 2015 for Options 3 & 4
Replacement bridge taken as $16 million in 2015 for Option 5
Higher Refurb and Maintain
As per Options described above, except cost the substructure & superstructure repairs including RCO in 2011, and cost for substructure & superstructure
maintenance in 10 years & 20 years for Options 1 & 2 slightly increased.
Old Mandurah Traffic Bridge NPV Analysis (5 options).xls
Summary
Old Mandurah Traffic Bridge (Bridge No. 230) over Mandurah Estuary - Scenario 3
Option 1 - Upgrade bridge capacity to 100% T44 & Grp 1 Vehicles
Assumptions:
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $8.613 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Replace bridge with new bridge in 30 years at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $200k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $260k as per cost indication.
Carry out routine maintenance over the bridges life, say $50k per 5 year cycle
Discount & inflation rates as below
Values below in $000's
Sources of Cash Flow
Capital - substructure & superstructure repairs
Capital - new bridge
Substructure maintenance in 10 yrs
Superstructure maintenance in 10 yrs
Substructure maintenance in 20 yrs
Superstructure maintenance in 20 yrs
Routine maintenance every 5 years
($ 000's)
Year
8,613
25,000
700
200
700
260
50
Yr 0
Yr 30
Yr 10
Yr 10
Yr 20
Yr 20
Yr 5 cycle
NPV Analysis
Discount Rate:
Inflation Rate:
6.00%
3.50%
Discount Factor
1.00
0.94
0.89
0.84
0.79
0.75
0.70
0.67
0.63
0.59
0.56
0.53
0.50
0.47
0.44
0.42
0.39
0.37
0.35
0.33
0.31
0.29
0.28
0.26
0.25
0.23
0.22
0.21
0.20
0.18
0.17
Escalation Factor
1.00
1.04
1.07
1.11
1.15
1.19
1.23
1.27
1.32
1.36
1.41
1.46
1.51
1.56
1.62
1.68
1.73
1.79
1.86
1.92
1.99
2.06
2.13
2.21
2.28
2.36
2.45
2.53
2.62
2.71
2.81
Year
Year number
2011
0
2012
1
2013
2
2014
3
2015
4
2016
5
2017
6
2018
7
2019
8
2020
9
2021
10
2022
11
2023
12
2024
13
2025
14
2026
15
2027
16
2028
17
2029
18
2030
19
2031
20
2032
21
2033
22
2034
23
2035
24
2036
25
2037
26
2038
27
2039
28
2040
29
2041
30
Capital Expenditure
Maintenance - Substructure
Maintenance - Superstructure
Maintenance - Routine
-8613
Cash Flow
-8613
0
0
0
0
-50
0
0
0
0
-950
0
0
0
0
-50
0
0
0
0
-1010
0
0
0
0
-50
0
0
0
0
-25000
Discounted Cash Flow
Inflated Cash Flow
-8613
-8613
0
0
0
0
0
0
0
0
-37
-44
0
0
0
0
0
0
0
0
-530
-748
0
0
0
0
0
0
0
0
-21
-35
0
0
0
0
0
0
0
0
-315
-627
0
0
0
0
0
0
0
0
-12
-28
0
0
0
0
0
0
0
0
-4353
-12217
NPV
-25000
-700
-200
-50
-50
-700
-260
-50
-50
-50
-22,312
Option 2 - Retain bridge at existing 17 tonne load capacity
Assumptions:
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $8.230 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Replace bridge with new bridge in 30 years at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $130k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $200k as per cost indication.
Carry out routine maintenance over the bridges life, say $50k per 5 year cycle
Discount & inflation rates as below
Values below in $000's
Sources of Cash Flow
Capital - substructure & superstructure repairs
Capital - new bridge
Substructure maintenance in 10 yrs
Superstructure maintenance in 10 yrs
Substructure maintenance in 20 yrs
Superstructure maintenance in 20 yrs
Routine maintenance every 5 years
($ 000's)
Year
8,230
25,000
700
130
700
200
50
Yr 0
Yr 30
Yr 10
Yr 10
Yr 20
Yr 20
Yr 5 cycle
NPV Analysis
Discount Rate:
Inflation Rate:
6.00%
3.50%
Discount Factor
1.00
0.94
0.89
0.84
0.79
0.75
0.70
0.67
0.63
0.59
0.56
0.53
0.50
0.47
0.44
0.42
0.39
0.37
0.35
0.33
0.31
0.29
0.28
0.26
0.25
0.23
0.22
0.21
0.20
0.18
0.17
Escalation Factor
1.00
1.04
1.07
1.11
1.15
1.19
1.23
1.27
1.32
1.36
1.41
1.46
1.51
1.56
1.62
1.68
1.73
1.79
1.86
1.92
1.99
2.06
2.13
2.21
2.28
2.36
2.45
2.53
2.62
2.71
2.81
Year
Year number
2011
0
2012
1
2013
2
2014
3
2015
4
2016
5
2017
6
2018
7
2019
8
2020
9
2021
10
2022
11
2023
12
2024
13
2025
14
2026
15
2027
16
2028
17
2029
18
2030
19
2031
20
2032
21
2033
22
2034
23
2035
24
2036
25
2037
26
2038
27
2039
28
2040
29
2041
30
Capital Expenditure
Maintenance - Substructure
Maintenance - Superstructure
Maintenance - Routine
-8230
Cash Flow
-8230
0
0
0
0
-50
0
0
0
0
-880
0
0
0
0
-50
0
0
0
0
-950
0
0
0
0
-50
0
0
0
0
-25000
Discounted Cash Flow
Inflated Cash Flow
-8230
-8230
0
0
0
0
0
0
0
0
-37
-44
0
0
0
0
0
0
0
0
-491
-693
0
0
0
0
0
0
0
0
-21
-35
0
0
0
0
0
0
0
0
-296
-589
0
0
0
0
0
0
0
0
-12
-28
0
0
0
0
0
0
0
0
-4353
-12217
NPV
-25000
-700
-130
-50
-50
-700
-200
-50
-50
-21,837
Old Mandurah Traffic Bridge NPV Analysis (5 options).xls
Scenario 3
-50
Option 3 - Convert bridge to pedestrian-only footbridge (5 kPa load capacity)
Assumptions:
Construct substructure & superstructure repairs including RCO as detailed in report in 2011. Estimated cost $6.567 million as per cost indication.
Life of bridge after refurbishment is estimated to be 30 years, providing at the least that the following maintenance works are carried out over the bridge life.
Construct new traffic bridge in 2015 at cost of $25 million as per AECOM Concept Report cost for incrementally launched bridge.
Carry out substructure maintenance works in 10 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out superstructure maintenance works in 10 years time as detailed in report. Estimated cost $70k as per cost indication.
Carry out further substructure maintenance works in 20 years time as detailed in report. Estimated cost $700k as per cost indication.
Carry out further superstructure maintenance works in 20 years time as detailed in report. Estimated cost $200k as per cost indication.
General maintenance works for the new bridge costing $50k every 10 years are incurred.
Carry out routine maintenance over the old bridges life, say $50k per 5 year cycle
Discount & inflation rates as below
Values below in $000's
Sources of Cash Flow
Capital - substructure & superstructure repairs
Capital - new bridge
Substructure maintenance in 10 yrs
Superstructure maintenance in 10 yrs
Substructure maintenance in 20 yrs
Superstructure maintenance in 20 yrs
New bridge general maintenance - 10 yr cycle
Routine maintenance every 5 years
($ 000's)
Year
6,567
25,000
700
70
700
200
50
50
Yr 0
Yr 4
Yr 10
Yr 10
Yr 20
Yr 20
Yr 14, 24
Yr 5 cycle
NPV Analysis
Discount Rate:
Inflation Rate:
6.00%
3.50%
Discount Factor
1.00
0.94
0.89
0.84
0.79
0.75
0.70
0.67
0.63
0.59
0.56
0.53
0.50
0.47
0.44
0.42
0.39
0.37
0.35
0.33
0.31
0.29
0.28
0.26
0.25
0.23
0.22
0.21
0.20
0.18
0.17
Escalation Factor
1.00
1.04
1.07
1.11
1.15
1.19
1.23
1.27
1.32
1.36
1.41
1.46
1.51
1.56
1.62
1.68
1.73
1.79
1.86
1.92
1.99
2.06
2.13
2.21
2.28
2.36
2.45
2.53
2.62
2.71
2.81
Year
Year number
2011
0
2012
1
2013
2
2014
3
2015
4
2016
5
2017
6
2018
7
2019
8
2020
9
2021
10
2022
11
2023
12
2024
13
2025
14
2026
15
2027
16
2028
17
2029
18
2030
19
2031
20
2032
21
2033
22
2034
23
2035
24
2036
25
2037
26
2038
27
2039
28
2040
29
2041
30
-50
-50
Capital Expenditure
Maintenance - Substructure
Maintenance - Superstructure
General & Routine Maintenance
-6567
Cash Flow
-6567
0
0
0
-25000
-50
0
0
0
0
-820
0
0
Discounted Cash Flow
Inflated Cash Flow
-6567
-6567
0
0
0
0
0
0
-19802
-22724
-37
-44
0
0
0
0
0
0
0
0
-458
-646
0
0
0
0
NPV
-25000
-700
-70
-50
-50
-700
-200
-50
-50
-50
0
-50
-50
0
0
0
0
-950
0
0
0
-50
-50
0
0
0
0
0
0
0
-22
-36
-21
-35
0
0
0
0
0
0
0
0
-296
-589
0
0
0
0
0
0
-12
-28
-12
-28
0
0
0
0
0
0
0
0
0
0
-30,697
Option 4 - Construct incrementally launched, 3-lane bridge as per AECOM Concept Report
Assumptions:
Construct new incrementally launched, 3-lane bridge as per AECOM Concept Report in 2015. Estimated cost is $25 million as specified in this report.
Estimated cost above includes contractor site facilities and overheads, but excludes contingency & risk, contract administration, design & consultancy fees,
road approaches, fishing platform, services relocation and escalation as noted in AECOM report.
Estimated life of new bridge is 100 yrs, with associated maintenance works carried out as per below.
General maintenance works costing $50,000 every 10 years are incurred following completion of the bridge.
Discount & inflation rates as below
Values below in $000's
Sources of Cash Flow
Capital
General maintenance - 10 yr cycle
($ 000's)
Year
25,000
50
Yr 4
Yr 14, 24
NPV Analysis
Discount Rate:
Inflation Rate:
6.00%
3.50%
Discount Factor
1.00
0.94
0.89
0.84
0.79
0.75
0.70
0.67
0.63
0.59
0.56
0.53
0.50
0.47
0.44
0.42
0.39
0.37
0.35
0.33
0.31
0.29
0.28
0.26
0.25
0.23
0.22
0.21
0.20
0.18
0.17
Escalation Factor
1.00
1.04
1.07
1.11
1.15
1.19
1.23
1.27
1.32
1.36
1.41
1.46
1.51
1.56
1.62
1.68
1.73
1.79
1.86
1.92
1.99
2.06
2.13
2.21
2.28
2.36
2.45
2.53
2.62
2.71
2.81
Year
Year number
2011
0
2012
1
2013
2
2014
3
2015
4
2016
5
2017
6
2018
7
2019
8
2020
9
2021
10
2022
11
2023
12
2024
13
2025
14
2026
15
2027
16
2028
17
2029
18
2030
19
2031
20
2032
21
2033
22
2034
23
2035
24
2036
25
2037
26
2038
27
2039
28
2040
29
2041
30
Capital Expenditure
General Maintenance
-25000
-50
-50
Cash Flow
0
0
0
0
-25000
0
0
0
0
0
0
0
0
0
-50
0
0
0
0
0
0
0
0
0
-50
0
0
0
0
0
0
Discounted Cash Flow
Inflated Cash Flow
0
0
0
0
0
0
0
0
-19802
-22724
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-22
-36
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-12
-28
0
0
0
0
0
0
0
0
0
0
0
0
NPV
-22,788
Old Mandurah Traffic Bridge NPV Analysis (5 options).xls
Scenario 3
Option 5 - Construct incrementally launched, 2-lane bridge (with rates factored down from AECOM Concept Report)
Assumptions:
Construct new incrementally launched, 2-lane bridge (for purposes of comparing new structure of equivalent width to existing structure). Cost is estimated as
$19.5 million by factoring down cost of 3-lane bridge specified in AECOM Concept Report
Estimated cost above includes contractor site facilities and overheads, but excludes contingency & risk, contract administration, design & consultancy fees,
road approaches, fishing platform, services relocation and escalation as noted in AECOM report.
Estimated life of new bridge is 100 yrs, with associated maintenance works carried out as per below.
General maintenance works are estimated at $40,000 every 10 years following completion of the bridge, calculated by factoring down maintenance works for 3-lane bridge.
Discount & inflation rates as below
Values below in $000's
Sources of Cash Flow
Capital
General maintenance - 10 yr cycle
($ 000's)
Year
19,500
40
Yr 4
Yr 14, 24
NPV Analysis
Discount Rate:
Inflation Rate:
6.00%
3.50%
Discount Factor
1.00
0.94
0.89
0.84
0.79
0.75
0.70
0.67
0.63
0.59
0.56
0.53
0.50
0.47
0.44
0.42
0.39
0.37
0.35
0.33
0.31
0.29
0.28
0.26
0.25
0.23
0.22
0.21
0.20
0.18
0.17
Escalation Factor
1.00
1.04
1.07
1.11
1.15
1.19
1.23
1.27
1.32
1.36
1.41
1.46
1.51
1.56
1.62
1.68
1.73
1.79
1.86
1.92
1.99
2.06
2.13
2.21
2.28
2.36
2.45
2.53
2.62
2.71
2.81
Year
Year number
2011
0
2012
1
2013
2
2014
3
2015
4
2016
5
2017
6
2018
7
2019
8
2020
9
2021
10
2022
11
2023
12
2024
13
2025
14
2026
15
2027
16
2028
17
2029
18
2030
19
2031
20
2032
21
2033
22
2034
23
2035
24
2036
25
2037
26
2038
27
2039
28
2040
29
2041
30
Capital Expenditure
General Maintenance
-19500
-40
-40
Cash Flow
0
0
0
0
-19500
0
0
0
0
0
0
0
0
0
-40
0
0
0
0
0
0
0
0
0
-40
0
0
0
0
0
0
Discounted Cash Flow
Inflated Cash Flow
0
0
0
0
0
0
0
0
-15446
-17724
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-18
-29
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-10
-23
0
0
0
0
0
0
0
0
0
0
0
0
NPV
-17,776
Old Mandurah Traffic Bridge NPV Analysis (5 options).xls
Scenario 3