2018-12-11 Services & Organisation Committee Agenda

SERVICES & ORGANISATION COMMITTEE MEETING AGENDA                               11 DECEMBER 2018


Option 1
Remove bridge and replace with existing Mary River Pedestrian Bridge
Utilising this option provides an overall cheaper capital cost of $128,435. This option has a reduced
remaining life of only 25 years compared to the other options of 50 year life spans. As well as a
shorter life span the annual maintenance costs are higher due to the bridge’s overall age and
condition.


Option 2
Remove bridge and replace with Steel Framed Recycled Products Bridge
Option 2 considered utilisation of a recycled plastic product for the bridge deck with a prefabricated
steel frame. This option had lower annual maintenance costs as the deck would not need
maintenance as often as a timber deck type. The capital costs for this option was the second
highest option at $188,355. This option provides the best whole of life outcomes should the bridge
be considered for replacement.


Option 3
Remove bridge and replace with Landmark Style Bridge
The landmark style bridge option is considered an “off the shelf” approach to replacing the bridge.
Due to the large span required of 15 metres to replace the bridge, this has increased the overall
capital costs to $193,435 as Landmark style bridges are more suited to smaller spans of 10 metres
or less. As a result, this option had the highest overall costs to replace the bridge.


Option 4
Remove bridge and replace with Prefabricated Timber Bridge
This option is for a fully constructed prefabricated timber bridge. The option carries an element of
risk as timber girders greater than 12 metres are sourced from overseas and the exact costs are
not readily available. Contingency costs were added into the overall capital cost to factor this in
and this option was considered the lowest based on the construction of a new bridge with a 50-
year life span. Timber bridges do require more frequent maintenance than steel or recycled plastic
products and this has been considered in calculating the whole of life costs.

2.    Bridge Usage

Council resolved for staff to undertake a research process designed to obtain an estimate of
forecast bridge usage. In determining potential pedestrian usage, staff set up a camera to monitor
pedestrians that approached the closed Gumtree Drive pedestrian bridge. It should be noted that
it is difficult to gauge potential usage with the bridge currently fenced off from public access. The
survey was undertaken over a four day period that included a weekend. The results of the survey
are below and identified that an average of three pedestrians per day walked within the proximity
of the Gumtree Drive Bridge.




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