2015-03-31 Infrastructure and Services Committee Meeting Agenda

INFRASTRUCTURE & SERVICES COMMITTEE MEETING AGENDA                                        31 MARCH 2015


Following lengthy delays in announcement of the funding, Council was eventually advised in
March 2015 that the funding application was unsuccessful.
As structural elements of the bridge are now urgent, this report aims to inform Council of the
rehabilitation options, the estimated costs involved and the extension to bridge life offered by the
various options.
Consulting engineers have informed Council that, as a minimum, the installation of an additional
column to each pier must be undertaken urgently this financial year.

2.      Rehabilitation options

Based on the consulting engineer’s level 3 report, the below table describes the rehabilitation
options.

     Budget option        Description of works             Timing           Bridge life        Cost
                                                                           extended by
Option A) - Least     •    Installation of additional   Required         2-4 years         Approx.
initial cost               columns to each pier         immediately                        $200,000-
                                                                                           $250,000
Option B) - Works     •    Above plus;                  Columns          2-4 years         Approx. $1.4M
to match current      •    Repair pilecap beams         required
funded budget of      •    Encase piles                 immediately,
$1.4M                 •    Cathodic protection to       remainder of
                           pilecap beams                works required
                                                        to be
                                                        completed in
                                                        2-4 years

Option C) - Full      •    Above plus;                  Columns          50 years          Approx. $3.05M
scope, (partially     •    60 pile encasements          required                           (budget
funded)               •    deck waterproofing &         immediately,                       shortfall of
                           scupper linings              remainder of                       $1.65M)
                      •    replace deck joints          works required
                      •    silane coatings to           to be
                           pilecap beams,               completed in
                           columns, headstocks,         2-4 years
                           abutments and deck
                           underside + sides
                      •    clean up and coat all
                           stressing bar ends
                      •    clean up and coat traffic
                           barriers & handrails


The Least Cost - Option A) of installing additional strengthening columns will alleviate the
immediate structural risk to the bridge however this option is only expected to give a few years
additional life to the bridge before more rehabilitation works are required.

The Intermediate Scope - Option B) is arbitrarily set to match the existing budget of $1.4Million
and also alleviates the immediate structural risk, however the remainder of the rehabilitation
works will also be required in a few years.

The Full Scope – Option C) allows the rehabilitation of the entire structure. This option allows all
risks to be dealt with as soon as possible under a single contract and under a single procurement
process. It is estimated that the full scope of works could be delivered in 6-9 months and likely to
span over the 14/15 and 15/16 financial years. The expected life of the bridge would be extended
by 50 years. This forms the basis of recommending that this is the preferred option and to carry
out the full scope of works and make the necessary budget adjustments.

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