2015-03-31 I&S Committee - Item 5 - Attachment 1 - Munna Pt Bridge Repairs Level 3 Bridge Report

Executive Summary
In early 2014, the new Noosa Council (NSC) required a Level 3 structural report for the
Munna Point road bridge along Noosa Parade. Noosa Parade is a principal connector
road between the Noosaville and Hastings St business districts. The road also serves
significant residential and holiday-stay areas. NSC engaged Tod Consulting to prepare
the report.

The bridge is approximately 1.5 kilometres southwest of Hastings St, and crosses a wide
saltwater canal connecting Weyba Creek and the Noosa River. Bridge details are as
follows:

• Developers built the 105 metre long concrete bridge (according to an NSC report
  dated 6 Aug 2002).
• Estimated construction date is 1979 (according to TMR reports for the bridge).
• Some original drawings are available, and these can be seen in Appendix B.
• The bridge has showed worsening signs of concrete “cancer” since 1999. In particular:
          o The bridge deck has cracks caused by Alkali Silica Reaction (ASR).
          o Three pilecap beams are in very poor condition, with large cracks and
             moderately to seriously corroded reinforcement near the sides and ends
             (Piers 3, 4 & 5)
          o Many piles have cracks caused by ASR.
• TMR has numerous bridges in saltwater environments that have experienced similar
  problems at a similar age. The reason is that industry knowledge of reinforced
  concrete corrosion was less advanced before the 1990s, and is still being heavily
  researched now. This issue has resulted in significant, costly repairs for TMR. For
  example, the 2.74 kilometre long Houghton Highway bridge at Redcliffe (opened
  1979) suffered ASR cracking of the piles, and in 1991, 500 piles were concrete
  encased below water level, and wrapped with composite fibre wraps above water
  level.

Tod Consulting reviewed all of the previous Munna Point Bridge reports prepared by
TMR, Opus and Arup. A condensed summary of these can be found in Section 2 of this
document. In essence, the TMR reports (1999-2004) recommended repairs that were
required several years ago. No repairs were carried out. At that time, NSC believed a
replacement bridge would be a similar cost: this is certainly not the case in 2014. Later
reports also recommended repairs that were not carried out.

We carried out site inspections on the 14th, 21st and 28th February 2014, in the presence
of NSC’s Mr Adam Britton (Project Coordinator). Noosa Jetty Builders with equipment
and personnel. NSC commissioned ALS Industrial to take material tests on the same
days as Tod Consulting’s site inspections.

Chemical contaminants (chlorides and ASR) in the concrete have reached the level
where simple repairs alone will not be effective. Three pilecap beams have dilapidated to


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