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

                            Figure 1: Bridge components



2.0 Review of Existing Reports & Site Observations
The bridge condition in 2014 can be quickly understood by looking at drawing 02600-SK1
in Appendix F.

A condensation of the various bridge condition reports & assessments that have been
prepared since 1999 follows:

1999 – 2002: TMR prepared bridge condition reports and recommendations for
NSC

o   Deck units
       § Some dilapidation of deck units in Spans 3 and 4 was observed
       § Fine longitudinal cracks were found along the bottom of some deck units.
          TMR suggests that alkali silica reaction (ASR) may be present.

o   Pilecap Beams
        § Large cracks had appeared in the sides, about 150mm to 400mm from the top
           of pilecap beams at Piers 3, 4 and 5.
        § Chlorides (salts) exceeded corrosion threshold value at TMR’s assumed
           reinforcement depth of 70 to 77mm.
           Notes: TMR probably obtained these depths from the original drawings. TMR
           concluded that reinforcement had started corroding and this would accelerate
           at time went on. (Tod Consulting found that reo was significantly deeper than
           this in 2014. Extrapolation of TMR results suggests chlorides in the pilecaps
           may have been below the corrosion threshold value in 2002 for the real
           depths).


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