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

        §   ASR was confirmed to be present in the deck units. Predominate damage was
             limited to the kerb units and deck units with drainage scuppers.

o   Headstocks
       § Chlorides were below the corrosion threshold value for the tested headstocks
       § Carbonation had not penetrated far (10-20mm) into the headstocks
       § ASR potential is present in the headstocks, but has not commenced yet.
          Likely to be a problem in the future if action isn’t taken

o   Pilecap Beams
        § New cracks had appeared in the sides near the bottom of the pilecap beams
           at Piers 3, 4 and 5. Cracks had also appeared across the tops and ends of the
           same pilecap beams. There were rust stains evident at various points along
           side and end cracks, which indicated that reinforcement had corroded.
        § Chlorides (salts) exceeded corrosion threshold value at Opus’ assumed
           reinforcement depth of 75mm, on the sides of Pier 3’s pilecap beam.
           Chlorides were below the corrosion threshold value on the top of the same
           pilecap beam. The bottom was not tested.
           Notes: Opus probably obtained these depths from the original drawings. (Tod
           Consulting later found that reo was deeper than this in 2014. Extrapolation of
           Opus’ results suggests chlorides in the uncracked sections of the sides may
           have been just below the corrosion threshold value in 2010 for the real side
           cover of 89 to 93mm).
        § Carbonation had not penetrated far (1-2mm) into the pilecap beams
        § ASR was found to be present in the pilecap beams. (Pier 3 concrete was lab
           tested)

o   Piles
        §   10 piles were inspected by diver: the majority of these had vertical cracks
             which were 1-5mm wide at the surface. 2 of the piles had cracks that were 5-
             10mm wide at the surface – these were Pile 1 (Pier 2) and Pile 2 (Pier 5).

o   Opus recommendations
       § Remove existing asphalt, apply waterproofing to top and protective coating to
          underside of deck; and resurface deck with new asphalt
       § Coat abutments, headstocks, columns and pilecap [beams] with surface
          protective coating
       § Cathodic protection system, concrete encasement of the piles or underpinning
          of the pilecaps were also major remedial work items

o   Repair actions
       § None taken

2011: Arup prepared a design for bridge substructure replacement per SCC brief

SCC directed Arup to design a complete replacement of the substructure (with driven
piles and long-spanning headstocks) with a 100-year design life. The headstocks were

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