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

•   Precast = concrete poured in a remote casting yard and then transported to the
    bridge site. Precast concrete is usually finished to a better quality than cast-insitu
    concrete

•   Precast Deck Unit = narrow concrete planks that are laid side by side to form the
    bridge deck. These are made of precast concrete, and contain high strength steel
    strands (cables) that are tensioned (pulled tight) during construction, to give the
    deck unit sufficient strength to carry traffic loads. Without high strength steel
    strands, the deck units would be unable to carry traffic loads.

•   Reinforcement / reo = medium strength steel bars that are designed to take the
    tensions that occur within a concrete structure when it gets loaded (e.g. by traffic
    on the bridge). Without steel reinforcement, the concrete in the headstocks,
    columns and pilecap beams would be unable to carry traffic loads.

•   Reinforcement cover = the depth that the outside face of reinforcement is
    embedded below the surface of the concrete. As a basic rule, the greater the
    reinforcement cover, the better the protection against corrosion

•   Safety factor = measures how close a structure or structural component is to
    failure (partial or total). Sometimes it’s called a factor of safety:
         o 1 or less means the structure/component isn’t strong enough to carry its
             loads. This is often described as having “no safety factor”.
         o 2 to 3 is normal for a bridge.
         o Bridges are designed with larger safety factors than buildings because
             trucks are often overloaded beyond their legal load limits, and because
             newer trucks with heavier configurations come along years after the bridge
             gets designed. For example, Munna Point Bridge was designed for a
             loaded semi-trailer (known as a T44) in both lanes. New bridges must be
             designed for much heavier trucks.

•   SCC = Sunshine Coast Council, formed by the 2008 amalgamation of Noosa
    Shire, Maroochy Shire and Caloundra City Councils

•   Substructure is everything below the superstructure such as pilecaps, pilecap
    beams, abutments, wing walls, headstocks, columns, piles, and other types of
    foundation systems.

•   Superstructure is everything above the supporting structure. Superstructure items
    include deck units, the bridge barriers, footpaths, etc.

•   Transverse stressing bars = high-strength steel bars that are pulled tight during
    construction, to hold the deck units tightly against each other, so that the deck
    units effectively act as one slab.
•   TMR = Department of Transport & Main Roads Queensland and its previous
    entities




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