Marlborough District Council Roading Assets - Activity Management Plan 2015 - 2018 SECTION 1 EXECUTIVE SUMMARY Type Composition Description Quantity A C,C,C A monolithic structure where all elements contribute to the integrity of the structure 46 and are not separable A structure where the abutments and piers, if applicable, are isolated components B C,C,C and the superstructure elements are monolithic i.e. the beams and the deck are a 127 single component (composite) A structure where abutments and piers, if applicable, are isolated components, the C C,S,C steel beams are isolated components and the deck system consists of bolted on 19 concrete precast units, all separate D C,S,C Similar to Type C except the concrete deck has been cast against and locked by 19 welded on cleats to the steel beam forming a composite system not separable A structure where the abutments and piers, if applicable, are isolated components E C,S,S where the beam systems (including overhead trusses or cables) are steel and 10 isolated units with prefabricated steel deck systems which are not permanently affixed F T,S,S Similar to Type E, except different component types, that are all separable 1 G S,S,S Structures are all steel, typically pipe or arch culverts 13 Structures with concrete abutments and piers, if applicable, as isolated H C,S,T components, with attached steel beams and a separate timber deck system nailed 51 on to timber spiking pieces bolted to the steel beams, all separable I C,T,T Structures with concrete abutments and piers, if applicable, as isolated components 45 with separate timber beams and separate timber deck, all separable J T,S,T Similar to Type K except steel beams 14 K T,T,T A structure constructed entirely of timber with all components able to be 22 comparatively readily repaired or replaced Table 6.4.2.2: Categories and type of bridges in the Marlborough road network 1.6.4.2.3 Bridge Structure Age The distribution of structural age is shown in Figure 6.4.2.3. The key issues associated with structural age are: A significant number of timber structures were built in the 1940-1960’s era and these bridges have reached or are approaching the end of their useful life; Older structures from the 1910-1930’s era were designed to lower design loadings, and although frequently robustly built they have age-related condition issues that are most economically addressed through renewal; A significant number of structures are weight or speed restricted, and because renewals are not currently keeping pace with deterioration of timber structures in particular, a significant number of additional structures are likely to be restricted in the near future; Due to the significant exposure of Council to liability and other effects as a result of failure of a bridge, bridge assets are identified as high risk when nearing the end of their useful life; 30 September 2014 Page 65 of Section 1