Marlborough District Council Roading Assets - Activity Management Plan 2015 - 2018 SECTION 1 EXECUTIVE SUMMARY Stacked Stone Walls These wall types exist from when roads were originally constructed. They are typically low height, and found at locations where competent rock is locally available. Cattle Stops Cattle stop structures vary in age and condition between modern concrete units and old, light weight rail iron units. The foundation box structure in most cattle stops is robust and failure is usually confined to the grid (deck). Failure in the grids is related to the light weight of some rail irons used and to the problems caused by welding used rail iron. Many of the cattle stops that have light rail iron grids are also located on a section of road with poor horizontal alignment, and vehicle impact hastens the failure of welds. Concrete Fords All the concrete fords are in reasonable condition and with an average age of 15 – 20 years. Damage to concrete fords normally occurs during flood periods with the damage generally related to scouring of the downstream lip or blockage of pipes. 1.6.5.3 Level of Service Section 3 of this AMP discusses customer Levels of Service. The detailed list of technical performance measures are listed in the Marlborough Roads Safety Management System Manual. Structures are constructed and maintained in accordance with the relevant Council building codes. In order to meet the appropriate level of service Network Performance Measures (NPM’s) are set in the network maintenance contract specifications. Steel Column Walls and Gabion Walls The current level of service requires that these structures are monitored as part of the structural integrity inspection regime. As the age of the older, unrestrained steel column walls increases, specific and programmed replacement or modernisation is necessary. The repair of gabion walls will generally be on a reactive basis which addresses sudden failures in the wall materials. Any proposal to construct new steel column or significant gabion retaining walls undergoes a specific engineering assessment and regulatory checks. Dry Stone and Rip Rap Walls These walls are not specifically monitored. Due to low height and the natural materials used in construction, in most situations their existence is masked by age and vegetation. Any failure in these structures is typically identified in the road pavement or verge, and monitored by the routine road inspections. Cattle Stops These are monitored by the routine road inspections, and any recommendations for repair are passed to the Asset Manager. Many of the light grid cattle stops which were previously private structures are anticipated to require early intervention to address strength and traffic impact problems. Concrete Fords These are monitored by the routine road inspections, and any recommendations for repair are passed to the Asset Manager. 1.6.5.4 Demand / Growth The installation of new retaining walls is primarily associated with seal widening, and occasionally subdivision and/or new road development. The number of cattle stops is not expected to rise as farm land development tends to involve fencing which makes cattle stops redundant. The number of formal fords could potentially increase as various informal fords come under pressure from traffic volume increases on the remote unsealed roads. However due to Resource Management Act restraints, in future it is more likely that fords will be replaced by bridges. 1.6.5.5 Life Cycle Management 30 September 2014 Page 78 of Section 1