SCOPING AND SPECIFICATION PHASE Sample Clauses

SCOPING AND SPECIFICATION PHASE. Scoping and specification works were undertaken by SCIRT’s Orange Design Team. During this stage the Design Team liaised closely with the ▇▇▇▇▇▇-▇▇▇▇▇▇▇▇ Delivery Team to obtain early contractor involvement, which ensured that potential issues were addressed in the specification and project scoping. It was identified that the rehabilitation methods and product should: • Provide resistance to hydrostatic pressure, including pressure due to silt liquefaction, at the depth of the sewer in which it is installed; • Provide internal support to weakened sewer structures, up to the level of fully structural lining in the case of the worst damaged sewers; • Provide resilience, to allow for minor ground movements and vibration which will probably continue to occur in the Christchurch area; • Provide for a sealed junction between the lateral connections and the main sewer, to prevent silt infiltration; • Provide a system which does not fail in a catastrophic manner (i.e. it should not collapse) if major earthquakes occur in the future. Cured-In-Place Lining (CIPP) was identified as the only viable rehabilitation method for the egg shaped wastewater sewers and other non-circular pipes. For the circular stormwater pipes either CIPP or spiral wound liner were identified as suitable solutions. Sliplining was not favoured, due to loss of cross-sectional area, and because of the cost and disruption from the excavations when gaining access to the pipes. It was also considered unlikely that sliplining would be a cheaper lining option. Rehabilitation methods that required personnel to enter un-rehabilitated pipes were excluded due to the possibility of an earthquake causing a pipe collapse whilst personnel were inside the pipe. The following points were considered at this stage and addressed in the technical specifications: • Design life – liners are to have a design life of at least 50 years. • Design Methodology – the WRc method was identified as the appropriate standard for liner design, as it specifically covers design of liners in brick barrel pipes, including egg-shape and oval pipes, as well as circular pipes. • Liquefaction – Liquefaction had occurred in the vicinity of the brick barrel pipes and it was possible that further liquefaction could occur in future earthquake events. This was allowed for by using a density of 22kN/m3, as opposed to 10kN/m3, to determine the hydraulic load applied to the liner in a liquefaction event. This meant that the liners would be 2.2 ...