SCIRT (MacDow-Fletcher JV)
Open trench pipe laying
During the Christchurch earthquake of 2010 the main trunk sewer constructed in the 1950’s was significantly damaged and required replacing along 130m length running under Woodham rd. This would require the removal of the 1.5m square concrete culvert (320t worth) and replacing it with 2000mm twin wall HDPE pipeline while live flows were maintained.
The replacement required March to install over 300t of sheet piles to facilitate the excavation of the open trench that would house the future pipeline. A 1200mm HDPE temporary bypass line with a live cut in to the existing sewer had to be undertaken. Well point dewatering facilitated the trench bottom to be dry during installation. Over 3000m3 of compacted back fill was required to fill the trench and reinstate the road surfaces, all the while only 3m away from residential properties.