The Surrey Lake Greenway is a multi-use pathway for pedestrians, cyclists, and other non-motorised users, which will eventually run along Surrey’s Hydro corridor from 140 Street to 148 Street and along 76 Avenue from 148 Street to 152 Street.
The Surrey Lake Greenway site is located between residential backyards and agricultural land and, when A.C. Civil Contracting Ltd. were contracted to construct the first section of the 4-metre wide asphalt pathway, between 140 Street and 144 Street, they were faced with the challenge of building over very soft ground conditions, as well as having to carry out the work in the late fall.
Although the end use traffic for the pathway would mostly be bikes and pedestrians it was essential that the very soft soil be reinforced and stabilized to withstand the weight of heavy dump trucks and asphalt paving equipment during construction. Engineers decided to mechanically stabilise the ground using geogrids and Combigrid® 30/30 Q1 151 GRK3 was selected for the project. Combigrid® is a composite product of a Secugrid® geogrid with a needle-punched Secutex® non-woven geotextile firmly welded between the reinforcement bars. This technology has proven to be ideal for reducing excavation depth requirements and providing a stable platform on soft ground. Combigrid® geogrids provide immediate reinforcement, separation, filtration and drainage. They have a high resistance to installation loads and can effectively prevent the migration of fine particles into the base course. Combigrid® 30/30 Q1 151 GRK3 combines a 30kN polypropylene geogrid and a 150 g/m2 geotextile and is supplied in 4.75m wide rolls.
In total, 1000m of 4.75m wide Combigrid® was installed over the poor and wet subgrade prior to a 250mm layer of 75mm crushed material and a further 100mm layer of 19mm granular material. The pathway was completed with a 50mm layer of asphalt.
Installing Combigrid® enabled the building of a strong and stable platform, over poor soils, during periods of heavy rainfall. Despite the challenging conditions, heavy plant and paving equipment could readily access the pathway throughout all construction phases, and the team was able to fully meet the completion date for the project.
Project Name: Surrey Lake Greenway Foot and Bike Path
Location: City of Surrey, British Columbia, Canada
Date: December 2015
Contractor: AC Civil Contracting Ltd
Product: Combigrid® 30/30 Q1 151 GRK3