Landform Inc., has been on site in Riley Park as Project Manager and Prime Contractor for the drinking fountain’s installation.
This week, the Landform crew laying the foundation encountered an unexpected need for a geotechnical opinion. This was a last minute surprise for the Water for Riley team.
Apparently, the engineering assumption was that the site had approximately 6-12 inches of topsoil. Landform found 45-50 inches of topsoil/unsuitable material and called the engineering consultants, who determined that a geotechnical opinion was needed.
The geotechnical engineer recommended a bridging structure of geotextile/gravel to provide a support structure for the rubber surfacing. The unsuitable soil was described as:
a silty sand fill soil overlying a native sand. The silty sand fill was approximately 500mm thick and was dilatant, loose, and medium brown with some black organics throughout. The native sand was moist, compact, and medium brown in colour.
Water for Riley thanks McIntosh Lalani Engineering Ltd., a division of Englobe, for swift action in getting the site specifics that Landform needed. It prevented both delay in completing the work and the risk of installing an inadequate foundation.
The geotechnical engineer recommended a non woven geotextile fabric overlaid with a biaxial geogrid reinforcement for compaction of approximately 300mmm of base gravels to bring the subgrade up to design elevation.
It’s easiest to let the photographs translate that into plain language.
The next, almost last, step is to lay a rubber surface that is the same as the mat under the playground.