Beyond the Build

Construction Trends


Last spring, I wrote about a great retail site with tough soils, and how we were approaching the job. Nature then turned this project into a case study in weather extremes, from the record-setting drought over the summer, to late fall monsoons.

In case you are not familiar with Geogrid, it is basically a woven polymer designed to strengthen sub soil conditions. Our experience is with parking fields, where it performs by spreading the concentrated wheel loads, and keeps soils from pulling apart under the loads exerted. My first experience was circa late ‘70s in Virginia Beach, where I watched a D-6 sink to the cab. With the grid material properly applied, we were able to change 5’ of muck into a decent parking field. (It was good material, just extremely wet.) I became a believer.
Here is how our folks approached this particular panhandle site:
  • Geotechnical inspectors were onsite to record any particularly wet locations.
  • Fine graded, then compacted sub-sub grade with low impact equipment.
  • Placed one layer of Tensar TX160 triaxial geogrid, with a 3 foot overlap of grid at all joints.
  • Followed by a 12″ course of a sandy clay mix of soils, using 2 compacted lifts
  • Finished with base and asphalt.

Throughout the site, the compaction requirement was 98% of maximum density. We did exercise the option to add another layer of geogrid in any areas where proof rolling materials failed.

Merrill Stewart Jr.

Merrill Stewart is Founder and CEO of The Stewart/Perry Company, a commercial building contractor based in Birmingham.