Atlanta Pipeline Project Spotlight

Atlanta Gas Light

Location: Atlanta, GA
Application: Grouting

Key Players

Owner: Atlanta Gas Light
Installer: Gibson Pressure Grouting

Background Information

Earlier this year, Atlanta Gas Light (AGL) began a project to retire 26 miles of its underground gas lines in Metro Atlanta, Georgia. The line dated back to the 1950’s and were past due for replacement. When new gas lines are required, it often occurs that the old lines are retired, left in place, and ﬁlled with cellular concrete when located beneath structures, roads & right-of-ways, and completely new lines are built, which is the project that Atlanta Gas Light embarked upon in June of 2015.

Project Details

This project required intensive labor and unavoidable traﬃc delays, as 12.5 of the 26 miles of gas lines were located underneath roadways. First, the sites were excavated to expose the underground pipes, and bulkheads built for the cellular concrete placement points approximate-ly every 1,000-1,500 feet. Then, between three and six days after these grout points were excavated and bulkheads built, the specialty contractor pumped cellular concrete into the gas lines, making sure they were completely ﬁlled. The construction team from Gibson Pressure Grouting designed, mixed and pumped 6,500 cubic yards of cellular concrete, ﬁlling approximately 12.5 miles of gas line in 30 working days. Gibson Pressure Grouting chose to use AERLITE-iX to ﬁll the gas lines, as it would provide the 40 pcf density and minimum 125 psi compressive strength required by the Georgia Department of Transportation. The strength of the cellular concrete was essential to the successful completion of this project, and wet density veriﬁcation testing was performed every 15-20 cubic yards to ensure the cellular concrete met these requirements.

Aerix Added Value

The use of AERLITE-iX not only provided the support necessary to ensure the safe retirement of these gas lines and function of the above roadways, it also sped up the construction process and minimized the impact on regional traffic. All the lines were located in Metro Atlanta, and were in heavily trafficked areas thus it was essential that this project be completed as quickly as possible while still meeting GDOT’s strict requirements. Because AERLITE-iX is durable and can be pumped long distances, the team from Gibson was able to routinely pump 300 cubic yards per day, pumping the cellular concrete at distances of 1,250 – 2,400 linear feet. The strength, ﬂuidity and pumpability of AERILITE-iX enabled the Atlanta motorists to return to their normal routes of commute with minimal disruption and with stronger roadways that will support their vehicles for a long time to come.