designed its signature lift hole plug to be used in storm pipe, with a constant flow of water offering no internal pressure.
The rough lift hole dimensions were measured in randomly selected Hanson stock pipe to compare their range of the lift hole sizes with that of the testing samples, confirming that study results are widely applicable to most concrete pipe.
The full "Internal Pressure and Backfill Load Resistance Characteristics of 'Popit' Lift Hole Plugs" report can be obtained from the What's New section at the American Concrete Pipe Association home page, www.
Park from the University of Texas Center for Structural Engineering and Research Simulation developed a procedure and conducted a testing program to evaluate the pressure resistance characteristics of Popit plugs installed in mechanical (smooth) and handmade (rough) lift holes.
diameter concrete pipes with rough lift holes were randomly selected to offer a range of void dimensions.