Precast Solutions - March/April 2008 - (Page 15)

RCP arrives on site as a proven structure with a tested concrete compressive strength that is known to the engineer. along with ASTM performance specifications to satisfy engineering needs. The reinforced concrete pipe industry has kept pace with these modern expectations of joint integrity. Harland Couillard, plant manager with Upper Peninsula Concrete Pipe Co., Escanaba, Mich., and Jim Skinner, president of Press-Seal Gasket Corp., Fort Wayne, Ind., offer these 10 rules of thumb for the pipe specifier: 1. Specifier knowledge of material properties for all pipe products is critical to prevent leakage in stormwater installations. 2. Much of the older concrete pipe installed decades ago was not intended to have watertight joints; stormwater pipe that helped to lower water tables was, in fact, desirable. 3. When properly specified, installed and inspected, concrete pipe and flexible pipe have the ability to deliver joint integrity and watertightness. 4. While HDPE pipe cost is generally lower than that for RCP, the installed condition of flexible pipe can be more costly. 5. Because soils are variable, the engineered installation details for flexible pipe must include bedding materials, bedding width and compaction requirements below the pipe, at the sides of the pipe and above the pipe. In poor soils, bedding width becomes critical (ASTM 2321). 6. Concrete pipe is a load-bearing structure requiring bedding control from the spring line to the bottom of the pipe only (ASTM C1479). 7. HDPE pipe comes with pre-mounted gaskets. Joint seals for RCP are supplied separately from the pipe or cast into the product. Both systems require proper installation to achieve good joint integrity. 8. Most regional-based standards (like those for the Great Lakes region) allow for some leakage from stormwater pipes. 9. In general, contractors installing flexible pipe need to be more careful. Because stormwater pipes are typically of a large diameter, greater loads must be supported by the pipe and the surrounding soil. Contractors must take greater care in installation of flexible pipe than for rigid pipe to ensure that the fill material or stone is properly placed and compacted to provide required lateral support. 10. If pipe stiffness values are low and installed soil stiffness is low, deflection of HDPE pipe will likely increase. MARCH/APRIL 2008 | PRECAST SOLUTIONS 15

Table of Contents Feed for the Digital Edition of Precast Solutions - March/April 2008

Precast Solutions - March/April 2008 Contents Smooth Move Riding the Waves Comparing RCP With Plastic Pipe Cost-Value Analysis of Storm Sewer Pipe Concrete Testing On a Grand Scale Building Confidence

Precast Solutions - March/April 2008

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