Case-Study-of-the-Month: North Des Moines Sewer Main - Joint Repair

The City of Des Moines, Iowa was installing over 4 miles of 60" diameter Reinforced Concrete Pipe with Ameron Lining, bell and spigot in 8' sections for a sewer main that would serve communities in the northern part of the city. After a large portion of the pipe had been installed and backfilled, the project engineer inspected the pipes and found groundwater leaking at the connection joints. Many of the gasket seals between the pipe sections were not sealing properly and hydrostatic pressures were significant enough to produce leaks. The Ameron Lining System that had been welded at the joint connections had formed "blisters" at the leaking joints. The city contracted S.J. Louis Construction, Inc. to repair the problem joints.

To continue reading this case study, visit http://www.primeresins.com/casestudies/sjlouis.php.

Have you recently used Prime Resins chemical grouts or epoxies in a repair? Submit details of your repair and you may see your story as the next Case-Study-of-the-Month! Email your details and contact information to mrobinson@primeresins.com or call 800-321-7212 and ask for Michelle Robinson in the marketing department.

From Our Engineer's Corner: Longevity of Chemical Grout

The members of NASSCO want you to know that chemical grouting is an effective process for
stopping groundwater infiltration into sewer collection systems. Chemical grouting is not a
structural repair. Chemical grout stabilizes the soil and forms an impermeable mass outside of
leaking pipe joints and manhole walls ... thereby stopping infiltration. Click here to read NASSCO's report on the longevity of chemical grouting.

The Engineer's Corner is a section of our website specifically developed to inform engineers and specifiers of technical updates and to provide assistance in accessing technical and test information, service education and documentation for the specification of our products.

MIT Engineers Develop Hand-held Device That Can "See" Damage in Concrete Structures

According to an article written by Denise Brehm of MIT's Civil and Environmental Engineering department, Engineers at the educational institute have developed a hand-held device that can detect damaged areas in concrete structures, allowing aging infrastructure to be inspected quickly, easily and without interrupting the area around the structure. The device uses radar to "see" through the fiberglass-polymer wrapping often used to strengthen aging concrete columns. It can detect damage behind the wrapping not visible to the naked eye. Professor Oral Buyukozturk of MIT's Department of Civil and Environmental Engineering (CEE) developed the technique with CEE graduate student Tzu-Yang Yu and Dennis Blejer of MIT Lincoln Laboratory, where prototype radar measurements were made.

To view the complete article, visit http://web.mit.edu/newsoffice/2007/inspection-0518.html.

Repair Leaking Joints and Pipe Penetrations Using the Activated Oakum Technique

Step by step instructions for sealing gushing leaks, leaking joints, and pipe penetrations.

MATERIALS NEEDED:

1. Prime-Flex material.
2. Pail or plastic bag.
3. Rubber Gloves
4. Oil Free Oakum , Open Cell Urethane Foam, or Burlap.
5. Screwdriver and Hammer

INSTALLATION TECHNIQUES:

1. Clean the area in the joint.  Dust, laitance, dirt, grease, and any chemical contamination must be removed. Be sure to remove any unsound concrete.  (Cut a "V" joint around the pipe if there is not enough room to insert the oakum when sealing around a pipe.)

2. Cut the oakum (foam or burlap may be substituted) into sections that are the proper size for the job and put it into the pail or plastic bag.

3. Pour enough Prime-Flex onto the oakum to cover it up entirely (approximately 1-3/4 gallons for every 10 feet of oakum).  Let it soak up as much Prime-Flex as possible. Be sure to wear rubber gloves while handling the activated oakum.  Avoid breathing urethane vapors and use adequate ventilation.

4. Take the Prime-Flex saturated oakum out of the pail or bag and submerse it in water for 10-60 seconds.

5. If the joint is dry, spray it with water before inserting the activated oakum.

6. Remove the oakum from the water and force it into the joint or between the pipe and concrete. Drive it in as deep as possible using the screwdriver and hammer.

7. The Prime-Flex will expand and bite into the wet concrete to achieve a tenacious bond. This will prevent further water infiltration at the joint or around the pipe.

To view illustrations of this repair process, visit http://www.primeresins.com/onlineresources/activatedoakum.php.

Visit us at APWA's 2007 International Public Works Congress and Exposition, September 9-11

We are excited to be a part of "The Best Show in Public Works," exposition at the Henry B. Gonzales Convention Center in San Antonio, Texas, September 9-11, 2007. This will be our first year exhibiting at this show and we can't wait to see what Texas has in store for us. Watch for future updates about APWA's 2007 International Public Works Congress and Exposition in upcoming e-newsletters!

For more information about APWA's International Public Works Congress and Exposition, visit www.apwa.net/congress.