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ALMEDA ROAD CAVE-IN EMERGENCY INVESTIGATION AND REPAIR; HOUSTON, TEXAS

The Texas Council of Engineering Companies has awarded Pate Engineers, Inc. the Eminent Conceptor Award for the submission of "Almeda Road - Cave-In Repair," a City of Houston project. The winner was announced on Monday, April 18, 2005 in Austin, Texas at the annual Texas Council of Engineering Companies Engineering Excellence Awards Reception. The recipient of this award is determined after all First Place Winners in the Engineering Excellence Awards are selected in each category, and the project with the highest overall score is awarded the Eminent Conceptor Award.

The Texas Council of Engineering Companies (TCEC) awarded Pate Engineers, Inc., (PATE) a Gold Medal in the 2005 Engineering Excellence Awards Competition in the category of Water and Wastewater for their work on the Almeda Road Cave-In Repair for the City of Houston. PATE previously earned a Silver Medal in 2004 for its investigative work regarding this cave-in.

In October 2002, the Almeda Cave-In occurred measuring more than 10 feet deep, 95 feet wide and 160 feet long. PATE, in conjunction with the City of Houston, evaluated an 84-inch, 28,000-foot Monolithically Cast in Place (MCIP) sanitary sewer interceptor built in the 1970's. As part of the investigation phase, the flow of 3,000 gallons per minute of sewage was diverted; then came the installation of 6 ground water wells, a liner plate shaft and then construction of a 55 foot deep by 160 foot long by 18 foot wide "trench box."

Findings revealed 3,000-feet of fine silts with extremely low soil strengths (N - 0 to 5) at the depth of the interceptor. In addition, fine cracks in the wall of the sewer allowed fine silt particles to enter the interceptor. To address the cracks, the sewer was lined with Hobas Pipe, a proven technology. To address the weak soils, a new process was employed utilizing the patented Hayward-Baker, Inc., Super Jet grout process. After field testing confirmed the viability of the method, 52 pairs of 12 to 13 feet radius, soilcrete columns with a compressive strength exceeding 400 psi (pounds per square inch) were built 28-feet apart along the length of the interceptor.

PATE's solution of installing soilcrete columns saved the City of Houston over $1,000,000.