Trends Spring 2015 - Page 16

The City’s main potable water supply – an old 20-inch cast iron pipe – was relocated outside the pavement area. The pipe provides water to more than half of the City’s 24,000 people. The City’s goal was no interruption of water service for residents and businesses during the project, Schurman said. Ayres Associates’ custom-designed thrust blocks and anchors allowed for the process to be completed smoothly. Schurman said he is amazed the utility portion of the project went as well as it did. “In preparation for the project, we did a lot of study on the water line itself – testing valves, 16│ TRENDS determining which ones worked, which ones didn’t,” he said. “We went through the whole exercise in case there was any kind of failure. Our staff was trained in what to do. Failure of a 20-inch water line would have been a big deal.” The corridor required miles of retaining walls that included cast-in-place, concrete sheet pile, steel sheet pile, and mechanically stabilized earth-type, said Hisham Sunna, who oversaw structural engineering for Ayres Associates. Groundwater elevations and lack of available right-of-way required various types of walls to be used depending on site conditions. Many walls were designed so the contractor could