The Ada City Council signed off Monday on a change order for additional dirt work related to construction of the new Irving Community Center.
The council voted 5-0 to approve the change order, which was submitted by MacHill Construction. The Ada-based company is overseeing construction of the Irving Community Center at 704 N. Oak St., which will replace the old senior center.
MacHill submitted the proposed change order because demolition of the old Irving Center unearthed a subterranean system of what appeared to be utility tunnels, according to a memo from the Fort Worth, Texas-based firm D & S Engineering Labs. The company said demolition also revealed a variety of soils that were apparently placed during different construction periods over time.
“Further, review of the final construction foundation plans indicates that the foundation and Finished Floor elevations will be lower than those envisioned at the time of the original geotechnical report,” the company said.
In light of the new information and to reduce the potential for differential movement, D & S recommended placing at least 2 feet of uniformly placed consistent material under the foundation. The company also recommended scarifying the base of the exposed soils to a depth of 12 inches, with moisture added as needed, then recompacting the base. The company said the different soils on the site should be suitable as grade-raise soil rework material and as backfill for the utility tunnel excavations.
The work will cost $46,246, boosting the total cost of building the new senior center from $4.04 million to about $4.08 million.
The city is funding the project with part of the proceeds from the second “Penny for Our City” sales tax, which was approved in 2015 to finance a series of capital improvements.