City Improvement Project 12-20; Sunwood Drive Realignment - Consider Change Order #1

On June 26, 2012 the City Council awarded a contract to North Pine Aggregate for City Improvement Project 12-20; Sunwood Drive Realignment.  The construction plans for this project identified an existing 65" x 92" Reinforced Concrete Arch Pipe stub out of Structure 5004 that was constructed with the original improvements for Sunwood Drive.  Structure 5004 is located in the old alignment of Sunwood Drive, approximately 500 feet west of Zeolite, and will be entirely within the proposed COR TWO plat.  The purpose of the stub was to serve future development when needed.  The construction plans have recently been submitted for the COR TWO plat and the storm sewer stub discussed herein is not proposed to be utilized, therefore, the stub should be permanently abandoned or removed.  Abandoning the pipe will consist of installing blow pipes on both sides, filling the pipe full of sand and bulk-heading at the structure.

The construction project also included the partial excavation of Lake Ramsey.  We have been informed that the excavation area was subject to extensive uncontrolled fill by a number of parties over the years.  The fill included stockpiles of clay, street sweepings, sod chunks, and other mixed materials.  We have further been informed that this issue was discussed with the former City Engineer during the mass grading effort and it was concluded that extensive testing and mapping would be necessary to identify and quantify the uncontrolled fill.  The costs of the mapping and testing were presumed to be in excess of the costs that would be incurred by simply dealing with the material in the field with the Contractor, and the design engineer proceeded accordingly.  The design engineer has reviewed this Change Order request and recommends approval to compensate the Contractor for unforeseen conditions.

In relation to the Abandon Arch Pipe at Structure 5004 Change Order item - Additional expense would be incurred if the City were to consider removal of the pipe.  The additional expense would include costs for dewatering and rebuilding/replacing the 12' diameter manhole.  The estimated cost savings for abandoning vs. removing the pipe is $15,000 - $20,000. 

In relation to the Additional Topsoil Excavation and Handling Change Order item - this item will compensate the Contractor for additional work already performed that was outside of the scope of the original contract.  The proposed Change Order unit price was obtained through negotiations with the Contractor and is a fair price for the additional work. 

Staff recommends approving Change Order #1 in the amount of $19,237.60. 

The funding package for this project has been previously identified. 

Motion to approve proposed Change Order #1 in the amount of $19,237.60 for City Improvement Project #12-20; Sunwood Drive Realignment.