03-12-07 Item 4F, Arnt Construction Change Order 3

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Attachment to Change Order No.3 Owner: Contractor: Project: City of Arden Hills Amt Construction Company, Inc. 2006 Pavement Management Program Description of changes: The Contract modifications associated with Change Order No, 3 include aspects of Roadway, Storm Drainage, Watermain, and Sanitary Sewer construction activity. There are Contract Items where additional quantities were needed to complete construction. The Roadway items include; sub grade excavation, select granular borrow, aggregate base CL 5, modular block retaining wall, and special walk, The Storm Drainage items where additional quantities were needed include; raingarden excavation and sodding. There were also modifications to proposed storm sewer, existing sanitary sewer, and existing watermain that were deemed necessary due to unforeseen field conditions and those will be paid for as lump sum items. Another item specified to be part of the Roadway Schedule is the bituminous density calculation, The density of the pavement is tested and either a bonus or a deduction is imposed based on the results. Details for each item are summarized below: Schedule A - Roadway Many of the work items within the Roadway portion of the project, as detailed below, are related. The sub grade excavation quantity is included in the project as a contingency item in the event that any unsuitable soil needed to be removed for utility or roadway construction. Three separate occurrences during construction contributed to the subgrade excavation quantity listed below; unsuitable pockets discovered during storm sewer construction (1200 CY total), excavation of unsuitable material behind retaining walls on Ridgewood Road and Siems Court (1192 CY total), and the removal of aggregate base class 5 materials placed in response to resident requests for access road maintenance during construction (1082 CY total). The first subgrade excavation occurrence was during storm sewer construction, Four to five foot deep pockets of unsuitable soils were discovered at the low point of Ridgewood Road adjacent to the wetland, on Siems Court south of Lake Johanna Boulevard, on Arden Place near the intersection of Ridgewood Road, and on Lake Johanna Boulevard west of Siems Court. These locations contained soils that needed to be removed to provide the storm sewer with a specified base. The select granular borrow quantity is also related to subgrade excavation in that after the unsuitable material is excavated, the hole needs to be filled with an approved material. The Contractor attempted to use on-site material as much as possible to backfill but there was not always adequate material on site, Select granular borrow was then used to completely backfill which accounts for the 145 CY of extra select granular borrow listed below. The occurrence of subgrage excavation for retaining walls included excavation for two new walls on Ridgewood Road and one on Siems Court as well as the three retaining walls identified in the original Contract. The new wall located across Ridgewood Road from the Island Beach Club wetland was necessary because of a desire to maintain the tree-lined slope while the other two were requests by residents. In all cases, material behind the proposed location of the walls needed to be removed and replaced with appropriate soils to maintain structural integrity, The three additional walls mentioned here also account for the additional 283 SF of Modular Block Retaining Wall listed below, For the third occurrence of sub grade excavation, access road maintenance, there are two separate items that need to be paid for; a volume of subgrade excavation and an excess quantity of aggregate base CL 5. Included in the project as a contract item, aggregate base CL 5 was to be used as a contingency item, like subgrade excavation, During the project, the aggregate base CL 5 item was used almost exclusively as access road maintenance along Siems Court and Ridgewood Road after the existing pavement was removed and before the proposed pavement was placed in response to resident requests following rain events, Aggregate Base CL 5 was placed on the roadway in order to maintain a clean and sufficiently wide driving surface, The CL 5 material placed for access maintenance amounts to 1,120 tons over the 1,000 tons originally identified in the contract for a total of2,120 tons, With respect to subgrade excavation, all 2,120 tons of CL 5 placed for the access road had to be excavated when it came time to construct the roadway. The 1082 CY of subgrade excavation referenced above is calculated using the MnJDOT conversion factor of 1.96 tonslCY The other portion of the construction