R2010-232 AUTHORIZING SUPPLEMENT #1 TO AGREEMENT WITH URS CORPORATION

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,_. . � Supplement#I to Work Order No. ] 14/20/09) �ity of Decatur Phase I Engineering f'or Bridge Replacement South Shore Drive over Sand Creek Arm oi'Lake Decatur �xisting SN OSfi-6003 Scone of'Work URS will evaluate the impacts oi�providing an additional three (3) feet oi�vertical cleai•ance undet� the proposed bridge r-elative to the existing low beam elevation. The i�ollowing is a sumtnary of the additional engineerin� services to be provided beyond those described in Attachment A to Work Order No. 1 : 1.0 Conduct pick-up survey as necessary to gather additional data regarding the sanitary sewer and manholes and to extend survey coverage at properties that will be impacted by raising the roadway profile. 2.0 Evaluate the impacts to the proposed structure as a result of providing an additional three (3)feet of vertical clearance under the bridge. The structure type will influence the final pr•ofile grade elevation and therefore the cost of the roadway. Cofferdams will be required to construct piers in the lake. These issues will be considered in re- evaluating the structure type and span arrangement for the additional vertical clearance. The method of supporting the raised sewer�pipe may also depend on the structure type. The opinion of probable cost for the structure will be revised accordingly. �.0 Develop a roadwa}� profile and alignment based on raising the vertical clearance under the bridge by three (3) feet. Develop cross sections and determine impacts to local property owners. Evaluate constructabilit}� issues fo1-placing roadway embankment in the lake. Work will include the development of an opinion of probable cost for the roadway work. It is assumed that the roadway template developed in the previous Phase I work will be used. 4.0 Evaluate the option of raising the sewer to provide a minimum additional vertical clearance of three (3) feet relative to the existing low beam of the pipe bridge. Based on discussions with the Sanitary District of Decatur, raising the sewel�using a gravity main, without a pump station, will be evaluated. URS will assess the iinpacts of the raised sewer pipe to local properties. Work relaled to the sanitary sewer will be tr-acked under a specific cost code dedicated to thal task. 5.0 Evaluate any resulting conflicts between the raised sanitary sewer and the proposed roadway embankment. If conflicts exist, URS will determine if the roadway alignment can be shifted to avoid impacts to the sanitary sewer oi-if the sewer alignment wil] need to be shifted. A preliminary cost estimate may need to be developed to evaluate the most economical option. The estimate will consider the cost of additional 1•oadway embankment in Lake Decatui�resulting fi•om a shift in the roadway alignment and the cost of new supports for the sanitary sewer. An assessment will be made.to determine if it will be feasible to use the existing pipe supports. 1 of 3