Recovery--C--118339 approach walls chickamauga lock and DAM modification to existing delivery order.

SCOPE OF SERVICES FOR MODIFICATION TO TASK ORDER NO. 5

ARCHITECT-ENGINEERING SERVICES FOR
APPROACH WALL PLANS AND SPECIFICATIONS UPDATES
CHICKAMAUGA LOCK REPLACEMENT PROJECT
CHATTANOOGA, TENNESSEE


I. REFERENCES.

A. This modification will be issued for Task Order No. 5 under IDC W912P5-08-D-0005.

B. Original Scope of Services for Task Order No. 5, awarded 23 September 2009 under IDC W912P5-08-D-0005.


II. GENERAL

A. The general requirements of the original Scope of Services (dated September 10, 2009) shall still apply.

B. The following additional requirements are for performing additional design on the approach wall skirts to allow connection to an existing dam pier as well as conducting additional consolidation drawing and specification revisions to finalize the Chickamauga Consolidation Package.


III. ADDITIONAL REQUIREMENTS

A. Drawing and Specification Revisions

The quantity of drawing and specification revisions on the installation of the Miter Gates and Approach Walls has exceeded the assumptions set forth in the original scope of services. This situation will require additional A/E professional time to complete and document the plans and specifications.

B. Additional Skirt Detailing

The A/E shall accurately detail the location of two skirts on the upstream approach walls as directed by the Nashville District to prevent flow vortices from occurring during filling and emptying operations. Additionally the A/E shall provide a design adequate to support a skirt spanning between the upper guard wall and existing Dam Pier 5. The decision on the installation of this skirt will not be made until lock testing is conducted; however adequate detailing is needed to expedite a contractor modification if the need arises.

IV. SUBMITTALS (Refer to applicable requirements in the original Scope of Services).


V. COORDINATION OF WORK (Refer to applicable requirements in the original Scope of Services).

VI. ADDITIONAL ASSUMPTIONS
For purposes of this task order modification for additional engineering services, it is assumed that in addition to the assumptions set forth in the original scope of services, the additional plans and specifications updates will constitute at least 220 hours of additional professional engineers time. The assumed additional engineering time includes 24 hours for a Senior Structural Engineer to attend the 95% Consolidation Review Workshop in Chicago, IL the week of February 1-5, 2010.

VII. REVISED SCHEDULE
Design support services will continue to be performed for the duration the consolidation effort. The consolidation effort is currently scheduled for completion in the spring 2010. Therefore the revised Period of Performance is established as 30 April 2010.