City of Lawrence

Utilities Department 

MEMORANDUM

 

TO:

David L. Corliss, City Manager

 

Cynthia Wagner, Assistant City Manager

 

Diane Stoddard, Assistant City Manager

FROM:

Leah Morris, Project Engineer

CC:

Dave Wagner, Director of Utilities

 

Mike Lawless, Deputy Director of Utilities

 

Philip Ciesielski, Assistant Director of Utilities

 

Beth Krishtalka, Assistant to Director

 

Bob Brower, Superintendent/Field

 

Dave King, Utilities Maintenance Superintendent

 

Mark Hegeman, Utilities Operations Superintendent

DATE:

February 26, 2014

RE:

March 4, 2014 Agenda Item – Project UT1302CS, Pump Station 04 Redundant Force Main, Approve Change Order No.1

 

 

Please include the following items on the City Commission agenda for consideration at the March 4, 2014 meeting:

 

Authorize the City Manager to execute Change Order No.1 to the existing Construction Contract with BRB Contractors, Inc. for Project UT1302CS Pump Station 04 Redundant Force Main increasing the contract amount by $25,000.00.

 

Project Description:

Sanitary sewer Pump Station PS04 is located at 810 Walnut Street and has a firm capacity of 2800 gpm. PS04 delivers all of North Lawrence’s sanitary sewer flows south across the Kansas River to the Wastewater Treatment Plant (WWTP) at 1400 E. 8th Street. PS04 has two existing force mains; one each 1956 8” diameter steel which is currently out of service, and one each 1974 18” diameter cast iron and steel.

 

In January 2013 the Department of Utilities was alerted by a citizen to the presence of an exposed section of pipe in the north riverbank. Investigation by staff determined the exposed pipe to be the 8” 1956 force main from PS04. Approximately 75 feet of the force main has become exposed due to riverbank erosion.

 

After an evaluation of the force main’s existing condition, risk of failure and the operational parameters of PS04, it was determined that the force main should be isolated from the system to prevent any discharge of sewage to the Kansas River in the event the pipe failed. In preparation for taking the forcemain out of service it was “pigged” clean and flushed out. The 8” force main is now isolated from the system. The existing 18” force main is hydraulically adequate to convey the pump station’s firm pumping capacity.

 

Information from the original plans shows the construction of the 8” forcemain to have been to a depth of only five (5) feet below the river bed as it existed in 1956. Based on this, the condition of the exposed pipe and the risk associated with attempting to recover the exposed section, the Department of Utilities recommended pursuing the installation of a new, redundant forcemain from PS04 to the Wastewater Treatment Plant to provide reliable sanitary sewer service to North Lawrence.

 

Professional Engineering Consultants was selected to provide engineering and construction services for the Pump Station 04 Redundant Force Main project.  In order to meet current and future demand, two new force mains (12” and 14” diameter, each respectively) will be installed from Pump Station PS04 to the WWTP.  The section of the pipe that crosses the levee and the Kansas River will be installed by horizontal directional drilling.

 

The project was awarded to the low bidder BRB Contractors as part of the January 14th, 2014 City Commission agenda and notice to proceed was given on February 24, 2014. 

 

Details:

Change Order No.1 represents a net increase to the construction contract of $25,000.00 and no adjustments to the contract time. The attached change order describes the additional work covered. Professional Engineering Consultants Staff have reviewed the proposed Change Order No.1 and recommend authorizing its execution.

 

Change Order No. 1 includes the mobilization and use of a second boring machine and the operating crew to bore the proposed force mains from the WWTP, as opposed to being stationed at 8th and Walnut as originally planned (see attached map).  Staff recommends this change based on discussions with the Contractor regarding the size of equipment, noise, and construction activity that would take place around the in the residential area of 8th and Walnut in North Lawrence.

 

Project Schedule:

 

Original Contract       Substantial Completion        May 25, 2014

Final Completion                June 24, 2014

 

Change Order No. 1  Substantial Completion        May 25, 2014

Final Completion                June 24, 2014

 

Construction Contract Costs:

 

Original Contract                     $1,435,000

Change Order No. 1                    $25,000

Current Contract Total             $1,460,000

 

To date Change Order adjustments are 1.74% of the original contract amount.

 

Project Funding:

The project is included in the Department of Utilities 2013 Capital Improvements Program.

 

Action Request.

Authorize the City Manager to execute Change Order No.1 to the existing Construction Contract with BRB Contractors, Inc. for Project UT1302CS Pump Station 04 Redundant Force Main increasing the contract amount by $25,000.