CONSENT AGENDA- Dan Schluender, City Engineer
Title
AUTHORIZE CHANGE ORDER NO. 2 IN THE AMOUNT OF $14,442.00 FOR THE 2020 SEWER SLIP LINING PROJECT, IMPROVEMENT PROJECT NO. 20-31
Background
Insituform Technologies was recently awarded the contract for the 2020 Sewer Slip Lining project to slip line certain sanitary sewer lines on the I 35W Service Road and Flanders Street north of 95th Avenue (see the attached map for locations).
The original bidding specifications for the project specified the anticipated depth of groundwater to be 1/2 of the soil depth over the existing sewer pipes, which has been typical on past slip lining projects. Due to the 30 foot depth of this sanitary sewer, the actual depth of groundwater is closer to 2/3 of the soil depth over the existing pipes.
As a result of this error in the specifications, the wall thickness of the slip liner was slightly thinner than the installer would normally recommend. In consultation with the installer it was determined that the thinner wall thickness was still within the design parameters but would have a somewhat reduced design safety factor. Staff requested a quote to upgrade to the recommended liner thickness and return the safety factor to specifications.
This change order will amend the contract to increase the wall thickness of the slip liner to reflect the correct groundwater elevations.
The funding source for this change order will be the Sanitary Sewer Utility Fund.
Recommendation
By motion, approve Change Order No. 2 in the amount of $14,442.00, amend the total contract budget to $828,351.00, and authorize the Director of Public Works to sign said Change Order No. 2.
Attachments
Overview Map