IMCO General Construction Inc. 11/4/2020 Change Order 5

Project: WPCF Chlorination Building Upgrade Change Order No. 05 Change Order Effective Date: September 20, 2020 Inside the 96-inch manhole, weld the stainless-steel washers to the stainless-steel restraint straps. This shall be done at all washers on all interior restraints. Backfill and compact around the manhole and restore the crushed rock trail/road. Spread topsoil along the sides of the trail/road. Place erosion control matting over the topsoil and hand broadcast grass seed. Increases the Contract Amount by$141,760.16. JUSTIFICATION: Item No. 14:A 24-inch culvert, passing through the dike between Smith Island and the Snohomish River, was failing.This allowed river water to flow onto Smith Island during high tides and hindered the drainage of water from Smith Island during low tides. The failing culvert had caused a sinkhole to develop in the dike causing a public safety hazard as well as a dike stability risk. The location of the culvert was adjacent to the FEN outfall manhole worksite that was part of the WPCF FEN Chlorination Building Upgrade Project.The City's Contractor on the WPCF FEN Chlorination Building Upgrade Project had the experience, manpower and equipment to excavate and expose the ends of the culvert and to install an 18-inch liner pipe through the failing culvert. City Drainage Crews then installed a tide gate on the river side of the liner pipe. Bid Item No. 14 compensates the Contractor for the additional work required to install the liner pipe through the failing culvert and make repairs to the dike. Item No. 15:The per plan 48-inch effluent pipe was not restrained at the new outfall manhole. As a result, the pipe pulled out of the manhole approximately%-inch.This caused a leak around the 48- inch effluent pipe. Due to pressure inside the outfall manhole, some of the joints between the manhole sections had separated, causing leaks.Temporary repairs were made last January; however, long term repairs were required. The City's Contractor proposed a concept to cast a concrete sleeve around the manhole. The concrete sleeve would seal the leaking joints and provide a location to restrain the 48-inch effluent pipe.The City's design Engineers, refined the Contractor's concept by adding a diameter for the repair sleeve. Our Engineers also specified reinforcing steel and concrete requirements. Bid Item No. 15 compensates the Contractor for the additional work required to provide long term repairs to the FEN outfall manhole. CONTRACT TIME: Change Order No. 5 adds ten calendar days to the contract time. Page 4 of 4