IMCO General Construction Inc 4/15/2020 Change Order 4

Project: WPCF Chlorination Building Upgrade Change Order No. 04 Change Order Effective Date: March 31, 2020 Work Change Directive 038:The per plan effluent pipe was not restrained at the outfall manhole. As a result,the pipe pulled out of the manhole approximately%-inch. This caused a leak around the 48- inch effluent pipe. Because the leak developed during the high flow season and record rainfalls,the discharge from the Water Pollution Control Facility's north end could not be shutdown. After consulting with the Department of Ecology and the Corps of Engineers, the City's contractor was directed to create a temporary French drain by excavating a 5-foot deep trench around the outfall manhole and backfilling the trench with quarry spalls. This work was necessary to allow the treated leaking effluent a path to the river,while maintaining the integrity of the dike.The City's Consultant Engineering firm, HDR, is currently designing a permanent repair. Work Change Directive 041:The per plan discharge piping for the carrier water pumps placed high strains on the connection between the discharge piping and the pumps. The specified pipe support material was fiberglass, which flexed enough to cause fittings between the piping and the pumps to crack and leak several times. Contributing to the weight problem,the discharge piping contained unnecessary valves and fittings. WCD 041 revised the pipe supports to stainless steel and reconstructed the discharge piping, eliminating the unnecessary valves and fittings. CONTRACT TIME: Change Order No. 4 adds four calendar days to the contract. Page 4 of 4