HomeMy WebLinkAbout2024-05-14 Brotherton Site Buildout Addendum 4815 Center Street Tacoma, WA 98409-2319 (253) 474-9449 / sittshill.com Kathy A. Hargrave, PE Larry G. Lindell, PE, SE Michael A. McEvilly, PLS Andrew J. Boileau, PE, SE David C. Boileau, AIA Donald C. Davis, PE Civil | Structural | Architectural | Survey Memorandum To: Nathan Janders, P.E., Development Engineering Manager From: Don Davis, P.E.; Damian Matzen, E.I.T., Sitts & Hill Engineers, Inc. Date: May 14, 2024 CC: Scott Lindley, J.M. Riley Company; Jim Castino, Castino Architecture Subject: Brotherton Site Buildout Addendum During construction of the new Brotherton Cadillac Dealership, a decision was made by the owner to postpone construction of the Brotherton Buick-GMC Dealership Addition. Since these two projects are located on contiguous properties, the overall project was initially designed assuming sequential or simultaneous construction of both projects, and was permitted under one civil construction permit. As such, the current civil construction permit cannot be closed until all work associated with both projects is complete, and occupancy of the new Cadillac dealership cannot be granted. Therefore, we are proposing to detach the Buick-GMC Addition project from the current civil construction permit, and we understand the City of Renton can administratively issue a new standalone civil construction permit for the Buick-GMC Addition. In this scenario, once the Cadillac Dealership construction is complete to the City of Renton’s satisfaction, the certificate of occupancy for the building can also be issued. Construction of the Buick-GMC Addition can commence when the owner is ready, on the condition that associated permits are renewed/extended as required. Current Design: Under the current approved stormwater design, additional storage and flow control capacity was incorporated into the stormwater system on the Cadillac site. The intent was to accommodate flow control requirements for the Buick-GMC site, by slightly enlarging the proposed flow control features on the Cadillac site, while also limiting construction disturbance of the Buick-GMC site. Interim Condition (after completion of the Cadillac Dealership project, but before the Buick-GMC Addition project): In this condition, the lift station floats are designed to match peak flow conditions for the Cadillac and Buick-GMC projects combined. with appropriate storage. This means that if only the Cadillac Dealership project is constructed, the lift station will discharge less stormwater than would be required if the site was built to plan with replaced surface area contribution from the Buick-GMC Addition. Therefore, we are not proposing any modification to the designed discharge rates or float elevations from the lift station in the interim condition. Final Condition (after the Buick-GMC Addition project is completed): In the final condition, no alterations will be necessary since the system will already be appropriately configured for the complete design, unless flow control standards have changed by the time the Buick-GMC project is executed. See the approved TIR, signed May 8, 2023 for a more detailed explanation of the design process for the Lift Station.